LIB n *.RY 
 
 JNIV 3ITY OF 
 CAi FORNIA 
 
 EARTH 
 
 SCIENCES 
 
 LIBRARY 
 
 u 
 
 
THE LIBRARY 
 
 OF 
 
 THE UNIVERSITY 
 OF CALIFORNIA 
 
 PRESENTED BY 
 
 PROF. CHARLES A. KOFOID AND 
 MRS. PRUDENCE W. KOFOID 
 
HANDBOOK 
 
 OP 
 
 GEOLOGICAL TERMS 
 
" In this, as in every other field of labour, no man can put aside the curse pro- 
 nounced on him that by the sweat of his brow he shall reap his harvest. Before 
 he can reach that elevation from whence he may look down upon and comprehend 
 the mysteries of the natural world, his way is steep and toilsome, and he must read 
 the records of creation in a strange, and to many minds a repulsive language, which, 
 rejecting both the senses and the imagination, speaks only to the understanding. 
 But when this language is once learned, it becomes a mighty instrument of thought, 
 teaching us to link together the phenomena of past and future times ; and gives 
 the mind a domination over many parts of the material world, by teaching it to 
 comprehend the laws by which the actions of material things are governed." 
 SEDGWICK'S Cambridge Discourse. 
 
HANDBOOK 
 
 GEOLOGICAL TERMS 
 
 GEOLOGY 
 
 AND 
 
 PHYSICAL GEOGRAPHY 
 
 BY 
 
 DAVID PAGE, F.K.8.E. F.G.S. 
 
 AUTHOR OK ' TEXT-BOOKS OF OBOLOOY AND PHYSICAL GKOfJRAPHY,' ' PASF AND PRBSBNT 
 I.IFB UP THE OI.OBE,' ' PHILOSOPHY OF OBOIXX3Y,' KTC. 
 
 SECOND EDITION, REVISED AND ENLARGED 
 
 WILLIAM BLACKWOOD AND SONS 
 
 EDINBURGH AND LONDON 
 
 MDCCCLXV 
 
 The Right of Translation is reserved 
 
7=3 
 
 5- 
 
 EARTH 
 
 SCIENCES 
 
 LIBRARY 
 
 PREFACE 
 
 SHOULD it be asked why I publish this volume, I answer, 
 along with many others, Because I believe such a Handbook 
 to be greatly needed ; and under this conviction have done 
 my best, within moderate limits, to render it useful. Go 
 where you will to the popular platform, the public lecture- 
 room, or the private parlour and yon hear immense interest 
 professed in the science of Geology ; but the profession, for 
 the most part, accompanied by the regret that its " hard 
 words and forbidding technicalities" should render it so 
 difficult of acquirement. Now, while deprecating, in the 
 strongest manner, the introduction of unnecessary terms, it 
 is quite evident that every science must have its own tech- 
 nicalities and modes of expression : new objects require new 
 names, and new facts new phrases to express their relations. 
 There is no avoiding this necessity in any progressive branch 
 of human knowledge, and the only thing that can be done to 
 lessen the difficulty next to the rigid exclusion of whatever 
 seems superfluous is to explain these terms in brief and 
 simple language. This I have endeavoured to do, chiefly 
 with a view to the requirements of the general reader, at the 
 
 M363286 
 
PKEFACE. 
 
 same time appending such details as might render the volume 
 an acceptable Handbook of Reference to the student and 
 professed Geologist. Thus the ordinary reader will generally 
 find the information he requires in the first and second sen- 
 tences of a definition ; what follows is addressed more espe- 
 cially to the professional inquirer to the student, miner, 
 engineer, architect, agriculturist, and others, who may have 
 occasion to deal with geological facts, and yet who might not 
 be inclined to turn up half-a-dozen volumes, or go through a 
 course of geological readings, for an explanation of the term 
 in question. 
 
 Such is the aim and object of this " Handbook of Geolo- 
 gical Terms." I lay claim to little more than the arrange- 
 ment of the matter, which has been gleaned and sifted from 
 many sources care having always been taken to present the 
 science in its newest aspects, and to express its facts in the 
 clearest and simplest language. Sensible of many imperfec- 
 tions, I would respectfully solicit corrections from those who 
 may generally approve of the work, in order that any subse- 
 quent edition may be rendered more worthy of the Science 
 whose truths we are labouring to establish a science which, 
 whether intellectually or economically considered, stands 
 second to none on the roll of human acquirements. 
 
 D. P. 
 
 GILMORE PLACE, EDINBURGH, 
 August 1859. 
 
SECOND EDITION 
 
 IN preparing this edition, alterations rendered necessary by 
 the progress of the science have "been freely made, and the 
 more important terms introduced by recent discovery ex- 
 tensively inserted. To have inserted all or nearly all would 
 have increased the volume beyond the limits of a " Hand- 
 book," and merely cumbered its pages with names, a great 
 proportion of which are avowedly provisional, and many even 
 of doubtful validity. As a new feature, the leading techni- 
 calities of Physical Geography have been given along with 
 those of Geology the Author believing that the two sciences 
 are inseparably associated, and that the readiest way to a 
 comprehension of the world's past is through the study of 
 its existing phenomena. 
 
 August 1865. 
 
CONTENTS 
 
 i. 
 
 TABULAR SCHEMES OF THE CHEMICAL, MINERAL, LITHOLO- 
 GICAL, AND VITAL ASPECTS OF THE GLOBE. 
 
 II. 
 
 DICTIONARY OF TERMS AND TECHNICALITIES EMPLOYED 
 IN GEOLOGY AND PHYSICAL GEOGRAPHY. 
 
 III. 
 
 EXPLANATION OF SPECIFIC APPELLATIONS MADE USE OF 
 BY BRITISH AND FOREIGN PALEONTOLOGISTS. 
 
NOTE. " It is, indeed," says Agassiz, in his recent 'Essay on Classifica- 
 tion,' "a very unfortunate tendency, which prevails now almost universally 
 among naturalists, with reference to all kinds of groups, of whatever value 
 they may be, from the branches down to the species, to separate at once 
 from one another any types which exhibit marked differences, without even 
 inquiring first whether these differences are of a kind that justifies such 
 separations. In our systems, the quantitative element of differentiation 
 prevails too exclusively over the qualitative. If such distinctions are 
 introduced under well-sounding names, they are almost certain to be 
 adopted ; as if science gained anything by concealing a difficulty under a 
 Greek or Latin name, or was advanced by the additional burden of a new 
 nomenclature. Another objectionable practice, prevailing quite as exten- 
 sively also, consists in the change of names, or the modification of the 
 extent and meaning of old ones, without the addition of new information 
 or of new views. If this practice is not abandoned, it will necessarily end 
 in making Natural History a mere matter of nomenclature, instead of 
 fostering its higher philosophical character." Influenced by this opinion, 
 I have adopted in the following tabulations such arrangements of the 
 Mineral, Vegetable, and Animal kingdoms as have been sanctioned by our 
 leading naturalists which appear to be most intelligible to the general 
 reader and on which, indeed, the greater portion of the nomenclature of 
 Geology and Palaeontology has been founded. 
 
CHEMICAL SCHEME, 
 
 Exhibiting the so-called "Elementary Substances" in alphabetical 
 order, with their symbols and chemical equivalents Hydrogen being 
 taken as 1. 
 
 Elements. Symbols. Equivalents. 
 
 Aluminium Al 13.69 
 
 Antimony (Stibium) Sb 129.03 
 
 Arsenic As 75. 
 
 Barium Ba 68.64 
 
 Bismuth Bi 70.95 
 
 Boron B 10.90 
 
 Bromine Br 78.26 
 
 Cadmium Cd 55.74 
 
 Caesium Cs 133. 
 
 Calcium Ca 20. 
 
 Carbon C 6. 
 
 Ceritim Ce 46. 
 
 Chlorine Cl 35.50 
 
 Chromium Cr 28.15 
 
 Cobalt Co 29.52 
 
 Copper (Cuprum) Cu 31.66 
 
 Didymium 48. 
 
 Erbium 
 
 Fluorine F 18.70 
 
 Glucinium or Beryllium Gl 26.50 
 
 Gold(^l*mim) Au 98.33 
 
 Hydrogen H 1. 
 
 Ilmenium II 
 
 Iodine I 126.36 
 
 Iridium Ir 98.68 
 
 Iron (Ferrum) Fe 28. 
 
 Lanthanum Ln 48. 
 
 Lead (Plumbum) Pb 103.56 
 
 Lithium Li 6.43 
 
 Magnesium Mg 12.67 
 
 Manganese Mn 27.67 
 
 Mercury (Hydrargyrum) Hg 100.07 
 
 Molybdenum '. Mo 47.88 
 
 Nickel Ni 29.57 
 
 Niobium Nb 
 
 Nitrogen N 14. 
 
 Norium No 
 
 11 
 
CHEMICAL SCHEME. 
 
 Elements. Symbols. E<pmvalents. 
 
 Osmium Os 95.56 
 
 Oxygen O 8. 
 
 Palladium Pd 53.27 
 
 Pelopium Pe - 
 
 Phosphorus P 32. 
 
 Platinum Pt 98.68 
 
 Potassium (Kalium) K 39. 
 
 Rhodium R 52.11 
 
 Ruthenium Ru 52.11 
 
 Selenium Se 39.57 
 
 Silicium, Silicon Si 21.35 
 
 Silver (Argentum) Ag 108. 
 
 Sodium (Natrium) Na 22.97 
 
 Strontium Sr 43.84 
 
 Sulphur S 16. 
 
 Tantalum or Col umbium ... Ta 92.30 
 
 Tellurium Te 66.14 
 
 Terbium 
 
 Thallium Tl 204. 
 
 Thorium Th 59.59 
 
 Tin (Stannum) Sn 58.82 
 
 Titanium Ti 24.29 
 
 Tungsten or Wolfram W 94.64 
 
 Uranium U 60. 
 
 Vanadium V 68.55 
 
 Yttrium Y 32.20 
 
 Zinc Zn 32.52 
 
 Zirconium .. . Zr . .. 33.62 
 
 Of the preceding elementary or ultimate substances only a few enter 
 largely into the composition of the earth's crust ; and of the others many 
 are extremely rare, or only evolved from their natural unions by chemical 
 analysis. In the following list the most important (geologically speak- 
 ing) are printed in capitals, their characters being given as under the 
 ordinary pressure and temperature of the atmosphere : 
 Gases HYDROGEN, OXYGEN, nitrogen, CHLORINE, and FLUORINE. 
 Non-Metallic Liquids and Solids Bromine, iodine, SULPHUR, PHOS- 
 PHORUS, selenium, CARBON, boron, SILICON. 
 
 Metals being the basis of the Eartlis and A IJcalies POTASSIUM, SODIUM, 
 lithium ; barium, strontium, CALCIUM ; MAGNESIUM, ALUMINIUM, 
 thorium, glucinium, zirconium, yttrium. 
 
 The Metals MANGANESE, ZINC, IRON, TIN, cadmium, COBALT, NICKEL ; 
 ARSENIC, CHROMIUM, vanadium, molybdenum, tungsten, columbium, 
 ANTIMONY, uranium, cerium, BISMUTH, titanium, tellurium, COPPER, 
 LEAD ; MERCURY, SILVER, GOLD, PLATINUM, palladium, rhodium, 
 osmium, iridium, ruthenium ; (and the following, of which little is 
 yet determined), caesium, erbium, terbium, didymium, lanthanum, 
 niobium, norium, ilmenium, pelopium, thallium. 
 12 
 
MINERAL SCHEME, 
 
 Exhibiting the simple minerals, or constituents of rock-masses, as ar- 
 ranged by Professor Weiss, of Berlin, into Orders and Families. 
 
 I. ORDER OXIDISED STONES. 
 
 Families: I. QUARTZ. 7. MICA. 
 
 2. FELSPAR. 8. HORNBLENDE. 
 
 3. SCAPOLITE. 9. CLAYS. 
 
 4. HALOID STONES. 10. GARNET. 
 
 5. LEUCITE. 11. GEMS. 
 
 6. ZEOLITES. 12. METALLIC STONES. 
 
 II. ORDER-SALINE STONES. 
 
 Families: 1. CALC-SPAR. 4. GYPSUM. 
 
 2. FLUOR-SPAR. 5. ROCK-SALT. 
 
 3. HEAVY-SPAR. 
 
 III. ORDER SALINE ORES. 
 
 Families: 1. SPARRY IRON ORES. 3. LEAD SALTS. 
 
 2. COPPER SALTS. 
 
 IV. ORDER OXIDISED ORES. 
 
 Families:!. IRON ORES. 4. RED COPPER ORES. 
 
 *. 2. TINSTONE. 5. WHITE ANTIMONY ORES. 
 
 3. MANGANESE ORES. 
 
 V. ORDER-NATIVE METALS. 
 
 Form only one Family. 
 
 VI. ORDER -SULPHURETTED METALS. 
 
 Families: I. IRON PYRITES. 4. GREY COPPER ORE. 
 
 2. GALENA. 5. BLENDE. 
 
 3. GREY ANTIMONY ORE. 6. RUBY BLENDE. 
 
 VII. ORDER INFLAMMABLES. 
 
 Families: 1. SULPHUR. 4. MINERAL RESINS. 
 
 2. DIAMOND. 5. COMBUSTIBLE SALTS. 
 
 3. COAL. 
 
 13 
 
MINERAL SCHEME. 
 
 The following list contains the so-called SPECIES usually arranged under 
 the respective families the more abundant and better known being marked 
 in Italics. 
 
 ORDER OXIDISED STONES. 
 
 1. QUARTZ FAMILY (2 Species). Quartz, Opal. 
 
 2. FELSPAR FAMILY (14 Species). Orlhoclase, Ryacolite, Albiie, Andesin, 
 
 Saccharite, Labradorite, Couzeranite, Anorthite, Oligoclase, Petalite, 
 Spodumene, Kastor, Pollux, Amorphous Felspar. 
 
 3. SCAPOLITE FAMILY (13 Species). Scapolite, Nuttalite, Barsowite, Ottre- 
 
 lite, Palagonite, Dipyr, Nepheline, Davyne, Gehlenite, Humboldtilite, 
 Prehnite, Zeuxite, Nephrite. 
 
 4. HALOID STONES (9 Species). Lazulite, Calaite, Wavellite, Wagnerite, 
 
 Amblygonite, Alunite, Aluminite, Pissophane, Latrobite. 
 
 5. LEUCITE (8 Species). Leucite, Porcelain spar, Sodalite, Hauyne, 
 
 Nosean, Ittnerite, Lapis Lazuli, Eudialite. 
 
 6. ZEOLITES (22 Species). Analcime, Natrolite, Scolezite, Damourite, 
 
 Thomsonite, Stilbite, Aedelforsite, Heulandite, Brewsterite, Epistilbite, 
 Apophyllite, Okenite, Pectolite, Chabasite, Faujasite, Harmotome, Phil- 
 lipsite, Zeagonite, Laumonite, Leonhardite, Glottalite, Edingtonite. 
 
 7. MICA FAMILY (31 Species). Potash Mica, Lithia Mica, Magnesia Mica, 
 
 Lepidomelane, Chloritoid, Chlorite, Ripidolite, Talc, Schillerspar, 
 Antigorite, Hydropite, Serpentine, Picrosmine, Villarsite, Spadaite, 
 Gymnite, Chonikrite, Pyrosklerite, Kammererite, Pyrosmalite, Cron- 
 stedtite, Stilpnomelan, Brucite, Hydromagnesite, Nemalite, Seybertite, 
 Margarite, Pyrophyllite, Anauxite, Pholerite, Rosellan. 
 
 8. HORNBLENDE FAMILY (19 Species). Hornblende, Augite, Hypersthene, 
 
 Bronzite, Diallage, Rhodonite, Tephroite, Troostite, Wollastonite, Ach- 
 inite, Sordawalite, Krokydolite, Pyrallolite, Pyrargillite, Karpolite, 
 Babbingtonite, Isopyre, Polylite, Tachylite. 
 
 9. CLAYS (24 Species). Kaolin, Clay, Rock-soap, Plinthite, Ch-een-Earth, 
 
 Yellow - Earth, Halloysite, Fullers' -Earth, Allophane, Schrbtterite, 
 Challilite, Sole, Teratolite, Kollyrite, Lithomarge, Miloschin, Kerolite, 
 Agalmatolite^, Soapstone, Pipestone, Meerschaum, Pimelite, Dermatin, 
 Retinalite. 
 
 10. GARNET FAMILY (15 Species). Garnet, Pyrope, Helvine, Idocrase, 
 Epidote, Axinite, Cy anile, Sillimanite, Bamlite, Andalusite, Staurolite, 
 Diaspore, Hydrargillite, Periclase, Glaucophane. 
 
 11. GEMS (16 Species). Zircon, Malacon, Spinel, Automalite, Corundum, 
 Crysob&ryl, Topaz, Pycnite, Leucophane, Euclase, Emerald, Phenakite, 
 lolite, Tourmaline, Crysolite, Chondrodite. 
 
 12. METALLIC STONES (22 Species). Lievrite, Hisingerite, Anthosiderite, 
 Nontronite, Pinguite, Chloropal, Chlorophceite, Thorite, Eulytine, Gado- 
 linite, A llanite, Tschewkinite, Cerite, Pyrochlore, Keilhauite, Polymig- 
 nite, Polycrase, Peroskite, Aeschynite, Mengite, Monazite, Samarskite. 
 
 14 
 
MINERAL SCHEME. 
 
 ORDER SALINE STONES. 
 
 1. CALC-SPAR FAMILY (6 Species). Gale-spar, Dolomite, Breunnerite, Mag- 
 
 nesite, Mesitine Spar, Arragonite. 
 
 2. FLUOR-SPAR FAMILY (14 Species). Fluw-spar, Yttrocerite, Fluocerite, 
 
 Fluocerine, Cryolite, Chyolite, Hopeite, Apatite, Herderite, Children- 
 ite, Xenotime, Boracite, Hydroboracite, Datholite. 
 
 3. HEAVY-SPAR FAMILY (7 Species). Barytes, Dreelite, Witherite, Alston- 
 
 ite, Baryto-Calcite, Celestine, Strontianite. 
 
 4. GYPSUM FAMILY (7 Species). Gypsum, Anhydrite, Polyhalite, Olau- 
 
 berite, Pharmacolite, Haidingerite, Berzelite. 
 
 5. ROCK-SALT FAMILY (28 Species). Rock-Salt, Alum, Alunogene, Glau- 
 
 ber Salt, Melanterite, Botryogene, Copiapite, Coquimbite, Tectizite, 
 Cyanose, Goslarite, Bieberite, Johannite, Natron, Thermonatrite, 
 Trona, Gaylussite, Borax, Sassoline, Nitre, Nitratine, Nitrocalcite, 
 Nitro-Magnesite, Sal-Ammoniac, Mascagnine, Arcanite, Thenardite, 
 Epsomite. 
 
 ORDER SALINE ORES. 
 
 1. SPARRY IRON ORES (17 Species). Siderite, Ankerite, Diallogite, Man- 
 
 ganoealcite, Lanthanite, Parisite, Calamine, Galmei, Williamite, Tri- 
 plite, Zwi^selite, Triphyline, Hureaulite, Heterozite, Alluaudite, 
 Pitticite, Diadochite. 
 
 2. COPPER SALTS (32 Species). Dioptase, Chrysocolla, Azurite, Malachite, 
 
 Aurichalcite, Chalcophyllite, Tirolite, Erinite, Liroconite, Olivenite, 
 Euchroite, Klinoclase, Phosphorocalcite, Thrombolite, Libethenite, 
 Tagilite, Ehlite, Atacamite, Volborthite, Arseniosiderite, Pharmako- 
 siderite, Scorodite, Symplesite, Brochantite, Vivianite, Dufrenite, 
 Uranite, Chalcolite, Erythrine, Nickeline, Langite, Lyellite. 
 
 3. LEAD SALTS (27 Species). Cerussite, Anglesite, Leadhillite, Lanarkite, 
 
 Caledonite, Linarite, Phosgenite, Mendipite, Cotunnite, Pyromorphite, 
 Mimetesite, Bleinierite, Vanadinite, Wulfenite, Scheelitine, Plomb- 
 gomme, Crocoisite, Melanoehroite, Vauquelenite, Bismuthite, Kerate, 
 Calomel, lodite, Coccinite, Bromite, Romeite, Scheelite. 
 
 ORDER OXIDISED ORES. 
 
 1. OXIDISED IRON ORES (9 Species). Magnetite, Chromite, Franklinite, 
 
 Haematite, Irite, Limonite, Gotheite, Ilmenite, Iserine. 
 
 2. TIN ORE FAMILY (13 Species). Cassiterite, Wolfram, Columbite, Tan- 
 
 talite, Yttrotantalite, Euxinite, Fergusonite, Sphene, Brookite, Ritiile, 
 Anatase, Pechurane, Plattnerite. 
 
 3. MANGANESE ORES (20 Species). Pyrolusite, Polianite, Manganite, 
 
 Hausmannite, Braunite, Psilomelane, Crednerite, Cupreous Manganese, 
 
 Earthy Cobalt, Wad; (Ochres), Cobalt 0., Molybdena 0., Bismuth 
 
 0., Antimony 0., Tungsten 0., Uranium 0., Minium, Lead 0., Chrome 
 0., Tellurite. 
 
 4. RED COPPER ORES (4 Species). Cuprite, Chalcotrichite, Tenorite, 
 
 Zincite. 
 
 5. WHITE ANTIMONY ORES (2 Species). Valentinite, Arsenite. 
 
 15 
 
MINERAL SCHEME. 
 
 ORDER-NATIVE METALS. 
 
 1. THE METALS (18 Species). Platinum, Palladium, Osmiumiridium, 
 Iridium, Gold, Silver, Antimony-Silver, Mercury, Amalgam, Anti- 
 mony, Arsenic-Antimony, Arsenic, Tellurium, Lead, Tin, Bismuth, 
 Copper, Iron. 
 
 ORDER SULPHURETTED METALS. 
 
 1. PYRITES FAMILY (21 Species). Pyrite, Marcasite, Pyrrhotine, Leuco- 
 pyrite, Mispickel, Cobaltine, Smaltine, Modumite, Linne'ite, Grunauite, 
 Gersdorffite, Ullmannite, Breithauptite, Plakodine, NicMine, Ram- 
 melsbergite, Millerite, Chalcopyrite, Bornite, Domeykite, Arseniate of 
 
 2. LEAD GLANCE FAMILY (17 Species). Galena, Cuproplumbite, Glaus- 
 
 thalite, Selencopper Lead, Onofrite, Naumannite, Argentite, Strome- 
 yerite, Redruthite, Kupferinding, Eukairite, Berzeline, NagyagiU, 
 Altaite, Hessite, Tetradymite, Molybdenite. 
 
 3. GREY ANTIMONY ORES (16 Species). Stibine, Jamesonite, Zinckenite, 
 
 Plagionite, Boulangerite, Geokronite, Steinmannite, Plumosite, Duf- 
 re"ynoysite, Wolfsbergite, Kermes, Berth ierite, Bismuthine, Aciculite, 
 Kobellite, Sylvanite. 
 
 4. GREY COPPER ORES (11 Species). Fahlore, Tennantite, Bournonite, 
 
 Wolchite, Freieslebenite, Stephanite, Polybasile, Sternbergite, Stan- 
 nine, Cupreous Bismuth, Bismutfiic Silver. 
 
 5. BLENDES (5 Species). Blende, Woltzine, Alabandine, Hauerite, Green - 
 
 oclcite. 
 
 6. RUBY BLENDES (6 Species).' Pyrargyrile, Miargyrite, Xanthokon, 
 
 Cinnabar, Realgar, Orpiment. 
 
 ORDER-THE INFLAMMABLES. 
 
 1. SULPHUR FAMILY. Sulphur, Selen-Sulphur. 
 
 2. DIAMOND. Diamond. 
 
 3. COALS (5 Species). Graphite, Anthracite, Common Coal, Lignite, Peat. 
 
 4. MINERAL RESINS (21 Species). Bitumen, Elaterite, Asphaltum, Piauz- 
 
 ite, Ixolyte, Amber, Retinite, Walchowite, Copaline, Berengelite, Guy- 
 aquillite, Hartine, Middletonite, Ozokerite, Satchetine, Fichtelite, Hart- 
 ite, Konlite, Scheererite, Idrialite, Scleretinite. 
 
 5. INFLAMMABLE SALTS (2 Species). Mellite, Oxalate. 
 
 16 
 
VEGETABLE SCHEME. 
 
 The Vegetable Kingdom may be arranged into two grand divisions the 
 CELLULAR and VASCULAR ; and these, according to their modes of growth 
 and reproduction, into the following groups and classes : 
 
 I. CELLULAR Without regular vessels, but composed of fibres which 
 
 sometimes cross and interlace each other. The Confervce (green scum- 
 like aquatic growths), the Lie/tens (which incrust stones and decaying 
 trees), the fungi (or mushroom tribe), and the Algce (or sea- weeds), 
 belong to this division. In some of these families there are no appa- 
 rent seed-organs. From their mode of growth viz., sprout-like in- 
 crease of the same organ they are known as THALLOGENS or AMPHI- 
 
 GENS. 
 
 II. VASCULAR With vessels which form organs of nutrition and repro- 
 
 duction. According to the arrangement of these organs, vascular 
 plants have been grouped into two great divisions CRTPTOGAMIC 
 (no visible seed-organs), and PHANEROGAMIC (apparent flowers or 
 seed-organs). These have been further subdivided into the following 
 classes : 
 
 1. CRYPTOGAMS Without perfect flowers, and with no visible seed- 
 
 organs. To this class belong the mosses, equisetums, ferns, and 
 lycopodiums. It embraces many fossil forms allied to these 
 families. From their mode of growth viz., increase at the 
 top or growing point only they are known as ACROGENS. 
 
 2. PHANEROGAMIC MONOCOTYLEDONS Flowering plants with one 
 
 cotyledon or seed-lobe. This class comprises the water-lilies, 
 lilies, aloes, rushes, grasses, canes, and palms. In allusion to their 
 growth, by increase within, they are termed ENDOGENS. 
 
 3. PHANEROGAMIC GYMNOSPERMS This class, as the name indicates, 
 
 is furnished with flowers, but has naked seeds. It embraces 
 the cycadece or pine-apple tribe, and the coniferce or firs. In 
 allusion to their naked seeds, these plants are also known as 
 GYMNOGENS. 
 
 4. PHANEROGAMIC DICOTYLEDONS Flowering plants with two 
 
 cotyledons or seed-lobes. This class embraces all forest trees 
 and shrubs the composites, leguminosce, umbelliferce, cruciferce, 
 and other similar orders. None of the other families of plants 
 have the true woody structure, except the coniferce or firs, which 
 seem to hold an intermediate place between monocotyledons 
 and dicotyledons ; but the wood of these is readily distinguished 
 from true dicotyledonous wood. From their mode of growth, 
 increase by external rings or layers, they are termed EXOGENS. 
 17 B 
 
VEGETABLE SCHEME. 
 
 18 
 
 2 e oj'oj'43 
 
 111" 
 
VEGETABLE SCHEME. 
 
 Or, following the arrangement adopted by Professor Lindley, we have the 
 subjoined classes, sections, and alliances: 
 
 Class I. THALLOGENS -Asexual or Flowerless plants, without proper 
 stems or leaves. These include three alliances Algales, 
 Fungales, and Lichenales. 
 
 Class II. ACROGENS Asexual or Flowerless plants with stems and 
 leaves. Includes three alliances Muscales, Lycopodales, 
 and Filicales. 
 
 Class III. RHIZOGENS Sexual or Flowering plants with Acotyledonous 
 embryos and fructification, springing from a thallus as in 
 Rafflesiacece. 
 
 Class IV. ENDOGBNS Monocotyledonous Flowering plants with Endo- 
 genous stems, parallel venation, and ternary symmetry. 
 This class is subdivided into four sections : 
 
 1. Plants with glumaceous flowers formed by imbricated 
 
 bracts. 
 
 2. Petaloid unisexual flowers. 
 
 3. Petaloid hermaphrodite flowers adherent to the ovary. 
 
 4. Petaloid hermaphrodite flowers free from the ovary. 
 Under these sections are included 11 alliances, such as 
 Qlumales, Arales, Palmales, Narcissales, Orchidales, Juncales, 
 and Liliales. 
 
 Class V. DICTYOGENS Monocotyledonous plants with reticulated ven- 
 ation, including such orders as Discoreacece, Smilacece, and 
 Trilliacece. 
 Class VI. GYMNOGENS Polycotyledonous Exogens with naked seeds, as 
 
 Coniferce and Cycadacece. 
 
 Class VII. EXOGENS Dicotyledonous plants with seeds in a seed-vessel. 
 Under this head are arranged the following sub-classes : 
 Sub-class 1. DICLINOUS EXOGENS, or Dicotyledons with 
 unisexual flowers, and no tendency to form hermaphro- 
 dite flowers ; includes 8 alliances, such as Amentales, 
 Urticales, Euphorbiales, Menispermales, Cucurbitales. 
 Sub-class 2. HYPOQYNOUS EXOGENS, or Dicotyledons with 
 hermaphrodite or polygamous flowers, and stamens 
 entirely free from the calyx and corolla ; including 14 
 alliances, such as Violates, Cistales, Malvales, Nymph- 
 ceales, Ranales, Eerier ales, Ei-icales, Rutales, Geraniales, 
 Silenales, Chenopodales, and Piperales. 
 Sub-class 3. PERIGYNOUS EXOGENS, or Dicotyledons with 
 .hermaphrodite or polygamous flowers, the stamens 
 growing to the side of either the calyx or corolla, 
 ovary superior, or nearly so ; includes 10 alliances, 
 such as Daphnales, Resales, Saxifragales, Gentianales, 
 Solanales, Echiales, and Bignoniales. 
 Sub-class 4. EPIGYNOUS EXOGENS, or Dicotyledons with 
 hermaphrodite or polygamous flowers, the stamens 
 growing to the side of either the calyx or corolla, 
 ovary inferior or nearly so. This includes 7 alliances 
 Campanales, Myrtales, Cactales, Grossales, Cinchon- 
 ales, Umbellales, and Asarales. 
 19 
 
VEGETABLE SCHEME. 
 
 EH -g 
 
 O 
 
 o 
 
 20 
 
DIATOMACE^E. 
 
 Of these minute vegetable organisms, the following genera and species 
 are those usually given as occurring most abundantly in the diatomaceous 
 or microphytal earths that have been submitted to the microscope. The 
 shields or cases of the Diatoms are siliceous ; hence their beautiful and 
 almost perfect preservation. The Desmidiese or Desmids, also micro- 
 scopic plant-growths consisting of one or only a few cells, are found in flint 
 and hornstone, but they secrete little or no silica ; hence their less fre- 
 quent occurrence in a fossil state. 
 
 Actinocyclus. 
 
 bioctonarius. 
 
 Actinoptychus. 
 
 biternarius. 
 
 senarius. 
 
 Amphora. 
 
 elliptica. 
 
 ovalis. 
 
 Bacillaria. 
 
 paradoxa. 
 
 Campylodiscus. 
 
 clypeus. 
 
 noricus. 
 
 Chsetotyphla. 
 
 pyritse. 
 
 Cocconeis. 
 
 pediculus. 
 Cocconema. 
 
 cistula. 
 
 cornutum. 
 
 cymbiforme. 
 
 gracile. 
 
 lanceolata. 
 
 Coscinodiscus. 
 apiculatur. 
 
 gigas. 
 
 Cyclotella. 
 minutula. 
 
 operculata. 
 
 Cymbella. 
 
 cuspidata. 
 
 Ehrenbergii. 
 
 Helvetica. 
 
 maculata, 
 
 Dictyocha. 
 
 crux. 
 
 Epithemia. 
 
 gibba. 
 
 21 
 
 Epithemia granulata. 
 
 Hyndmanii. 
 
 ocellata. 
 
 proboscidea. 
 
 turgida. 
 
 zebra. 
 
 Eunotia. 
 
 gibba. 
 
 granulata. 
 
 levis. 
 
 longicornis. 
 
 monodon. 
 
 tridentula. 
 
 zebrina 
 
 Fragilaria. 
 
 pinnata. 
 
 rhabdosoma. 
 
 striolata. 
 
 virescens. 
 
 Gallionella. 
 
 granulata. 
 
 decussata. 
 
 distans. 
 
 procera. 
 
 sulcata. 
 
 Gomphonema. 
 
 accuminatus. 
 
 constrictus. 
 
 geminatum. 
 
 gracile. 
 
 minutum. 
 
 pohliaeforme. 
 Grammatophora. 
 
 oceanica. 
 
 parallela. 
 
 Himantidium. 
 
 arcus. 
 
 pectinale. 
 
VEGETABLE SCHEME. 
 
 Meloscira. 
 
 arenaria. 
 
 Italioa. 
 
 orichalcea. 
 
 subflexilis. 
 
 Navicula. 
 
 bacillum. 
 
 binodus. 
 
 dicephala. 
 
 elliptica. 
 
 forma. 
 
 gracilis. 
 
 inflata. 
 
 lata. 
 
 lineolata. 
 
 major. 
 
 mesolepta. 
 
 nobilis. 
 
 nodosa. 
 
 oblonga. 
 
 radiosa. 
 
 rhomboides. 
 
 sigma. 
 
 sphserophora. 
 
 tripunctata. 
 
 Navicula viridis. 
 Peridinium. 
 
 pyrophorum. 
 
 Pinnularia. 
 
 pengnna. 
 
 taeniata. 
 
 viridis. 
 
 Pyxidicula. 
 
 prisca. 
 
 Stauroneis. 
 
 amphicephala. 
 
 cardinalis. 
 
 lanceolata. 
 
 Phoenicentron. 
 
 platystoma. 
 
 punctata. 
 
 Surirella. 
 
 elliptica. 
 
 Solea, 
 
 Synhedra. 
 
 capitata. 
 
 Tabellaria. 
 
 fenestrata. 
 
 ventricosa. 
 
 22 
 
ANIMAL SCHEME. 
 
 The following arrangement being chiefly that of Cuvier, with such 
 modifications as the progress of science demands will render sufficiently 
 apparent the main subdivisions and relations of the animal kingdom, and 
 enable the reader to determine more readily the position of any fossil form 
 in the scheme of vitality : 
 
 VERTEBKATA, 
 
 Or animals with, backbone and bony skeleton, and comprehending 
 MAMMALIA ; AVES ; REPTILIA ; and PISCES. 
 
 I. MAMMALIA or Swklers, subdivided into Placental and Aplacental. 
 1. PLACENTAL, bringing forth mature young. 
 
 BIMANA (Two-handed) Man. 
 
 QUADRUMANA (Four-handed) Monkeys, Apes, Lemurs. 
 CHEIROPTERA (Hand-winged) Bats, Vampyre-bats, Fox-bats. 
 INSECTIVORA (Insect-eaters) Mole, Shrew, Hedgehog, Banxring. 
 CARNIVORA (Flesh-eaters) Dog, Wolf, Tiger, Lion, Badger, Bear. 
 PINNIPEDIA (Fin-footed) Seals, Walrus. 
 
 EODENTIA (Gnawers) Hare, Beaver, Rat, Squirrel, Porcupine. 
 EDENTATA (Toothless) Ant-eater, Armadillo, Pangolin, Sloth. 
 RUMINANTIA (Cud-chewers) Camel, Llama, Deer, Goat, Sheep, Ox. 
 SOLIDUNGULA (Solid-hoofs) Horse, Ass, Zebra, Quagga. 
 PACHTDERMATA ( Thick-skins) Elephant, Hippopotamus, Rhinoceros, Pig. 
 CETACEA ( Whales) Whale, Porpoise, Dolphin, Lamantin. 
 
 2. APLACENTAL, bringing forth immature young. 
 
 MARSUPIALIA (Pouched) Kangaroo, Opossum, Pouched Wolf, &c. 
 MONOTREMATA (One-vented) Ornithorhynchus, Porcupine-ant-eaters. 
 
 II. AVES or BIRDS. 
 
 RAPTORES (Seizers) Eagles, Falcons, Hawks, Owls, Vultures. 
 INSESSORES (Perchers) Jays, Crows, Finches, Sparrows, Thrushes. 
 SCANSORES (Climbers) Woodpeckers, Parrots, Parroqueets, Cockatoos. 
 CoLUMBjE (Pigeons) Common Dove, Turtle Dove, Ground Dove. 
 
 23 
 
ANIMAL SCHEME. 
 
 RASORES (Scrapers) Barnfowl, Partridge, Grouse, Pheasant. 
 CURSORES (Runners) Ostrich, Emu, Rhea, Apertyx. 
 GRALLATORES ( Waders) Rails, Storks, Cranes, Herons, Bitterns. 
 NATATORES (Sioimmers) Divers, Gulls, Ducks, Pelicans. 
 
 III. REPTILIA, subdivided into Reptiles Proper and Batrachians. 
 1. REPTILES PROPER. 
 
 CHELONIA (Tortoises) Turtles, Tortoises. 
 
 LORICATA (Covered with Scutes) Crocodile, Gavial, Alligator. 
 
 SAURIA (Lizards) Lizard, Tguana, Chameleon. 
 
 OPHIDIA (Serpents) Vipers, Snakes, Boas, Pythons. 
 
 2. BATRACHIANS or FROGS. 
 
 AKOURA (Tail-less) Toad, Frog, Tree-Frog. 
 URODELA (Tailed) Siren, Triton, Salamander. 
 APODA (Footless) Lepidosiren, Blindworm. 
 
 IV. PISCES or FISHES. 
 
 SELACHIA (Cartilaginous) Chimsera, Sharks, Sawfish, Rays. 
 GANOIDEA (Enamel-scales) Amia, Bony-pike, Sturgeon. 
 TELEOSTIA (Perfect-bones) Eels, Salmon, Herring, Cod, Pike. 
 CYCLOSTOMATA (Circle-mouths) Lamprey. 
 LEPTOCARDIA (Slender-harts) Amphioxus. 
 
 INVEETEBRATA, 
 
 Or animals void of backbone and bony skeleton, and comprehending 
 ARTICULATA, MOLLUSCA, RADIATA, and PROTOZOA. 
 
 I. ARTICULATA, subdivided into Articulates and Vennes. 
 1. ARTICULATA or Jointed Animals Proper. 
 
 INSECTA (Insects) Beetles, Butterflies, Flies, Bees. 
 MYRIAPODA (Many-feet) Scolopendra, Centipedes. 
 ARACHNIDA (Spiders} Spiders, Scorpions, Mites. 
 CRUSTACEA (Crust-clad) Crayfish, Crabs, Shrimps, Woodlice. 
 CIRRHOPODA (Curl-feet} Acorn-shells, Barnacles. 
 
 2. VERMES or Worms Proper. 
 
 ANNELIDA (Small rings} Lobworm, and almost all the marine worms. 
 ROTIFERA (Wheel-learns). Rotifers, Hydatina. 
 GEPHYRIA (Intermediates urchin-like) Sipunculus, Echinurus. 
 LUMBRICINA (Earth-worms) Earth-worms, Nais. 
 HIRUDINEI (Leeches) Leeches, Branchellion. 
 TURBELLARIA ( Turbellaries) Planaria, Ribbon- worms. 
 HELMINTHES (Gut-worms) Intestinal worms. 
 
 24 
 
ANIMAL SCHEME. 
 
 II. MOLLUSCA, subdivided into Mollusca and Molluscoida. 
 1. MOLLUSCA or Shell-fish Proper. 
 
 CEPHALOPODA (Head- footed) Cuttle-fish, Octopus, Calamary, Nautilus. 
 PTEROPODA (Wing-footed) Clio, Hyalaea. 
 GASTEROPODA (Belly-footed) Snails, Slugs, Whelks, Cowries. 
 ACEPHALA (Headless) Oysters, Mussels, Cockles, Shipworms. 
 BRACHIOPODA (Arm-footed) Terebratula, Lingula. 
 
 2. MOLLUSCOIDA, or Mollusc-like Animals. 
 TUNICATA (Coated, but Shell-less)- { 
 
 POLTZOA (Compound animals) \ 
 
 or VFlustra, Eschara, Plumatella, &c. 
 
 BRYOZOA (Moss-like animals) ) 
 
 III. RADIATA or ZOOPHYTES Ray-like Animals. 
 
 ECHINODERMATA ( Urchin- skinned) Sea-urchins, Star-fishes. 
 
 ACALEPH.E (Sea-nettles) Jelly-fish, Beroes. 
 
 POLYPI (Many-feet) Coral animals, Sea- anemones, Hydras. 
 
 IV. PROTOZOA or LOWEST-LIFE Globular Animals. 
 
 INFUSORIA (Infusories) Monads, Volvoces, Vorticella. 
 PORIFERA (Pore-bearers) Sponges, Fresh-water Sponges. 
 RHIZOPODA (Root-footed) Amoeba, Polythalamia (Foraminifera). 
 
 The following tabulations exhibit, in detail, the orders, families, and 
 genera of those Classes which come most frequently under the notice of 
 the Paleontologist, in order that the reader may perceive, at a glance, the 
 relation which the extinct forms already determined bear to those still ex- 
 isting, and thus be in some measure enabled to arrive at broader concep- 
 tions of the great creational scheme of vitality : 
 
 25 
 
MAMMALIA. 
 
 Sub-class I. PLACENTALI A bringing forth perfect young. 
 
 Order I. BIMANA Man. 
 
 Sub-fossil in recent formations only. 
 
 Order II. QUADEUMANA. 
 
 Fam. 1. Galeopithecidse ... Flying Lemurs. 
 
 Fam. 2. Chiromydse Aye- Ayes. 
 
 Fam. 3. Tarsidse Thumbed Lemurs. } 
 
 Fam. 4. Nycticebidse Slow Lemurs. VProsimiae. 
 
 Fam. 5. Lemuridse Lemurs. J 
 
 Fam. 6. Hepalidse Marmosets. ^ 
 
 Fam. 7. Cebidse New World Apes. V Simise. 
 
 Fam. 8. Simiidre Old World Apes. ) 
 
 Fossil Forms. Pliopithecus, Dryopithecus, Mesopithecus, 
 Semnopithecus, and species of the existing genus Macacus. 
 
 Order III. CHEIROPTEKA. 
 
 Fam. 1. Vespertilionidae... True Bats. 
 
 Fam. 2. Khinolophidse Horseshoe Bats. 
 
 Fam. 3. Phyllostomidse ... Vampyre Bats. 
 
 Fam. 4. Pteropodidse Fox Bats. 
 
 Fossil Forms. Species of Vespertilio, Rhinolophus, and 
 other existing gen era in bone-caves. 
 
 Order IV. INSECTIVORA. 
 
 Fam. 1. Talpidse Moles. 
 
 Fam. 2. Soricidse Shrews. 
 
 26 
 
ANIMAL SCHEME. 
 
 Sub-fam. Soricinse True Shrews. 
 
 ,, Macroscelidinse Long-legged Shrews. 
 
 , , Erinaceinse Hedgehogs. 
 
 Tupainae Banxrings. 
 
 Fossil Forms. Paloeospalax, Spalacodon, Spalacotherium, 
 and species of the existing genera Erinaceus, Talpa, and 
 Sorex. 
 
 Order V. CARNIVOBA. 
 
 Fam, 1. Canidae Dogs. \ 
 
 Fam. 2. Felidse Cats. VDigitigrade. 
 
 Fam. 3. Hyaenidse Hyaenas, j 
 
 Fam. 4. Viverridaa Civets. ) i-^j 
 
 Fam. 5. Mustelidse Weasels. } Semiplantigrade. 
 
 Fam. 6. Melidae Badgers. \ 
 
 Fam. 7. Ursidae Bears. ^Plantigrade. 
 
 Fam. 8. Cercoleptidse Kinkajous. j 
 
 Fossil Forms. Machairodus, Galecynus, Palceocyon, Ampki- 
 cyon, Hycenodon, Cynodon, Leptarctus, and species of the 
 existing genera Canis, Vulpes, Felis, Hyaena, Putorius, 
 Mustela, Meles, Ursus, &c. 
 
 Order VI. PINNIPEDIA. 
 
 Fam. 1. Phocidae Seals. 
 
 Fam. 2. Trichecidse Walruses. 
 
 Fossil Forms. Species of existing genus Phoca. 
 
 Order VII. RODENTIA. 
 
 Fam. 1. Leporidse Hares. 
 
 Fam. 2. Cavidae Cavies. 
 
 Fam. 3. Hystricidse Porcupines. 
 
 Fam. 4. Castoridae Beavers. 
 
 Fam. 5. Muridae Rats. 
 
 Fam. 6. Psammorychidse Sand-Rats. 
 
 Fam. 7. Georychidae Mole-Rats. 
 
 Fam. 8. Chinchillidae Chinchillas. 
 
 Fam. 9. Dipopidse Jerboas. 
 
 Fam. 10. Myoxidae Dormice. 
 
 Fam. 11. Sciuridae Squirrels. 
 
 Fossil Forms. Trogontherium, Archceomys, Adelomys, Chali- 
 comys, Eumys, Plesiarctomys, and species of existing 
 genera Arvicola, Castor, Arctomys, Lagomys, Lepus, 
 and Mus. 
 
 27 
 
ANIMAL SCHEME. 
 
 Order VIII. EDENTATA. 
 
 Fam. 1. Myrmecophagidae Ant-eaters. 
 
 Fam. 2. Dasypodidse Armadilloes. 
 
 Fam. 3. Bradypodidse Sloths. 
 
 Fossil Forms. Glyptodon, Megatherium,' Megalonyx, Mylo- 
 don, Macrotherium, Scelidotherium, &c. 
 
 Order IX. KUMINANTIA. 
 
 Fam. 1. Camelidse Camels, Llamas. 
 
 Fam. 2. Moschidae Musk-deers. 
 
 Fam. 3. Cervidse Deers. 
 
 Fam. 4. Camelopardidse ... Giraffe. 
 
 Fam. 5. Bovidse Oxen, Sheep, Antelopes. 
 
 Fossil Forms. Several species of ox, sheep, goat, antelope, 
 
 deer ; Megaceros; species of musk-deer ; species of camel ; 
 
 giraffe ; Leptauchenia, Macrauchenia, Dorcatherium, Siva- 
 
 therium, Merycotlierium, M&rycodus, Protomeryx, Camelops, 
 
 &c. 
 
 Order X. SOLIDUNGULA or SOLIPEDIA. 
 
 Fam. 1. Equidae Horses, Asses, Zebras. 
 
 Fossil Forms. Anchitherium, Hipparion, Hippotlwrium, 
 , Merychippus; and species of the existing genera Equus 
 and Asinus. 
 
 Order XI. PACHYDERMATA. 
 
 Fam. 1. Elephantidse Elephabts. ) _ 
 
 Fam. 2. Tapiridaa Tapirs. { Proboscidea. 
 
 Fam. 3. Hippopotamidse... Hippopotami. 
 
 Fam. 4. Khinoceridee Khinoceroses. 
 
 Fam. 5. Suidaa Swine. 
 
 Fam. 6. Hyracidse : Conies. 
 
 Fossil Forms. Palceotherium, Paloplotherium, Anoplother- 
 ium, Tilanothei^ium ; Hyopotamits, Ch<xropotamus, Micro- 
 chcerus; Dichobune, Coryphodon, Dichodon, Oreodon; Hyra- 
 cotlierium; Mammoth, Mastodon; and several species of 
 elephant, hippopotamus, rhinoceros, &c. 
 
 Order XII. CETACEA. 
 Sub-order I. CETE. 
 
 Fam. 1. Balsenidse True Whales. ^ 
 
 Fam. 2. Physeteridaa Sperm Whales. VZoophagous- 
 
 Fam. 3. Delphinidaa Dolphins. j 
 
 28 
 
ANIMAL SCHEME. 
 
 Sub-order II. SIRENIA. 
 
 Fam. 1. Ehytinidse Rhytines. ) _., . 
 
 Fam.2. Manatid* Sea-cows. } Phytophagous. 
 
 Fossil Forms. Balcenodon, Zeuglodon, Squalodon ; Hali- 
 therium, Dinotherium (?), Rhytina ; and sub-fossil species 
 of existing genera Balsena, Physter, Delphinus, &c. 
 
 Sub-class II. APLACENTALIA bringing forth imperfect young. 
 
 Order I. MARSUPIALIA. 
 
 Fam. 1. Phascolomydse ... Wombats, "j 
 
 Fam. 2. Macropodidse Kangaroos. > Phytophagous. 
 
 Fam. 3. Phalangistidse Phalangers. / 
 
 Fam. 4. Peramelidse Bandicoots. \ 
 
 Fam. 5. Didelphidae Opossums. I Rapa- 
 
 Fam. 6. Myrmecobiidse ... Banded Ant- Eaters. Tcious. 
 
 Fam. 7. Dasyuridae Dasyures. 
 
 Fossil Forms. AmphitJierium, Phascolotherium, Droma- 
 therium, Thylacotherium, Triconodon, Plagiaulax, Micro- 
 lestes, Amphilestes, Nototherium, Diprotodon, Zygomaturus, 
 Thylacoleo ; and sub- fossil species of existing genera. 
 
 Order II. MONOTREMATA. 
 
 Fam. 1. Ornithorhyncidse. . Ornithorhynchus. 
 Fam.2. Echidnidse Porcupine Ant- Eaters. 
 
AVES, OR BIRDS. 
 
 There is no other zoological form so slenderly represented in geological 
 times as the Birds. The footprints of Runners and Waders are thought 
 to occur on the slabs of the Trias ; one doubtful portion of bone is said to 
 have been found in the Upper Trias of America ; an imperfect skeleton 
 has been recently discovered in the Oolites of Germany ; one questionable 
 bone has been detected in the Chalk ; and comparatively few bones and frag- 
 ments in the Tertiaries. It is only in Post-tertiary times that bird-remains 
 bones and eggs occur in anything like notable abundance. Whatever 
 the cause, the paucity of ornithic remains is undoubted ; and hence the 
 merest resume of the orders will suffice for palseontological purposes : 
 
 Order I. EAPTORES or Seizers. Remains of vulturine birds in the 
 Tertiaries; Lithornis, <&c. 
 
 Order II. INSESSORES or Perchers. Remains of crow-like birds in the 
 Upper Tertiaries. 
 
 Order III. SCANSORES or Climbers. Remains of woodpecker-like birds 
 in the Tertiaries. 
 
 Order IV. COLUMRffi or Pigeons. Remains of several genera in Post- 
 tertiary and recent accumulations some, like the dodo, 
 solitaire, &c., of gigantic proportions. 
 
 Order V. RASORES or Scrapers. Remains of quail-like and pheasant- 
 like birds in the Tertiaries. 
 
 Order VI. CURSORES or Runners. Remains of ostrich-like birds in the 
 Tertiaries ; and gigantic genera, dinornis, cepiornis, palap- 
 teryx, &c., in the Post-tertiaries. 
 
 Order VII. GRALLATORES or Waders. Remains of waders occur in some 
 abundance in the Tertiaries, gastornis, halcyornis, &c. ; and 
 footprints (Brontozoum) are thought to be impressed on 
 flagstones of Triassic date. 
 
 Order VIII. NATATORES or Swimmers. Remains of this order (ducks, 
 gulls, auJcs, divers, &c. ) occur in the Tertiaries and Post- 
 tertiaries in some abundance. 
 
 30 
 
REPTILIA. 
 
 (After Professor Owen's arrangement of 1859.) 
 
 Order I. GANOCEPHALA (Head composed of enamelled bones). 
 
 Fossil Forms. Archegosaurus, Anihrakerpeton, Pholidogaster, 
 &c. 
 
 Order II. LABYEINTHODONTIA (Labyrinthine-teeth). 
 
 Fossil Forms. Labyrinthodon, Mastodonsaurus, Odontosaurus, 
 Capitosaurus, Trematosaurus, Zygosaurus, Anthracosaurus, 
 Baphetes, Bathygnathus, &c. 
 
 Order III. ICHTHYOPTERTQIA (Fish-finned saurians). 
 Fossil Form. Ichthyosaurus. 
 
 Order IV. SAUROPTEBTGIA (Lizard-finned saurians). 
 
 Fossil Forms. Plesiosaurus, Pliosaurus, Simosaurus, Pisto- 
 saurus, Nothosaurus, Polyptychodon. 
 
 Order V. ANOMODONTIA (Irregular-toothed). 
 
 Fam. 1. Dicynodontia Dicynodon, Ptychognaihus. 
 
 Fam. 2. Cryptodontia Oudenodon. 
 
 Fam. 3. Gnathodontia Rhynchosaurus. 
 
 Fossil Forms. As given in the preceding examples. 
 
 Order VI. PTEROSATJRIA (Winged saurians). 
 
 Fossil Forms. Pterodactylus, Rhamphorhynchus, Dimorphodon. 
 31 
 
ANIMAL SCHEME. 
 
 Order VII. THECODONTIA (Sheath or socket-toothed). 
 
 Fossil Forms. Thecodontosauriis, Stagonolepis, Prot&rosaurus, 
 Palceosaurus, Cladydon, Belodon, &c. 
 
 Order VIII. DINOSAURIA (Terrible saurians). 
 
 Fossil Forms. Iguanadon, Hylceosaurus (Herbivorous), Mega- 
 losaurus, Regnosaurus (Carnivorous), Scelidosauriis. 
 
 Order IX. CROCODILIA (Crocodiles). 
 
 Sub-order 1. Amphicoelia Having bi-concave vertebrae. 
 
 Fossil Forms. Teleosaurus, Mistriosaurus, Macrospondylus, 
 Massospondylus, Pelagosaurus, Steneosaurus, Suchosaums, 
 Gfoniopholis, Pcecilcepleura, &c. 
 
 Sub-order 2. Opisthocoelia Having convexo-concave vertebrae. 
 
 Fossil Forms. Cetiosaurus, Streptospondylus. 
 
 Sub-order 3. Procoelia Having concavo-convex vertebrae. 
 
 Fossil Forms. Species of the existing genera Crocodilus, Alli- 
 gator, and Gavialis. 
 
 Order X. LACEKTTLIA (Lizards). 
 
 Fam. 1. Scincidse Skinks. 
 
 Fam. 2. Chalcidsa 
 
 Fam. 3. Lacertidje Lizards. 
 
 Fam. 4. Teidse Ameivas. 
 
 Fam. 5. Varanidae Varanas. 
 
 Fam. 6. Iguanidae Iguanas. 
 
 Fam. 7. Geckotidse Geckos. 
 
 Fam. 8. Chamaeleonidse Chameleons. 
 
 Fossil Forms. Telerpeton, Dendrerpeton, Hylerpeton, Hylono- 
 mits, Leiodon, Macellodus, Lacerta, Coniosaurus, Dolicho- 
 saurus, &c. 
 
 Order XL OPHIDIA. 
 
 Fam. 1. Crotalidae Eattlesnakes. 
 
 Fam. 2. Viperidse Vipers. 
 
 Fam. 3. Colubridse Snakes. 
 
 Fam. 4. Hydrophidae Water-Snakes. 
 
 Fam. 5. Dendrophidae Tree-Snakes. 
 
 Fam. 6. Boidae Boas. 
 
 Fossil Forms. Palceophis, Laophis. Paleryx; detached bones 
 and eggs of undetermined genera apparently related to the 
 water-snakes and pythons. 
 32 
 
ANIMAL SCHEME. 
 
 Order XII. CHELONIA. 
 
 Fam. 1. Chelonidae Turtles Marine. 
 
 Fam. 2. Tryonicidae Soft Tortoises Fluvial. 
 
 Fam. 3. Emydidse Box Tortoises Marsh. 
 
 Fam. 4. Testudinidae Land Tortoises Terrestrial. 
 
 Fossil Forms. Colossockelys, Pleurosternon, Protemys, Platemys; 
 fossil footprints, as Chelichnus, &c. ; and species of the exist- 
 ing genera Chelone, Testudo, Tryonyx, and Emys. 
 
 Order XIII. BATEACHIA OR AMPHIBIA. 
 
 Sub-order I. APODA. 
 
 Fam. 1. Cceciliidae Blindworms. 
 
 Fam. 2. Lepidotidse Lepidosiren. 
 
 Sub-order II. UEODELA. 
 
 Fam. 1. Proteidse Proteus. 
 
 Fam. 2. Sirenidse Sirens. 
 
 Fam. 3. Amphiumidae Amphiuma. 
 
 Fam. 4. Salamandridae Tritons. 
 
 Fossil Forms. Parabatrachus, Palceophrynos, Andrias, &c. 
 
 Sub-order III. ANURA. 
 
 Fam. 1. Pipidse Surinam Toads. 
 
 Fam. 2. Bufonidse Toads. 
 
 Fam. 3. Ranidae Frogs. 
 
 Sub-fam. Hylinesa Tree-Frogs. 
 
 Fossil Forms. Raniceps; Batrachopus, Sauropus, and other 
 frog-like footprints. 
 
 33 
 
PISCES, OR FISHES. 
 
 (Chiefly from Morris's Catalogue of British Fossils, as modified from 
 Miiller and Owen.) 
 
 Order I. DERMOPTERI. [Cycloidei, Agass.] 
 
 Sub-order I. Pharyngobranchii, seu Cirrhostomi. 
 Fam. 1. Amphioxidse Lancelet. 
 
 Sub-order II. Marsipobranchii. [Cyclostomi, Cuv.] 
 
 Fam. 1. Myxinidae.... Myxine. 
 
 Fam. 2. Petromyzontidae Lamprey. 
 
 Order II. MALACOPTERI (Physostomi, Miiller). [Cycloidei, Agass.] 
 
 Sub-order I. M. apodes. 
 
 Fam. 1. Symbranchidse Cuchia. 
 
 Fam. 2. Mursenidae Eel. 
 
 Fam. 3. Gymnotidae Gymnotus. 
 
 Sub-order II. M. abdominales. 
 
 Fam. 1. Heteropygii Amblyopsis. 
 
 Fam. 2. Clupeidae Herring. 
 
 Fam. 3. Salmonidse Salmon. 
 
 Fam. 4. Scopelidae Saurus. 
 
 Fam. 5. Characinidse Myletes. 
 
 Fam. 6. Galaxidse Galaxias. 
 
 Fam. 7. Esocidse Pike. 
 
 Fam. 8. Mormyridae Mormyrus. 
 
 Fam. 9. Cyprinodontidae Umber. 
 
 Fam. 10. Cyprinidae Carp. 
 
 Fam. 11. Siluridae Sheat-fish. 
 
 Order III. PHARYNGOGNATHI (Muller). [Cycloidei et Ctenoidei, Agass.] 
 
 Sub-order I. Ph. malacopterygii. 
 
 Fam. 1. Scomber-esocidae Saury-Pike. 
 
 Sub-order II. Ph. acanthopterygii. 
 
 Fam. 1. Chromidae Chromis. 
 
 Fan:. 2. Cycloabridas Wrasse. 
 
 Fam. 3. Ctenolabridse Pomacentrus. 
 
 34 
 
ANIMAL SCHEME. 
 
 Order IV. ANACANTHINI (Miiller). [Cycloidei et Ctenoidei, Agass.] 
 
 Sub-order I. A. apodes. 
 
 Fam. 1. Ophididae Ophidium. 
 
 Sub-order II. A. thoracica. 
 
 Fam. 1. Gadidae Cod. 
 
 Fam. 2. Pluronectidae Plaice. 
 
 Order V. ACANTHOPTERI (Miiller). [Cycloidei et Ctenoidei, Agass.] 
 
 Fam. 1. Percidae Perch. 
 
 Fam. 2. Sclerogenidse Gurnard. 
 
 Fam. 3. Sparidae Sparus. 
 
 Fam. 4. Sciaenidae Maigre. 
 
 Fam. 5. Labyrinthobranchii Anabas. 
 
 Fam. 6. Mugilidae Mullet. 
 
 Fam. 7. Notacanthidae Notacanth. 
 
 Fam. 8. Scomberidae Mackerel. 
 
 Fam. 9. Squammipennes Chaetodon. 
 
 * Fam. 10. Taeniodei Riband-fish. 
 
 Fam. 11. Theutyidaa Lancet-fish. 
 
 Fam. 12. Fistularidae Pipe-mouth. 
 
 Fam. 13. Gobiidae Goby. 
 
 Fam. 14. Blenniidse Wolf-fish. 
 
 Fam. 15. Lophiidse Angler. 
 
 Order VI. PLECTOGNATHI (Cuvier). [Ganoidei, Agass.] 
 
 Fam. 1. Balistini File-fish. 
 
 Fam. 2. Ostraciontidae Trunk-fish. 
 
 Fam. 3. Gymnodontidae Globe-fish. 
 
 Order VII. LoPHOERANCmi(Cuvier). [Ganoidei, Agass.] 
 
 Fam. 1 . Hippocampidae Sea-horse. 
 
 Fam. 2. Syngnathidae Pipe-fish. 
 
 Order VIII. GANOIDEI, seu Goniolepidoti (Agass.; as restricted by Miiller). 
 
 Fam. 1. Salamandroidei Lepidosteus and Polypterus. 
 
 (Sauroidei, Agass.) 
 
 Fam. 2. Pycnodontidae Pycnodus. 
 
 Fam. 3. Lepidoidei Dapedius. 
 
 Fam. 4. Sturionidae Sturgeon. (Acipenserini, Agass.) 
 
 fe, 
 
 . . . 
 
 Fam. 5. Acanthodei Acanthodes. 
 
 Fam. 6. DipteridaD Dipterus. (Sauroidei-dipterini, Agass.) 
 
 Fam. 7. [Coelacanthi, Agass Ccelacanthus.] 
 
 Fam. 8. Cephalaspides Cephalaspis, Pteraspis. 
 
 Order IX. PROTOPTERI. [Ganoidei, Agass.] 
 
 Fam. 1. Sirenoidei Lepidosiren. 
 
 35 
 
ANIMAL SCHEME. 
 
 Order X. HOLOCEPHALI. [Placoidei, Agass.] 
 
 Fam. 1. Chimaeridae Chimaera. 
 
 Fam. 2. Edaphodontidae Edaphodon. 
 
 Order XL PLAQIOSTOMI. [Placoidei, Agass.] 
 
 Fam. 1. Hybodontidae Hybodus. 
 
 Fam. 2. Cestraciontidse Cestracion. 
 
 Fam. 3. Notidanidae Grey Shark. 
 
 Fam. 4. Spinacidse Piked Dog-fish. 
 
 Fam. 5. Scylliadse Spotted Dog-fish. 
 
 Fam. 6. Nictitantes Tope. 
 
 Fam. 7. Lamnidae Porbeagle. 
 
 Fam. 8. Alopecidse Fox Shark. 
 
 Fam. 9. Scymniidse ' Greenland Shark. 
 
 Fam. 10. Squatinse Monk-fish. 
 
 Fam. 11. Zygsenidse Hammerhead Shark. 
 
 Fam. 12. Pristidse Saw-fish. 
 
 Fam. 13. Rhinobatidse Rhinobates. 
 
 Fam. 14. Torpedinidae Electric Ray. 
 
 Fam. 15. Raiidse Skate. 
 
 Fam. 16. Trygonidse Sting Ray. 
 
 Fam. 17. Myliobatidae Eagle Ray. 
 
 Fam. 18. Cephalopteridae Cephalopterus. 
 
INSECTA. 
 
 Frail and fragile as they may seem, the insect tribes are nevertheless 
 pretty numerously represented in all the formations, from the Coal- 
 measures upwards. The following outline of the leading Orders may 
 assist the student in his discriminations : 
 
 1. Furnished with hard coriaceous jaws or mandibles. 
 
 Order I. HYMENOPTERA, having four membranous veined wings, the 
 anterior the larger ; as the Bee, Humble-bee, Wasp. 
 
 Order II. NEUROPTERA, having four similar membranous reticulated 
 wings, as the Dragon-fly, Termes, Caddis-fly, Day-fly. 
 
 Fossil genera (Libellula, Ephemera, Phryganea, &c.) have 
 been found in the Coal, Oolite, and Tertiaries. 
 
 Order III. ORTHOPTERA, having the wings straight and the outer pair 
 a little coriaceous, as the Locust, Grasshopper, Cock- 
 roach. 
 
 Fossil genera of this order (Blattina, Gryllus, Dictyoneura, 
 &c.) have been found in the Coal, Oolite, and Tertiaries. 
 
 Order IV. COLEOPTERA, having the outer wings wholly coriaceous and 
 neatly meeting along the back, so as to form a sheath or 
 shield for the inner pair when at rest, as in the various 
 Beetles. 
 
 Fossil genera (Carabus, Curculioides, Elater, &c.) have 
 been found in the Coal, Oolite, Wealden, and Tertiaries. 
 37 
 
ANIMAL SCHEME. 
 2. Furnished with sucking mouths and probosces. 
 
 Order V. HEMIPTERA, having the outer wings coriaceous for about 
 half t their length only, as the Squash-bug, or uniformly 
 thin, as in the Crickets. 
 
 Fossil genera are said to occur in the Oolite and Fresh- 
 water Tertiaries. 
 
 Order VI. DIPTEKA, having two membranous wings only, as the House- 
 fly. 
 
 Fossil genera (Asilus, Culex, Rhyphus, &c.) have been found 
 in the Lias and Purbeck beds of England. 
 
 Order VII. LEPIDOPTERA, having large wings covered with minute 
 scales, as the Butterflies and Moths. 
 
 Fossil genera are said to occur in the Tertiaries. 
 
CRUSTACEA. 
 
 (Extinct Families and Genera are pi'inted in Italics.) 
 
 Sub-Class I. ENTOMOSTRACA. 
 Legion 1. LOPHYROPODA. 
 Order 1. COPEPODA. 
 
 Fam. 1. Cyclopidae. 
 Order 2. OSTRACODA. 
 
 Fam. 1. Cyprididae. 
 Genus Cypris. 
 
 Candona. 
 Cypridea. 
 
 Fam. 2. Cytheridae. 
 Genus Cythere. 
 Sub-genus Bairdia. 
 
 Cytheridse. 
 Cythereis. 
 Cytherella. 
 
 Fam. 3. Cypridinidse. 
 Genus Cypridina. 
 Cypridella. 
 Cyprella. 
 Daphnoidea. 
 
 Legion 2. BRANCHIOPODA. 
 Order 1. CLADOCERA. 
 
 Fam. 1. Daphniadae. 
 Genus Daphnia, &c. 
 
 Order 2. PHTLLOPODA. 
 
 Fam. 1. Linnadiadae. 
 Genus Limnadia. 
 Estheria. 
 Leperditia. 
 Beyrichia. 
 Peltocaris. 
 
 Fam. 2. Nebaliadaa. 
 Genus Nebalia. 
 
 Ceratiocaris. 
 
 Hymenocaris. 
 
 Kampecaris. 
 
 Fam. 3. Apodidae. 
 Genus Apus. 
 
 Dithyrocaris. 
 
 Fam. 4. Branchiopodidae. 
 
 Genus Cheirocephalus, &c. 
 Extinct Group. Trilobitce. 
 Fam. flarpedidce. 
 Paradoxidce. 
 Proetidce. 
 Asaphidce. 
 Phacopidce. 
 CalymenidcK. 
 Licliadidce. 
 Trinucleida. 
 Acidaspidce. 
 Cheiruridce. 
 BronteidcK. 
 Agnostidce. 
 
 Legion 3. P(ECILOPODA. 
 
 Fam. 1. Limulidse. 
 
 Genus Limulus, &c. 
 
 Extinct Fam. 2. Eurypteridce. 
 Genus Eurypterus. 
 Pterygotus. 
 Slimonia. 
 Stylonurus. 
 
 Legion 4. SIPHONOSTOMATA. 
 
 Sub-Class II. MALACOSTKACA. 
 Legion 1. PODOPHTHALMIA. 
 Order 1. DECAPODA. 
 
 Fam. 1. Brachyura=Crabs, 
 
 &c. 
 Fam. 2. Anomura= Hermit 
 
 Crab, &c. 
 Fam. 3. Macrura= Lobster, 
 
 ** 
 
 Order 2. STOMAPODA= Squills, &c. 
 Legion 2. EDRIOPHTHALMIA. 
 
 Order 1. AMPHiPODA=Gammar- 
 
 us, &c. 
 Order 2. LCEMIPODA = Caprella, 
 
 &c. 
 Order 3. IsoPODA=Oniscus, &c. 
 
 39 
 
MOLLUSC A. 
 
 (Modified from Woodwards Manual, tlie fossil families and genera 
 being printed in Italics.) 
 
 CLASS I. CEPHALOPODA. 
 
 Order T. DIBRANCHIATA = ACETABULIFERA (CUTTLE-FISHES.) 
 a. OCTOPODA. 
 
 Fam. 1. Argonautidse. Argonauta. 
 
 Fam. 2. Octopodidse. Octopus, Pinnoctopus, Eledone, Cirroteu- 
 this, PMlonexis. 
 
 &. DECAPODA. 
 
 Fam. 3. Teuthidae. Loligo, Gonatus, Sepioteuthis, Beloteuthis, 
 Geoteuthis, Leptoteuthis, Cranchia, Sepiola, Loligopsis, Cheiro- 
 teuthis, Onychoteuthis, Enoploteuthis, Ommastrephes. 
 
 Fam. 4. Belemnitidce. Belemnites, Belemnitella, Acanthoteuthis, 
 Belemnoteuthis, Conoteuthis. 
 
 Fam. 5. Sepiadae. Sepia, Spirulirostra, Beloptera, Belemnosis. 
 
 Fam. 6. Spirulidse. Sptrula. 
 
 Order II. TETRABRANCHIATA=TENTACULIFEBA (NAUTILOID CEPHALOPODS). 
 Fam. 1. Nautilidse. Nautilus, Lituites, Trochoceras, Clymenia. 
 Fam. 2. Ortfioceratidce. Ortkocems, Gomphoceras, Oncoceras, 
 
 Phragmoceras, Cyrtoceras, Gyroceras, Ascoceras. 
 Fam. 3. Ammonitidce. Goniatites, Bactrites, Ceratites, Ammonites, 
 Crioceras, Turrilites, Hainites, Ptychoceras, Baculites. 
 
 CLASS II. PTEROPODA. 
 
 a. THECASOMATA. 
 
 Fam. 1. Hyaleidae. Hyalea, Cleodora, Cuvieria, Theca, Ptero- 
 
 theca, Conularia, Eurybia, Cymbulia, Tiedemannia. 
 Fam. 2. Limacinidse. Limacina, Spirialis. 
 
 b. GYMNOSOMATA. 
 
 Fam. 3. Cliidse. Clio, Pneumodermon, Pelagia, Cymodocea. 
 40 
 
ANIMAL SCHEME. 
 
 CLASS TIL GASTEROPODA. 
 Order I. PROSOBRANCHIATA. 
 
 a. SlPHONOSTOMATA. 
 
 Fam. 1. Strombidae. Strombus, Pteroceras, Rostellaria, Seraphs. 
 
 Fam. 2. Muricidse. Murex, Pisania, Ranella, Triton, Fasciolaria, 
 Turbinella, Cancellaria, Trichotropis, Pyrula, Fusus. 
 
 Fam. 3. Buccinidse. Buccinum, Pseudoliva, Anolax, Halia, Tere- 
 bra, Eburna, Nassa, Phos, Ringicula (?), Purpura, Purpurina, 
 Monoceros, Pedicularia, Ricinula, Planaxis, Magilus, Cassis, 
 Oniscia, Cithara, Cassidaria, Dolium, Harpa, Columbella, 
 Oliva, Ancillaria. 
 
 Fam. 4. Conidae. Conus, Pleurotoma. 
 
 Fam. 5. Volutidae. Voluta, Cymba, Mitra, Volvaria, Marginella. 
 
 Fam. 6. Cypraeidae. Cyprsea, Erato, Ovulum. 
 
 &. HOLOSTOMATA. 
 
 Fam. 1. Naticidse. Natica, Sigaretus, Lamellaria, Narica, Vel- 
 
 utina. 
 Fam. 2. Pyramidellidae. Pyramidella, Odostomia, Chemnitzia, 
 
 Eulima, Stylina, Loxonema, Macrocheilus. 
 Fam. 3. Cerithiadae. Cerithium, Potamides, Nerincea, Fastigiella, 
 
 Aporrhais, Struthiolaria. 
 
 Fam. 4. Melaniadae. Melania, Paludomus, Melanopsis. 
 Fam. 5. Turritellidae. Turritella, Aclis, Caacum, Vermetus, Sili- 
 
 quaria, Scalaria. 
 Fam. 6. Litorinidse. Litorina, Solarium, Phorus, Lacuna, Litiopa, 
 
 Rissoa, Skenea, Truncatella (?), Lithoglyphus. 
 Fam. 7. Paludinidas. Paludina, Ampullaria, Amphibola, Valvata. 
 Fam. 8. Neritidse. Nerita, Pileolus, Neritina, Navicella. 
 Fam. 9. Turbinidaa. Turbo, Phasianella, Imperator, Trochus, 
 
 Rotella, Monodonta, Delphinula, Adeorbis, Euomphalus, Sto- 
 
 matella, Broderipia. 
 Fam. 10. Haliotis. Haliotis, Stomatia, Scissurella, Pleurotomaria, 
 
 Murchisonia, Trochotoma, Cirrus, lanthina. 
 Fam. 11. Fissurellidaa. Fissurella, Puncturella, Rimula, Emar- 
 
 ginula, Parmophorus. 
 Fam. 12. Calyptraeidse. Calyptraea, Crepidula, Pileopsis, Hippo- 
 
 nyx. 
 
 Fam. 13. Patellidse. Patella, Acmaea, Gadinia, Siphonaria. 
 Fam. 14. Dentaliadae. Dentalium. 
 Fam. 15. Cbitonidae. Chiton. 
 
 Order II. PULMONIFERA. 
 
 a. INOPERCULATA. 
 
 Fam. 1. Kelicidse. Helix, Vitrina, Succinea, Bulimus, Achatina, 
 
 Pupa, Cylindrella, Balea, Tornatellina, Paxillus, Clausilia. 
 Fam. 2. Limacidae. Limax, Incilaria, Arion, Parmacella, Tes- 
 
 tacella. 
 
 Fam. 3. Oncidiadae. Oncidium, Vaginulus. 
 41 
 
ANIMAL SCHEME. 
 
 Fam. 4. Limnseidse. Limnsea, Cbilinia, Physa, Ancylus, Plan- 
 
 orbis. 
 Fam. 5. Auriculidse. Auricxila, Conovulus, Carychium (Siphon - 
 
 aria). 
 b. OPERCULATA. 
 
 Fam. 6. Cyclostomidse. Cyclostoma, Ferussina (?), Cyclophorus, 
 
 Pupina, Helicina, Stoastoma. 
 Fam. 7. A.ciculidse. Acicula, Geomelania. 
 
 Order III. OPISTHOBRANCHIATA. 
 
 a. TECTIBRANCHIATA. 
 
 Fam. 1. Tornatellidse. Tornatella, Cinulia, Ringicula, Globicon- 
 
 cha, Varigera, Tylostoma, Pterodonta (?), Tornatina (?). 
 Fam. 2. Bullidse. Bulla, Acera, Cylichna, Ampbispbyra, Aplus- 
 
 trum, Scapbander, Bullsea, Doridium, Gastropteron. 
 Fam. 3. Aplysiadse. Aplysia, Dolabella, Notarcbus, Icarus, Lo- 
 
 biger. 
 Fam. 4. Pleurobrancbida. Pleurobrancbus, Posterobranchsea, 
 
 Runcina, Umbrella, Tylodina. 
 Fam. 5. Pbyllidiadse. Pbyllidia, Dipbyllidia. 
 
 b. NUDIBRANCHIATA. 
 
 Fam. 6. Doridae. Doris, Goniodoris, Triopa, ^Egirus, Thecacera, 
 
 Polycera, Idalia, Ancula, Ceratosoma. 
 Fam. 7. Tritoniadae. Tritonia, Scyllsea, Tetbys, Bornella, Den- 
 
 dronotus, Doto, Melibaea, Lomanotus. 
 Fam. 8. uEolidse. uEolis, Glaucus, Fiona, Embletonia, Procton- 
 
 otus, Antiopa, Hermaea, Alderia. 
 Fam. 9. Phyllirboidse. Pbyllirhoe. 
 Fam. 10. Elysiadse. Elysia, Acteonia, Cenia, Limapontia. 
 
 Order IV. NUCLEOBRANCHIATA. 
 
 Fam. 1. Firolidse. Firola, Carinaria, Cardiapoda. 
 Fam. 2. Atlantidse. Atlanta, Porcellia, Bellerophon, Cyrtolites, 
 Maclurea (?). 
 
 CLASS IV. ACEPHALA = CONCHIFERA. 
 
 a. ASIPHONIDA. 
 
 Fam. 1. Ostreidse. Ostrea, Anomia, Placuna, Pecten, Lima, Spon- 
 
 dylus, Pedum, Plicatula. 
 Fam. 2. Aviculidae. Avicula, Posidonomya, Aviculopecten, Ger- 
 
 villia, Pema, Inoceramw, Pinna. 
 Fam. 3. Mytilidae. Mytilus, Myalina, Modiola, Lithodomus, 
 
 Crenella, Dreissena. 
 Fam. 4. Arcadse. ^Arca, Cucullsea, Pectunculus, Limopsis, Nu- 
 
 cula, Isoarca, Leda, Solenella, Solemya. 
 
 Fam. 5. Trigoniadse. Trigonia, Myophoria, Aximis, Lyrodesma. 
 Fam. 6. Unionidae. Unio, Castalia, Anodon, Iridina, Mycetopus, 
 
 ^Etheria, Miilleria. 
 
 b. SIPHONIDA ; Integro-pallialia. 
 
 Fam. 7. Chamidae. Cbama, Monopleura, Diceras, Requienia. 
 42 
 
ANIMAL SCHEME. 
 
 Fam. 8. ffippuritidce.Hippurites, Radiolites, Caprinella, Cap- 
 rina, Caprotina, Maclurea (?). 
 
 Fam. 9. Tridacnidae. Tridacna, Hippopus. 
 
 Fam. 10. Cardiadae. Cardium, Hemicardium, Lithocardium, Ser- 
 ripes, Adacna, Conocardium. 
 
 Fam. 11. Lucinidse. Lucina, Cryptodon, Corbis, Tancredia, Dip- 
 lodonta, Ungulina, Kellia, Montacuta, Lepton, Galeomma. 
 
 Fam. 12. Cycladidse. Cyclas, Cyrenoides, Cyrena. 
 
 Fam. 13. Cyprinidae. Cyprina, Circe, Astarte, Crassatella, Iso- 
 cardia, Cypricardia, Pleurophorus, Cardilia, Megalodon, Pa- 
 chydomus, Pachyrisma, Opis, Cardinia, Myoconcka, Hippo- 
 podium, Cardita, Venericardia, Verticordia. 
 
 c. SIPHONIDA ; Simu-pallialia. 
 
 Fam. 14. Veneridae. Venus, Cytherea, Meroe, Trigona, Gratelou- 
 
 pia, Artemis, Lucinopsis, Tapes, Venerupis, Petricola, Glau- 
 
 comya. 
 
 Fam. 15. Mactridse. Mactra, Gnathodon, Lutraria, Anatinella. 
 Fam. 16. Tellinidae. Tellina, Diodonta, Capsula, Psammobia, 
 
 Sanguinolaria, Semele, Syndosmya. Scrobicularia, Mesodes- 
 
 ma, Ervilia, Donax, Galatea. 
 Fam. 17. Solenidse. Solen, Cultellus, Ceratisolen, Machsera, Sole- 
 
 curtus, Novaculina. 
 Fam. 18. Myacidae. Mya, Corbula, Sphenia, Nesera, Thetis, Pan- 
 
 opsea, Saxicava, Glycimeris. 
 Fam. 19. Anatinidae. Anatina, Cochlodesma, Thracia, Pkola- 
 
 domya, Myadtes, Goniomya, Ceromya, Cardiomorpha, Ed- 
 
 mondia, Lyonsia, Pandora, Myadora, Myochama, Chamos- 
 
 trea. 
 Fam. 20. Gastrochaenidae. Gastrochaena, Chsena, Clavagella, As- 
 
 pergillum. 
 Fam. 21. Pholadidae. Pholas, Pholadidea, Jouannetia, Xylopha- 
 
 ga, Teredo, Teredina. 
 
 CLASS V. BRACHIOPODA. 
 
 Fam. 1. Terebratulidae. Terebratula, Terebratella, Argiope, The- 
 
 cidium, Stringocephalus. 
 
 Fam. 2. Spiriferidce. Spirifera, Athyris, Retzia, Uncites. 
 Fam. 3. Khynchonellidae. Rhynchonella, Camarophoria, Penta- 
 
 merus, Atrypa. 
 Fam. 4. Orthidce. Orthis, Strophoniena, Leptcena, Koninckia, 
 
 Davidsonia, Calceola. 
 
 Fam. 5. Productidce. Producta, Aulosteges, StropJialosia, Chonetes. 
 Fam. 6. Craniadaa. Crania. 
 Fam. 7. Discinidse. Discina, Siphonotreta. 
 Fam. 8. Lingulidae. Lingula, Obolus. 
 
 *+* All the Brachiopodous families occur largely in a fossil state ; the 
 genera, species, and individuals, being much more abundant in Palaeozoic 
 than in Mesozoic or Cainozoic times. 
 
 43 
 
MOLLUSCOIDA. 
 
 CLASS I. TUNICATA : doubtfully known in a fossil state. 
 
 CLASS II. BRYOZOA or POLYZOA. 
 
 Fam. 1. Escharidae. Eschara, Ptilodictya, Glauconome, Lunulites, 
 
 Vincularia. 
 Fam. 2. Celleporidae. Cellepora, Flustra Lepralia, Discopora, 
 
 Escharina. 
 Fam. 3. Reteporidse. Retepora, Fmestella, Polypora, Phyllo- 
 
 pora, Ptilopora, Synocladia. 
 Fam. 4. Crisidse. Crisia, Idtnonea, Hippothoa. 
 Fam. 5. Myriaporidce. Fascicularia, Terebellaria, Theonoa. 
 Fam. 6. Tubuliporidse. Tubulipora, Heteropora, Ceriopora, Ac- 
 
 tinopora, Diastopora, Cricopora, Petallopora, Pustulo- 
 
 pwa, Zonopwa. 
 
 44 
 
ECHINODERMATA. 
 
 (Fossil Families and Examples printed in Italics.) 
 
 Order I. CRINOIDEA. 
 
 Examples. 
 
 Fam. 1. Comatulidse Comatula. 
 
 Fam. 2. Marsupitidce Marsupites. 
 
 Fam. 3. Apiocrinidce Apio(rinus,Bourgueticriniis,Mttlericrinus. 
 
 Fam. 4. Pentacrinidae Pentacrinus, Extracrinus, Cainocrinus. 
 
 Fam. 5. Cyathocrinidce Cyathocrinus, Poteriocrinus, Rhodocrinus, 
 
 Taxocrinus. 
 
 Fam. 6. Melocrinidae Actinocrinu^, Hexacrinus, Platycrinus. 
 
 Fam. 7. Cupressocrinidce Cupressocrimis. 
 
 Fam. 8. Polycrinidce JEucalyptoci-inus. 
 
 Order II. CYSTOIDEA. 
 
 Fam. 1. Cystidce Pseudocrinites, ffemicosmites, Caryotistites, 
 
 Echinosphcerites. 
 
 Order III. BLASTOIDEA. 
 Fam. 1. Penlremitidce Pentremites, Codonaster, Elceacrinus. 
 
 Order IV. OPHIUROIDEA. 
 
 Fam. 1. Ophiuridae Ophiura, Amphiura, Aspidura, Ophio- 
 
 derma, Protaster. 
 
 Order V. AsTERoroEA. 
 
 Fam. 1. Asteridse Asterias, Astropecten, Ooniaster, Or easier, 
 
 Solaster, Uraster. 
 Fam. 2. Crenasteridae Crenaster, Euryale. 
 
 Order VI. PERISCHO-ECHINOrDEA. 
 
 Fam. 1. Palcechinidce Palcechinus. 
 
 Fam. 2. Archceocidaridoe ArcluKoddaris, Perischodomus. 
 
 45 
 
ANIMAL SCHEME. 
 
 Examples. 
 Order VII. ECHINOIDEA. 
 
 Fam. 1. Echinidse Echinus, CypJiosoma, Diadema, Discoidea, 
 
 Echinopsis, Hemiaster, Hemicidaris, Sa- 
 
 Fam. 2. Cidaridse Cidaris. 
 
 Fam. 3. Galeritidce Galerites ) Dysaster,Holectypus,Hyboclypus. 
 
 Fam. 4. EcMnoneidce EcMnocyamus, Echinarachnius. 
 
 Fam. 5. Cassidulidae Nucleolites, Pygaster, Py gurus. 
 
 Fam. 6. Ananchytidce Ananchytes, Cardiaster, Hemipneustes. 
 
 Fam. 7. Spatangidae Spatangus, Micraster, Schizaster. 
 
 Order VIII. HOLOTHUROIDEA. 
 
 Fam. 1. Holothuridse Holothuria, Psolus. 
 
 Fam. 2. Synaptidse Synaptis. 
 
 40' 
 
ZOOPHYTA. 
 
 POLYPI = ANTHOZOA= CCELENTERATA. 
 
 (Fouil Families and Examples printed in Italics.) 
 
 Sub-class I. CORALLARIA = ACTINOZOA. 
 Order I. ZOANTHARIA. 
 
 Sect. a. APOROSA. 
 
 Fam. 1. Turbinolidcu. Turbinolia, Cyathina, Cyclocyathus, Disco- 
 
 cyaihus. 
 
 Fam. 2. Oculinidse. Oculina, Diphelia, Synhelia. 
 Fam. 3. Astraeidse. Astrsea, Cladophyllia, Montlivaltia, Paras- 
 
 milia. 
 Fam. 4. Fungidae. Fungia, Anabacia, Micrabacia. 
 
 Sect. 6. PERFORATA. 
 
 Fam. 1. Eupsammidaa. Balanophyllia, Stephanophyllia. 
 Fam. 2. Madreporidae. Stereopsammia, Dendrophyllia. 
 Fam. 3. Poritidse. ffolorcea, Litharcea, Pleurodictyum. 
 
 Sect. c. TABULATA. 
 
 Fam. 1. Milleporidse. Millepora, Astrceopora, Heliolites. 
 Fam. 2. Favositidse. Favosites, Alveolites, Chaetetes, Halysites. 
 Fam. 3. Seriatoporidse. Dendropora. 
 Fam. 4. Thecidae. Thecia, Columnaria. 
 
 Sect. d. RUGOSA. 
 
 Fam. 1. Stauridce. Stauria, Polyccelia, Holocystis. 
 
 Fam. 2. Cyathoxonidce. Cyathoxonia. 
 
 Fam. 3. Cyatkophyllidce. Cyathophyllum, Acervularia, Amplexus, 
 
 Clisiophyllum, Lithodendron, Lithostrotion, Zaphrentis, &c. 
 Fam. 4. Cystiphyllidce. Cystiphyllum. 
 
 Sect. e. CAULICULATA. 
 
 Fam. 1. Antipathidae. Antipathes. 
 47 
 
ANIMAL SCHEME. 
 
 Order II. ALC YON ARIA. 
 
 Fam. 1. Alcyonidse. Alcyonium, Cladochonus. 
 Fam. 2. Tubiporidse. Tubipora, Stromatopora. 
 Fam. 3. Gorgonidae. Gorgonia, Mopsea, Pyritonema, Virgularia, 
 
 Protwirgularia. 
 Fam. 4. Graptolitida.Graptolithus, Didymograpsus, Diplograp- 
 
 sus, Rastrites. 
 Fam. 5. Pennulatidae. Pennatula, Graphnlaria. 
 
 Order III. POD ACTIN ARIA. 
 
 Sub-class II. HYDROIDEA=HYDROZOA. 
 
 Fam. 1. Hydridse. Hydra. 
 
 Fam. 2. Sertularidse. Sertularia. 
 
 Fam. 3. Corynidse. Coryne. 
 
 Fam. 4. Calycophoridse. 
 
 Fam. 5. Physophoridse. 
 
 Fam. 6. Lucernidae. Lucernaria. 
 
 Fam. 7. Medusidse. Medusa, Cyansea, Equorea. 
 
 43 
 
PORIFERA = AMORPHOZOA = SPONGLE. 
 
 (Sponge-like organisms occurring most abundantly in British formations.) 
 
 Fam. AMORPHOSPONGIDJE. 
 Gen. Acanthospongia. 
 Achilleum. 
 Plocoscyphia. 
 Spongia. 
 Steganodictyum. 
 Talpina. 
 Tragos. 
 
 Fam. CALCISPONQID^:. 
 Gen. Grantia. 
 
 Fam. HALICHONDRID^;. 
 Gen. Cliona. 
 
 Cnemidium. 
 
 Cceloptychium. 
 
 Corn's. 
 
 Coscinopora. 
 
 Halichondria. 
 
 Fam. LYMNOREHXE. 
 Gen. Mammillopora. 
 
 Fam. SPARSISPONGID^B. 
 Gen. Chenendopora. 
 Manon. 
 
 Fam. SiPHONiD2B. 
 Gen. Choanites. 
 Hippalimus. 
 Jerea. 
 
 Paramondra. 
 Polypothecia. 
 Scyphia. 
 Siphonia. 
 VerticUlites. 
 
 Fam. VENTRICULIDJE. 
 Gen. Brachiolites. 
 Cephalites. 
 Guettardia. 
 Ventriculites. 
 
 49 
 
RHIZOPODA = POLYTHALAMIA = FOUAMINIFERA. 
 
 (Foraminifera whose calcareous cases occur most a 
 British strata}. 
 
 Ord. 1. MONOSTEGIA. 
 
 Operculina. 
 
 Gen. Lagena. 
 
 Planorbulina. 
 
 
 Planulina. 
 
 Ord. 2. CYCLOSTEGIA. 
 
 Pyrulina. 
 
 Gen. Orbiculina. 
 
 Kobulina. 
 
 Orbitalina. 
 
 Kosalina. 
 
 Orbitolites. 
 
 Rotalina. 
 
 Ord. 3. STICHOSTEGIA. 
 
 Spirolina. 
 
 Gen. Dentalina. 
 
 Truncatulina. 
 
 Frondicularia. 
 
 Verneulina. 
 
 Glandulina. 
 
 Ord. 5. ENTOMOSTEGIA. 
 
 Lingulina. 
 Marginulina. 
 
 Gen. Amphistegina. 
 Robertina. 
 
 Nodosaria. 
 
 
 Vaginulina. 
 
 Ord. 6. ENALLOSTEGIA. 
 
 Webbina. 
 
 Gen. Cuneolina. 
 
 
 Globulina. 
 
 Ord. 4. HELICOSTEGIA. 
 
 Guttulina. 
 
 Gen. Alvelolina. 
 Anomalina. 
 Bulimina. 
 
 Polymorphina. 
 Sagrina. 
 Textularia. 
 
 Cristellaria. 
 
 Vulvulina. 
 
 Eudothyra. 
 
 
 Flabellina. 
 
 Ord. 7. AGATHESTEGIA. 
 
 Guadryina. 
 
 Gen. Biloculina. 
 
 Globigerina. 
 
 Fusulina. 
 
 Lituola. 
 
 Quinqueloculina. 
 
 Nonionina. 
 
 Spiroloculina. 
 
 Nummulites. 
 
 Triloculina. 
 
 %* The Polycystina, an allied group, are furnished with siliceous and 
 not with calcareous shells. 
 
 50 
 
GEOLOGICAL SCHEME. 
 
 All our ideas of geological arrangement are founded on the fact, that in 
 the earth's crust there are two great sets of rocks, the STRATIFIED and the 
 UNSTRATIFIED the former the results of deposition in water, and hence 
 also known as Aqueous and Sedimentary, the latter the products of igneous 
 fusion, and consequently termed igneous and eruptive, thus : 
 
 I. STRATIFIED, SEDIMENTARY, AQUEOUS, or NEPTUNIAN the results of 
 
 deposition in water, and consequently arranged in layers or strata 
 more or less persistent and regular, as sandstone, shale, limestone, 
 coal, and the like. 
 
 II. UNSTRATIFIED, ERUPTIVE, IGNEOUS, or PLUTONIC the products of 
 igneous fusion, and cast forth, for the most part, in irregular and 
 amorphous masses, as granite, greenstone, basalt, lava, and the like. 
 
 The following arrangement of the STRATIFIED FORMATIONS is that which 
 gave direction and consistency to the researches of British Geologists 
 during the earlier portion of the present century is still, in part, retained 
 in its nomenclature, and continues less or more to influence our ideas of 
 succession and chronology : 
 
 RECENT. All superficial accumulations, as sand, gravel, silt, marl, 
 peat-moss, coral-reefs, &c. Contain the remains of existing plants 
 and animals only partially fossilised or sub-fossil. 
 
 TERTIARY. Local and limited deposits of regular strata occurring 
 above the Chalk. Contain the remains of plants and animals not 
 differing ividely in character from those now existing. 
 
 SECONDARY. Embracing all the strata known as Chalk, Oolite, Lias, 
 Coal-measures, Mountain Limestone, and Old Red Sandstone. 
 Contain fossil plants and animals of species totally different from 
 those now existing. 
 
 TRANSITION. Strata of slaty and siliceous sandstones, known as 
 "greywacke," calcareous shales, and limestones. Contain few 
 or no fossil plants, and the remains of no higher animals than 
 Crustacea, shell-fish, and zoophytes. 
 
 PRIMARY. All slaty and crystalline strata as roofing-slate, mica- 
 schist, and gneiss, very hard and compact, and totally destitute 
 of organic remains. 
 
 51 
 
GEOLOGICAL SCHEME. 
 
 Although the Igneous rocks burst through and appear among the strati- 
 fied without order or arrangement, it is customary to speak of them as 
 GRANITIC, TRAPPEAN, and VOLCANIC ; meaning, by the term Granitic, the 
 igneous rocks which, like granite, are usually found associated with the 
 older strata ; by the term Trappean, the igneous rocks most frequently 
 associated with the Secondary and Tertiary strata ; and by the term Vol- 
 canic, those that have made their appearance during the current epoch. 
 Classifying them according to this view, we have 
 
 VOLCANIC. Lava, trachyte, tufa, pumice, scoriae, &c., associated 
 with recent accumulations. 
 
 TRAPPEAN. Trap-tuff, amygdaloid, greenstone, basalt, &c., as- 
 sociated for the most part with Tertiary and Secondary strata. 
 
 GRANITIC. Granite, syenite, porphyry, &c., associated in greatest 
 force with Transition and Primary strata. 
 
 By a more extensive examination of the strata in different countries, 
 and especially by a more minute investigation of their fossil contents, the 
 " formations " of the earlier geologists have, to a certain extent, become 
 obsolete, and other subdivisions and groupings been adopted. This new 
 arrangement has been founded either on mineral or on fossil distinctions 
 such differences being sufficient to warrant the conclusion that each set 
 of strata was formed during successive epochs, under different distributions 
 of sea and land, and consequently under different conditions of climate and 
 other modifying influences; and as geological investigation advances, it 
 is more than probable that we must still farther abandon our Rock Forma- 
 tions, and adhere to great Life Periods as the true exponents of the world's 
 progress and history. In the mean time the following arrangement gives 
 consistency to the researches of European and American geologists : 
 
 Systems. Periods. Cycles. 
 
 1. Post-Tertiary. | CAINOZOIC 
 
 2. Tertiary. J (Recent Life). 
 
 3. Cretaceous. \ ) NEOZOIC. 
 
 4. Oolitic or Jurassic. V MESOZOIC 
 
 5. Triassic. j (Middle Life). 
 
 6. Permian. 
 
 7. Carboniferous. 
 
 8. Devonian or Old Eed. 
 
 9. Silurian. 
 
 PALJEOZOIC 
 (Ancient Life). 
 
 10. Cambrian. ^ PALEOZOIC. 
 
 11. Lauren tian. 
 
 12. Metamorphic, \ 
 
 Crystalline, or V T Az< ? I T ., , 
 
 Non-fossiliferous. f (Void of Life). 
 
 52 
 
GEOLOGICAL SCHEME. 
 
 BEITISH STKATIFIED SYSTEMS. 
 
 The following tabulation exhibits the arrangement of the British stratified 
 rocks, as accepted by our leading geologists minor and local deviations 
 of superposition being subordinated for the sake of distinct comprehen- 
 sion and ready reference : 
 
 Systems. Groups. Periods. 
 
 POST-TERTIARY, j * n P ro ^ ress - 
 ( Recent. 
 
 
 
 I 
 TERTIARY. 
 
 Pleistocene. 
 Pliocene. 
 Miocene. 
 
 CAINOZOIC. 
 
 5:3 
 
 
 Eocene. 
 
 
 
 
 
 CRETACEOUS. j halk ' 
 ( Greensand. 
 
 
 > 
 o 
 
 o 
 
 
 
 Wealden. 
 
 
 
 
 OOLITIC. 
 
 Oolite. 
 
 
 o 
 
 
 
 Lias. 
 
 , MESOZOIC. 
 
 i 
 
 
 ( Saliferous Marls. 
 
 
 
 r*\ 
 
 TRIASSIC. j Muschelkalk (?). 
 
 
 
 1 
 
 ( Upper New Red Sandstone. 
 
 
 
 
 
 PERMIAN _f ^agnesian Limestone. ^ 
 
 *. 
 
 
 fej 
 
 ( Lower New Red Sandstone. 
 
 
 
 
 
 Coal-measures. 
 
 
 
 ft. 
 
 CARBONIFEROUS. 
 
 Millstone Grit. 
 
 
 
 3 
 
 
 Mountain Limestone. 
 
 
 
 8 
 
 
 Lower Coal-measures. 
 
 
 
 ^ 
 
 
 Yellow Sandstones. 
 
 
 
 
 
 
 Devonian Limestones and 
 
 
 s 
 
 ^ ^ 
 
 
 Schists. 
 
 
 
 
 1 
 
 DEVONIAN. 
 
 Red Sandstones, Conglom- 
 
 PALEOZOIC. 
 
 6 
 
 1 
 
 
 erates, and Cornstones. 
 
 
 o 
 
 fc 
 
 
 Grey fissile Sandstones 
 
 
 
 
 
 
 
 (" flags tones") and Con- 
 
 
 o 
 
 ft? 
 
 
 glomerates. 
 
 
 3 
 
 * 
 
 ( Upper Silurian. 
 SILURIAN. J Lower Silurian. 
 
 
 2 
 
 RQ 
 
 CAMBRIAN. Schists and Grits. 
 
 
 
 J| 
 
 LAURENTIAN. Hard Gneissic Schists, &c.^ 
 
 
 
 OH 
 
 METAMORPHIC. 
 
 Clay -slate, Mica -schist, ) A 
 _ , , i f AzoiC) OK 
 Gneiss, and Granitoid J HYPOZOIC 
 
 Schists. 
 
 
 53 
 
GEOLOGICAL SCHEME. 
 
 TABLE OF EUROPEAN FOSSILIFEROUS STRATA. 
 
 (After Sir Charles Lyell, 1865.) 
 
 1. Becent. 
 
 2. Post-Pliocene. 
 
 3. Newer Pliocene. 
 
 4. Older Pliocene. 
 
 5. Upper Miocene. 
 
 6. Lower Miocene. 
 
 7. Upper Eocene. 
 
 8. Middle Eocene. 
 
 9. Lower Eocene. 
 
 10. Maestricht Beds. 
 
 11. White Chalk. 
 
 12. Upper Greensand. 
 
 13. Gault. 
 
 14. Lower Greensand. 
 
 15. Wealden. 
 
 16. PurbeckBeds. 
 
 17. Portland Stone. 
 
 18. Kimmericlge Clay. 
 
 19. Coral Bag. 
 
 20. Oxford Clay. 
 
 21. Great or Bath Oolite. 
 
 22. Inferior Oolite. 
 
 23. Lias. 
 
 24. Upper Trias. 
 
 25. Middle Trias. 
 
 26. Lower Trias. 
 
 27. Permian. 
 
 28. Coal-measures. 
 
 29. Carboniferous Limestone. 
 
 30. Upper \ 
 
 31. Middle > Devonian. 
 
 32. Lower ) 
 
 33. Upper \ 
 
 34. Middle V Silurian. 
 
 35. Lower J 
 
 POST-TERTIARY. 
 PLIOCENE. 
 MIOCENE. 
 EOCENE. 
 
 CRETACEOUS. 
 
 3 
 
 63 <! 
 
 'JURASSIC. 
 
 > TRIASSIC. 
 
 PERMIAN. 
 1 CARBONIFEROUS. 
 
 DEVONIAN. 
 
 SILURIAN. 
 CAMBRIAN. 
 
 LAURENTIAN. 
 54 
 
GEOLOGICAL SCHEME. 
 
 AGES GEOLOGIQUES. 
 
 (After D'Orbigny, 1852.) 
 
 Terrains. 
 EPOQUE ACTUELLE. 
 
 British Equivalent*. 
 CURRENT EPOCH. 
 
 27. Subapennin Red and Coralline Crag of 
 
 Suffolk. 
 
 |26. Falunien 
 
 TERTJARIES ] ^' -P a " s ^ en Upper and Middle Eocenes' 
 
 \ 24. Suessonien Lower Eocene. 
 
 \23.Danien 
 
 22. Senonien Upper White Chalk. 
 
 21. Turonien Lower White Chalk. 
 
 20. Ce"nomanien Upper Greensand. 
 
 CRETACES. 19.Albien Gault. 
 
 1 8. Aptien Lower Greensand, in part. 
 
 17. Ne'ocomien Do. and Wealden. 
 
 16. Portlandien Portland Group. 
 
 (15. Kimme'ridgien Kimmeridge Clay. 
 
 14. Corallien Coral Rag. 
 
 1 3. Oxf ordien Oxford Clay. 
 
 12. Callovien Kelloway Rock. 
 
 JURASSIQUES. 11. Bathonien Bath Oolite. 
 
 10. Bajocien Inferior Oolite. 
 
 9. Toarcien Upper Lias. 
 
 8. Liasien Middle Lias; Marlstone. 
 
 7. Sinemurien Lower Lias. 
 
 6 . Salif Srien Salif erous Marls. 
 
 TRIASIQUES. 1 5. Conchylien Variegated Sandstones, in 
 
 part ; Upper New Red. 
 
 4. Permien Magnesian Limestone, &c. 
 
 PAL^EOZOIQUES. -j 3. Carboniferien Coal-Measures. 
 
 2. Devonien Old Red Sandstone. 
 
 SupeYieur Upper Silurian. 
 
GEOLOGICAL SCHEME. 
 
 STRATIFIED ROCKS OF NORTH AMERICA. 
 
 Stages. 
 UPPER. 
 LOWER. 
 
 UPPER. 
 
 MIDDLE. 
 
 LOWER. 
 
 UPPER. 
 LOWER. 
 
 UPPER. 
 MIDDLE. 
 
 LOWER. 
 
 UPPER. 
 MIDDLE. 
 
 LOWER. 
 
 UPPER. 
 
 MIDDLE. 
 LOWER. 
 
 (After Marcou, Bigsby, and Logan.) 
 
 Sections. 
 
 ( Peat-Mosses and Savannahs. ) 
 
 t River Alluvia and Deltas. \ 
 
 Superficial Gravels and Raised Beaches. J 
 
 J Boulder Formation of the Northern ^ 
 \ States and Canada. 
 ( Clays and Sands of North Carolina, &c. I 
 \ Greensand and Marls of Maryland, &c. / 
 j Limestones and Clays of the Carolinas, I 
 1 &c. J 
 
 Yellow Limestone and Greensand of) 
 New Jersey, &c. j 
 
 Sandstones, Shale, and Coal of Rich-) 
 mond, Virginia. J 
 
 Red Sandstones of Connecticut, Mass. &c. 
 ( Do. of Chatham, N. Caro- ) 
 
 t Una, &c. I 
 
 Coal-formation or Coal-measures. \ 
 
 Lower Carboniferous Limestone. 
 ( Sandstones and Conglomerates of Penn- V 
 \ sylvania. ' 
 
 \ Gypsum, Marls, and Conglomerates of 
 V Nova Scotia. 
 
 Old Red Sandstone. 
 ( Chemung Rocks ; Portage Sandstone ; 
 
 < Genessee Slate ; Tully Limestone ; 
 ( Hamilton Rocks ; Marcellus Shales. 
 /Carboniferous Limestone; Onondago 
 
 < Limestone ; Schoharie Grit ; Caudi- 
 ( galli Grit ; Oriskany Limestone. 
 
 Ajpper Pentamerus Limestone ; Delthy- 
 I ris shaly Limestone ; Lower Penta- 
 1 merus Limestone ; Waterlime Rocks ; 
 \ Onondago Salt Rock ; Coralline Lime- 
 j stone, Schoharie ; Niagara Shale and 
 \ Limestone. 
 
 ( Clinton Rocks ; Medina Sandstone ; 
 ( Oneida Conglomerate. 
 / Hudson-River Rocks ; Utica Slate ; 
 ) Trenton Limestone ; Birdseye Lime- 
 j stone ; Chazy Limestone ; Calcifer- 
 ^ ous Sandstone ; Potsdam Sandstone. 
 
 Huronian Sandstones ; Conglomerates ; ") 
 Chloritic and Quartzose Schists ; Crys- > 
 talline Limestones. J 
 
 Laurentian Gneissoid and Hornblende } 
 Schists ; Quartzites, Crystalline Lime- \- 
 stones, and Serpentines. J 
 
 56 
 
 British Equivalents. 
 
 POST-TERTIARY. 
 
 TERTIARY. 
 
 CRETACEOUS. 
 
 OOLITIC (?). 
 
 TRIASSIC (?). 
 PERMIAN (?). 
 
 CARBONIFEROUS. 
 DEVONIAN. 
 
 ) SILURIAN. 
 
 CAMBRIAN. 
 
 LAURENTIAN. 
 
GEOLOGICAL SCHEME. 
 
 PALAEOZOIC KOCKS OF PENNSYLVANIA. 
 
 (After Professor H. 1>. Rogers, 1859.) 
 
 Appalachian New York British Equivalents, 
 
 Series. Names. 
 
 (Serai, 
 
 < Umbral, ^CARBONIFEROUS. 
 
 (.Vespertine, 
 
 Ponent, Catskill Group. ^ 
 
 Vergent, Chemung Group. 
 
 Cadent, Hamilton Group. \DEVONIAN. 
 
 Post-Meridian, ... Upper Helderberg Limestone, i 
 
 Meridian, Oriskany Sandstone. 
 
 Pre-Meridian, ... Lower Helderbei 
 Scalent, Niagara Group. 
 
 Pre-Meridian, ... Lower Helderberg Limestone. N 
 
 Surgent, Clinton Group. ' SlLDRIAN - 
 
 Levant, Medina Group. 
 
 
 ( Matinal, Hudson and Trenton Riv. Gr. 
 
 ( Blue River, Chazy, and Calci- I _ 
 (Auroral, \ , /CAMBRIAN. 
 
 ffirnns SnTinsinTio l-lrniina i 
 
 
 ferous Sandstone Groups. 
 Primal, Potsdam Sandstone. 
 
 " These fifteen formations, or series of deposits," says Professor Rogers, 
 " defined by their prevalent organic remains, and by the physical horizons 
 which separate them as sediments, are called by names significant of their 
 relative ages the words employed suggesting metaphorically the different 
 periods of the day. Thus, beginning with the lowest or earliest, they 
 mean respectively Dawn, Daybreak, Morning, Sunrise, Mounting-day, 
 Climbing-day, Forenoon, Noon, Afternoon, Declining-day, Descending-day, 
 Sunset, Evening, Dusk, and Nightfall. Some such nomenclature, based on 
 time, is, for many reasons, preferable to the inexpressive ones which rest 
 for the most part on geographical terms, only locally correct, or on narrow 
 and inconstant palaeontological characters." 
 
 57 
 
GEOLOGICAL SCHEME. 
 
 CONTEMPORARY OR EQUIVALENT DEPOSITS. 
 
 I. PO'ST-TERTIAKY OR QUATERNARY SYSTEM. 
 
 HISTORIC. 
 
 PREHISTO- 
 RIC. 
 
 British. 
 
 Peat of Great Britain and 
 Ireland, with human re- 
 mains, &c. 
 
 Fens, marshes, and river- 
 deposits, with ancient 
 canoes, implements, &c. 
 
 Lake -silts, fresh -water 
 marls, &c., with canoes, J 
 metal implements, re- 
 mains of domesticated 
 animals, &c. 
 
 Accumulations of sand- 
 drift, shore- cave- and 
 beach-deposits, consid- 
 erably beyond the reach 
 of existing tides. 
 
 Peat- moss, Lake- silts, and 
 other alluvia, with tree- 
 canoes, pile-dwellings, 
 and stone implements. 
 
 Alluvia and river-deposits, 
 with remains of Irish- 
 deer, wild oxen, mam- 
 moth, and other extinct 
 mammals. 
 
 Cave-deposits in part, with 
 bones of extinct mam- 
 mals, stone implements, 
 and fragments of charred 
 wood. 
 
 58 
 
 Foreign, 
 
 Terrain quaternaire of French 
 authors, in part. Modern 
 portion of Deltas of Rhine, 
 Nile, Ganges, Mississippi, 
 &c. Marine strata enclos- 
 ing temple of Serapis at Puz- 
 zuoli. Fresh- water strata 
 enclosing temple in Cash- 
 mere. Tundras of Siberia ; 
 Tarai or Jungle soil of In- 
 dia ; Cypress swamps, &c. 
 of America. Modern part 
 of coral-reefs of Red Sea 
 and Pacific. Travertine of 
 Italy ; calcareous tufa of 
 Guadaloupe ; and Lavas of 
 Vesuvius and Etna, over- 
 spreading objects of human 
 art, &c. 
 
 Terrain quaternaire of French 
 authors, in part. Upper 
 river-gravels of the Somme, 
 Seine, &c., with flint imple- 
 ments, and bones of extinct 
 mammalia. Upper Alluvia 
 of Tigris and Euphrates. 
 River silt of Upper Egypt 
 in part. Upper portion of 
 cave - deposits of France, 
 Belgium, Mediterranean, 
 and Southern Europe, with 
 stone implements and char- 
 red wood. Plain of Holland 
 in part ; plain of China in 
 part ; and much of the river- 
 alluvia of America. Din- 
 ornis silts of New Zealand. 
 
GEOLOGICAL SCHEME. 
 
 POST- 
 GLACIAL. 
 
 British. 
 
 Shell - marl under peat, ^ 
 and submarine forests 
 of modern trees. 
 
 Raised beaches at various 
 heights, with species of 
 shells more boreal than 
 those of existing seas. 
 
 Ancient alluvia and gra- 
 vel of most of our carses, 
 straths,dales,and holmes 
 the "Brick Clay" of 
 many authors. Contains \ 
 remains of seals, whales, 
 &c. ; and of extinct 
 land mammals, as mam- 
 moth, rhinoceros, urus, 
 &c. 
 
 Cave-deposits in part, with 
 bones of extinct and liv- 
 ing carnivora and her- 
 bivora ursus, hysena, 
 megaceros, rhinoceros, 
 hippopotamus, &c. No 
 human remains. 
 
 Foreign. 
 
 Loess of the Rhine, with recent 
 fresh- water shells and mam- 
 moth bones. Volcanic tufa 
 of Ischia, with living species 
 of marine shells, and with- 
 out human remains or works 
 of art. Newer boulder for- 
 mation in Sweden. Bluffs 
 of the Mississippi. Drift- 
 wood and mammoth-gravel 
 of the Arctic seas. Tchor- 
 nozem or black-earth of the 
 Aralo-Caspian plain. Up- 
 per portion of great Chinese 
 plain. Auriferous Drift, in 
 part, of the Uralian, Au- 
 stralian, and Californian 
 gold-fields. 
 
 II. TERTIARY SYSTEM. 
 
 PLEISTOCENE 
 
 or 
 
 NEWER 
 PLIOCENE. 
 
 OLDER 
 PLIOCENE. 
 
 UPPER 
 MIOCENE. 
 
 Glacial drift or boulder for- 
 mation of Norfolk, of the 
 Clyde, of North Wales 
 the "Boulder Clay" 
 of many authors. Nor- 
 wich Crag. Cave-depo- 
 sits of Kirkdale, &c. 
 with bones of extinct 
 and living quadrupeds. 
 
 Red Crag of Suffolk, Coral- 
 line Crag of Suffolk. 
 
 Marine strata of this age 
 wanting in the British 
 Islands. Ferruginous 
 sands ofNorth Downs (?). 
 
 Terrain quaternaire, diluvium. 
 Terrain tertiaire suprieur. 
 Glacial drift of Northern 
 Europe; of Northern United 
 States ; and Alpine erratics. 
 Limestone of Girgenti 
 Kunkur of India (?) ; Au- 
 stralian cave-breccias. 
 
 Sub-Apennine strata. Hills 
 of Rome, Monte Mario, &c. 
 Antwerp and Normandy 
 Crag. Aralo-Caucasian de- 
 posits, older part. Pampas 
 Formation of South Amer- 
 ica, &c. 
 
 Falurien supe"rieur. Faluns 
 of Touraine. Part of Bor- 
 deaux beds. Bolderberg 
 strata in Belgium. Part of 
 Vienna Basin. Part of Mol- 
 lasse in Switzerland. Sands 
 of James River and Rich- 
 mond, Virginia. Green- 
 sands and marls of Mary- 
 land, United States. 
 
GEOLOGICAL SCHEME. 
 
 LOWER 
 
 MIOCENE. 
 
 UPPER 
 
 EOCENE. 
 
 MIDDLE 
 
 EOCENE. 
 
 LOWER 
 EOCENE. 
 
 British. 
 
 Hempstead beds near Yar- 
 mouth, Isle of Wight. 
 Lignites and clays of / 
 Bovey, in Devonshire. 
 Leaf-bed of Mull. Lig- 
 nites of Antrim. 
 
 1. Bembridge or Binsted 
 Beds, Isle of Wight. 
 
 2. Osborne or St Helens 
 series. 
 
 3. Headon Series. 
 
 4. Headon Hill sands and 
 Barton clay. 
 
 1. Bagshot and Brackles- 
 ham Beds. 
 
 2. White clays of Alum 
 Bay, Isle of Wight. 
 
 1. London Clay and Bog- 
 nor Beds. 
 
 2. Plastic and mottled 
 clays and sands ; Wool- 
 wich Beds. 
 
 3. Thanet Sands. 
 
 Foreign. 
 
 Lower part of Terrain terti- 
 aire moyen. Calcaire lac- 
 ustre superienr, and gres de 
 Fontainebleau. Part of the 
 Lacustrine strata of Au- 
 vergne. Limburg beds,Bel- 
 gium. (Rupelian and Ton- 
 grian system of Dumont). 
 Mayence Basin. Part of 
 brown coal of Germany. 
 Hermsdorf tile - clay, near 
 Berlin. Lignites of New 
 Zealand (?). 
 
 ^1. Gypseous series of Mont- 
 
 martre, and Calcaire lacustre 
 
 supe'rieur. 
 
 2 and 3. Calcaire Silicieux. 
 2 and 3. Gres de Beauchamp, 
 
 or sables moy ens. Laecken 
 
 beds, Belgium. 
 4. Upper and Middle Calcaire 
 
 grossier. 
 
 fl. Bruxillien or Brussels Beds 
 
 of Dumont. 
 
 1. Lower Calcaire grossier, or 
 glauconie grossiere. 
 
 1. Caiborne beds, Alabama. 
 
 1 and 2. Nummulitic forma- 
 tion of Europe, Asia, &c. 
 
 2. Soissonnais Sands, or Lits 
 . Coquilliers. 
 
 1. Wanting in Paris Basin, 
 occurs at Cassel in French 
 Flanders. Limestones and 
 Clays of the Carolinas (?). 
 
 2. Argile Plastiqueet Lignite. 
 
 3. Lower Landenian of Bel- 
 gium, in part. 
 
 III. CRETACEOUS SYSTEM. 
 
 UPPER 
 WHITE 
 CHALK. 
 
 Wanting in England. 
 
 White Chalk, with flints. 
 
 Danien of d'Orbigny. 
 
 Calcaire pisolitique, Paris. 
 
 Maestricht Beds. 
 | Coi'alline limestone of Faxoe 
 \ in Denmark. 
 
 f Senonien of d'Orbigny. 
 I Obere Kreide and Upper Qua- 
 der-sandstein of the Ger- 
 / mans. 
 
 1 La Scaglia of the Italians. 
 I Yellow Limestone and Green- 
 l sand of New Jersey, in part. 
 
GEOLOGICAL SCHEME. 
 
 LOWER 
 WHITE 
 CHALK. 
 
 UPPER 
 
 GREENSAND. 
 
 WEALDEN. 
 
 British. 
 
 Chalk without flints. 
 Chalk Marl. 
 
 Loose sand, with bright' 
 
 Foreign. 
 
 Turonian of d'Orbigny. 
 
 Calcaire a hippurites, Pyre- 
 n6es. 
 
 Upper Planer Kalk of Saxony. 
 
 Yellow Limestone and Green- 
 sand of New Jersey, in part. 
 
 Limestones of the West Indies 
 and Colombia, S. America. 
 
 of d'Orbigny. 
 
 Marly stone, with Chert, Lower Quadersandstein of the 
 I Isle of Wight. ) bermans - 
 
 Albien of d' Orbigny. 
 Glauconie Crayeuse. 
 
 Dark-blue Marl, Kent. 
 
 LOWER 
 GREENSAND. 
 
 Greensand of Kent and 
 Sussex. 
 
 Limestone (Kentish Rag). 
 
 Sands and Clay, with cal- 
 careous concretions and 
 chert, Atherfield, Isle of 
 Wight. 
 
 Speeton Clay, Yorkshire. 
 
 Clay, with occasional bands 
 of limestone and sand- 
 stone ; Weald of Kent, 
 Surrey, and Sussex. 
 
 Sand, with calcareous grit 
 and clay ; Hastings, 
 Cuckfield, Sussex. 
 
 Gres Vert Infeneur. 
 Neocomien SupeYieur. 
 Aptien of d'Orbigny. 
 H ils Conglom e rat of G ermany . 
 Hils-thon of Brunswick. 
 
 Neocomien InfeYieur. 
 Formation Waldienne. 
 Walderformation of North 
 Germany. 
 
 IV. OOLITIC OR JURASSIC SYSTEM. 
 
 1. PurbeckBeds. 
 UPPER 2. Portland Stone 
 
 OOLITE. Sand. 
 
 3. Kimmeridge Clay. 
 
 1. Calcareous Grit. 
 MIDDLE ) 2. Coral Rag. 
 OOLITE. \ 3. Oxford Clay. 
 
 4. Kelloway Rock. 
 
 and 
 
 Gl 
 
 1. Serpuliten Kalk and Wal- 
 derformation of N. Ger- 
 many, in part. 2. Portlan- 
 dien of d'Orbigny. 3. Kim- 
 meridgien of d'Orbigny. 
 Calcaire a gryphees virgules, 
 of Thirria. Argiles de Hon- 
 fleur of de Beaumont. 
 
 1 and 2. Corallien of Beudant 
 and d'Orbigny. Calcaire a 
 Nerinnees of Thurmann. 
 
 13. Oxfordien SupeYieur. 4. 
 Oxfordien Inferieur or Cal- 
 lovien of d'Orbigny. 
 
GEOLOGICAL SCHEME. 
 
 LOWER 
 OOLITE. 
 
 LIAS. 
 
 British. Foreign. 
 
 1. Cornbrash and Forest \ 
 
 Marble. J 1 and 2. Bathonien ; Grand 
 
 2. Great (or Bath) Oolite Oolithe ; Calcaire de Caen, 
 and Stonesfield Slates. \ 3 and 4. Oolithe inferieur ; 
 
 3. Fuller's Earth, Bath. f Oolithe ferrugineux of Nor- 
 
 4. Calcareous Freestone I mandy; Oolithe de Bay eux; 
 and Yellow Sands (In- Bajocien of d'Orbigny. 
 ferior Oolite). ) 
 
 1. Toarcien of d'Orbigny. 
 
 2. Lias Moyen ; Liasien of 
 i TT T d'Orbigny. 
 
 o S PP i 6 ^ 4. Calcaire a gryphee arquee ; 
 
 2. Marlstone. / Sinemuri en of d'Orbigny ; 
 
 3. Lower Lias. \ Coal-field of Richmond, Vir- 
 
 ginia (?) ; and Coal-fields of 
 India (?). 
 
 V. TEIASSIC SYSTEM. 
 
 UPPER. 
 
 LOWER. 
 
 Bone - bed of Axmouth ; 
 Dolomitic Conglomerate 
 of Bristol ; Saliferous 
 and Gypseous Shales 
 and Sandstones of Che- 
 shire. 
 
 MIDDLE. < Wanting in England. 
 
 Red and White Sandstones 
 and Quartzose Conglo- 
 merates of Lancashire 
 and Cheshire. White 
 sandstones of Lossie- 
 mouth and Cumming- 
 stone, Moray shire (?). 
 
 Saliferien of d'Orbigny; 
 Marnes irisees of the French; 
 St Cassian or Rhaetic beds ; 
 Keuper of the Germans. 
 Coal-fields of Richmond, 
 Virginia, and of Chatham, 
 North Carolina. 
 
 Conchylien of d'Orbigny, in 
 part; Calcaire a C6ratites 
 of Cordier ; Muschelkalk of 
 Germany. 
 
 Bunter Sandstein of the Ger- 
 mans ; Gres bigarre" of the 
 French ; Conchylien of 
 d'Orbigny, in part ; Red 
 Sandstones of Connecticut, 
 U.S. 
 
 VI. PERMIAN SYSTEM. 
 
 MAGNESIAN 
 LIMESTONE. 
 
 RED 
 SANDSTONE. 
 
 1. Laminated and Concre- 
 tionary Limestones of 
 York and Durham. 
 
 2. Brecciated Limestone do 
 
 3. Fossiliferous Limestone, 
 
 4. Compact Limestone, do, 
 
 5. Marl-slate of Durham. 
 
 IRed Sandstones, Grits, and 
 Marls ; Dolomitic Con- 
 glomerate of Bristol, 
 Exeter, Annandale, &c. 
 
 62 
 
 1. Stinkstein of Thuringia. 
 
 2. Rauchwacke do. 
 
 3. Dolomit or Upper Zech- 
 stein. 
 
 4. Zechstein proper. 
 
 5. Mergel or Kupfer schiefer, 
 
 Rothliegendes of Thuringia. 
 
 Permian sandstones, conglo- 
 merates, and magnesian 
 limestones of Russia. 
 
 Gres des Voyages of French. 
 
GEOLOGICAL SCHEME. 
 
 VII. CARBONIFEROUS SYSTEM. 
 
 TTPPFR 
 UPPER. 
 
 MIDDLE. 
 
 LOWER. 
 
 British. 
 
 Foreign. 
 
 1. Upper or True Coal-}!. Coal-fields of the United 
 
 Measures. 
 
 1. Millstone Grit of Eng- 
 land. 
 
 2. Mountain or Carboni- 
 ferous Limestone. 
 
 1. Lower Coal - measures \ 
 and " Calciferous Sand- 
 stones" of Scotland. I 
 Lower Limestone Shale, / 
 Mendips. Carbonifer- 1 
 ous Slates of Ireland. I 
 
 r- 
 
 States. 
 
 2. Calcaire Carbonifere of the 
 French. Bergkalk or Kohl- 
 enkalk of the Germans. 
 Pentremite Limestone, U.S. 
 
 1. Kiesel Schiefer and Jiingere 
 Grauwacke of the Germans. 
 Gypseous Beds and Encrin- 
 ital Limestones of Nova 
 Scotia. Cypridina Schiefer 
 of Nassau, Saxony, &c. 
 
 UPPER. 
 
 VIII. DEVONIAN OR OLD RED SANDSTONE. 
 
 f\. Yellow Sandstones of 
 j Dura Den, Fifeshire ; 
 
 Kilkenny Ireland : and , TT -^ 
 
 Pilton and Petherwyn ( 1- Upper Devonians of Russia; 
 / Groups Devonshire. ' > CyP"dina Schiefer of Ger- 
 . 2. White and chocolate- L ^X. P art ' 
 
 coloured Sandstones and 2 ' Catskm Grou P> 
 
 Grits of Berwick and 
 \ Roxburgh. J 
 
 MIDDLE. 
 
 LOWER. 
 
 1. Red Sandstones and 
 Marls of Fife, Perth, 
 Forfar, Hereford, &c. 
 
 2. Middle Schists and 
 Limestones of Devon- 
 shire. 
 
 3. Micaceous and Bitu- 
 minous Flags of Caith- 
 
 of 
 
 1. Lower Devonian 
 North Devon. 
 
 1. Eifel Limestone ; and Up- 
 per and Middle Devonians 
 of Russia, in part. 
 
 2 and 3. Middle Devonians of 
 Russia, in part ; Chemung, 
 Genessee, and Hamilton 
 Groups, North America. 
 
 1. Spirifer Sandstone and 
 
 2. Grey Flagstones of 
 
 Slate. 
 
 Perth andForfar. Great V 2 ' R^ian Devonian, lower 
 Pebbly conglomerate of / P a f*' and Onondago and 
 Scotland; Tilestones of Onskany Groups, North 
 Hereford, in part. America. 
 
 UPPER. 
 
 IX. SILURIAN SYSTEM. 
 
 1. Upper Ludlow Rocks ; 
 Lesmahago Tilestones. 
 
 2. Aymestry Limestone. 
 
 3. Lower Ludlow. 
 
 4. Wenlock Limestone and 
 Shale. 
 
 5. Llandovery Rocks. 
 
 63 
 
 1-5. Upper stages of Bohe- 
 mian Basin ; E to H of 
 Barrande. 
 
 1-3. Pentamerus, Delthyris, 
 and Onondago Groups, New 
 York. 4. Schoharie Coral- 
 line Limestone. 5. Medina 
 Sandstone. 
 
GEOLOGICAL SCHEME. 
 
 LOWER. 
 
 British. 
 
 1. Caradoc Sandstone. 
 
 2. BalaBeds. 
 
 3. Llandeillo and Lingula 
 Flags. 
 
 4. Longmynd or " Bottom 
 Rocks." 
 
 Foreign. 
 
 1 and 3. Lower stages of Bo- 
 hemian Basin; C and D 
 Barrande. 4. Primordial 
 zone of Barrande ; Slates of 
 Angers, France. 1-4. From 
 Oneida Conglomerates to 
 Potsdam Sandstone inclu- 
 
 X. CAMBRIAN SYSTEM. 
 
 f Fossiliferous Schists of } Alum Schists of Sweden ; 
 UPPER. < Wicklow ; Schists and V lowest f ossilif erous rocks of 
 
 ( Slates of North Wales. J Wisconsin and Minnesota. 
 
 r Lower Grits and Schists "\ 
 
 of Dumfries ; and Grits, Hiironian Sandstones and 
 LOWER. < Schists, and Conglome- y 
 
 rates of Northern High- I 
 lands. 
 
 Chloritic 
 Schists. 
 
 and Gneissic 
 
 XL LAURENTIAN SYSTEM. 
 
 UPPER. 
 
 LOWER. 
 
 / Gneiss and Crystalline "N Gneissic and horneblende 
 J Schists of the Northern I Schists of the St Lawrence 
 j Hebrides ; Hypersthene f and Adirondack Moun- 
 V. rocks of Skye, &c. ) tains. 
 
 /Gneissic Schists, quartzites, 
 crystalline limestones and 
 (?) \ serpentines of the Lauren- 
 
 V, tide Mountains, Canada. 
 
 64 
 
II. 
 
 GENEEAL TEEMS AND TECHNICALITIES 
 
GENEBAL TEEMS AM) TECHNICALITIES. 
 
 A ABN 
 
 A. Tn words derived from the Greek, the prefix a is used privatively, or 
 in a negative sense, and has the effect of the English word ^v^tkout, as 
 apodous, without feet ; acephalous, without a head ; acotyledonous, having 
 no seed-lobes ; and azoic, destitute of organic remains. 
 
 A'bbeville Flints. Rude flint implements in the form of spear-heads, 
 &c., found in great abundance in the Post- Tertiary sands and gravels of 
 the Somme, in the neighbourhood of Abbeville. These were first discov- 
 ered in 1847, by M. Boucher de Perthes, associated with bones of extinct 
 mammalia in such a way as to lead him to the inference that the flint im- 
 plement makers and the Mammoth (ElepJias primigenius), the Tichorhine 
 Rhinoceros, Hippopotamus Major, Irish Elk (Megaceros ffibernicus), &c., 
 had been contemporaneous an inference that has since been corroborated 
 by similar discoveries in other parts of Europe. 
 
 Abd6men (Lat. aldo, I conceal). In animals, the belly or cavity contain- 
 ing the viscera. Abdominal. Pertaining to the belly. 
 
 Abdominales (Lat. aldo, I conceal ; hence abdomen, the belly). In the 
 zoological arrangement of Cuvier, a section of the Malacopterygian, or soft- 
 finned fishes, which have their ventral fins placed on the abdomen, behind 
 the pectorals. The section includes the carps, the silures, the salmons, 
 the herrings, and the pikes. 
 
 Aberrant (Lat. ab, and erro, I wander from). Applied in natural his- 
 tory classification to those species (" aberrant species") which differ widely 
 from the type of the natural group or family to which they belong, or 
 rather under which they are usually arranged. 
 
 Abietites (Lat. abies, the fir-tree). A genus of coniferse occurring in the 
 Wealden and Lower Greensand. The genus has been founded chiefly on 
 the fossil cones, which are often found in great perfection these cones 
 being composed of scales that terminate in a point, and not in a rhomboi- 
 dal disc as in Pinus, which see. 
 
 Abnormal, Abnormous (Lat. ab, from, and norma, a rule). Without 
 rule or order ; irregular ; in a condition differing from that produced in 
 the regular course of nature ; deviating from the general type or form ; not 
 
 67 
 
ABO ACA 
 
 occurring in the usual order, or according to that which is generally con- 
 sidered as the natural law. Abn6rmity. Irregularity, deformity. 
 
 Aborigines (Lat. ab, from; origo, a beginning or origin). The first 
 or primitive inhabitants of a country ; the original stock (flora or fauna) 
 of any geographical area. Aboriginal. First, primitive, original. 
 
 Abortive (Lat. abortio, a miscarriage). Failing to arrive at a state of 
 perfection or maturity ; applied in botany and zoology to such organs as 
 appear only in an imperfect or rudimentary state, or which stop short at 
 a certain stage of their growth, and never attain to full or perfect develop- 
 ment. 
 
 Abranchiata (Gr. a, without, and branchia, gills). Applied to animals 
 which have no apparant external organs of respiration, as the leech, earth- 
 worm, &c., and which respire by the entire surface of the skin, or by inter- 
 nal cavities. The Abranchiala constitute the third order of the Anne- 
 lida of Cuvier. The term Abranchia has also been applied to certain 
 amphibia, as the menopoma and amphiuma, which do not undergo meta- 
 morphosis, but breathe by lungs during the whole of their existence. See 
 BRANCHIA and its compounds. 
 
 Abrasion (Lat. ab, from, and rasus, rubbed or scraped). The opera- 
 tion of wearing away by rubbing or friction. Currents of water laden 
 with sand, shingle, and other rock-debris are the chief abrading agents in 
 nature. Abrason may also result from the passage of icebergs, the de- 
 scent of glaciers, &c. ; hence the frequency of abraded rock-surfaces in 
 connection with the Boulder-clay. Abrasion, as a geological result, 
 presents some important distinctions, as compared with Denudation and 
 Degradation, which see. 
 
 A'brazite (Gr. a, without; brazo, to bubble). One of the Zeolite family, 
 known also as zeagonite and gismondine, and so named from its not effer- 
 vescing under the blowpipe. Its crystals occur in hemispherical bundles 
 in the cavities of volcanic rocks ; are of a greyish-white to a reddish-brown 
 or red colour ; and consist essentially of silica, alumina, lime, and potash. 
 
 Absorbent (Lat. ab, and sorbeo, I suck in). Capable of sucking in fluids ; 
 in geology, applied to soils, rocks, and minerals which have the quality of 
 readily imbibing water into their pores and interstices. 
 
 Abstergent (Lat. abstergo, I cleanse). Having a cleansing property ; 
 fuller's earth is an abstergent. 
 
 Acalephse (Gr. akattphe, a nettle). A zoological term for the soft 
 gelatinous radiata known as medusae, sea-nettles, jelly-fish, &c. The term 
 has reference to the property which many of them possess, of causing, 
 when touched, a hot stinging sensation like that produced by the nettle. 
 
 Acanthodes (Gr. akantha, a spine or thorn). One of Agassiz's genera of 
 ganoid fishes occurring from the lower Old Red Sandstone to the Permian, 
 inclusive, and characterised by its thorn-like ichthyodorulites or fin-spines. 
 The type of the family A canthodidce, in which all the fins are furnished with 
 strong spinous rays the dorsal and anal being single. 
 
 Acanthopterygian (Gr. akantha, a spine or prickle, and pterygion, a 
 winglet or fin). A term applied to fishes having the back or dorsal fin 
 composed of spiny rays, as the perch, gurnard, &c. The Acanthopterygii 
 constitute one of Cuvier's orders of osseous fishes. 
 
 Acanthoteiithis (Gr. akdntha, a thorn, and teuthis a cuttle-fish). A 
 genus of fossil cuttle-fishes occurring in oolitic strata} and so termed from 
 the horny booklets that arm their tentacles, which appear to have been ten 
 
 63 
 
ACA ACE 
 
 in number. These booklets, the horny sucking-discs, and internal bones 
 or osselets (belemnites), are'generally the only portions preserved. 
 
 Acanticonite. An all but obsolete synonyme for pistacite, a sub-species 
 of prismatic augite spar or epidote, which see. Is said to derive its name 
 from Gr. aJc&nthis, a goldfinch, and konis, powder, because the colour of 
 the powdered mineral resembles that of the plumes of the goldfinch. 
 
 Acaridse or Acarea (Lat. acarus, a mite). The Mite family (so called 
 from the typical genus acarus), to which the mite, the tick, the water-mite, 
 and other minute arachnidans belong. They are chiefly of geological 
 interest from the experiments of Crosse, who imagined he could produce 
 some species (Acarus Crossei, &c.) at will, by passing long-continued cur- 
 rents of electricity through certain siliceous solutions. 
 
 Accipenseridse (Lat. accipenser, the sturgeon). The Sturgeon family, a 
 well-known but limited group of ganoid fishes belonging to the sub-order 
 Chondrostea or Loricata, and especially characterised by the almost total 
 absence of an osseous vertebral column, and by the presence, in most 
 species, of a strong dermal covering or exo-skeleton consisting of large 
 bony tuberculated plates arranged in rows on the upper surface of the 
 body, and shielding the head as if in solid piece. The existing sturgeons 
 are chiefly of large size, and inhabit the sea, but ascend the larger rivers 
 for the purpose of spawning : the fossil species seem to have been governed 
 by a similar habit, and are found from the lower Tertiaries upwards. 
 
 Accipitres (Lat. accipiler, a hawk ; from accipere, to seize). The ornitho- 
 logical term for the rapacious birds, such as the eagles, falcons, hawks, 
 c., which seize their prey with their talons. There are two subdivisions, 
 the diurnal and the nocturnal. Their remains occur, though very spar- 
 ingly, from the lower Tertiaries upwards. 
 
 Acclimatise (Fr. acclimater). To accustom a plant or animal to a 
 climate not natural to it; to accustom to the temperature of a new region. 
 Plants and animals may, within certain limits, become acclimatised, and 
 flourish and increase in a new country, though not indigenous to it. Ac- 
 climated. Accustomed to a climate. 
 
 Accretion (Lat. accrelio). Increase by external addition of new matter; 
 applied strictly to mineral or inorganic increase. Plants and animals grow 
 by alimentation, or the assimilation of additional matter ; minerals enlarge 
 by accretion. 
 
 Aceous. Terminations in dceous denote resemblance to, or partak- 
 ing of the qualities of, a substance, as argillaceous, less or more clayey; 
 carbonaceous, partaking of the qualities or appearance of carbon ; sapon- 
 aceous, having a soapy feel. 
 
 Acephala, Acephalous (Gr. a, without, and kephale, the head). Applied 
 to those mollusca which, like the oyster and scallop, have no distinct head, 
 in contradistinction from the JEncephalous, or those with a distinct head. 
 The division AcepJiala comprehends most of the bivalve molluscs, and 
 several that are destitute of shells in other words, the Irachiopoda, con- 
 chifera, and tunicata. 
 
 Acescent (Lat. acesco, to become sour). Slightly acid ; having a tendency 
 to pass into an acid state ; applied to substances which, like vegetable and 
 animal juices, become sour spontaneously that is, on exposure to the 
 oxygen of the atmosphere. 
 
 Acetabulifera (La$. acetab&lum, a sucker, and fero, I bear). Literally 
 " sucker-bearers ; " that section of the cephalopodous molluscs whose arms 
 
ACE ACR 
 
 or tentacles are furnished with rows of little cups or suckers, a character- 
 istic peculiar to Neozoic genera. See tabulations, "MoLLUSCA." 
 
 Acetabttlum (Lat. a sucker). Applied in zoology to such organs as the 
 cup-like sucking-discs (acetabula) with which the arms of the cuttle-fish are 
 provided. So far as yet known, the arms of the Palaeozoic cephalopods 
 were void of sucking-discs organs abundantly common to Mesozoic and 
 Neozoic genera. 
 
 A'chmite (Gr. akme, a sharp point). One of the hornblende family oc- 
 curring in the granites and syenites of Norway in long greenish-black pris- 
 matic crystals, which terminate very acutely ; hence the name. It con- 
 sists of 55.6 silica, 32 iron peroxide, and 12.4 soda. 
 
 A'chroite (Gr. a, without, and chroa, colour). A term employed by 
 Hermann to designate the colourless varieties of tourmaline, as distin- 
 guished from the dark-coloured varieties (Schorl), and from the red 
 (Rubellite). 
 
 Acicular (Lat. acicula, a little needle). Mineral crystals occurring in 
 slender needle-like prisms or prickles, as actynolite, are said to be acicular. 
 Irregular aggregations of these slender prisms constitute the " acicular 
 texture " of actynolite-rock and actynolite-slate. 
 
 Aciculite (Lat. acicula, a needle). Needle ore ; a plumbo-cupreous 
 sulphuret of bismuth occurring imbedded in quartz in long, thin, steel- 
 grey crystals, strongly marked with vertical striae, and apparently in four 
 or six-sided prisms. It consists of 35.8 lead, 11 copper, 36.7 bismuth, and 
 16.5 sulphur, and usually accompanies native gold. 
 
 Acidaspis (Gr. akis, spear-point, and aspis, buckler). A genus of tri- 
 lobites, so named by Murchison from the central lobe of the head-plate 
 or cephalic shield projecting over the body in the form of a pointed 
 stomacher. 
 
 Acidulous, Acidulated. Slightly acid or sub-acid. Applied to certain 
 waters and springs that hold in solution a small percentage of sulphuric or 
 other acid. 
 
 Acin6se (Lat. acinus, a seed or germ). Granulated ; applied to mineral 
 textures and surfaces which have a granulated appearance like the fruit of 
 the raspberry. 
 
 Acotyledonous (Gr. a, without, and cotyledon, seed-lobe). Plants whose 
 embryos have no seed-lobes or seminal leaves are so termed, in contra- 
 distinction to Monocotyledons and Dicotyledons. See tabulations, "VEGE- 
 TABLE SCHEME." 
 
 A'crita (Gr. akrltos, indistinct). In some zoological classifications, a 
 primary division of the animal kingdom, comprising the lowest classes of 
 radiata, which are characterised by an indistinct, diffused, or molecular 
 condition of the nervous system The Acrita constitute the Protozoa, the 
 Cryptoneura, the Oozoa, and Globular zoophytes of other systematists. 
 
 Acrocephalic (Gr. akros, raised to a point, high ; and kephale, the head). 
 High-headed or pyramidal-headed ; e.g., the pyramidal or high- skulled 
 tribes of the human family. 
 
 A'crodont (Gr. akros, the summit, and odous, tooth). A term applied by 
 Professor Owen to those squamate or loricated saurians whose teeth are 
 anchylosed to the summit of the alveolar ridge. See THECODONT. 
 
 A'crodus (Gr. akros, the ridge, and odous, tooth). Literally "ridge-tooth;" 
 a genus of Cestraciont fish-teeth occurring abundantly in the Oolitic and 
 Chalk formations, and characterised by their enamelled surface being 
 
 70 
 
ACR ADA 
 
 covered with fine grooves and strise which diverge from a central longi- 
 tudinal ridge. They are known to collectors as fossil leeches, from a fanci- 
 ful resemblance to a contracted leech. 
 
 Acr6genous (Gr. akros, the top, and ginomai, I am formed). Applied to 
 those cryptogamic plants which increase by growth at the summit, or 
 "growing-point," as the tree-ferns. Acrogens are therefore separated as 
 a great botanical division from Thallogens, Endogens, and Exogens. See 
 tabulations, " VEGETABLE SCHEME." 
 
 Acrognathns (Gr. akros, high, and gnathos, the jaw). Literally "deep- 
 jaw ; " a genus of fishes from the Lower Chalk, and arranged by Agassiz 
 under the Salmonidce, or Salmon-family. 
 
 Acrosaurus (Gr. akros, the point or summit, and sauros, lizard). One 
 of the extraordinary fossil reptiles discovered by Mr Bain in the supposed 
 Triassic sandstones of South Africa. It has thirty or forty teeth on the 
 alveolar ridge (hence the name), and a broad process of the cheekbone 
 extending downwards over the side of the lower jaw. 
 
 Acteosaurus (Gr. akte, the sea-shore, and sauros, lizard). A lacertian 
 reptile of the Chalk period, with concavo-convex vertebrae, remarkably 
 small extremities, and allied to Dolichosaurus (which see), but of consider- 
 ably smaller dimensions. The genus was established by Von Meyer from 
 a finely preserved specimen in the City Museum of Trieste, and so named 
 from its having been found near the Istrian shore, and also from the belief 
 that the creature when living had a littoral habitat. 
 
 Actinia (Gr. aktin, a ray). The sea-anemone ; so called from the ray- 
 like arrangement of its tentacles, which surround the mouth like the petals 
 of a flower. The Actiniae belong to the class Polypi, or true polypes, and 
 from their structure are sometimes named " Fleshy Polypes." It has been 
 suggested by Dr Mantell that some of the minute siliceous spicules so 
 abundant in Chalk, and commonly ascribed to sponges, may have belonged 
 to Actiniae, in whose structure such organisms also occur. 
 
 Actin6crinus, Actin6crinite (Gr. aktin, a ray or thorn). A genus of 
 encrinites found chiefly in the Carboniferous limestone, and distinguished 
 by the thorn-like side-arms which project from the main column or stalk 
 at irregular distances. See ENCRINITE. 
 
 Actynolite, Actin6te (Gr.aktinotos, radiated, and lithos, stone). A mineral 
 occurring in the crystalline rocks, composed of radiating or thorn-like crys- 
 tals of a dark or greenish hue, and in composition closely allied to horn- 
 blende ; in fact, comprehends the glassy fibrous and granular varieties of 
 that mineral. Actynolite-rock and actynolite-schist are the common forms 
 in which the mineral appears the latter consisting of a basis of felspar 
 with intermingled crystals of actynolite. According to Bonsdorf, speci- 
 mens from Taberg consist of 59.75 silica, 21.10 magnesia, 14.25 lime, 3.95 
 protoxide of iron, with traces of manganese and fluoric acid. 
 
 A'damant (Gr. adamas, adamantos, unsubdued, strong). An old term 
 given to several minerals having the property of excessive hardness, as to 
 the diamond. Adamantine and Adamantean. Hard as adamant ; exces- 
 sively hard ; having the lustre of diamond. 
 
 Adamantine Spar. The diamond spar of Werner ; a variety of corundum 
 occurring in rough crystals, with very distinct cleavage, hair-brown 
 colour, and adamantine lustre. 
 
 Adamic. Of or pertaining to Adam ; Adamic earth, an old term for com- 
 mon red clay, from the belief that the name "Adam" signifies red earth. 
 
 71 
 
ADA AER 
 
 A'dapis (Gr. a, not, and dapis, a carpet). Literally "no-carpet ;" a name 
 given in allusion to its rough or prickly skin. An extinct Tertiary pachy- 
 derm, somewhat resembling a hedgehog, but three times the size of that 
 animal. It seems, according to Cuvier, to have formed a link connecting 
 the Pachyderms with the Insectivora. 
 
 Adhesion (Lat. ad, and hcero, to stick together). The force of cohesion 
 acting between solid masses which come in contact at many points ; the 
 more intimate the contact the greater the force. 
 
 Adiautites .(Gr. adiantos, of a dry nature, membranaceous). A genus 
 of fossil ferns found in the Coal-measures, and so termed from their resem- 
 blance to the existing adiantum or maiden-hair. 
 
 Adipocere (Lat. adeps, fat, and cera, wax). A light, waxy, fatty sub- 
 stance, of a light-brown or whitish-grey colour, into which animal muscle is 
 converted when buried in moist earth, or when subjected to long immersion 
 in water. It is occasionally found in graveyards (hence "grave- wax"), 
 in peat-bogs, and other similar situations ; and is frequently cast up in 
 lumps on the shores of tidal estuaries. It is chiefly margarate of am- 
 monia, and is obviously generated by the reaction of the ammonia 
 upon the margarine and oleine of the animal substances from which it 
 is produced. 
 
 Adipocerite, or Adipocere Mineral. A fatty unctuous matter found in 
 certain peat-mosses (the "creeshy clods" of the Scotch peat-digger); in 
 connection with ironstone of the Coal-measures, as at Merthyr ; and with 
 sandstone strata, as at Binny in Linlithgowshire. 
 
 Adit (Lat. ad&tus, an approach or entrance). An underground horizon- 
 tal gallery or tunnel, generally opening from the lower level of a ravine or 
 hill-side into a mine for the purpose of carrying off its waters, or for the 
 purposes of entrance, and removal of the ores. 
 
 Adularia (Gr. adularos, sweetly-fair, in allusion to its soft lustre). A 
 transparent or translucent variety of potash felspar, known also as ice- 
 spar, with splendid lustre, and either colourless and white, or slightly 
 tinged with grey, green, or yellowish-brown. Specimens with a bluish 
 opalescence are termed Moonstones, which see. 
 
 JE'chmodiis (Gr. aichme, a point, and odous, tooth). A genus of ganoid 
 fishes belonging to the Lepidoid family, and so named from their small, 
 sharp-pointed teeth. They are almost exclusively confined to the Lias 
 formation, and are readily distinguished by their deeply oval contour 
 their bodies being about as deep as long, and covered with transversely- 
 arranged four-cornered oblong scales. Formerly ranked under the genus 
 tetragonolepis, or " four-cornered scale." 
 
 JEpy6rnis, 2Epi6rnis (Gr. aipus, immense, and ornis, bird). An extinct 
 cursorial bird of gigantic dimensions, the eggs and a few scattered bones of 
 which have been discovered in the alluvial deposits of Madagascar. The 
 egg has six times the capacity of that of the ostrich ; but judging from 
 the large size of the egg of the New Zealand Apteryx, Professor Owen does 
 not believe that the Mpiornis exceeded, if indeed it equalled, the Dinornis 
 in stature. The bones would seem to indicate a bird at least double the 
 size of the ostrich ; and from their recentness, it appears not improbable 
 that the creature may still be in existence in the interior of the island, 
 which is almost unknown to Europeans. 
 
 Aerial (Gr. a'er, the air). Of or belonging to the air or atmosphere ; fre- 
 quenting the air ; growing in the air. Sab-aerial. Taking place under 
 
 72 
 
AER AFF 
 
 the air, or on the earth's surface, in contradistinction to Sub-aqueous, or 
 under the water. 
 
 Aeriform (Lat. a'er, the air, and forma). Air-like ; applied to gaseous 
 fluids, from their resemblance to common air; hence we hear of solid, 
 liquid, and aeriform bodies. 
 
 Aerolite (Gr. aer, air, and lithos, stone). Literally air- stone ; a meteoric 
 stone or mineral mass, which falls through the air, emitting light in its 
 passage as if red hot, generally accompanied with a hissing or crackling 
 sound, and occasionally with a report like thunder. Aerolites are by no 
 means uncommon ; and according to Schroebers, the greater number of 
 them have always the same general form, which is that of an oblique or 
 slanting pyramid ; and they are also alike in external appearance, present- 
 ing to view a black shining crust, as if the body had been coated with 
 pitch. This crust or film is extremely thin, and is of the same composition 
 with the mass, which, when broken, displays a semi-metallic ash-grey 
 colour. So like are they to one another in colour and in external appear- 
 ance, that Berzelius remarks, " We might believe them to have been 
 struck out of one piece." In composition they are also remarkable for 
 containing malleable metallic iron, nickel, and chrome metals which, in a 
 native state, are rarely if ever found in terrestrial substances. Besides 
 these ingredients, they contain upwards of a dozen others (silica, magnesia 
 potash, cobalt, &c.) ; and their specific gravities range from 3.35 to 4.28. 
 These common characteristics seem to indicate a common origin, and 
 many ingenious arguments have been advanced to prove that they are not 
 of terrestrial production. This is not the place to enter upon such specu- 
 lations, but we may indicate briefly the leading hypotheses that have been 
 advanced to account for the origin of these extraordinary bodies, which 
 cannot in the mean time be associated with any known terrestrial minerals. 
 It has been supposed 1st, That they are ejected from terrestrial vol- 
 canoes ; 2d, That they are produced in the atmosphere, being generated 
 from vapours exhaled from the earth, and containing volatilised metallic 
 products ; 3d, That they are thrown from lunar volcanoes ; and 4th, That 
 they are celestial bodies, revolving either about the earth or the sun, in 
 the manner of planets, and being involved in the earth's influences are 
 carried downwards by the force of gravitation. See METEORITE. 
 
 .ZErugo (Lat. ces, ceris, copper). Literally copper-rust; verdigris; a 
 sub-acetate of copper formed by the action of weak acids on its sur- 
 face, as that produced naturally by the oxygen and carbonic acid of the 
 atmosphere. 
 
 .ZEstuary. See ESTUARY. 
 
 .ffithiops (Gr. aitho, I burn, and ops, the eye or countenance). Applied 
 to various chemical compounds in allusion to their black appearance, re- 
 sembling that of the Ethiop. Thus we have jEthiops mineral, the black 
 sulphuret of mercury ; jEthiops per se, the grey oxide of mercury, &c. 
 
 JCtites or 2Etites Lapis (Gr. aetos, an eagle). A variety of nodular iron- 
 stone or geode, consisting of concentric layers, and either hollow or contain- 
 ing a loose central core. Is said to derive its name from a popular notion 
 that it was found in eagles' nests, where it was supposed to prevent the 
 eggs from becoming rotten. See EAGLE-STONE. 
 
 Affinity (Lat. affinis, neighbouring, bordering on, related to). A term 
 frequently, but often very loosely, used by writers on natural history. 
 " Affinity," as first defined by Macleay in contradistinction from "analogy," 
 
 73 
 
AFF AGN 
 
 signifies the relationship which one animal bears to another in its structure, 
 and is the closer as the similarity of structure is greater. Swainson illus- 
 trates this idea by comparing a goatsucker with a swallow and with a bat : 
 with the one its relation is intimate, with the other remote; the goatsucker 
 has affinity with the swallow, inasmuch as the structural organisation of 
 the one bird is intimately related to the other ; but it has only "analogy" 
 to the bat, inasmuch as bird and mammal, though differing in structure, 
 have the common function of feeding in the same manner on insects, and 
 flying at the same hour of the day. See ANALOGY and HOMOLOGT. 
 
 Affluent (Lat. ad, to, and fluens, flowing). Applied to any stream that 
 flows directly into another the larger or more important being regarded 
 as the recipient, and the smaller the affluent. See TRIBUTARY. 
 
 After-Damp. Another name for " choke-damp," or carbonic acid, as 
 occurring in coal mines after an explosion of "fire- damp," or light car- 
 buretted hydrogen. 
 
 Agalmatolite. (Gr. agalma, an image, and lithos, stone). A variety 
 of altered clay or clay-slate (a silicate of alumina with potash), usually 
 brought from China, and so called from its being carved into images and 
 other figures. See FIGURE-STONE and PAGODTTE. 
 
 Agaric Mineral (Lat. agaricus, a species of fungus). A soft variety of 
 carbonate of lime found in clefts and on other surfaces of rocks, in light 
 and loosely-cohering incrustations. It is so light as to float for a time on 
 water, and obtains its name from its resemblance to a fungus in texture 
 and colour. 
 
 Agate (said to be from the river Achates in Sicily, where fine varieties 
 occur, and by others from the Phoenician word nakadt, signifying spotted). 
 A mixed, siliceous, semi-pellucid mineral usually found in veins, in 
 nodules, and in geodes within igneous rocks. The geodes often consist of 
 alternating bands or deposits of carnelian, calcedony, jasper, opal, quartz, 
 &c. ; hence the varieties of the mineral are known by such names as 
 ribbon-agate, fortification-agate, brecciated agate, moss-agate, and the 
 like. When cut and polished, the ribbon-agates exhibit the calcedony, 
 jasper, quartz, &c., in parallel stripes; the fortification-agates show the 
 alternating bands in zigzag arrangements like the plan of a modern forti- 
 fication ; the brecciated consist of irregular fragments of the two former 
 imbedded in a matrix of amethyst ; and the moss-agates exhibit minute 
 dendritic ramifications resembling fragments of moss, confervse, &c. ; hence 
 their respective names. The finer varieties of agate are termed oriental ; 
 the Arabian moss-agates are known to the jeweller as mocha-stones; and 
 the most beautiful British varieties, being found in the traps of Scotland, 
 are termed Scotch pebbles. The colouring matter of agates being due to 
 metallic oxides, factitious colours of greater intensity can be produced by 
 heat or by boiling in various chemical solutions. 
 
 Agglomerate. A term employed by Sir Charles Lyell to designate those 
 accumulations of angular fragments of rock which are thrown up by vol- 
 canic eruptions, and showered to greater or less distances around the cone 
 or crater of eruption. When they are carried to a distance by running 
 water, and get worn and rounded, they become conglomerates. 
 
 Agnostus (Gr. agnostos, unknown, obscure). A genus of minute trilo- 
 bites supposed to be characteristic of, and peculiar to, the lowest Silurian 
 zones. Little, however, is known of them either as to their zoological 
 characteristics or geological distribution. 
 
 74 
 
AIG ALB 
 
 Aiguille (Fr.) A needle ; applied in physical geography and geology to 
 the sharp serrated peaks of lofty mountains. It is generally the crystalline 
 rocks, such as gneiss, quartz, and the like, which weather into the aiguille 
 or needle-top. 
 
 Air-course. In coal-mining, a general name for the air-traversing work- 
 ings where ventilation is going on. The fresh air descending into the 
 mine is termed the " intake ; " and that which ascends after having passed 
 through the workings is the "return." 
 
 Aix, Aix Beds. A town in Provence, situated in a deep valley, the 
 immediate flanks of which are composed of a thick fresh-water Tertiary 
 formation, consisting of greyish- white calcareous marls, calcareo-siliceous 
 grits, and beds of gypsum ; the whole being a perfect storehouse of fossil 
 fishes, plants, and insects. 
 
 A'kumite Series (Gr. akttmos, tranquil). According to Dr Fleming ('Lith- 
 ology of Edinburgh'), the modern epoch, from the commencement of the 
 Boulder-clay upwards, may be divided into three series viz., the Taragmite, 
 the Akumite, and the Phanerite. The first embraces the Boulder-drift, or 
 period of disturbance; the second, those laminated clays and sands which 
 immediately overlie the Boulder-clay, and seem to indicate the assorting 
 power of water under circumstances of comparative tranquillity; and the 
 third, all those more superficial deposits whose modes and causes of for- 
 mation are sufficiently evident. See MODERN or POST-TERTIARY EPOCH. 
 
 Alabandine. Sulphuret of manganese or hexahedral glance-blende. It 
 occurs crystalline, but usually massive, granular, and disseminated, of an 
 iron-black colour and semi-metallic lustre. It is found in veins with 
 foliated tellurium, blende, and quartz, in Saxony, Mexico, and Brazil ; and 
 consists of 6.36 manganese, and 36.4 sulphur. 
 
 Alabaster (Gr. alabastron). There are two well-known varieties of this 
 marble-like mineral the gypseous and the calcareous. The former is a 
 semi-transparent, granular - crystalline variety of gypsum, or sulphate of 
 lime, of various colours, but most esteemed when of a pure snow-white, 
 and usually compact enough to stand the turning-lathe ; the latter is a 
 carbonate of lime (Oriental alabaster), usually white or yellowish-white, 
 and found as a stalactite or stalagmite. Alabaster is a mineral of common 
 occurrence in Secondary and Tertiary formations (Cheshire, Montmartre 
 near Paris, Volterra in Tuscany, &c.) ; and being soft and readily turned 
 by the lathe, is manufactured into statuettes, vases, and other domestic 
 ornaments ; hence, perhaps, the term alabastron, an ink or perfume vase. 
 Others derive it from Alabastron, a town in Egypt famous for the manu- 
 facture of such vases. See GYPSUM. 
 
 Albani Stone (Lat. lapis albanus). The peperino of the Italians; a well- 
 known volcanic rock, much used at Rome before building with marble 
 became common. See PEPERINO. 
 
 Albert Coal, Albertite. The name given to a bituminous mineral oc- 
 curring at Hillsboro', Albert County, in the province of New Brunswick, 
 and within four miles of the Peticodiac river. It is an injected vein, cut- 
 ting the associated strata almost vertically, and from one to sixteen feet 
 in thickness. The accompanying rocks are highly charged with bitumen ; 
 but the vein, though called a " coal," has none of the stratigraphical char- 
 acteristics or accompaniments that distinguish coal deposits. The mineral 
 is extremely brilliant, breaks with a conchoidal fracture, does not soil the 
 fingers, and is strongly electric. It melts and drops in the flame of a 
 
 75 
 
ALB ALL 
 
 candle, and dissolves in naphtha and other solvents, forming a varnish. 
 It has all the essential properties of asphalt, while it is void of those 
 which constitute true coal. According to Gesner its composition is 
 carbon 85.4, hydrogen 9.2, nitrogen 3.0, sulphur a trace, oxygen 2.2, and 
 ash 12. Known also as Melanasphalt, which see. 
 
 Albite (Lat. alba, white). A variety of felspar of a greyish- white or 
 milky-white colour, composed of silex 70.5, alumina 19.5, soda 9.5, and 
 traces of lime and manganese. It is a frequent constituent of granites, 
 syenites, and greenstones, and is known also as Cleavlandite and soda 
 felspar. 
 
 Album Grsecum. The whitish hardened excrement of dogs, wolves, 
 hysenas, and other carnivora partially feeding on bones. It consists of the 
 earth-of -bones or lime, in combination with phosphoric acid. Dr Buckland 
 (Reliq. Diluv., &c.) detected the substance in a fossil state in ossiferous 
 caverns, such as those of Kirkdale and Kent's Hole, which are therefore 
 concluded to have been, the dens of Tertiary carnivora. More recently, Dr 
 Falconer has found it abundantly in the bone-caves near Palermo, and 
 indicative of animals of greater size than any of the existing hysenas. 
 
 Alc^onite. A general term for the spongiferous fossils so common in the 
 Chalk formation. They are fossil alcyonia, and very frequently form the 
 basis or organic nucleus round which flints have collected. It has also 
 been surmised by Dr Mantell that some of the minute siliceous spicules so 
 common in the Chalk may have belonged to alcyonia. 
 
 Alethdpteris (Gr. alethos, true; pteris, fern). One of Sternberg's genera 
 of fossil ferns, closely allied to pecopteris, and merged by Lindley into that 
 genus. It abounds particularly in the lower Coal formation, but some of 
 the species range up through the Oolite and Wealden. See PECOPTERIS. 
 
 A'lgae (Lat. alga, sea-weed). Cellular aquatic plants, mostly of marine 
 habitat, though many genera are strictly fluviatile or lacustrine. They 
 are found fossil, less or more, in every formation from the Silurian up- 
 wards : and are known by such terms as fucit.es, chondrites, palceochorda, 
 &c., from their resemblance to the living fucus, chondrus, chorda, &c. 
 
 Algodonite. A new mineral, consisting of copper 83.30, and arsenic 
 16.23, with a trace of silver ; found in the silver mines of Algodes, near 
 Coquimbo, in Chili whence the name. 
 
 Alkalies (Arabic, al, the, and kali, the name of a plant yielding the 
 alkali). In chemistry, a class of bodies which possess a strong acrid and 
 caustic taste ; exercise a corrosive action upon all animal matter ; turn 
 vegetable blues green, and vegetable yellows brown, and which neturalise 
 the acids by combining with them in definite proportions, and forming 
 compounds called salts. The principal mineral alkalies are potass, soda, 
 lithia, and ammonia. 
 
 Alkaline Earths. A term applied to baryta, lime, magnesia, and 
 strontia, in consequence of their possessing alkaline properties, as caus- 
 ticity, action on vegetable colours, and the like. 
 
 Allanite. A silico-aluminate of cerium, containing varying proportions 
 of iron, lime, and magnesia, &c. It is named after the late Mr Allan, of 
 Edinburgh, and is closely allied to, if not identical with, the cerine and 
 orthite of other mineralogists. 
 
 Alligator. The generic term for the crocodilians of the American con- 
 tinent, which have abroad, obtuse snout, and the canine teeth of the lower 
 jaw received into a pit of the upper. Kemains of closely allied forms have 
 
 76 
 
ALL ALU 
 
 been found in the Tertiaries of Europe; e.g.,A.Hantoniensis, from the Eocene 
 beds of the Hampshire basin. 
 
 All6chroite (Gr. allos, different, and cAroa, colour). A fine-grained, 
 massive variety of iron-garnet, so called from the colours it exhibits when 
 melted with phosphate of soda before the blowpipe. 
 
 Allophane (Gr. allos, different, and phaino, I appear). One of the clay 
 family, consisting essentially of silica, alumina, and water of crystallisation. 
 It occurs in translucent, reniform, or encrusting masses, of a pale blue, 
 white, green, or brown colour ; lustre resinous, and very brittle. 
 
 All6tropy, Allotr6pic (Gr. allotrSpos, turning otherwise, of a different 
 nature). A term employed by Berzelius to denote the fact that the same 
 body may exist in more than one usual condition, and have different 
 physical characteristics. Carbon is a good example of this condition, as 
 it crystallises perfectly in the diamond, imperfectly in graphite, and is 
 amorphous and quite distinct in anthracite and coal. 
 
 All6y (Fr. aloi, mixture of one metal with another). A natural or arti- 
 ficial compound of one or more metals ; as brass, an alloy of copper and 
 zinc ; bell-metal, a compound of copper and tin ; bronze, an alloy of copper 
 and tin ; type-metal, an alloy of lead and antimony. 
 
 Alluvium, Alluvial (Lat. luere, to wash, and ad, together). Matter 
 washed or brought together by the ordinary operations of water is said to 
 be alluvial, and the soil or land so formed is spoken of as alluvivm. The 
 soil of most of our river-plains (the " straths" and " carses" of Scotland, 
 and the "dales" and " holmes" and "fens" of England) is chiefly of alluvial 
 formation ; these low grounds having once been the sites of lakes, estuaries, 
 and shallow arms of the sea. All mud-deposits, as silt, warp, and the like, 
 when converted into dry land, constitute alluvium. See DILUVIUM. 
 
 A'lmandine. A lapidary's term for the violet or violet-red varieties of 
 the spinel-ruby ; for the noble garnet, which is also of a columbine red 
 approaching to violet ; and for the pyrope or " Elie ruby," which see. 
 
 Alpine. Pertaining to the Alps, or to any lofty mountain-range; ap- 
 plied to plants and animals whose natural stations and habitats are the 
 higher zones of lofty mountains like the Alps. 
 
 Alstonite. The baryto-calcite of Johnston, a carbonate of baryta and 
 lime, so called from occurring in the lead mines of Alston Moor, in Cumber- 
 land. See BARYTO-CALCITE. 
 
 Altaite. Hexahedral tellurium; a metallic ore occurring massive in 
 granular aggregates of a yellowish- white colour, and consisting of 60.35 
 lead, 1.28 silver, and 38.87 tellurium. It is found mixed with tellur- 
 silver in the Sawodinski mine in the Altai mountains ; hence the name. 
 
 Alternate Generation. A mode of reproduction, not unfrequent among 
 the radiata, in which the young do not resemble the immediate parent form 
 but that of the grand-parent. The species is thus maintained by an alter- 
 nating series of generations. 
 
 Alum (Lat. alumen, Gr. als, alos, salt). Alum is a double salt, the sul- 
 phate of alumina and potash, the crystals of which contain nearly 50 per 
 cent of water. Mineralogists mention several varieties, differing slightly 
 in external and other characters, according as one isomorphic element is 
 replaced by another, as potash- alum (34 sulphuric acid, 18 alumina, 10 
 potash, and 46 water), soda- alum, ammonia-alum, magnesia-alum, andiron 
 or feather alum. The alum of commerce is chiefly manufactured from 
 certain transition slates (Norway), from coal shales (Lanarkshire, &c.), 
 
 77 
 
ALU AMA 
 
 lias shales (Yorkshire), from lignite shales (Germany), and it occurs also 
 in the volcanic formations of Sicily, &c. ; hence the geological terms alum- 
 slate, alum-shale, aluminite, alum-stone, &c. Eocks containing alum in 
 notable proportion generally manifest its presence, when exposed to air and 
 moisture, by emitting whitish or yellowish- white efflorescences of the salt ; 
 and these as well as the water which trickles from the rocks are readily 
 detected by their strong styptic taste. 
 
 Alumina. The pure plastic principle of clay, which is usually a silicate 
 of alumina. Alumina is, in fact, an oxide of the metal aluminium, consist- 
 ing of aluminium 12, and oxygen 8. Alumina is rarely found in a pure 
 state in nature, and occurs chiefly as the basis of the clays, boles, loams, 
 and other argillaceous earths. In its pure crystallised state it constitutes 
 the sapphire, corundum, and other of our hardest gems. 
 
 Aluminite. The mineralogical term for the native hydrated sub-sulphate 
 of alumina, which generally occurs in roundish or reniform masses of a white 
 or yellowish- white colour. 
 
 Aluminum, Aluminium, or Alumium. The metallic base of alumina; 
 as calcium is the metallic base of lime, or sodium of soda. As a metal it 
 is now being prepared to some extent, in France and England, from the 
 Cryolite of Greenland ; and from its lightness and brilliant white colour 
 has been employed, though as yet with very indifferent success, as a sub- 
 stitute for silver. One of its most important applications is the manufac- 
 ture of a bronze, consisting of from 90 to 95 of copper, and from 10 to 15 of 
 aluminium. This bronze is extremely hard and tenacious, and bars of it 
 may be worked hot as easily as the best quality of steel. 
 
 A'lunite (Fr. alun, alum). Alumstone; occurring in minute rhombo- 
 hedral crystals, but very frequently in fine, granular, earthy, or compact 
 masses, intimately mixed with quartz or felspar. The mineral in its 
 purity consists of about 37 alumina, 39 sulphuric acid, 11 potash, and 13 
 water ; but the compact rock varies largely in its proportions of silica, some 
 kinds being so silicious as to be suitable for millstones. It is found in 
 Hungary, the Greek Isles, and in many parts of Italy the Roman alum, 
 valued on account of its purity, being chiefly obtained from this mineral by 
 repeated roasting and lixivation. " In volcanic regions," says Nicol, " it 
 is often formed by the action of sulphurous vapours on trachyte, and in 
 other felspar rocks by the decomposition of iron-pyrites." 
 
 Aliinogene (ahm, alum, and ginomai, I produce). A sulphate of 
 alumina, known also as hair-salt or feather-alum. It occurs in fine capil- 
 lary fibres forming crusts, and irregular botryoidal masses ; has a silky 
 lustre, yellowish-white colour; tastes like alum; and consists of 36.05 
 sulphuric acid, 15.40 alumina, and 48.55 water. It seems to be, for the 
 most part, a product of chemical changes now in progress ; often forms in 
 volcanic solfataras, or in clays, and felspar rocks containing pyrites ; and 
 is a frequent efflorescence on the walls of quarries and mines. 
 
 Alveolus (Lat.) A little trough or hollow channel ; applied variously in 
 natural history, as the alveolus or conical chamber of the belemnite. 
 Alveolites. A genus of corals composed of concentrically arranged tables 
 of short tubes, externally angular, and rounded within. 
 
 Amalgam. A compound of mercury with other metals is termed an 
 amalgam ; the union of any other metal with another, an alloy. Some 
 derive the term from the Greek ama, together, and gameo, I wed ; others 
 with more probability from malagma, a poultice or paste (from malasso, I 
 
 78 
 
AMA AMB 
 
 soften), in reference to the pasty nature of the admixture. A native 
 amalgam (of 36 silver and 64 mercury) occurs in the mines of Sweden, 
 Hungary, Spain, and South America, in fine silver-white plates, crusts, 
 and arborescent forms ; and in America another, under the name of ar- 
 querite, is worked as an ore of silver. 
 
 Amalgamation. The process of making an amalgam of mercury with 
 some other metal, for the purpose of separating the silver and gold they 
 may contain. This operation is founded on the property which mercury 
 possesses of dissolving these metals out of the minerals with which they 
 are associated. 
 
 Amazon-Stone. A variety of common felspar coloured green by the 
 oxide of copper, and so named from its occurring in rolled masses near the 
 river Amazon. See AXE-STONE. 
 
 Amber (Arabic). A well-known fossil gum or gum-resin, usually found 
 in connection with Tertiary lignites. It is hard, rather brittle, easily cut, 
 of various shades of yellow, and semi-transparent. It is very light, becomes 
 negatively electric by friction, and burns, like other hydro-carbons, with 
 much smoke and flame. It consists of about 70 carbon, 12 hydrogen, and 
 8 oxygen ; and frequently encloses chips of leaves, insects, and the like 
 showing that it must once have been in the state of a gummy or viscous 
 exudation. It occurs in irregular nodules, from the size of a hazel-nut to 
 that of a man's head, the latter size, however, being very rare. It is found 
 in Sicily, Poland, Saxony, Siberia, and Greenland, in Tertiary clays ; on 
 the Yorkshire coast of our own country ; but in particular on the Baltic 
 coast of East Prussia, where it is thrown up after storms, and strewn like 
 pebbles along the shore. It is also, but very seldom, obtained by digging 
 down to the looser beds of the Tertiary lignites in Northern Germany ; and 
 there it appears in connection with coniferous trunks and branches. These 
 forests of Amber Pines (Pinites succinifer) seem to have been situated in 
 the south-eastern part of what is now the bed of the Baltic (about 55 N. 
 lat., and 37 to 38 E. long.), and were probably destroyed at the com- 
 mencement of the Drift period. 
 
 Ambergris (Fr. Grey -amber, in allusion to its amber-like character). 
 An odorous solid substance, supposed by some to be a morbid secretion 
 from the liver or intestines of the spermaceti whale, analogous to the 
 biliary calculi ; and by others, to be merely the indurated faeces of the 
 animal, perhaps somewhat altered by disease. It is usually found floating 
 or cast on shore, in irregular lumps. No analogous fossil substance is yet 
 known to geologists. 
 
 Amblygonite (Gr. amblygonios, having an obtuse angle). A phosphate 
 of alumina and lithia occurring in granitic rocks, either massive or in 
 oblique rhombic prisms, which are rough externally and of a greenish- 
 white or sea-green colour ; translucent ; with a vitreous lustre inclining 
 to pearly. 
 
 Amblypterus (Gr. amUys, blunt, and pteron, fin). Literally "blunt or 
 broad fin ; " a genus of ganoid fishes belonging to the Lepidoid family, 
 occurring in the Carboniferous formation, and characterised, as the name 
 implies, by their very large and wide fins, composed of numerous rays. 
 Scales rhomboidal and highly enamelled ; tail boldly heterocerque. 
 
 Amblyiirus (Gr. amblys, blunt, and tnira, a tail). Literally "blunt or 
 broad tail ; " a genus of Lepidoid fishes, found fossil in the Lias formation, 
 and so named from the full development of the caudal fin. 
 
 79 
 
AMB AMM 
 
 Ambulacra (Lat. ambulacrum, an avenue or walking-place). The per- 
 forated series of plates in the crust of the sea-urchins, through which the 
 walking-feet are protruded, and which form marked bands or zones on the 
 exterior when the crust is denuded of its spines. Ambulacra!. Applied to 
 these plates in contradistinction to the imperforate qr interamlulacral ones. 
 
 A'methyst. Quartz or rock-crystal, coloured by a minute portion of 
 iron and manganese. The amethyst is a transparent gem of a purple or 
 violet-blue colour ; it is sometimes naturally colourless, and may at any 
 time be deprived of its colour by the action of heat. Some derive the 
 name from its colour, which resembles wine mixed with water ; while 
 others think it obtained its name (Gr. a, priv., and methystes, drunkard), 
 from its supposed virtue of preventing intoxication, and hence worn by 
 topers as an amulet. Amethystine. Possessing the properties of an am- 
 ethyst ; having that violet-blue tinge or colour peculiar to the amethyst, 
 as "Amethystine Quartz." 
 
 Amethystoline. The name given to the volatile fluid observed by Sir 
 David Brewster in the minute cavities of amethyst. 
 
 AmiantMnite. A massive variety of actinolite, of a yellowish-grey or 
 ash colour, and having a confusedly foliated and fibrous fracture, whence 
 the name. 
 
 Amianthus (Gr. a, priv., and miaino, to soil). This term, though often 
 used as synonymous with asbestos, properly includes only the varieties 
 which occur in delicate and regular silky fibres. The name is said to 
 be derived from the incombustible nature of the mineral, which, when 
 woven into cloth, admits of being cleansed by being thrown into the fire. 
 That small fancy fabrics can be manufactured of amianthus is well known : 
 it was occasionally so employed by the ancients, and is still used for that 
 purpose in Siberia, Italy, and the Pyrenees. It is also employed as incom- 
 bustible lamp- wicks ; for filling gas-grates the fibres remaining red-hot 
 without being consumed ; and attempts have been made to manufacture 
 it into an incombustible paper. Amianthus is found abundantly in many 
 countries, particularly in primitive districts ; and occurs in veins in which 
 the filaments or fibres are perpendicular to the surfaces of the vein, and of 
 various lengths, according to the thickness of the vein, which is sometimes, 
 though rarely, a foot. Like the Hornblendes, to which it belongs, it con- 
 sists chiefly of silica (58), magnesia (25), lime (12), with traces of alumina, 
 iron, manganese, and water. See ASBESTOS. Amianthiform and Amian- 
 thoid. Having the form or likeness of amianthus. 
 
 Ammite (Gr. ammos, sand). An old mineralogical term for roestone or 
 oolite, and indeed for all those sandstones composed of rounded and loosely 
 compacted grains like oolite. 
 
 Ammonia. A transparent pungent gas, formed by the union of nitrogen 
 and hydrogen, and named from sal-ammoniac (muriate of ammonia), of 
 which it forms the basis. Ammonia is of geological interest, as being one 
 of the products given off by active volcanoes. See SAL-AMMONIAC. 
 
 A'mmonite. The fossil shell of a numerous and varied genus of cephalo- 
 podous mollusca, coiled in a plane spiral, and chambered within like the 
 existing nautilus ; so called from the resemblance of the shell to the horns 
 on the statue of Jupiter Ammon. " Cornu Ammonis," " Whitby snakes," 
 and "snakestones," are obsolete synonymes. See AMMONITID^S. In the 
 ammonites proper, the shell is discoidal ; inner whorls more or less con- 
 cealed ; septa undulated ; sutures lobed and foliated ; siphuncle dorsal. 
 
 80 
 
AMM AMP 
 
 The range of the genus is from the Trias to the Chalk inclusive ; and already 
 upwards of 500 species have been described. These have been arranged 
 by paleontologists (Von Buch and D'Orbigny) into six sections, according 
 as the back of the shell is keeled, crenated, sharp, channeled, squared, or 
 round and convex ; and these sections have been again divided into fifteen 
 groups, according to form, armature, sutures, or other peculiarity. They 
 are as follows : 
 
 1. Arietes. \ 
 
 2. Falciferi. V Back keeled. 
 
 3. Cristati. ) 
 
 **- ted - 
 
 6. Disci Back sharp. 
 
 7. Dentati. Back channeled. 
 
 8. Armati. ") 
 
 9. Capricorni. V Back squared. 
 
 10. Ornati. ) 
 
 11. Heterophylli. \ 
 
 12. Ligati. 
 
 13. Annulali. \ Back round, convex. 
 
 14. Coronati. 
 
 15. Fimbriati. } 
 
 Figures of these types or groups are given by D'Orbigny, and on the Palae- 
 ontological Map of the British Islands in Johnston's ' Physical Atlas.' 
 
 Ammonitidae. A numerous extinct family of tetrabranchiate cephalo- 
 pods of which the well-known ammonite is the type. The family ranges 
 from the Devonian to the Chalk inclusive, becoming extremely abundant 
 and varied in form in the upper Secondary formations. It includes the 
 goniatites, bactrites, ceratites, ammonites proper, criocerites, toxocerites, ancy- 
 locerites, scaphites, heliocerites, turrilites, hamites, ptychocerites, and baculites, 
 which see. In the Ammonitidse the shell is external and many-chambered ; 
 body-chamber elongated ; aperture guarded by processes, and closed 
 by an operculum ; sutures angulated, lobed, or foliated ; siphuncle ex- 
 ternal (or dorsal as regards the shell). The shell has essentially the same 
 structure as that of the nautilus a porcellanous layer externally, and a 
 nacreous lining internally. In some species of ammonite the shell is armed 
 with prominent spines or tubercles ; and in others the outer margin is 
 furnished with curious projecting processes. The Ammonitid, in one or 
 other of their genera, are perhaps the most remarkable of Secondary 
 mollusca. See CEPHALOPODA. 
 
 Amorphous (Gr. a, without, and morphe, form). Applied in geology and 
 mineralogy to rock-masses and minerals that have no regular or determi- 
 nate structure, in contradistinction from those which, like basalt and rock- 
 crystal, always appear in some definite form. Void of structure ; massive. 
 
 Amorphozoa (Gr. a, without ; morphe, form ; and 20071, an animal). The 
 lowest class of the animal kingdom, containing the sponges and their allies ; 
 so called from their want of regular symmetrical structure. Fossil remains 
 of this class occur in notable abundance in the Chalk formation. 
 
 A'mpelite (Gr. ampelos, the vine). A term used by Brongniart for alum- 
 slate, which occurs both in the metamorphic and fossiliferous series. 
 
 Amphi. A Greek prepositional prefix signifying about, on both sides, 
 near to, or concerning ; and frequently used to imply doubt as to which of 
 
 81 P 
 
AMP AMY 
 
 two sides, or to which of two things, the object in question belongs ; as 
 amphibious, capable of living either in the water or on land. 
 
 Amphibia (Gr. amphi, both, and bios, life). Applied to animals capable 
 of living either in water or on land ; but in zoology more strictly to those 
 batrachians or frog-like reptiles the axolotls, menobranchi, sirens, and 
 proteus which have both lungs and gills, and consequently adapted for 
 life in either element. 
 
 Amphibichnites (amphibia, animals capable of living on land or in 
 water, and ichnon, a footstep). The generic term for fossil footprints 
 that seem to have been impressed by the feet of amphibious reptiles as 
 they passed over the soft yielding beach to and from the waters. 
 
 Amphibole and Amphibolite. The names usually given by French 
 geologists to Hornblende and Hornblende Rock, which see. The terms are 
 derived from the Greek amphibolos, ambiguous or equivocal, in allusion to 
 the difficulty of distinguishing hornblende from augite, which is similarly 
 constituted. 
 
 Amphicyon (Gr. amphi, implying doubt, and Jcuon, dog). A large car- 
 nivorous quadruped, found principally in miocene Tertiaries, and so termed 
 from its intermediate position between the digitigrade and plantigrade 
 families, as indicated by its tuberculated molars or carnassial teeth. 
 
 A'mphigens (Gr. amphi, all around, and ginomai, I am formed). Plants 
 which increase by the growth or development of their cellular tissue on all 
 sides, as the lichens. See tabulations, " VEGETABLE SCHEME." 
 
 Amphilestes (Gr. amphi, implying doubt, and lestes, beast of prey). A 
 small quadruped of doubtful relationship, only the lower jaw of which has 
 yet been found in the Stonesfield oolite, Oxfordshire. From the structure 
 of its teeth the molars having three cusps, the large middle one of which 
 has two small accessory tubercles or cuspules it is supposed to be an in- 
 sectivorous marsupial, allied perhaps to amphitherium. 
 
 AmpMpeltis (Gr. amphi, doubtful, and peltis, provided with a shield or 
 buckler). A provisional genus of small crustaceans from the Devonian 
 rocks of Nova Scotia, and so called from the doubtful affinity of its frag- 
 mentary carapace and segments to any existing order. Apparently allied 
 to the phyllopods. 
 
 Amphistegina (Gr. amphi, on both sides, and stege, a roof). A genus of 
 foraminiferous shells, occurring abundantly in the Tertiary basin of Vienna, 
 and so termed from the flatly conical or roof-like aspect both of its upper 
 and under surface. According to D'Archiac, it takes the same place among 
 the foraminifera of the Miocene era which the nummulites occupy in the 
 Eocene period. 
 
 Amphitherium (Gr. amphi, implying doubt, and therion, wild beast). An 
 insectivorous mammal of the Oolitic epoch, whose teeth and jawbones 
 have been found in the Stonesfield slate of Oxfordshire. The doubt that 
 hangs over the tme affinities of these remains (whether marsupial or 
 placental) has necessitated the provisional name of amphitherium. 
 
 Aniphoracrinus (Lat. amphora, a cup or goblet.) A genus or rather sub- 
 genus of Carboniferous crinoids, chiefly distinguished by the arrangement 
 of their radial plates. The "cup" or body of this genus is small and 
 shallow as in actinocrinus, to which it is closely related. 
 
 Amygdaloid (Gr. amygdalon, an almond, and eidos, appearance). This 
 term is applied to certain igneous rocks containing small almond-shaped 
 vesicular cavities, either partially or entirely filled with agate, jasper, calc- 
 
 82 
 
ANA 
 
 spar, and other minerals. These minerals being of a different colour from 
 the mass of the rock in which they are imbedded, look like almonds in a 
 cake ; hence the terms amygdaloid and amygdaloidal. The amygdaloids 
 as "amygdaloidal trap-tuff," "amygdaloidal wacke," &c. are especially 
 abundant in the Trap series, and many of them seem to have originally 
 been open vesicular lavas, through which water charged with siliceous and 
 calcareous solutions had percolated for ages, until, finally tilling up the 
 cavities with the agates, calc-spars, &c., already alluded to, they became 
 the amygdaloids in question. 
 
 Anadromous (Gr. ana, upwards, and dromos, a flight or running). Liter- 
 ally "running up;" applied in zoology to aquatic animals which, like the 
 salmon and sturgeon, periodically forsake the waters of the ocean and 
 ascend into fresh-water lakes and rivers for the purpose of spawning. 
 Fishes are thus spoken of as marine, fresh-water, and anadromous, the 
 two former never quitting their native elements, and incapable of subsist- 
 ing in any other, and the latter possessing the power and habit already 
 alluded to. 
 
 Anal (Lat. anus). Pertaining to or situated near the anus, as the anal 
 fin. The anal fin in fishes is that which is placed between the vent and 
 tail, and expands vertically downwards. 
 
 A'nalcime (Gr. a, without, and alkimos, strong). A zeolitic mineral found 
 abundantly in trappean rocks, and so named by Haiiy on account of its 
 feebly electric properties. A specimen from Kilpatrick Hills consisted 
 (according to Connel) of silica 55.07, alumina 22.23, soda 13.71, potash 
 and lime a trace, and water 8.22. 
 
 A'nalogue (Gr. ana, with, and logos, reasoning). An object that has a re- 
 semblance to, or correspondence with, another. "Analogue" has reference 
 to similarity of function; "homologue" to identity of parts. Thus, the wing 
 of a bird and the dermal expansion of a bat are analogues, because they 
 each enable their respective possessors to fly or sustain themselves in the 
 air ; but the wing-bones of the bird and the arm-bones of the quadruped 
 are homologues, being anatomically identical. Analogue and homologue 
 (which see), and analogo^ls and homologous, are contradistinguishing terms. 
 
 Analogy (Gr. ana, with, and logos, reasoning). That relationship, re- 
 semblance, or correspondence which one object bears to another in 
 functional duty or performance. For the precise differences between 
 analogy, affinity, and homology, see these terms. 
 
 Ananchytes. A genus or subdivision of fossil sea-urchins belonging to 
 the tribe Spatangidce, and especially characteristic of the upper Chalk 
 formation. They are readily distinguished by their elevated helmet-like 
 form, by their simple ambulacra converging towards the summit, and by 
 the transverse mouth and oblong outlet situated on the inferior face of the 
 flat base, and towards the margin. Known in the south of England as 
 " shepherd's crowns," and "fairy-loaves." See SPATANGID^B. 
 
 Andstomose (Gr. ana, and stoma, mouth). To inosculate, to unite the 
 mouth of one vessel with that of another, as the arteries with the veins ; 
 hence such vessels are said to be anastomosing, or running one into the other. 
 
 A'natase (Gr. anatasis, stretching forth). Another name for pyramidal 
 titanium ore, or octcedrite, which is all but a pure oxide of titanium. Anatase 
 is remarkable for its electrical properties ; occurs in the granitic and 
 crystalline rocks ; of a dark indigo blue, hyacinth red, or yellowish-brown 
 colour; and in elongated pyramidal crystals whence the name. 
 
ANC ANI 
 
 Anchorage or Anchor-ground. Any portion of a bay, estuary, channel, 
 or arm of the sea, where the bottom is unimpeded by rocks, and the water 
 of a suitable depth for ships riding at anchor. 
 
 Ancyloceras (Gr. ankulos, incurved ; keras, horn). A genus of the Am- 
 monitidse peculiar to the Oolite and Chalk, and so named from the singular 
 shape of the shell, which is at first discoidal, with separate whorls, after- 
 wards produced at a tangent, and bent back again like a hook or crosier. 
 
 Andaliisite. One of the garnet family, found chiefly imbedded in mica- 
 schist, or in druses in other crystalline rocks, and so called from its being- 
 first discovered in Andalusia. It occurs for the most part in large pris- 
 matic crystals ; is always coloured, grey to green, flesh of peach-blossom 
 red, violet blue or reddish-brown ; and consists of 40 silica and 60 alumina, 
 with traces of iron, manganese, and lime. 
 
 A'ndesite. The name given by Gustavus Rose to a trachyte of the 
 Andes, which contains the felspar called Andesine, together with glassy 
 felspar (orthoclase) and hornblende disseminated through a dark-coloured 
 
 Andrias. The generic name given by Cuvier to the great aquatic Sala- 
 mander, from the Miocene fresh- water beds of GEningen, whose remains 
 in 1700 were supposed to be human, and described by Scheuchzer as " homo 
 diluvii testis." 
 
 Anemometer (Gr. anemos, the wind, and metron, a measure). An instru- 
 ment for determining the direction and measuring the force and velocity 
 of the w inds, which see. 
 
 A'neroid (Gr.) Literally without fluid. In the aneriod larometer the pres- 
 sure of the atmosphere is measured by the elevation or depression of the 
 surface of a closed metallic vessel partially exhausted of air. The pres- 
 sure of the atmosphere being marked at a given time, any alteration is 
 indicated by the movements of the surface of the thin corrugated metal, 
 and communicated to wheels marking the change on a dial furnished with 
 an index. Being easily carried about, the aneriod is extremely useful in 
 enabling the geologist and traveller to approximate the relative heights of 
 situations. 
 
 Angiosperms (Gr. angeion, a vessel, and sperma, seed). Plants whose 
 seeds are encased, or in seed-vessels, in contradistinction to gymnosperms. 
 See tabulations, " VEGETABLE SCHEME." 
 
 Anhydrite (Gr. a, without, and hydor, water). A transparent gypsum 
 or sulphate of lime occurring in a crystalline form without water of crystal- 
 lisation. Anhydrite occurs chiefly with rock salt and gypsum, or in the 
 clays associated with these deposits. The fine crystalline varieties are 
 known as muriacite the granular asvulpinite; and all are much harder 
 and heavier than ordinary gypsum, into which, however, they become con- 
 verted by the slow absorption of water. 
 
 Anhydrous (Gr. a, without, and hydor, water). Without water ; applied 
 to minerals which do not contain water as an ingredient. Without water 
 of crystallisation. The opposite of Enhydrous. 
 
 Animalcules (Lat., diminutive of animal). A general term in zoology 
 for exceedingly minute animals which cannot be stiidied without the 
 assistance of the microscope. Speaking of the fossil animalcules of the 
 Chalk, Dr Mantell remarks that " for the most part the microscopic shells 
 in chalk and flint are filled with amorphous mineral matter; but recent 
 observations have shown that in numerous examples the shell contains the 
 
 84 
 
ANN ANO 
 
 body of the animal, in some instances silicified, but in others in the state of 
 a dried animal substance like the ink-bag of the cuttle-fish in lias, the soft 
 part of cephalopoda in clay, and the capsule of the eye, and the membranes 
 of the stomach of certain fishes in chalk." 
 
 Annealing. The process by which glass and porcelain are rendered less 
 brittle, and by which the metals become tougher and more malleable. 
 It is performed by placing the materials to be operated on in furnaces or 
 ovens heated to a certain temperature, and then allowing them to cool gra- 
 dually and slowly. During the process the molecular arrangement of the 
 material undergoes a change analogous to what takes place in lava, which 
 forms granular or glassy rocks according to the rapidity with which it is 
 cooled the quicker the process, the glassier and more brittle the product. 
 
 Annellida (Lat. annellus, a little ring). Annelids. One of the classes of 
 the animal kingdom having their bodies formed of a great number of small 
 rings like the earth-worm, a double-ganglionated nervous cord, and red 
 blood. They have been variously subdivided ; but that arrangement which 
 ranks them as Errantia, walking or swimming annelids, like the nereis; 
 Tiibicola, those which inhabit solid tubes, like the serpula ; Terricola, 
 those burrowing in the earth, as the earth-worm (lumbricus); and Suctoria, 
 those furnished with a sucking cavity at each end, like the leech (kirudo), 
 is perhaps the most intelligible. The casts, and tracks, and burrow-holes 
 of annelids occur in all formations, arenicolites, scolites, &c. 
 
 Annularia (Lat. anmilus, a ring). A genus of fossil herbaceous plants 
 with verticillate foliage like asterophyllites, but having the whorls arranged 
 on the same plane with the stems on which they grew. It is supposed that 
 they were aquatic plants, and that the stems and leaves floated on the 
 surface of the water. 
 
 Annul6sa (Lat. anmilus, a ring). A designation given by Macleay to 
 the Articulata, in allusion to their ringed or annulated bodies. The term 
 in this sense is seldom employed by other zoologists. 
 
 A'nodon, Anod6nta (Gr. a, priv., and odous, odontos, a tooth). The swan 
 mussel ; a genus of the Unionidce or river mussels, deriving its name from 
 the circumstance that its shell has no teeth or articular processes at the 
 hinge. Recent and fossil. 
 
 Anomalous (Gr. a, not, and omalos, like to, or similar). Irregular, 
 deviating from a general rule, order, method, or analogy. Anomaly. Ir- 
 regularity, deviation from the common rule. 
 
 Anomodontia (Gr. anomos, irregular, and odous, a tooth). One of Pro- 
 fessor Owen's orders of extinct reptiles, embracing three families the 
 Dicynodonts, Cryptodonts, and Gnathodonts and apparently restricted 
 to the Triassic period. The order is characterised by the teeth being either 
 wanting, or confluent with tusk-shaped premaxillaria, or confined to a 
 single pair in the upper jaw, having the form and proportions of canine 
 tusks. The vertebrae are bi-concave, the pleura-pophyses of the trunk 
 long and curved, the pelvic bones large, and the limbs formed for walking. 
 
 Anom6pteris (Gr. anomos, without rule, and pteris, fern). Literally 
 " anomalous fern," and so named because the plants differ from all recent 
 and fossil ferns. In this genus, which is peculiar to the New Red Sand- 
 stone, the leaves are very large, and deeply pinnate ; the leaflets long, 
 linear, entire, and traversed by a distinct median rib ; the secondary veins 
 are simple, perpendicular to the mid-rib, and thickening towards their free 
 extremities. 
 
 
ANO ANT 
 
 Anomoiira, Anomura (Gr. anomos, irregular, without rule ; and oura, tail). 
 A family or sub-order of the decapod crustaceans characterised by 
 their irregular tails e.g., the hermit-crab and so named in- contradistinc- 
 tion to the brachyurous or short-tailed crabs, and the macrurous or long- 
 tailed lobsters, &c. 
 
 Anoplotherium (Gr. a, without ; oplon, weapon ; and therion, beast). 
 A genus of quadrupeds found in European Tertiaries, and so called from 
 being destitute of any organs of defence, as tusks, claws, or horns. The 
 common anoplothere (A . commune) has been taken as the type of a small 
 family, the ANOPLOTHEKID^;, which seem to constitute a sort of transi- 
 tion from the pachyderms to the ruminants. There are several species, 
 from the size of a hare to that of a dwarf ass ; and from the situations in 
 which they are found, they appear to have lived in herds, in swamps and 
 marshes. In some the tail is long and thick, as if it had assisted the 
 animal in swimming, in others it is short and taper ; in all, the legs are 
 slender, and the feet terminate in two large toes as in the ruminants, while 
 their tarsal bones resemble those of the camel. Their dentition is peculiar 
 there being six incisors in each jaw, on each side of which was a small 
 canine, and behind these (without leaving any interval) seven molars, re- 
 sembling those of the rhinoceros. According to Cuvier, the anoplothere 
 stands in one respect between the rhinoceros and horse, and in another be- 
 tween the hippopotamus, hog, and camel. 
 
 An6rtliite (Gr. a, without, and orthos, upright). One of the felspar 
 family ; and so called (without right angles) to distinguish it from orthoclase, 
 two of whose cleavages are at right angles to each other. 
 
 Anoiira (Gr. a, without, and oura, tail). Tailless ; a class of the batra- 
 chian reptiles, including the frog, toad, &c., which are all anourous, or 
 destitute of tails. See tabulations, "ANIMAL SCHEME." 
 _ Antagonist Forces. Two powers in nature, one counteracting the other, 
 and preserving a general equilibrium on or within the earth's crust ; e.g., 
 fire and water. 
 
 Antarctic (Gr. and, opposite, and arctic). Applied to the regions sur- 
 rounding the South Pole, as being directly opposite to those of the Arctic 
 or North Pole; hence we speak of the "Antarctic Circle," "Antarctic 
 Seas," &c. 
 
 Antholites or Antholithes (Gr. anthos, flower, and lithos, stone). The 
 general term for the fossil inflorescence of plants, or rather the impress of 
 their flowers. Such inflorescence occurs in the shales of the Coal-measures, 
 and more abundantly in Tertiary strata. The affinities of the Palaeozoic 
 antholites are altogether undetermined ; those of the Tertiary epoch seem 
 related to the Liliacece and other existing orders. 
 
 Anthophyllite (Gr. anthos, flower, and phyllon, a leaf). A species of 
 hornblende (tremolite), of a clove-brown colour, occurring in radiating 
 columnar aggregates ; and so named from the resemblance of its colour 
 to that of the anthophyllum, or clove. 
 
 A'nthracite (Gr. anthrax, carbon). A species of coal almost wholly de- 
 prived of its bitumen. It may be regarded as a natural coke or charcoal, 
 formed by subterranean or chemical heat. Ordinary bituminiferous coal is 
 often found converted into a kind of coke by the contact of igneous rocks ; 
 and in this way some anthracites may have originated, though the majority 
 seem to be the result of that slow change or metamorphosis which all rock- 
 masses seem to undergo in the course of ages. As a mineral, anthracite 
 
ANT 
 
 occurs massive and amorphous (though portions have occasionally a slaty, 
 columnar, or fibrous structure), has a sub-conchoidal fracture, less or more 
 of a metallic lustre, or a greyish-black or iron-black colour, streak un- 
 altered, conducts electricity perfectly, and burns open with a very weak or 
 no flame. It varies greatly in composition, though good American sorts 
 generally yield about 90 cabron, 3 hydrogen, 5 ashes, and the remainder 
 oxygen and hydrogen. Submitted to the microscope, either in thin slices 
 or in a state of ash, many varieties exhibit the vegetable structure, and 
 leave no doubt as to the organic origin of all. Though not so convenient 
 in an industrial point of view as ordinary coal, anthracite is gradually 
 rising in importance for the manufacture of the metals, steam-raising, and 
 even for household purposes the United States at present consuming 
 annually about six millions of tons. " It is very common " (Nicol's ' Man. 
 of Mineral.') "in many parts of the English, Scottish, and Irish coal-fields. 
 It forms whole beds in the Alps, as in the Valais, Piedmont, Savoy, and 
 Dauphine* ; in the Pyrenees ; and in various parts of France. In Germany 
 it occurs in Silesia, Bohemia, Saxony, and the Harz, but not in very large 
 amount. It is especially abundant in the United States, as in Rhode 
 Island, Massachusetts, and above all in Pennsylvania, where it seems to be 
 an altered portion of the common bituminous coal of the Western States." 
 See COAL FAMILY. 
 
 Anthraconite (Gr. anthrax, coal). A mineralogical term applied to 
 those varieties of marble which, like the Kilkenny, have a coal-black lustre 
 when polished. Most of the black marbles contain bitumen, and yield a 
 sulphureo-bituminous odour when struck by the hammer ; and in this case, 
 like other fetid limestones, are known as swinestones or stinksteins. 
 
 Anthracopalaemon (Gr. anthrax, coal ; palcemon, prawn). A genus of 
 macrurous crustacean, from the Carboniferous formation of Lanarkshire, 
 and founded by Mr Salter on the carapace, and some other fragments 
 from the Shotts coal-field. Carapace rectangular-oblong, serrate in front 
 and along the sides, with a faint cervical furrow at the anterior third. 
 Rostrum strong, projecting ; posterior ridge prominent, complete to the 
 hinder margin, separated abruptly from the rostrum by the transverse 
 furrow. See PAL^EOCRANGON. 
 
 Anthracosaiirus (Gr. anthrax, coal, and sauros). Literally "coal- 
 saurian ; " a large labyrinthadont saurian occurring in some abundance in 
 the coal-fields of Lanarkshire, and founded by Professor Huxley, in 1862, 
 on a beautifully preserved skull, with palatine surface, exhibiting all the 
 teeth in situ, from the black-band ironstone of Airdrie. This skull (see 
 ' Geological Journal') was 15 inches long, by 12 inches in width ; but frag- 
 ments since discovered indicate individuals nearly double these dimensions. 
 
 Anthracotherium (Gr. anthrax, coal, and therion, beast). A fossil pachy- 
 dermatous animal, first found in the Tertiary lignites or wood-coals of 
 Cadibona in Liguria; hence the name. So far as yet determined, the 
 genus seems to stand intermediate between river-hog and hippopotamus. 
 In the lignites of Savone, remains of carnivora, marsupialia, bats, birds, 
 crocodiles, tortoises, and fish occur along with those of the anthracothere. 
 
 Anthrakerpeton (Gr. anthrax, coal ; erpeton, lizard). A genus of rep- 
 tiles, founded by Professor Owen, in 1864, on some remains (teeth, ribs, 
 and portions of the cranial bones) from the coal-field of Glamorganshire. 
 According to its describer, this small reptile "belonged to that low, pro- 
 bably primitive, air-breathing type, which, with developmental condi- 
 
 87 
 
ANT APA 
 
 tions of the bones like those in some fishes, and very common in Devonian 
 fishes, showed forms of the skeleton more resembling those in saurian 
 reptiles than are attained by any of the more specialised batrachian air- 
 breathers of the present day." 
 
 Anthrop6graphy. That branch of physical geography which treats of 
 the distribution of the human species, as distinguished by physical features, 
 language, institutions, and customs. 
 
 Anthropoid (Gr. anthropos, man, and eidos, form). Resembling the 
 human form ; applied, for example, to those species of the monkey tribe 
 (the "anthropoid apes ") that most closely approach to the form of man. 
 
 Anthrdpolite (Gr. anthropos, man, and lithos, stone). A petrifaction of 
 the human body ; a term which has been applied to the petrified human 
 bones from Guadaloupe and other localities. These remains can scarcely 
 be considered fossil, or even sub-fossil ; but must be regarded in the same 
 light as any recent petrifaction produced by the incrusting action of 
 calcareous waters. 
 
 Anthropology. Literally a discourse or reasoning about human nature ; 
 the science that treats of man in a natural history point of view ; the 
 natural history of the human species, physiological, intellectual, and moral. 
 Anthropological. Pertaining to the science or natural history of Man. 
 
 Anticlinal (Gr. anti, on opposite sides, and klino, I bend). Applied to 
 strata which dip in opposite directions from a common ridge or axis, like 
 'the roof of a house, and form what is termed an "anticline" or " saddle- 
 back." Syncline and Synclinal are the opposite terms, which see. 
 
 A'ntimony. One of the metals, of a tin- white colour, with a greyish or 
 yellowish tarnish ; somewhat sectile, but so brittle as to be easily reduced 
 to powder by trituration ; fuses at 900, and has a specific gravity of 6.712. 
 The most abundant ore is the sulphuret of antimony, occurring in veins in 
 the older Secondary and Transition strata. The metal is used in medicine, 
 but principally to form alloys with other metals, as type-metal, which is a 
 compound of lead and antimony. The name is derived by some from the 
 Greek words anti and monos, signifying that it is never found by itself, but 
 in combination with other metals ; and by others from antimoine, that is 
 "anti-monk," in allusion to a ridiculous story told of Basil Valentine, its 
 discoverer in 1620, who, observing that hogs fattened rapidly on receiving 
 small doses of it, administered it to his fellow-monks, but unluckily in such 
 proportions as to prove fatal to them ; hence the term anti-moine. 
 
 Antipodes (Gr. anti, opposite, and pous, podos, foot). Applied to those 
 who dwell on opposite sides of the globe, as having their feet opposed to 
 each other. Those dwelling in New Zealand, for example, are the anti- 
 podes of those in Britain. 
 
 Antiseptic (Gr. anti, opposed to, and sepo, I putrefy). Substances which, 
 like common salt and tannin, prevent putrefaction in animal and vegetable 
 matter, are said to be antiseptics, or to possess antiseptic properties. 
 
 Apateon (Gr. a cheat; deceptive). The name originally proposed by 
 Von Mayer for the then imperfect remains of the arcliegosaurus ; because, 
 so far as the fragments admitted of discrimination, "its head might be 
 that of a fish, as well as that of a lizard or of a batrachian." See ARCHE- 
 
 GOSAUEUS. 
 
 Apatite (Gr. apate, deceptive). A genus of calcareous earths, composed 
 of 55.75 lime, and 44.25 phosphoric acid ; hence known as phosphates of 
 lime. In most varieties hydrochloric acid is also present, from a mere 
 
 88 
 
APR APO 
 
 trace up to 2.10 per cent. Apatites are of various colours, white, yellow- 
 ish-white, greenish-white, brown, blue, &c., and occur both massive and 
 crystallised. From their fracture, &c., they are spoken of as foliated, 
 conchoidal, and massive the massive having an uneven fracture, and 
 being generally known by the name of "phosphorite." Apatite occurs in 
 connection with metalliferous veins in the metamorphic and granitic rocks, 
 and is found in Cumberland, Devon, and Cornwall ; in Spain, Germany, 
 Norway, and America. The phosphorites of Spain and Norway have 
 recently acquired additional interest from the proposal to employ them in 
 the preparation of phosphatic manures a purpose to which the phosphatic 
 nodules of the English greensand have been applied with eminent success. 
 According to Daubeny, the phosphorite of Estramadura consists of 81.15 
 phosphate of lime, 14.00 fluoride of calcium, 3.15 peroxide of iron, 1.70 
 silica, and 0.2 per cent chlorine. There is also a talc-apatite or magnesian- 
 apatite, found in the Ural Mountains, which is probably a decomposed 
 apatite the lime being replaced to the extent of from 6 to 8 per cent by 
 magnesia. From their variety of colour, fracture, &c., the apatites are apt 
 to be mistaken for other minerals ; hence the designation deceptive. 
 
 A'phanite (Gr. aphanes, not discernible). A compact homogeneous rock 
 of the Trap family, breaking with a smooth surface like some basalts, and 
 consisting of hornblende, quartz, and felspar, in combination so intimate, 
 that they are individually ^lndiscernible ; hence the name. It is known 
 also as cornean (cornu, a horn), in allusion to its toughness and compact 
 texture. 
 
 Aphelion (Gr. apo, from ; kelios, the sun). The point in a planet's orbit 
 at which it is farthest from the sun ; its perihelion being the point at which 
 it is nearest. 
 
 A'phrite (Gr. apkros, froth or foam). Known also as earth-foam and 
 foam-spar. A fine scaly variety of calcareous spar or carbonate of lime, 
 having a shining pearly lustre and somewhat greasy feel. Found in veins 
 and cavities in various formations. 
 
 Apiocrinite (Gr. apion, a pear, and encrinite, which see). A sub-genus of 
 encrinites, distinguished by their pear-shaped receptacle, and peculiar to 
 the Chalk and Oolitic formations. In the Pear Encrinite the roots seem to 
 have been confluent, the stem round and of moderate length, the digestive 
 cavity pear-shaped, the arms rather short than slender. "When living," 
 says Dr Buckland (' Bridgewater Treatise '), " their roots were confluent, 
 and formed a thin pavement or crust over the bottom of the sea, from 
 which their stems and branches rose into a thick submarine forest, com- 
 posed of those beautiful zoophytes. Its stems and bodies are occasionally 
 found united, as in their living state ; the arms and fingers have almost 
 always been separated ; but their dislocated fragments still remain cover- 
 ing the pavement of roots that overspreads the surface of the subjacent 
 Oolitic limestone." 
 
 A'podal (Gr. a, without, pous, podos, foot). Literally without feet; ap- 
 plied in zoology to those fishes which, like the eel, sword-fish, wolf- fish, &c., 
 are destitute of ventral fins. The Apodes constitute the fourth order in 
 Cuvier's arrangement, but merely a sub-order in more recent systems. 
 
 A'pogee (Gr. apo, from ; ge, the earth). That point of the moon's orbit 
 in which she is farthest from the earth ; her perigee being the point in 
 which she is nearest the earth. 
 
 Apophyllite (Gr. apophyllizo, to strip off leaves). One of the Zeolite 
 
APO ARA 
 
 family, known also as ichthyopUkalmite or fish-eye-stone, and deriving its 
 present name from its lamellar or leaf -like texture, and ready exfoliation 
 under the action of ttte blowpipe. It consists of 52.7 silica, 26 lime, 4.4 
 potash, and 16.7 water. 
 
 Ap6physis (Gr. springing from, of the same nature). A process of a 
 bone, and part of the same bone; and in this respect differing from 
 epiphysis, which is a process attached to a bone, and not a part of the 
 same bone. 
 
 A'pteryx (Gr. a, without; pteryx, a wing). Literally " wingless ;" a rare 
 cursorial bird peculiar to New Zealand, and apparently approaching the 
 verge of extinction. The existing apteryx, or "kiwi," of which there are 
 two or three species, is little larger than a Guinea-fowl ; but an extinct 
 species, the palapteryx, has been found in the ancient river-silts of New 
 Zealand, rivalling in size the emeu and ostrich. 
 
 A'ptychus (Gr. a, without, and ptyche, fold). A term applied by some 
 authors to the shelly or horny organisms better known as trigonellites, 
 which see. The name Aptychus refers to the plates or valves being with- 
 out fold or hinge. 
 
 Aquaf6rtis. Literally strong water ; a familiar term for nitric acid, in 
 allusion to its power of dissolving the metals. 
 
 Aqua Marine. A lapidary's designation for the finest beryls, in allusion to 
 the varying shades of " sea-green" which they usually present. See BERYL. 
 
 Aqua Regia. Literally royal water ; a designation of the alchemists for 
 nitro-muriatic acid, from its property of dissolving gold, the "king of the 
 metals." 
 
 Aquatic (Lat. aqua, water). Relating to the water; having its habitat 
 or usual position in water. Applied to plants which, like the water-lily, 
 grow in water, and to animals which, like the diver and duck, live in or 
 frequent the waters. 
 
 ' A'queous (Lat. aqua, water). Watery ; pertaining to, or formed by, 
 water. Usually applied to the sedimentary or stratified rocks, as having 
 been formed by deposition from water, in contradistinction to the unstrati- 
 fied, or those arising from igneous fusion. Sub-aqueous. Occurring under 
 the water ; in contradistinction to sub-aerial, or under the open air. 
 
 Aralo-Caspian. In physical geography this term is applied to the ex- 
 tensive basin or depressed area occupied by the Aral and Caspian Seas, and 
 which is a true " basin of continental streams," having no communication 
 with the ocean. In geology, the name Aralo-Caspian formation has been 
 given by Sir R. Murchison and M. de Verneuil to the limestone and asso- 
 ciated sandy beds of brackish- water origin, which have been traced over a 
 very extensive area, surrounding the Caspian, Azov, and Aral Seas, and 
 parts of the northern and western coasts of the Black Sea. The fossil 
 shells are partly fresh-water and partly marine ; partly belong to living 
 and partly to extinct species ; but are in both cases related to species now 
 inhabiting the seas and lakes of central Asia, rather than to oceanic types. 
 The limestone rises several hundred feet above the sea, and is supposed to 
 indicate the existence, in latter Tertiary times (Pliocene), of a vast sheet 
 of brackish water as large or even larger than the Mediterranean. 
 
 Araucarites. " This term," says Mantell, " is employed to designate 
 the fossil wood whose structure is identical with that of the living Arau- 
 cariee, having the same kind of medullary rays, and the woody fibre, 
 studded with discs or areolse, which are polygonal, often hexagonal, and 
 
 90 
 
ARB ARC 
 
 disposed in several alternating series." This wood is common in the 
 Chalk, Wealden, Oolite, and Lias of Britain ; and trunks closely resembling 
 the existing A . excelsa have been found in the Carboniferous formation, 
 as at Craigleith and Granton, near Edinburgh, and also in Fifeshire. The 
 Araucarice are natives of the southern hemisphere, and are all more or less 
 gigantic trees, growing from 150 to 200 feet in height, and often from 20 
 to 30 feet in circumference. It is an interesting fact, therefore, to find 
 that trees closely resembling those of Australia and the adjacent islands 
 should at one period have nourished extensively in the northern latitudes 
 now occupied by Great Britain. 
 
 Arborescence (Lat. arboresco). Literally growing like a tree ; applied 
 to those dendritic or tree-like forms of crystallisation often observable in 
 mineral productions. 
 
 Area (Lat. a chest). A genus of conchifera having a world-wide distribu- 
 tion, though most abundant in warm seas ; and occurring in many species, 
 from the Lower Silurian upwards. The species are characterised by their 
 equivalve, thick, strongly-ribbed, ventricose shells, which are smooth or 
 dentated at the margin, have a straight hinge with numerous teeth, and 
 their umbones anterior and separated by a flat, lozenge-shaped ligamental 
 area. The ARCADE or ark-shell family embraces such genera as cucullcea, 
 pectunculus, limopsis, nucula, isoarca, leda, Yoldia, and solanella. 
 
 A'rcanite (Lat. arcamis, hidden, concealed). Sulphate of potash, occur- 
 ring mostly in crusts and pulverulent coatings ; colourless or white ; having 
 a saline, bitter taste, and soluble in water. It is found in volcanic lavas, 
 and in solution in the water of some salt springs. 
 
 Archseocidaris (Gr. archaios, ancient, and cidaris, a turban, hence the 
 "sea-egg," from its turban shape). A genus of sea-urchins or cidaris, 
 occurring in Carboniferous and Permian strata, and characterised by their 
 small hexagonal plates, and long spines, which in some species are smooth, 
 in others notched and sharply denticulated. 
 
 Arch aeonf sens (Gr. archaios, ancient, and oniscus, woodlouse). A genus 
 of fossil Isopods (equal-footed crustaceans) occurring in the Purbeck or 
 uppermost Oolitic strata, and so termed by the Rev. P. B. Brodie, from 
 their close resemblance to the common woodlouse. 
 
 Archse6pteryx (Gr.) Literally " ancient wing or bird." A unique 
 specimen of bird-remains from the Oolitic limestone of Solenhofen, and not, 
 as was at first supposed, a creature intermediate between the birds and 
 reptiles. This ancient bird, according to Professor Owen, was about the 
 size of a rook, and differs from all known birds in having two free claws 
 belonging to the wing, and also in having the vertebrae of the tail (about 
 twenty in number) free and prolonged as in mammals each vertebra sup- 
 porting a pair of quill-feathers which give to the tail a long and vane-like 
 appearance. This unique specimen (now in the British Museum) exhibits 
 in its tail a retention of structure which is " embryonal and transitory in 
 the modern representatives of the class, Aves, and consequently a closer 
 adhesion to the general vertebrate type." See ORNITHOLITES. 
 
 Archegosaurus (Gr. archegos, beginning, and saurus, lizard). Literally 
 "primeval lizard ; " a reptile of the Carboniferous era, having, according 
 to Owen and Goldfuss, a near alliance to the proteus, lepidosiren, and other 
 perennibranchiate reptiles of the present day. 
 
 Archetype (Gr. arcke, beginning, and typos, type). An original model 
 or pattern ; the type after which subsequent forms are moulded. 
 
 91 
 
ARC ARG 
 
 Archipelago. A term originally applied to the numerous islands that 
 stud the JSgean Sea the Grecian Archipelago ; but now used to denote 
 any similar cluster of islands e.g., the Indian Archipelago, or East India 
 Islands. 
 
 A'rctic (Gr. arctos, a bear). Relating to the North Pole or Polar Regions ; 
 in reference to the constellations of the Great and Little Bears which occur 
 in the northern quarter of the heavens, and point, as it were, to the North 
 Pole. Arctic Regions, the high latitudes surrounding the North Pole ; 
 Arctic Circle, an imaginary line extending round the North Pole 62 5 from 
 the Equator, and parallel to it ; hence certain parts are said to " lie within 
 the Arctic Circle." The term is also familiarly used as synonymous with 
 cold, boreal, and frozen. 
 
 Arctic Current. A well-known ocean current which originates in the 
 polar regions of the north, and flows southwards towards the equator. 
 The main current seems to originate to the north of Spitzbergen, takes a 
 westerly direction, and thence runs southward along the eastern shores of 
 Greenland, till it meets with a minor branch flowing from Davis Strait. 
 The two then unite in one great current, which follows the Labrador 
 coast, runs to the east of Newfoundland, and evidently loses itself in the 
 " Gulf Stream ;" or rather perhaps, from its greater density, passes in 
 part under the Gulf Stream in latitudes 45-47, and holds on towards the 
 equator. It is to this current that we owe the phenomenon of icebergs in 
 the Atlantic ; and as these are frequently laden with boulders, gravel, and 
 other miscellaneous debris, together with the remains of arctic animals, 
 there must be now forming along the bed of the North Atlantic a deposit 
 analogous in many respects to the " Northern Drift " or " Boulder Clay " 
 of a former epoch. 
 
 Arendceous (Lat. arena, sand). Rocks composed of grains or particles 
 of sand, or containing sand in any notable degree (as grits and sandstones), 
 are said to be arenaceous. Compound rocks partaking of this quality are 
 spr ken of as arenaceo-calcareous, arenaceo-argillaceous, and so on, as their 
 composition may indicate. 
 
 Arenicolites. A term applied to those circular holes or markings which 
 appear in twos or twins on the upper surface of many sandstones, and 
 which seem to have been worm-burrows like those of the Arenicola or lob- 
 worm (arena, sand, and colo, I inhabit). 
 
 Argentiferous (Lat. argentum, silver, and/ero, I bear). Applied to veins, 
 rocks, and other matrices containing the ores of silver, or silver in the 
 native or metallic state. 
 
 Argentlte (Lat. argentum, silver). Sulphuret of silver; an important 
 ore of silver, occurring crystallised, also in crusts, or massive and dissemi- 
 nated ; of a blackish lead-grey ; feebly lustrous ; malleable and flexible. 
 It is found in the granitic, porphyritic, and crystalline rocks of many 
 countries, and is one of the most important of the ores of silver. Consists 
 of about 86.5 silver and 13.5 sulphur. 
 
 Argile Plastique. Towards the base of the Tertiary system in France 
 are extensive deposits of sands, with occasional beds of clay used for 
 pottery purposes ; hence the term argile plastique. See TERTIARY SYSTEM. 
 
 Argillaceous (Lat. argilla, clay). Applied to all rocks or substances 
 composed of clay, or having a notable proportion of clay in their composi- 
 tion, as roofing-slate, shale, &c. Argillaceous rocks are readily distin- 
 guished by the peculiar odour they emit when breathed on, and known in 
 
 92 
 
ARG ARS 
 
 mineralogy as the " argillaceous odour." Compound clayey substances are 
 spoken of as argillo-calcareous, argillo-arenaceous, &c., as the case may be. 
 
 Argillite (Lat. argilla, clay). A mineralogical term for clay-slate ; but 
 very seldom used in geology. 
 
 A'rkose. A name given by Brongniart to a compound of the same mate- 
 rials as granite, from which its materials have evidently been derived by 
 disintegration. " Tt is found/' says Lyell, " at the junction of granite with 
 formations of different ages, and consists of crystals of felspar, quartz, and 
 sometimes mica, which, after separation from their original matrix by 
 disintegration, have been reunited by a siliceous or quartzose cement." 
 In Sweden it immediately flanks the granite, and forms a coarse-grained 
 sandstone or grit. 
 
 Arm. In geography, any deep and comparatively narrow branch of the 
 sea running inland, in contradistinction to gulfs and firths. 
 
 Armadillo (Span.) A well-known genus of edentate quadrupeds peculiar 
 to the American continent, and so called from their being armed with an 
 external bony shield composed of separate plates like a coat of mail. The 
 Glyptodon and other gigantic congeners of the armadillo are found in the 
 Post-Tertiary deposits of South America. 
 
 Arquerite. A silver amalgam occurring in small octahedral crystals and 
 in arborescent crusts in the mines of Arqu6ros, near Coquimbo, in Chili, 
 whence the name. It is ductile and malleable, and consists of 86.5 silver 
 and 13.5 mercury. See AMALGAM. 
 
 Arrdgonite. One of the calc-spar family, generally found in radiated 
 and fibrous aggregates, in amygdaloidal cavities, and in fissures in basalt 
 and basaltic tufas. It derives its name from Arragon in Spain, where it 
 occurs in large macled crystals in gypsum. The coralloid varieties are 
 usually known as flos-ferri, and the finely-fibrous and silky as satin spar. 
 It differs from common calc-spar, or calcite, in containing from 1 to 3 per 
 cent of stron tia ; but " is most readily distinguished frem it by falling to 
 pieces at a low temperature which does not affect the latter, and also by its 
 prismatic cleavage." 
 
 A'rsenic (Gr. arsenikon^ masculine). The metal arsenic, so called from 
 its possessing strong or powerful properties. Arsenic occurs chiefly in 
 veins in the crystalline and transition strata, along with ores of antimony, 
 silver, and lead ; and the purest specimens usually contain traces of anti- 
 mony, iron, silver, or gold. As an ore it is generally found in granular 
 irregular masses or disseminated ; is brittle ; has a whitish lead-grey colour 
 when newly broken, but soon tarnishes on exposure to the atmosphere, 
 and becomes coated with a black sub-oxide of the metal. When struck 
 or heated it gives off a strong garlicky smell known as the " arsenical 
 odour ;" and on being pulverised and moistened it undergoes spontaneous 
 combustion. It has a strong tendency to combine with other metals, hence 
 such natural compounds as arsenic-silver, arsenic-antimony ', arsenic-glance, 
 &c. Arsenic is used in various pharamaceutical preparations and in metal- 
 lurgic processes, but is usually injurious when mixed with ores. The metal 
 and all its compounds are violent poisons. The white arsenic of the shops 
 is arsenious acid ; realgar or red arsenic is the protosulphuret ; orpiment or 
 yellow arsenic is the sesquisulphuret, and constitutes the colouring matter 
 of the pigment called King's yellow ; and the well-known pigment Scheele's 
 mineral green is an arsenite of copper. The metallic arsenic of commerce 
 is chiefly obtained from arsenical iron pyrites or mispickel, which see. 
 
 93 
 
ART ASC 
 
 Artesian Wells. Wells sunk by boring perpendicularly through the 
 solid strata, and in which the subterranean waters rise to the surface or 
 nearly so a method long known and practised in the province of Artois 
 (the ancient Artesium) in France. Many of the Artesian wells in London 
 and Paris are of great depth that in the plain of Grenelle being about 
 1800 feet deep, bore 10 inches in diameter, discharge 517 gallons per min- 
 ute, and temperature of water 82 Fahr. ; a depth exceeded by that at 
 Columbus, in Ohio, which in 1860 was 2575 ft., the thermometer register- 
 ing 88 Fahr., while the work was still proceeding. Artesian wells are 
 generally situated in plains or in basin-shaped valleys, towards which the 
 strata dip on one or more sides, and their principle depends upon the 
 hydrostatic pressure of the water percolating through the inclined strata 
 and forcing its way upward by the artificial orifice to the highest level of 
 the water-containing strata. The greater the depth the higher the tem- 
 perature ; and the lower the surface of the well compared with the outcrop 
 of the water-yielding stratum, the higher will the jet d'eau rise above the 
 orifice of the bore. 
 
 Articuldta (Lat. articulus, a joint). One of Cuvier's great subdivisions 
 of the animal kingdom, comprehending all the invertebrata with jointed 
 bodies as insects, spiders, crustaceans, myriapods, and worms. See tabu- 
 lations, " ANIMAL SCHEME." 
 
 Articulated (Lat. articulus, a joint). Jointed ; composed of parts united 
 by joint-like processes. Occasionally applied in geology to the columns 
 of basalt and greenstone, which, like those cf the Giant's Causeway, are 
 separable into blocks more or less regular, and thus seem jointed or articu- 
 lated. Indeed, in some of the more perfect columns there is a regular ball- 
 and-socket arrangement of the separable portions. 
 
 Arundinaceous (Lat. arundo, a reed). Eesembling, or having the struc- 
 ture of, reeds. Arundinaceous (that is, striated and jointed) stems are 
 common in the Coal-measures. 
 
 A'saphus (Grr. asaphes, obscure). A genus of trilobites, so called from 
 the obscurity which long rested on the true natm*e of these crustaceans. 
 In this genus the carapace is wide and much depressed ; the middle lobe 
 distinct ; the head-shield rounded in front, and terminating posteriorly in 
 a sharp process on each side. The eye of the asaphus is compound, and 
 contains several thousand lenses. 
 
 Asbestus, Asbestos (Gr. a, priv., and sbestos, consumable or extinguishable). 
 Known also as amianthus and byssolite. Fine fibrous varieties of several 
 of the hornblende family, as augite, tremolite, and actinolite, found chiefly 
 in connection with serpentine. The fibres, often readily separable, elastic, 
 and flexible, were used by the ancients in the manufacture of an incom- 
 bustible cloth ; hence the name asbestos, inconsumable. There are many 
 varieties, and these receive their names from their appearance and quality 
 as rock-wood, rock-cork, mountain-leather, fossil-paper, fossil-flax, &c. In 
 rock-wood the fibres are long, parallel, curved, and compact ; in rock-cork 
 they have a felted texture, and so light as to swim on water ; in mountain- 
 leather they form flat flexible pieces ; and in fossil-flax they are so loose 
 and silky that Dolomieu used it for packing his other minerals. Asbestos 
 thus passes from the silky flexibility of amianthus to a degree of compact- 
 ness which admits of receiving a fine polish. See AMIANTHUS. 
 
 Ascidia or Ascidians (Gr. askidium, a little leathern bottle). An order 
 of the Tunicata or shell-less mollusca, so called from their resemblance to 
 
 94 
 
ASP AST 
 
 small leathern pouches. They are either social or solitary, and appear as 
 pap-like gelatinous incrustations on rocks, dead shells, and other bodies. 
 
 Asparagus-Stone. The name given to a translucent variety of apatite, 
 from its greenish-yellow colour, which occasionally passes into wine-yellow. 
 
 A'sphalt (Gr. asphaltos). This term is usually applied to a black, hard, 
 brittle, and glossy variety of bitumen, which is distinguished from other 
 varieties chiefly by its more difficult fusibility, and by its fracture being 
 clean, conchoidal, and vitreous. It occurs in formations of all ages, and is 
 associated with different kinds of rocks, though most frequently in connec- 
 tion with sandstones and limestones. The asphalt found floating on the 
 Dead Sea (Lacus A sphaltites) was well known to the ancients ; it was ob- 
 tained from pits or springs near the Euphrates and Tigris, and used as 
 mortar by the Babylonians ; it is still largely found in Persia ; it forms 
 the principal feature of the " Pitch-lake" of Trinidad; an abundant com- 
 mercial supply is obtained from Seyssel and other places near the Jura 
 Mountains ; and it occurs sparingly in rents and cavities in the Carbonifer- 
 ous limestones of Britain. See BITUMEN. 
 
 Aspidiaria (Gr. aspis, aspidos, a shield). A genus of lycopodian-like 
 Coal- measure stems, so called from the shape of the leaf- scars, which 
 closely connect them with lepidodendron. 
 
 Aspidorhynchus (Gr. aspis, aspidos, a shield, and rhynchos, a beak). Liter- 
 ally "Buckler-beak;" a genus of sauroid fishes occurring in the Jurassic 
 and upper Secondary formations, and distinguished by the tapering or 
 beak-like prolongation of their upper jaws, which were armed with numer- 
 ous sharp-pointed conical teeth. 
 
 Aspidura (Gr. aspis, a shield, and oura, tail). A genus of star-fishes 
 peculiar to the Muschelkalk of Germany. They are closely related to the 
 existing ophiura, and are named from the buckler-like arrangement of the 
 ossicles that protect the arms, which are four in number. 
 
 Aspleni6pteris. A fossil fern from the Oolite and Lias ; so called from 
 its resemblance to the existing asplenium ; but regarded by Lindley as 
 identical with PTEROPHYLLUM, which see. 
 
 Assdy (Fr. essayer, to try). In mining and metallurgy, the determination 
 of the quantity of gold or silver contained in ores or alloys of these metals 
 by cupellation. It differs from chemical analysis in merely furnishing the 
 quantity of the precious metal contained in the sample examined, instead 
 of the nature and proportion of all the ingredients. 
 
 Assimilation (Lat. assimilo, I liken to). The process by which organ- 
 ised bodies convert aliment into the various tissues of their own proper 
 substance. Plants and animals increase by assimilation and transforma- 
 tion, minerals by attraction and aggregation. 
 
 Astacolite (Gr. astakos, the crayfish or lobster). Applied to fossil or 
 petrified crustaceans like the crayfish and lobster. 
 
 Asteracanthus (Gr. aster, star, and acantha, spine). Literally " Starry- 
 spine ;" a genus of ichthyodorulites, so termed from having their surfaces 
 richly ornamented with star-like tubercles. These fin-rays (often of 
 large size) are common in the Lias, Oolite, and Wealden strata. 
 
 Asteria (Gr. aster, a star). A variety of corundum or " star- sapphire," so 
 called because, when cut en cabochon perpendicular to the axis of the prism, 
 it shows a bright opalescent star of six rays corresponding to the other axes. 
 
 Asterialite (Gr. aster, star, and lithos, stone). A term, now rarely used, 
 for fossil or petrified asterias, or star-fish. 
 
 95 
 
AST ATA 
 
 Asteridse (Gr. aster, a star). The Star-fish family, of which the common 
 five-rayed star-fish (asterias), so abundant on our own coasts, has been 
 taken as the type. Representatives of the family occur, according to 
 E. Forbes, so early as Upper Silurian strata (Uraster); but this has been 
 questioned by others, who would restrict the family to Mesozoic and 
 Neozoic strata in which such forms as tropidatser, solaster, and goniaster 
 are unmistakable and abundant. 
 
 Aster6ida (Gr. aster, a star, and eidos, resemblance). An order of polypes, 
 so called from the star-like or rayed arrangement of their tentacles when 
 fully expanded. The asteroid polypes are all compound animals, inhabiting 
 a polypidom, which consists of a fleshy external layer, supported upon an 
 axis more or less calcareous and compact. The order embraces the tubipo- 
 ridce, or "organ-pipe corals;" the alyconidce, or " dead men's fingers ;" 
 the Gorgonidce, or ' ' sea-fans ;" and the pennatuldice, or " sea-pens." 
 
 Asteroids (Gr. aster, star; eidos, likeness). A term applied by Herschel 
 to the minor planets or planetoids Ceres, Pallas, Juno, Vesta, &c. of 
 which there are now upwards of seventy known to astronomers. 
 
 Asterolepis (Gr. aster, star, and lepis, scale). Star-scale ; a gigantic 
 ganoid fish of the Old Red Sandstone, so named from the stellate markings 
 on the dermal plates of the head, which are of great size, and form a 
 strong expanded buckler, the orbits of the eyes being situated near the 
 anterior border. The mouth of the asterolepis was furnished both with 
 rows of small fish-teeth, and a thinly-set row of huge reptile-teeth. The 
 true affinities of the asterolepis are yet undecided, if indeed it is en- 
 titled to rank even as a separate genus. See Hugh Miller's work, ' Foot- 
 prints of the Creator, or the Asterolepis of Stromness.' 
 
 Asterophyllites (Gr. aster, a star, and phyllon, a leaf). An assemblage of 
 plants found abundantly in the Coal-measures, Lias, and Oolite ; and so 
 called from the star-like whorls of linear leaves (verticillate leaves) which 
 surround the jointed stems, as in equisetum, hippuris, and the like. " The 
 genus asterophyllites is so vague," says Lindley, " that it will comprehend 
 any fine-leaved verticillate plants, the basis of whose leaves do not run into 
 an annular rim." Beyond this, and the fact that they are dicotyledonous 
 plants, botanists have not yet determined ; so that many remains now classed 
 under ( ' asterophyllites " may in reality belong to very different families. 
 
 Astrseidse (Gr. astrcea, from aster, a star). The family of "star-corals," 
 to whose stony calcareous secretions the formation of coral reefs is mainly 
 owing. They differ from the cyathophyllidce or " cup-corals," and from 
 the madreporidce or ' ' tree-corals," not only in their forms, but in the 
 arrangement of their cell-rays, as well as in their mode of reproduction. 
 The members of the family usually form thick stony masses ; have the rays 
 of the cells exceedingly numerous the cells penetrating deeply into the 
 mass of the coral ; and most of them appear to increase by spontaneous 
 division. The common astrcea or "star-coral," and meandrina or "brain- 
 coral," are familiar examples. 
 
 Astringent (Lat. ad, to, and slringo, I draw tight). Applied to those 
 substances which, like the gall-nut, oak-bark, alum, &c., have the property 
 of contracting or drawing together the muscular fibre ; hence also such 
 substances are spoken of as " astringents." 
 
 A'tacamite. A native muriate of copper, so called from being found in 
 the desert of Atacama, between Chili and Peru. It occurs in aggregates 
 of small prismatic crystals, or massive with a granular structure. In the 
 
ATH ATE 
 
 granular or arenaceous state it is known as "copper sand/' and consists 
 of 72 copper protoxide, 16 muriatic acid, and 12 water. It often appears 
 on copper long exposed to the atmosphere or sea- water, and is the aerugo 
 nobilis seen on antique bronzes. 
 
 Atherfield Point. On the southern coast of the Isle of Wight a locality 
 of geological importance, as elucidating the nature and relations of the 
 Greensand or lower group of Cretaceous system, and the subject of various 
 papers by Fitton, Mantell, Ibbetson, Forbes, and others. See Table of 
 " EQUIVALENT DEPOSITS." 
 
 Atm6meter (Gr. atmos, vapour, and metron, measure). An instrument 
 invented by Sir John Leslie for. measuring the amount of evaporation from 
 any moist surface in a given time. It consists of a thin hollow ball of 
 porous earthenware, in which is inserted a tube of glass with divisions. 
 The cavity of the ball and the tube are filled with water, and the top of the 
 tube closed. In this state the instrument is exposed to the free action of 
 the air, when the water transudes the porous substance and is evaporated 
 the scale on the glass tube marking the relative rapidity. 
 
 Atmosphere (Gr. atmos, vapour, and spltaira, sphere). The gaseous 
 envelope or volume of air which surrounds the earth on every side, and 
 which is either directly or indirectly the cause of numerous geological 
 operations, being the great laboratory in which all meteorological and 
 electrical phenomena are elaborated, as winds, clouds, rains, snow, hail, and 
 thunderstorms. As an air, it is composed of about 79 parts nitrogen and 
 21 oxygen, with variable traces of carbonic acid and other impurities. 
 Calculating from its decreasing density, as well as from its diminished 
 power of refracting light as we ascend from the earth, the height or extent 
 of the atmosphere has been estimated at 45 miles ; and the pressure of the 
 whole volume on every square inch of the earth's surface (at the ordinary 
 sea-level) at 14.6 Ib. avoirdupois. This pressure is counterbalanced by a 
 mercurial column of 30 inches in length ; hence a column of 60 inches will 
 be equal to two atmospheres ; and it is customary to estimate the force of 
 steam, of liquid lava, and other fluid pressures, by atmospheres that is, in 
 round numbers, at the rate of 15 Ib. per square inch for every atmo- 
 sphere. As a geological agent, it is indispensable to the life of plants and 
 animals, and any change in its normal composition would at once affect 
 their existence. Increasing in density as we approach the earth, it be- 
 comes, as it were, the retainer and equable diffuser of the sun's rays. It 
 is also the recipient and diffuser of all aqueous vapours arising from the 
 earth; hence clouds, rains, snow, hail, &c. Its denser strata being heated 
 in one region, they become lighter and ascend, and the colder and denser 
 masses from other regions rush in to supply their place ; hence aerial cur- 
 rents or winds ; and hence also, from the contact and friction of its cloudy 
 masses, the discharges of thunderstorms, and other electrical phenomena. 
 
 A' toll. The name given to a coral island of an annular form that is, 
 consisting of a circular belt or strip of coral reef more or less continuous, 
 with an enclosed lagoon. See CORA.L REEFS. 
 
 A'toin (Gr. a, priv., and temno, I cut). In chemistry, an ultimate particle 
 of matter incapable of further division or reduction. In geology, applied 
 loosely to minute particles or molecules of solid matter. 
 
 A'trypa (Gr. a, without, and trypa, a foramen). A genus of brachiopods 
 closely related to rhynconella, and often mistaken for species of terebratula. 
 They are rounded shells, not furrowed like spirifer, but ornamented with 
 
 97 a 
 
ATT AUR 
 
 squamous lines of growth ; the beak is small compared with terebratula, 
 often closely incurved, and the foramen either concealed or very small and 
 round (hence the name) ; hinge-line very short, and shell not punctured as 
 in terebratula. About a dozen species are found, from the Lower Silurian 
 to the Trias inclusive. 
 
 Attle. A Cornish term for rubbish thrown out of a mine, containing 
 little or no ore. 
 
 Attraction (Lat. ad, to, and traho, I draw). Literally a drawing towards; 
 a term denoting the mutual tendency of bodies towards one another a 
 power in nature which has been assumed as explanatory of many physical 
 and chemical phenomena; hence such phrases as Attraction of Cohesion, 
 Attraction of Gravitation, Attraction of Affinity, Capillary Attraction, Mag- 
 netic Attraction, and so forth. See COHESION, GRAVITATION, CAPILLARY 
 AND MAGNETIC. 
 
 Attrition (Lat. attritus, worn or rubbed down). The act of wearing by 
 friction or rubbing. In geology, the wearing and smoothing of rock- 
 surfaces by the passage of water charged with sand and gravel, by the 
 passage of sand-drift, the descent of glaciers, and the like. See ABRASION. 
 
 Auchenaspis (Gr. auchen, the back part of the neck, and aspis a buckler). 
 A provincial genus of Old Ked Sandstone fishes, closely allied to, and in 
 all likelihood identical with, cephalaspis, but separated by Sir P. Egerton 
 in consequence of the appearance of a post-cephalic or neck plate in a 
 single specimen from the neighbourhood of Ludlow. 
 
 Aiigite (Gr. auge, lustre). A mineral of the hornblende family, entering 
 largely into the composition of many trap and volcanic rocks, as of basalt, 
 greenstone, clinkstone, augite, porphyry, &c. In composition it is closely 
 allied to hornblende proper, but differs in the form of crystal, contains less 
 silica, is of greater specific gravity, and is also less fusible. Augite, 
 known also as Pyroxene, has several varieties, which are distinguished by 
 such names as diopside, sahlite, malacolite, Baikalite, Fassaite, coccolite, 
 Hedenbergite, &c., which see. Augite, as it usually occurs, is of a greenish- 
 black, pitch or velvet black, occasionally leek-green, but rarely brown ; 
 lustre vitreous to resinous ; translucent or opaque ; fracture conchoidal and 
 uneven : crystallises in six or eight sided prisms, terminated by dihedral 
 summits. Its constituents, taking the average of several analyses, are 53 
 silica, 19 lime, 15 magnesia, 6 iron protoxide, 2 manganese protoxide, and 
 5 alumina. 
 
 Augitic. Containing augite; resembling augite, as Augitic Porphyry, 
 a rock with a dark-grey or greenish base, containing crystals of augite and 
 Labrador felspar. Augitic traps are frequently spoken of in contradis- 
 tinction iofelspathic traps and claystones. 
 
 Auricle (Lat. auricula, a little ear). In natural history, any appendage 
 or projection resembling ears. Anricled. Furnished with such appendages. 
 Auriculated. Ear-shaped. 
 
 Auriferous (Lat. aurum, gold, and fero, I yield). Yielding or containing 
 gold ; applied to rocks and veins containing the precious metal, as " auri- 
 ferous veins," "auriferous sands," &c. 
 
 Auriform (Lat. auris, the ear, and forma, shape). Ear-shaped ; having 
 a form resembling the human ear. as the haliotis or ear-shell, the otopteris 
 or ear-fern, &c. 
 
 Aurora Borealis (Lat.) Literally the "Aurora of the North;" known 
 also as the Northern Lights, Polar Lights, Streamers, &c. A luminous 
 
AUIl AVA 
 
 meteor, generally appearing in the northern heavens, and so called from 
 its resemblance to the aurora or morning twilight. It is usually referred to 
 electrical agency in the upper regions of the atmosphere. Changing from 
 the purest and softest white to all the colours of the rainbow, and flickering 
 and flitting from the horizon to the zenith with inconceivable rapidity, the 
 aurora borealis is one of the most attractive of celestial phenomena. 
 
 Auroral (Lat.) Appertaining to the early morn ; the second of the 
 fi fteen series into which Professor Rogers subdivides the Palaeozoic strata 
 of the Appalachian Chain the " Daybreak " of the North American palaeo- 
 zoics, and the equivalent in part of our Middle Cambrians. See PALEO- 
 ZOIC FORMATIONS. 
 
 Aut6malite (Gr. automolos, inconstant). Octahedral corundum. A 
 variety of corundum containing oxide of zinc, found crystallised (some- 
 times simple, sometimes as a made) in talc schist, and associated with 
 zinc-blende and galena. Its constituents, according to Abich, are 57.09 
 alumina, 34.80 zinc oxide, 4.55 iron oxide, 2.22 magnesia, 1.92 silica, and 
 traces of manganese. 
 
 Autumn (Lat. ) The third quarter of the year, which commences when 
 the sum enters Libra, that is, about the 21st or 22d of September, when 
 the days and nights are equal; hence the term Autumnal Equinox or 
 Autumnal Point, referring to the descending point of the ecliptic. 
 
 Auvergne. A district in central France celebrated for its extinct vol- 
 canoes, its fresh-water limestones, lacustrine formations, and other ancient 
 alluvia. The subject of Mr Scrope's valuable monograph, ' The Volcanoes 
 of Central France.' 
 
 Avaldnche (Fr. avalange, lavange, lavanche). An accumulation of snow, 
 or of snow and ice, which descends from precipitous mountains like the 
 Alps into the valleys below. Avalanches originate in the higher regions 
 of mountains, and begin to descend when the gravity of their mass be- 
 comes too great for the slope on which it rests, or when fresh weather 
 destroys its adhesion to the surface. They are usually distinguished as 
 Drift, Rolling, Sliding, and Glacial 'Drift are those caused by the action 
 of the wind on the snow while loose and powdery; rolling, when a detached 
 piece of snow rolls down the steep, licks up the snow over which it passes, 
 and thus acquires bulk and impetus as it descends ; sliding, when the mass 
 loses its adhesion to the surface, and descends carrying everything before 
 it unable to resist its pressure ; and glacial, when masses of frozen snow 
 and ice are loosened by the heat of summer and precipitated into the plains 
 below. See GLACIER. 
 
 Avdnturine or Aventurine. A variety of quartz deriving its peculiar 
 play of colour from imbedded spangles of mica, or merely from the inter- 
 section of minute fissures. Also, a variety of felspar or sunstone (which 
 see), whose play of colour, according to Scheerer, arises from minute im- 
 bedded crystals of iron-glance. "The name Avanturine," says Jackson 
 ('Minerals and their Uses'), "is said to be derived from the following cir- 
 cumstance : A French workman having by accident, or par aventure, dropt 
 some copper filings into a vitreous mixture in fusion, gave the name Avan- 
 turine to the sparkling mass which was thus produced; and it is still 
 by a similar process, though greatly improved, that the artificial produc- 
 tion is now manufactured, to be employed for various ornamental purposes. 
 The artificial far exceeds in brilliancy the natural avanturine. A species 
 of avanturine is also produced by heating pieces of quartz to a certain 
 
ATI AZO 
 
 degree and suddenly cooling them ; this occasions a number of minute 
 fissures in the mass, which, by the unequal refraction of the light, gives the 
 stone the desired appearance." 
 
 Avicula (Lat. a little bird). A free, unequal-valved shell, fixing itself 
 by a byssus, the hinge without a tooth, and rather callous, valves some- 
 what gaping near the beaks. The type of the Aviculidce, which embraces 
 avicida, posidonomya, aviculopecten, gervillia, perna, inoceramus, and pinna. 
 " The living shells or pearl-oysters," says Woodward, " are natives of 
 tropical and temperate seas : there are no living species in northern lati- 
 tudes, where their fossil forms are very numerous." 
 
 Avicula Contorta Zone. A series of beds characterised by the presence 
 of the Avicula contorta, and by some regarded as the upper portion of the 
 Keuper, and by others as the basement of the Lias. From recent researches 
 it would seem that the facies of the fauna of this zone has more affinities 
 with the Trias than with the Lias, and may, therefore, be considered as the 
 capping of the former system. See RHAETIC BEDS. 
 
 Aviculopecten. The avicula-like pecten, an extensive genus of mon- 
 omyarian bivalves peculiar to the Carboniferous Limestone, and often so 
 well preserved that even the colours of the living shell are retained. The 
 form in the several species is more elongated than in pecten ; valves slightly 
 xmequal, and hinge without a tooth. 
 
 Axe-Stone. A sub-species of jade, of a deep sea-green or leek colour, 
 used by the New Zealanders, and other natives of the Pacific, for making 
 hatchets, hangers, &c. It is sometimes called Amazonian stone, from its 
 being found on the banks of the river Amazon. According to Dr Wake- 
 field, it occurs largely in the middle island of New Zealand. See JADE. 
 
 A'xinite (Gr. axine, an axe). One of the Garnet family, so called from 
 the axe-like form of its crystals ; the Thumerstein of Werner, who found 
 it at Thum, in Saxony. " The crystals are attached singly, or united in 
 druses ; it also occurs massive in laminar or broadly radiated aggregates, 
 lustre vitreous, colour clove-brown, inclining to smoke-grey or plain blue. 
 According to Wiegmann it consists of 45 silica, 19 alumina, 12.5 lime, 
 12.25 iron peroxide, 9 manganese peroxide, 2 boracic acid, and 25 magnesia. 
 It is not very abundant, and occurs chiefly in fissures, veins, or subordinate 
 beds, in granite and the metamorphic schists, associated with quartz, 
 felspar, asbestus, &c. The finest crystals are from Dauphine", and from 
 Cornwall." (Nicol's 'Man. of Mineral.') 
 
 Axis (Lat. axis, a pole or axle-tree). A word used largely and variously 
 in natural science ; applied to the line about which objects are symmetrical, 
 about which they are bent, around which they turn, or to which they have 
 some common relation ; hence " vertebral axis," " axis of elevation,'' 
 " synclinal axis," " axis of rotation," " axis of a crystal," &c. 
 
 Axotomous (Gr. axon, axis, and temno, I cut). Applied to minerals 
 cleavable in one particular direction. 
 
 A'ymestry Limestone. The middle member, according to Murchison's 
 sections, of the Ludlow group of Silurian strata ; so named from the village of 
 Aymestryin Herefordshire, where it is well exposed. See SILURIAN SYSTEM. 
 Ayr Stone. A soft variety of whet-stone, used also for polishing .marble, 
 copper-plates, and the like ; and so called from its being found near the 
 Water of Ayr. Sometimes called Snake-stone, from its mottled appearance. 
 See HONE. 
 
 Azoic (Gr. a, without, and zoe, life). Without life, void of life ; a term 
 
 100 
 
AZO BAG 
 
 applied to the lowest or deepest-seated strata in the crust of the globe, 
 such as gneiss, mica-schist, and other crystalline schists, which have yet 
 yielded no fossils or traces of life to the palaeontologist. The term is 
 merely provisional, and founded on negative evidence, as rocks at one 
 time regarded azoic have since been found to yield fossils. Used by many 
 as synonymous vtithHypozoic, Non-fossiliferous, audMetamorphic, which see. 
 
 Azote (Gr. a, priv., and zoe, life). An early, and still used, chemical 
 term for nitrogen, because of its fatal effects (when breathed) on animal 
 life. See NITROGEN. 
 
 Azure Stone (so named from its colour). A familiar term for Lapis 
 Lazuli, which see. 
 
 A'zurite (from its colour). Prismatic azure-spar, or lazulite. A mineral 
 usually occurring in mica-schist, and consisting of alumina, silica, magnesia, 
 lime, and oxide of iron. 
 
 B 
 
 Babel Quartz. A variety of rock crystal. " Instead of tapering gradually 
 towards their extremities," says Mr Bristow, " as is the case with many 
 crystals of quartz, these diminish suddenly at intervals, and are built up, as 
 it were, of a series of short steps, which, from their fanciful resemblance to 
 the successive storeys of the Tower of Babel, have given rise to the name." 
 
 Babingtonite (after Dr Babington). One of the hornblende family; the 
 " axotomous augite-spar" of Mohs. It occurs chiefly in beds of magnetic 
 iron ore, and in veins of quartz and felspar, in small, black, attached 
 crystals ; and consists essentially of silica, iron protoxide, and lime. 
 
 Bacillaria (Lat. bacillum,& little stick). A genus or rather group of Dia- 
 toms, consisting of simple siliceous frustules of a prismatic shape (whence 
 the name), and forming a brilliant chain, which often appears in zigzag, 
 in consequence of incomplete self-division. They abound in all waters, 
 fresh and marine ; and fossil species are equally abundant in all the so-called 
 infusorial or microphy tal earths. 
 
 Back. A miner's term for "joints ;" hence "backs and cutters" applied 
 to jointed structure ; the backs running in lines less or more parallel to the 
 strike of the strata, and the cutters crossing these generally at right 
 angles. Applied also in mining phraseology to that part of a mineral lode 
 which is nearest the surface. See JOINTS. 
 
 Bactrltes. According to Sandberger, a genus of straight, subconical- 
 chambered shells, peculiar to the Devonian epoch ; apparently the Steno- 
 ceras of D'Orbigny. 
 
 Baculite (Lat. baculum, a staff). A straight, many-chambered, conical 
 shell of the Chalk epoch, somewhat compressed, with marginal siphuncle, 
 and much elongated ; and so named from its straight, tapering, staff-like 
 shape. Like other Ammonitidce, it consists of numerous chambers divided 
 by transverse sinuous septa, the outer or inhabited chamber being much 
 larger than the others, and guarded by a dorsal process. The baculites, 
 though not specificallj' numerous, were individually abundant, and highly 
 characteristic of the Cretaceous epoch. From its prevalence in the Chalk 
 of Normandy, that rock is sometimes termed the Baculite Limestone. 
 
 101 
 
BAG BAR 
 
 Bagshot Sands. A series of Lower Tertiary beds, consisting chiefly of 
 siliceous sand, and occupying extensive tracts round Bagshot in Surrey, 
 and in the New Forest, Hampshire. They are the equivalents of the 
 Bracklesham beds, and may be separated into three divisions, the upper 
 and lower consisting of light yellow sands, and the middle of dark-green 
 sands and brown clays, the whole reposing on the London Clay. 
 
 Baikalite. A light green, finely-crystallised variety of augite, occurring 
 in acicular prisms, and found in granite in the vicinity of Lake Baikal 
 in Siberia. 
 
 Bala Limestone. (Bala in Merionethshire). A series of dark-coloured, 
 slaty, and sub-crystalline limestones, alternating with black slaty shales, 
 the whole rarely exceeding twenty feet in thickness, and forming a subordi- 
 nate group of the Lower Silurian, as developed in Wales. See SILURIAN 
 SYSTEM. 
 
 Balsenidse (Gr. phalaina, Lat. lalcena, a whale). The Whale family. 
 According to Owen, " the remains of great whales, referable to existing 
 genera or species, have been found in Britain, in gravel adjacent to estu- 
 aries or large rivers, in marine drift or shingle, and in the newer Pliocene 
 beds." The remains of the great Airthrey whale, discovered in 1825, and 
 of those found in the Clay-pits of Stirling in 1858 and 1864, were all im- 
 bedded in fine plastic marine silt, varying from twenty to thirty feet above 
 the present medium tide-level of the Firth of Forth. 
 
 Balaenodon (lalcena, and odous, odontos, tooth). Sub-fossil teeth of 
 whales not exactly referable to any known species ; e.g., B. physaloides, 
 which most nearly resembles the tooth of the cachalot (Physeter inacro- 
 cephalus). See Owen's 'Fossil Mammals.' 
 
 Balanite (Lat. baltlnus, a barnacle). The name given to fossils of the 
 barnacle family, whose shells in general consist of six principal valves 
 arranged in conical form. The cirripeds or barnacles are scarcely, if at all, 
 known till the commencement of the Oolitic era. 
 
 Balas or Balass Kuby. The ruby of Balaksh or Balakshan. A lapidary's 
 term for the fine rose-red varieties of the spinel ruby, which see. 
 
 Balistes (Gr. laleso, I strike as with a dart). The file-fish, so called from 
 its rough, jagged, and dart-like fin-spines ; a cartilaginous fish belonging 
 to the sclerodermatous or hard-skinned division of the Plectognathi. The 
 genus is characterised by its sub-globular body, hard, scaly, or granular 
 dermal covering, solid teeth implanted in the jaws, and somewhat resem- 
 bling the front teeth of man, and by their strong denticulated fin-spines. 
 Speaking of fossil fin-spines or ichthyodorulites, Dr Buckland remarks 
 " that the spines of balistes and silurus have not their base, like that of 
 the spines of sharks, simply imbedded in the flesh, and attached to strong 
 muscles ; but articulate, with a bone beneath them. The spine of balistes 
 also is kept erect by a second spine behind its base, acting like a bolt or 
 wedge, which is simultaneously inserted or withdrawn by the same mus- 
 cular motion that raises or depresses the spine." 
 
 Banwell Cave. An ossiferous cavern situated in the Carboniferous 
 Limestone of the Mendip Hills in Somersetshire, and celebrated for its 
 having yielded a number of mammalian remains characteristic of the 
 Pleistocene period. See OSSIFEROUS CAVERNS. 
 
 Barbadoes Tar. A commercial term for petroleum or mineral tar, which 
 is found in several of our West India islands. 
 
 Baregine. The name given to a curious infusorial deposit occurring in 
 102 
 
BAR 
 
 certain thermal waters, and so termed from its being first discovered in 
 the hot springs of Bareges in the Western Pyrenees. When these waters 
 are allowed to rest for some time, the barlgine falls to the bottom as a 
 greasy, amorphous, gelatinous substance, consisting (as shown by the mi- 
 croscope) of the exuviae of infusoria, and emitting an odour when cast on a 
 fire like that of burnt horn. The origin of such organic deposits has not 
 yet been satisfactorily accounted for by geological science. 
 
 Barilla (Span.) The ashes left by the combustion of salsola, salicornia, 
 chenopodium, and other maritime plants. It consists chiefly of an impure 
 carbonate and sulphate of soda, and is used in the manufacture of soap 
 and glass. Like British barilla or kelp (obtained from the burning of sea- 
 weed), barilla has fallen in demand since the introduction of Le Blanc's 
 method of obtaining soda from common sea-salt. 
 
 Barium (Gr. barys, heavy). The metallic basis of baryta, discovered by 
 Sir Humphrey Davy in 1808. Like sodium and potassium, it is known only 
 to the chemist ; is of a whitish-grey colour ; possesses little lustre ; and on' 
 exposure to air or water becomes rapidly converted into its oxide, baryta. 
 
 Barnacle (Sax. learn, child, and aac, oak). Literally "child of the 
 oak," expressive of the old belief that the barnacle or acorn-shell grew on 
 trees. Whether sessile or peduuculated, the barnacles are now well-known 
 articulated animals, either found on rocks or shells at a depth ranging from 
 eight to ten fathoms, or affixed to bottoms of ships and other floating 
 bodies. They belong to the Cirripeds or "curl-footed" order of the 
 Articulata. See CIRRIPEDA. 
 
 Bar elite (Gr. barys, heavy, and lithos, stone). Heavy stone ; carbonate of 
 baryta, or Witherite (which see). According to its discoverer, Dr Wither- 
 ing, it consists of 80 barytes and 20 carbonic acid. 
 
 Barometer (Gr. baros, weight, and metron, measure). A well-known in- 
 strument for measuring the weight or pressure of the atmosphere by 
 balancing a column of air against a column of mercury;; and by this test 
 determining variations in the state of the air, foretelling changes in the 
 weather, as dependent on the conditions of the air, and measuring heights 
 and depths as indicated by the proportional pressure of the air. 
 
 Baroselenite (barys and selenite ; selene, lustre). Heavy spar; native 
 sulphate of baryta. It occurs both massive and crystallised ; generally of 
 lustrous foliated texture, hence the name. Consists of 66 baryta and 34 
 sulphuric acid. 
 
 Barrier-Reef. A name given by voyagers to those coral-reefs which run 
 parallel (barrier-like] to the shores of islands and continents, but separated 
 therefrom by a lagoon-channel more or less extensive. The barrier-reefs 
 of Australia and of New Caledonia, owing to their enormous dimensions, 
 have long attracted the attention of voyagers. See CORAL-REEFS. 
 
 Barystr6ntianite (barys and strontian). Known also as Stromnite, from 
 its occurring at Stromness in Orkney. It occurs in greyish or yellowish- 
 white semi-translucent masses, with a faint pearly lustre and crystalline 
 structure ; consists, according to Dr Traill, of 68.6 carbonate of strontian, 
 27.5 sulphate of baryta, 2.6 carbonate of lime, and a trace of oxide of iron ; 
 and seems a mere mechanical mixture and not a true mineral species. 
 
 Barytes, Baryta (Gr. barys, heavy). One of the simple earths, deriving 
 its name from its great specific gravity, which is about 4.2. As determined 
 by Davy in 1808, it is a protoxide of the metal barium. In nature it occurs 
 chiefly as a sulphate or carbonate ; and both of these traversing the older 
 
 103 
 
 
BAR BAS 
 
 formations in veins are spoken of as " heavy-spars." The native sulphate 
 (65.63 baryta and 34.37 sulphuric acid) is generally known as cawTc or 
 heavy-spar; the carbonate (77.59 baryta and 22.41 carbonic acid) as With- 
 erite, after its discoverer Dr Withering. There is also a sulphate-carbonate 
 described by Dr Thomson. About 10,000 tons of the sulphate and 1500 
 tons of the carbonate are annually raised in Great Britain Derbyshire 
 being the principal seat of the former, and Northumberland that of the 
 latter. 
 
 Bar^to-Calcite. Known also as Alstoniie, from its occurring as a gangue 
 or vein-stone in the lead-mines of Alston Moor in Cumberland ; a mineral 
 consisting of 66 carbonate of baryta, and 34 carbonate of lime. 
 
 Basalt (Gr. and Lat. basaltes, but of unknown origin, some deriving it 
 from a Syriac word, basil, baked or burnt ; others from an Ethiopia word, 
 basal, iron ; and others again from als, salt, in allusion to its usually crys- 
 tallised or columnar structure). A well-known igneous rock occurring in 
 the Trap and Volcanic series, but most abundantly in the former. Basalt 
 belongs to the augitic division of trap-rocks, and consists essentially of 
 augite and felspar the former predominating. It is close-grained, hard, 
 usually black, and frequently columnar ; the columns or rather prisms 
 being three, five, or more sided, regular and jointed. The columnar 
 structure seems to be the result of cooling, and the columns always lie at 
 right angles to the cooling surface ; but the columnar structure is by no 
 means essential to basalt, which also occurs tabular and massive, and 
 passes insensibly through basaltic clinkstone and basaltic greenstone to 
 greenstone proper. The typical basalt (like that of Giant's Causeway, 
 Fingal's Cave, Samson's Ribs near Edinburgh, &c.) generally contains 
 crystals of the olive-green mineral divine, disseminated iron-pyrites, and 
 other substances. The most remarkable basaltic columns are perhaps 
 those of Mont Bonnevie near Murat in Auvergne, where they can be ob- 
 tained from 50 to 60 feet in length unbroken by joint or flaw, and not more 
 than 8 or 10 inches in diameter. See TRAPPEAN ROCKS. 
 
 Basaltic. Composed of basalt ; containing basalt. Basaltiform. Re- 
 sembling basalt in its columnar structure. 
 
 Basaltine. The name given by Kirwan to crystallised hornblende, be- 
 cause it is " mostly found in basalts and lavas." 
 
 Basanite (Gr. basanizo, to test ; hence basanos, a touchstone). Lydian 
 stone or touchstone ; a variety of schistose hornstone formerly, and still 
 occasionally, used for testing the purity of gold. Consists of upwards of 
 75 silica, with lime, magnesia, carbon, and iron. Also a name given by 
 Brongniart to a rock having a base of basalt, with more or less distinct 
 crystals of augite disseminated through it. 
 
 Basilosaurus (Gr. basileics, a king, and saurus, lizard). Literally "King 
 of the Saurians," the name originally given by Dr Harlan to the huge 
 skeleton (between 70 and 80 feet long) discovered in the Eocene beds of 
 Alabama, from the belief that it was of saurian affinity. Now known to 
 be a cetacean or whale, and termed ZEUGLODON, which see. 
 
 Basin. In geology, any dipping or disposition of strata towards a com- 
 mon centre or axis is termed a basin, trough, or syndine. As the natural 
 disposition of strata is less or more horizontal, such basins must have been 
 formed by upheaval and subsidence of the earth's crust; and just in pro- 
 portion to the intensity of the disturbing causes, so we find basins of 
 greater or less extent, and in which the beds dip at all angles towards the 
 
 104 
 
BAS BAT 
 
 axis of depression. The Tertiary formations often occupy limited areas, 
 and fill up such depressions in the older rocks ; hence the use of such 
 phrases as "London Basin," "Paris Basin," "Vienna Basin," &c. Ill 
 geography, the term applies to the whole extent of valley-shaped or basin- 
 shaped country drained by any river and its tributaries, as the "Basin of 
 the Forth," &c. In a wider sense, also, to the depression or receptacle of 
 seas and lakes and the areas from which they receive their waters, as the 
 "Basin of the Caspian," the "Basin of the Mediterranean," &c. 
 
 Basset or Basset Edge. A miner's term for the outcrop or surface-edge 
 of any inclined stratum. See OUTCROP. 
 
 Bastard (Fr.) Spurious ; not genuine. Often applied by workmen to 
 rocks and minerals that are impure, or contain such admixture of impu- 
 rity as to render them economically worthless ; as " bastard limestone," 
 an impure siliceous limestone incapable of being converted into quicklime 
 when burnt in the kiln. 
 
 Bath-Brick. A well-known material used for cleaning and polishing 
 metal goods and utensils. It is manufactured at Bridgewater from a tidal 
 deposit of fine siliceous silt, deposited in the river Parret in Somerset- 
 shire, at the junction of the fresh and salt water. " The peculiar proper- 
 ties of this material," says Ansted, " are probably owing to the siliceous 
 cases of infusorial animalcules destroyed by the salt tidal- water where it 
 meets the fresh water of the river." 
 
 Bath-Stone. A familiar term for the "Great Oolite," which is exten- 
 sively quarried for building purposes in the neighbourhood of Bath. When 
 raised from the quarry the Oolitic freestones are soft and easily dressed, 
 but become hard on exposure to the atmosphere. See OOLITE. 
 
 Bathymetrical (Gr. bathys, deep, and metron, measure). Applied to the 
 distribution of plants and animals along the sea-bottom, according to the 
 depth of the zone (measuring from the shore) which they inhabit. See ZONE. 
 
 Batrachia (Gr. Idtrdchos, a frog). A subdivision of the Reptilia, com- 
 prising the frog, toad, salamander, and siren. Regarding the Batrachia 
 as an order, Professor Owen (1859) specialises some as having biconcave 
 vertebrae (Siren), some concave before and convex behind, as the frog 
 (Rana), and others as concave behind and convex in front, as Ripa. In 
 all, the pleurapophyses are short and straight ; the occipital condyles two ; 
 two vomerine bones mostly dentigerous ; no scales or scutes. True batra- 
 chians are found chiefly in Tertiary and Post-Tertiary strata. See REP- 
 TILIA. 
 
 Batracholites (Gr. MlrXchos, frog, and lilhos, stone). Fossil remains of 
 true batrachians or animals of the frog kind. " The skeletons, vestiges of 
 the soft parts, and imprints of the feet of several genera of true batrachi- 
 ans," says Mantell, "occur in a fossil state in Tertiary deposits, all of which, 
 like existing races, appear to belong to fresh- water or terrestrial species. 
 In the Pliocene or newer Tertiary strata, on the banks of the Rhine at 
 GEningen, and in the papier-kohle of the Eifel, several species of frog, toad, 
 and newt have been discovered. Fossil frogs of a small species, very 
 similar to the recent, occur in numbers in a dark shale, overlaid by basalt, 
 in the vicinity of Bombay." 
 
 Batrichnis (Gr. bdlr&chos, a frog, and iclmon, footprint). A provisional 
 genus of batrachian or frog-like footprints occurring in the New Red or 
 Triassic sandstones of Corncockle Muir, Dumfriesshire, and described by 
 Sir W. Jardine in his ' Ichnology of Annandale.' 
 
 105 
 
BAY BEL 
 
 Bay. Any bending of the ocean into the land, less sudden and con- 
 tracted than a creek or harbour, and communicating more openly with the 
 main ocean than a sea or gulj '; "Bay of Biscay," "Bay of Bengal." Geo- 
 logically, bays are the grand recipients of marine drift, and are usually 
 fringed or headed by belts or expanses of sand-drift or sand-dunes. 
 
 Bay Salt. A general term for coarse-grained salt, but properly applied 
 to salt obtained by spontaneous or natural evaporation of sea-water in 
 large shallow tanks or bays, 
 
 Beach. The shore of the sea ; the strand. Strictly that space along 
 the margin of a tidal sea over which the tide alternately flows and ebbs. 
 See RAISED BEACHES. 
 
 Beatricea. A remarkable fossil occurring in the Middle Silurians of 
 Canada, and at first supposed by Mr Billings to be the stem of a tree-fern. 
 The appearance of vegetable structure has since, however, been ascertained 
 by Dr Hooker to be deceptive, and due to crystallisation. Mr Salter 
 believes that the Beatricea, though thirty feet long, may be a gigantic 
 annelide tube allied to Cornulites. The living Amphitrite has a shelly 
 tube several feet in length. 
 
 Bechera. One of Brongniart's genera of fossil plants with tumid articu- 
 late stems and verticillate leaves ; now merged into ASTEROPHYLLITES. 
 
 Bed. This term is usually applied both by geologists and quarry men to 
 a stratum of considerable thickness, and of uniform homogeneous texture 
 e.g., "bed of sandstone," "bed of clay," &c. Originally and strictly, 
 however, the term bed referred to the surface-junction of two different 
 strata, and seam to the line of separation between them. Thus the upper 
 surface of a stratum may be smooth, or it may be rough and irregular, and 
 the under surface of the stratum deposited on it must partake of this 
 smoothness or this irregularity this is bedding; the line that marks the 
 separation between two strata is the seam. 
 
 Beekites. After Dr Beeke, Dean of Bristol, by whom they were first 
 noticed. Concretionary forms of chalcedony found encrusting fossil 
 sponges, corals, shells, and the like ; and occurring for the most part in 
 the conglomerates of the New Red Sandstone. They resemble in form 
 the pebbles among which they are imbedded, but are readily distinguished 
 by their composition and tubercular surface. They are frequently hollow, 
 the organic nucleus being entirely decomposed. Abundant in the pebbly 
 conglomerate of Torbay. 
 
 Beetle-Stone. A name given to coprolitic nodules of ironstone, &c., 
 from the fanciful resemblance (when the nodule is split up) of the enclosed 
 coprolite, and its radiating films of calc-spar, to the body and limbs of a 
 beetle. The finest specimens are found in the ferriferous shales of the 
 Coal-measuresmany of them being susceptible of a fair polish, which 
 materially assists in bringing out the beetle-like aspects of the fossil 
 nucleus. See SEPT ARIA. 
 
 Belenmite (Gr. belemnon, a dart). An abundant Cretaceous and Oolitic 
 fossil, apparently the internal bone or shell of extinct naked cephalopods 
 allied to the squid and cuttle-fish. Belemnites are usually found as 
 straight, solid, tapering (dart-like) fossils ; but occasionally the upper or 
 chambered portion is attached, and even in some instances the colouring 
 matter of the ink-bag has not been altogether destroyed. The pen of the 
 common squid (loligo) is a slender and insignificant organ compared with 
 the belemnite and its extinct congeners, which seemed to have thronged 
 
 106 
 
BEL 
 
 the seas of the upper Secondary period. Upwards of eighty species have 
 been described, and nearly one half of these occur in British strata. "A 
 belemnite," says Dr Buckland ('Bridgewater Treatise'), "was a compound 
 internal shell, made up of three essential parts, which are rarely found 
 together in perfect preservation, first, A. fibro-calcareous cond-shaped 
 shell, terminating at its larger end in a hollow cone. Secondly, A conical 
 thin horny sheath or cup, commencing from the base of the hollow cone 
 of the fibro-calcareous sheath, and enlarging rapidly as it extends outwards 
 to a considerable distance. This horny cup formed the anterior chamber 
 of the belemnite, and contained the ink-bag and some other viscera. 
 Thirdly, A thin conical internal - chambered shell, called the alveolus, 
 placed within the calcareous hollow cone above described. This cham- 
 bered portion of the shell is closely allied in form, and in the principles 
 of its construction, both to the nautilus and orthoceratite. It is divided 
 by thin transverse plates into a series of narrow air-chambers or areolce 
 resembling a pile of watch-glasses, gradually diminishing towards the 
 apex. The transverse plates are outwardly convex, and are perforated by 
 a continuous siphuncle, placed on the inferior or ventral margin." 
 
 Belemnoteuthis (Gr. belemnon, a dart, and teuihis, the squid or cuttle- 
 fish.) A genus of the Belemnite family of cephalopods occurring in the 
 Lias and Oolite, and occasionally so well preserved that the receptacle and 
 ink-bag have been found in their natural relative positions, together with 
 the remains and impressions of the mantle, body, tentacles with their 
 hooks, and the fins ! According to Mr Woodward, the belemnoteuthis 
 had eight nearly equal arms, each furnished with twenty to forty pairs of 
 hooks, forming a double alternating row ; and the tentacles, which were 
 not longer than the arms, were similarly provided. In all essential points 
 of structure it is most nearly related to the existing calamaries ( Teuthidce), 
 but in consequence of its posteriorly-pointed shell, its fins were lateral in- 
 stead of terminal, whilst the chambered structure of its shell and the cha- 
 racter of tentacles show that it must be regarded as a type distinct from 
 and equal in importance to the existing calamaries. 
 
 Belemnoziphius (Gr. belemnon, dart, and xiphos, sword). A genus of 
 solid-beaked dolphins occurring in upper Tertiary strata, and so named by 
 Professor Huxley from their long straight snouts, the only portions of their 
 skeletons which have yet been detected. 
 
 Bellerophon (a fanciful appellation from Bellerophon, n fabulous hero of 
 Grecian antiquity). An extensive genus of fossil nautiloid shells, consisting 
 of a single chamber like the living argonaut. They occur in the Silurian, De- 
 vonian, and Carboniferous strata, upwards of twenty species being met with 
 in the mountain-limestone. The Bellerophontidce are most generally regard- 
 ed as belonging to the Heteropoda, and allied to the Glass-shell (carinaria) ; 
 though by some they are considered to be a simple form of Cephalopod. 
 
 Bell-Metal. A well-known alloy of copper and tin, to which small pro- 
 portions of other metals (zinc, lead, &c.) are occasionally added, according 
 to the quality of the tone required the larger the proportion of copper 
 the graver the tone. 
 
 Bell-Metal Ore. A Cornish miner's term for STANNINE or sulphuret of 
 tin, in allusion to its brilliant bell-metal colour. As an ore it consists 
 essentially of tin and copper-pyrites. 
 
 Bel6ptera (Gr. belos, a dart, and pteron, wing). A curious belemnite- 
 looking organism occurring in Tertiary strata, and evidently the internal 
 
 107 
 
BEL BER 
 
 bone of a cephalopod, but less pointed than the belemnites, and having 
 a wing-like projection or process on each side; whence the name. As 
 a genus it holds a place intermediate between the Cuttle-fish and the 
 Spirulirostra. 
 
 Belosepia (Gr. belos, a dart, and sepia, the cuttle-fish.) A provisional 
 genus of short, flattened, belemnite-looking organisms occurring in Terti- 
 ary strata, and evidently the internal bone or shell of a cephalopod allied 
 to the existing Sepia ; hence the name. 
 
 Beloteiithis (Gr. belos, a dart, and teuthis, a squid or calamary). A 
 genus of flattened, spear-head-shaped belemnites occurring in the Lias, 
 and so termed from their apparent affinity to the squids or calamaries of 
 existing seas. 
 
 Berengellite. One of the mineral resins, occurring, according to Profes- 
 sor Johnston, in large amorphous masses, having a conchoidal fracture, 
 dark-brown colour inclining to olive, a resinous unpleasant odour, and 
 bitter taste. It consists of 72.40 carbon, 9.28 hydrogen, and 18.31 oxygen. 
 It is said to form a lake in the province of St Juan de Berengela in South 
 America, and is used at Arica to caulk vessels. 
 
 Berg (Swedish berg, a mountain.) An abbreviated term for iceberg, 
 which see. 
 
 Berg-Mahl, Berg-Mehl (Swedish). Literally " mountain-meal ; " a re- 
 cent infusorial or rather microphytal earth of a whitish colour and mealy 
 grain ; hence the name, and hence also the term "fossil farina" by which 
 it is occasionally designated. Such earths are of common occurrence in 
 bog and ancient lake-deposits (as in Finland, Iceland, San Fiora in Tus- 
 cany, &c.), and consist almost exclusively of the siliceous shields of micro- 
 scopic plant-growths (Diatoms) and of Infusoriae. In times of scarcity the 
 Finns and Laps are said to mix the berg-mahl with their food, just as the 
 Indians swallow similar clays to appease the cravings of hunger ; but be- 
 yond mere traces of organic matter, analysis does not seem to indicate the 
 presence of any nutritive principle. 
 
 Beryl (Persian belur, Lat. beryllus). A lapidary's term for the less bril- 
 liant and colourless varieties of the emerald this want of colour arising 
 from the absence of chromium, which gives to the emerald its deep rich 
 green. The finest beryls or aqua marine are found in Siberia, chiefly in 
 druses or veins in granite, along with rock-crystal or tourmaline and topaz. 
 Some crystals exceed a foot in length, but others of still larger dimensions 
 have been found in the United States. Esteemed gems also occur in the 
 granites of Wicklow and Aberdeen ; in Norway, Bavaria, the tin-mines 
 of Bohemia, Brazil, and other localities. " Pebbles of quartz," says Mr 
 Bristow, " are sometimes taken for beryls, and vice versa. The two may 
 be distinguished by observing that the crystals of beryl are striated longi- 
 tudinally, while those of quartz are striated transversely, or at right angles 
 to the axis of the prism. Moreover, the fracture of the two minerals is 
 widely different, for the beryl breaks in smooth planes, the faces of which 
 are at right angles to the axis of the crystals, whereas the fractured sur- 
 face of quartz is invariably conchoidal." See EMERALD. 
 
 Beryx. A genus of ctenoid fishes belonging to the Perch family, the 
 living species of which inhabit the seas of Australia. A number of species 
 have been obtained from the Chalk of the south-east of England, where it 
 is one of the most common ichthyolites, and known to the quarrymen by 
 the name of "Johnny Dory." The specimens are short, robust, perch- 
 
 108 
 
BER BIM 
 
 like fishes from four to twelve inches long, having very large heads, large 
 eye-orbits, broad opercular pieces covered with sculptured rays, and the 
 margins of the jaws furnished with a broad band of brush-teeth. The 
 body is covered with large round scales having several concentric rows of 
 denticles, and the single dorsal fin has several spinous rays in front of the 
 soft rays. 
 
 Berzeline (after Berzelius, the chemist). Seleniuret of copper, occurring 
 in crystalline dendritic crusts in fissures of calc-spar in the copper-mines 
 of Sweden and Saxony. 
 
 Berzelite (after Berzelius). A name given to several minerals in honour 
 of the great Swedish chemist. The Berzelite of Kiihn is a honey-coloured, 
 massive arseniate of lime and magnesia ; the Berzelite of LeVy a muriate 
 of lead a very rare mineral, generally known as Mendipite, from its occur- 
 ring in the Mendip Hills, Somersetshire. 
 
 Bethersden Marble (from Bethersden in the Wealds of Kent). A fresh- 
 water limestone of the Wealden formation, and better known as Sussex or 
 Petworth Marble, which see. 
 
 BeyricMa (after M. Beyrich). A genus of minute phyllopodous crusta- 
 ceans belonging to the family Limnadiadce, of which the existing Limnadia 
 has been taken as the type. They are bivalved, and their minute three- 
 lobed-like coverings occur in profusion both in lower and upper Silurian 
 strata, but more abundantly in the latter where hundreds, from the size 
 of pin-heads and upwards, may be seen attached to the crusts of Euryp- 
 terites, as if they had led, like many of their existing congeners, a para- 
 sitic life on crustaceans and fishes. 
 
 Bezoar Stones. A term occasionally employed to designate those stony 
 concretions which are usually composed of several crusts, one within an- 
 other, and having these crusts closely cohering without any internal cavity. 
 
 Bi (Lat. bis, twice). A frequent prefix signifying two, twice, or in twos; 
 as bimana, two-handed ; biennial, living for two years, or occurring every 
 second year ; bifurcate, two-forked, and so on. 
 
 Bicuspid (Lat. bis, and cuspis, a spear). Two-pointed ; two-fanged; 
 two-pronged. The "false molars" or pre-molar teeth in the human sub- 
 ject are frequently termed the bicuspids. 
 
 Biennial (Lat. bis, and annus, a year). In botany, enduring through- 
 out two years and then perishing ; applied to plants which do not bear 
 flowers and seed till the second year, and then die. 
 
 Bifid (Lat. bis, twice, and findo, fidi, I cleave). Cleft or cloven into 
 two ; opening with a cleft, but not deeply divided. 
 
 Bifurcated, Bifurcation (Lat. bis, and furca, a fork). Forked ; divided 
 into two heads or branches. 
 
 Bilateral Symmetry (Lat. bis, both, and latus, the side). That con- 
 struction in veterbrate animals by which the organs of the body are 
 arranged more or less distinctly in pairs on each side of the body. 
 
 Bildstein (Ger. bild, shape, and stein, stone). A German term, some- 
 times used in English works for agalmatolite or figure-stone (which see). 
 Called steatite-pagodite by Brongniart, from its coming from China in gro- 
 tesque figures and pagodas. 
 
 Bimana (Lat. bis, twice, and manus, hand). Literally two-handed. In 
 zoology, the order of mammalia of which Man is the sole representative ; 
 the apes and monkeys being quadrumanous, or four-handed. See tabula- 
 tions, " ANIMAL SCHEME." 
 
 109 
 
BIN BIS 
 
 Bind. A minor's term for tough, argillaceous, or clayey shales ; but, like 
 many other local terms, not very precise in its application. 
 
 Bing (Scot, a heap). A miner's term for a certain amount of output of 
 ore or of other mineral. In the Alston Moor district the bing of lead ore 
 is 8 cwt. 
 
 Bin6mial System (Lat. bis, two, and nomen, a name). That system in 
 zoological nomenclature, according to which every animal receives two 
 names one indicating the genus to which it belongs, the other being its 
 own specific appellation. Thus, the genus Felis includes the cat, tiger, 
 leopard, panther, lion, &c. ; but these being different species, are each 
 distinguished by a second term, as Felis callus, the common cat ; Felis 
 tigris, the tiger ; Felis leopardus, the leopard, and so forth. 
 
 Biology (Gr. bios, life, and logos, doctrine). The science of Life, whether 
 vegetable or animal, embracing botany and zoology in their widest accep- 
 tation. Biological. Relating to the science of life ; life in all its multi- 
 farious manifestations and developments. 
 
 Biotite (after M. Biot, who first pointed out the optical differences between 
 various kinds of mica). Hausmann's term for the rhombohedral talc-mica 
 of Mohs, and the magnesia-mica of other mineralogists. See MICA. 
 
 Birds-eye Limestone. A well-known member of the Lower Silurian of 
 North America, deriving its name from the dark circular markings which 
 stud many portions of its mass. These markings have been referred to 
 the impressions of a fucoid (Phylopsis cellulosus) ; but Mr Salter, from a 
 comparison with British specimens, regards them as the filled-up burrows 
 of marine worms. 
 
 Bird-tongues. A familiar term in the north of England for the fossil 
 teeth of lamna, which are somewhat flattened and tongue-shaped. 
 
 Bise. A cold and cutting north-east wind which descends from the snow- 
 covered Alps in spring and early summer; often ravaging the south of 
 France. 
 
 Biserial (Lat. bis, twice, and series, a row or order). Arranged in two 
 courses or series ; e.g., the " biserial " footprints of a quadruped as com- 
 pared with the "uniserial" line of a biped. 
 
 Bismutli (Ger. wismuth). One of the metals, having a reddish silver- 
 white colour, very sectile, non-malleable, and readily fusible, even in the 
 flame of a candle. Its specific gravity is 9.727 ; hardness from 2 to 2.5 ; 
 and fusing point at 476 Fahr. It occurs native, associated with the ores 
 of cobalt, silver, and tin ; and also as an oxide, under the name of bismuth 
 ochre; as a sulphuret, called bismuthine or b^sm^t,th-glance ; as a sulphuret 
 with copper, known as copper bismuth ore ; with copper and lead, called 
 aciculite or needle ore ; and in several other less important combinations. 
 See FUSIBLE METAL. 
 
 Bismuth-blende. Silicate of bismuth, or rather a mixture of silicate of 
 iron and bismuth, with phosphate of alumina. Known also as EULYTINE, 
 which see. 
 
 Bismuthine. Sulphuret of bismuth or bismuth-glance ; occurring chiefly 
 in the granitic and metamorphic rocks, either in longitudinally-striated 
 prismatic crystals, or massive, or disseminated in granular or columnar ag- 
 gregates. It is rather soft, sectile, of a greyish tin colour, and consists of 
 81.5 bismuth, and 18.5 sulphur. 
 
 Bismuthite. A yellowish-grey ore of bismuth, occurring disseminated 
 or in investing incrustations, and consisting essentially of carbonate of 
 
 110 
 
BIT BLA 
 
 bismuth, with a little of the sulphate, and mixed with traces of iron, 
 copper, and sulphuric acid as impurities. 
 
 Bitterspar. Known also as Rhomb-spar ; a mineralogical term for the 
 larger-grained, distinctly-crystallised, and cleavable varieties of dolomite, 
 which see. " Biterspar, it has been well remarked, bears the same rela- 
 tion to dolomite and magnesian limestone that calcareous spar does to 
 common limestone." 
 
 Bitumen (Gr. pitus, the pine or pitch-tree). Mineral pitch or tar. As a 
 genus, the Bitumens belong to the family of " Mineral resins," or hydro- 
 carbons, are highly inflammable, and burn like pitch with much smoke 
 and flame. They occur in numerous localities, and are associated with 
 almost every formation from the Silurian upwards. They appear to be 
 natural distillations or chemical conversions from substances of organic 
 origin (animal as well as vegetable), and present themselves most abun- 
 dantly in volcanic districts. At the same time it must be noted, that 
 bituminous exudations take place among Lower Silurian or even Cambrian 
 strata, formations in which only a few scattered sea-weeds and zoophytes 
 occur; and hence the ingenious surmise of M. Abich, that in such cases 
 bitumen is a primitive compound, engendered in the interior of the earth, 
 whence it arises like carbonic acid and nitrogen, of which the real origin 
 is also unknown. Be this as it may (though the occurrence of anthracites 
 in these early formations would seem to negative the notion), there can be 
 no doubt of the organic origin of bitumen in a majority of instances. In 
 its purest and most fluid state it constitutes naphtha (86 carbon, 14 hydro- 
 gen) ; when of the consistence of oil, it is known as petroleum (1 to 8 per 
 cent of nitrogen, oxygen, and ashes) ; in its next stage of inspissation it 
 is called maltha, or slaggy mineral pitch ; then elaterite or elastic bitumen ; 
 and ultimately it becomes indurated into asphalt, which varies considerably 
 in purity some specimens yielding from 8 to 14 per cent of oxygen and 
 nitrogen, and from 4 to 6 per cent of inorganic ashes. 
 
 Bituminous, &c. (See BITUMEN). Containing bitumen, or having the 
 properties of bitumen ; bituminiferous, yielding bitumen naturally, or by 
 distillation ; bituminated, impregnated or prepared with bitumen ; bitumin- 
 ise, to prepare or coat with bitumen ; and bituminisation, the natural pro- 
 cess of being converted into bituminous matter, as vegetable debris into coal. 
 
 Bivalve (Lat. bis, and valvce, folding doors). Applied to mollusca that 
 have two valves or shells, as the cockle and mussel ; in contradistinction to 
 those that are one-shelled (univalve) and many-shelled (multivalve). 
 
 Black Amber. The name given by the Prussian amber-diggers to jet, 
 because it is found accompanying amber, and when rubbed becomes faintly 
 electric. 
 
 Black-Band. A Scotch miner's term for those ironstones (clay carbon- 
 ates) of the Coal-measures which contain coaly matter sufficient to calcine 
 the ore without any artificial addition of fuel. See IRONSTONE. 
 
 Black-Chalk. A soft black or bluish black clay or shale, occurring in 
 subordinate layers in several formations, and owing its colour and softness 
 to the presence of from 10 to 15 per cent of carbon ; e.g., Italian Chalk, 
 German Chalk, &c. 
 
 Black- Jack. A miner's term for the sulphuret of zinc ; the Blende of 
 the mineralogist, which see. 
 
 Blacklead. A familiar term for GRAPHITE, from its resemblance to 
 the metal lead ; called also, for the same reason, Plumbago, which see. 
 
 Ill 
 
BLA BOG 
 
 Black- Wad. An earthy ore of manganese, more commonly known as 
 Wad, which see. 
 
 Bladed. Applied in mineralogy to crystals composed of long and nar- 
 row plates, like the blade of a knife ; laminated ; arranged in thin slender 
 laminae. 
 
 Blanching (Fr. Uanche, white). The process of whitening the leaves 
 and stems of plants by excluding the light. See ETIOLATE. 
 
 Blastoidea (Gr. Uastos, bud, and eidos, form). A small group or order of 
 palaeozoic echinoderms, typified by Pentremites, which see, and deriving its 
 name from the bud-like disposition of the plates of the receptacle. 
 
 Blende (Ger. blenden, to dazzle). A term applied by mineralogists to 
 several minerals having a peculiar lustre or glimmer, as horn-blende, zinc- 
 blende, ruby-blende, &c. ; but now chiefly applied to a metallic ore of 
 zinc the sulphuret or " black-jack" of the English miner. This ore in its 
 normal state consists of 67 zinc and 33 sulphur ; but usually contains a 
 certain proportion of the sulphide of iron, which imparts to it its black 
 colour, whence the name of " Black-jack." As usually found in British 
 mines it consists of 62 zinc, 4 iron, and 33 sulphur. See ZINC. 
 
 Blind-Coal. A miner's term for anthracite, and for those varieties of 
 common coal which have been in a great measure deprived of their bitu- 
 men, and hence burn away blindly, or without flame and light. 
 
 Bloodstone. Known also as heliotrope; a jaspideous variety of Calce- 
 dony of a dark-green colour, and sprinkled with deep-red spots ; hence its 
 name. See HELIOTROPE. 
 
 Blowers. In coal mining, the puffs or jets of carburetted hydrogen 
 given off by fissures in the coal during the operations of the miner. These 
 discharges are frequently emitted with considerable force, and many are 
 of long continuance, evincing that certain coal-seams are still undergoing 
 the chemical process of mineralisation or metamorphosis. 
 
 Blue-John. A miner's term for fluor or Derbyshire spar, which see. 
 
 Bluestone. The Australian miners' term for the basaltic lava through 
 which they have to sink in search of the auriferous drift large areas of 
 which in Victoria, &c., are covered up frequently by one and sometimes by 
 two beds which must have flowed over the gold-bearing gravels during the 
 later Tertiary periods. 
 
 Blue- Vitriol A familiar term for sulphate of copper, in contradistinc- 
 tion to green-vitriol, or sulphate of iron. 
 
 Bluffs. An American term for high banks presenting a precipitous 
 front to the sea or to a river, as the Bluffs of the Mississippi. 
 
 Bog (Celtic, soft). In Scotland and Ireland the common designation for 
 a wet spongy morass, chiefly composed of decayed vegetable matter. Bog- 
 earth, soils consisting in the main of decomposed vegetable matter, with a 
 considerable portion of light siliceous sand. 
 
 Bog-Butter. A name given to fatty spermaceti-like masses, occasionally 
 found in the peat-mosses of Ireland and Scotland, apparently varieties of 
 adipocerite, which see. 
 
 Bog-Iron Ore. A porous ferruginous deposit occurring at the bottom of 
 many bogs and peat-mosses, and occasionally in such quantities as to be of 
 industrial importance. In general, bog-iron forms a thin cake or pan of 
 iron-peroxide, and evidently results from the decomposition and precipita- 
 tion of the carbonates and oxides of iron held in solution by the waters of 
 the morass, and which have been carried thither by springs and other dis- 
 
 112 
 
BOG BOL 
 
 charges of water. By the decay of the vegetable matter, certain acids 
 (carbonic, crenic, &c,) are formed, and a number of chemical changes and 
 interchanges are set agoing, which result in the precipitation of the ore 
 in question. It varies much in composition containing from 20 to 78 per 
 cent of peroxide of iron, with varying quantities of protoxides of iron and 
 manganese, phosphoric and organic acids, together with a considerable 
 percentage of water. Ehrenberg has detected numerous infusorial forms 
 in bog- iron, but these can only be considered co-ordinate with, and not the 
 primal cause of the formation in question. For an account of the chemical 
 actions and reactions concerned in the formation of bog-iron, and for con- 
 siderations connected with its formation, as bearing on the origin of iron- 
 stone in general, see Bischof s ' Physical and Chemical Geology,' vol. i. 
 
 Bog- Wood. The trunks and larger branches of trees dug up from peat- 
 bogs. The term is usually applied to the "black-oak" obtained from the 
 bogs of Ireland and Scotland, and which derives its ebony colour from an 
 impregnation of iron. 
 
 Bohemia, in central Europe, rendered classical in geology from its con- 
 taining one of the most complete and intelligible known developments of 
 Silurian strata, which have been made the subject of an admirable mono- 
 graph by M. Barrande 'Systeme Silurien de Bohe'me.' 
 
 Boiling Point. The precise temperature at which a liquid begins to boil 
 or bubble up under the influence of heat. The boiling points of liquids 
 are constant under precisely the same circumstances. The causes which 
 induce variation are increased or diminished atmospheric pressure, the 
 greater or less depth of the liquid, and the nature of the vessel in which 
 it is contained. Thus, the boiling point of water under ordinary circum- 
 stances, at the level of the sea, is 212 Fahr. ; but it will boil and bubble 
 up at a much lower temperature on the top of a high mountain, in conse- 
 quence of diminished pressure ; it will also boil sooner and more quietly in 
 a rough-surfaced vessel than in a smooth and polished one ; and also more 
 quickly in a shallow vessel, in consequence of the less resistance by the 
 superincumbent water to the escape of steam. The boiling point is also 
 raised considerably by saline admixture, so that pure water, which boils 
 at 212, requires 285 when fully saturated with salt. As water boils at 
 212 Fahr. when the barometer stands at 30 inches, and every rise and fall 
 of one-tenth of an inch alters the boiling point 0.176 of a degree, it leads 
 to a convenient method of ascertaining the heights of mountains. In 
 vacuo, all liquids boil at a temperature 124 lower than in the open air, at 
 the ordinary pressure of the atmosphere. From these facts the reader may 
 readily infer the enormous temperature to which water may be heated in 
 the depth of the earth without boiling or passing off in vapour, and may 
 also judge of the terrific force with which it must explode or pass off in 
 steam as it approaches the vents and orifices of volcanoes. 
 
 Bolder oerg Beds. The sands and gravels of the Bolderberg hill, about 
 forty miles E.N.E. of Brussels, are the Belgian representatives of the 
 Middle or Eocene Tertiaries, and often referred to by geologists. 
 
 Bole (Gr. bolos, a clod or lump of earth). A term somewhat loosely 
 applied by geologists to friable clayey earths, usually highly coloured by 
 peroxide of iron; hence their yellow, yellow- red, and brownish-black 
 colours, which render them fitted for pigments. In mineralogy, the term 
 is applied to certain hydrous silicates of alumina and iron peroxide, in 
 varying proportions, e.g., 32 silica, 26 alumina., 21 peroxide of iron, 17 water, 
 
 113 H 
 
BOL BOH 
 
 with traces of lime and magnesia. When the magnesia is in notable pro- 
 portion, the boles become greasy or soapy in feel ; hence the terms "moun- 
 tain-soap," the "fett-bol" of the Germans, and the "Sinopian" and 
 "Lemnian earths" of antiquity, which see. 
 
 Bol6gnian or Bolognese Stone. A radiated variety of sulphate of barytes, 
 found in rounded masses near Bologna, which, after being heated and 
 placed in the sun's rays, phosphoresces in the dark. 
 
 Bone Bed. A term applied to several thin strata or layers, from their 
 containing innumerable fragments of fossil bones, scales, teeth, coprolites, 
 and other organic debris. One of the best known is that which caps the 
 New Red Sandstone or Trias in the south of England. It is found at Ax- 
 mouth in Devonshire, and at Westbury and Aust in Gloucestershire 
 places fully sixty miles apart the bed itself never being more than two or 
 three feet thick, and frequently only as many inches. Another occurs at 
 the junction of the Upper Silurian and Old Red Sandstone in Hereford- 
 shire. This is rarely more than a foot thick, and often only one or two 
 inches, and has been traced at intervals over a space of forty-five miles, 
 from Pyrton Passage to the banks of the Teme near Ludlow. 
 
 Bone Breccia. A conglomerate, or rather admixture of fragments of 
 limestone and bones, cemented together into a hard rock by a reddish 
 calcareous concretion, and occurring in caverns, fissures, and the like, of 
 later Tertiary date. This breccia is found in almost all the islands on the 
 shores of the Mediterranean Sea, as at Gibraltar, Cette, Nice, Corsica, 
 Palermo, &c. ; in many of the ossiferous caverns of Europe ; and similar 
 admixtures occur also in the bone caves of England. Bone breccias of 
 analogous date, but containing the bones of marsupial animals only, have 
 been found in the caves of Australia. See OSSIFEROUS CAVERNS. 
 
 Bone Earth. The earthy or mineral part of bones, which consists 
 chiefly of the phosphate of lime. 
 
 Boracic Acid. The Sassoline of some mineralogists ; a compound of 
 boron and oxygen, occurring in minute pearly scales, in crusts, or stalactitic 
 aggregates, in the neighbourhood of hot springs and volcanoes. Upwards 
 of 200,000 lb. are annually obtained from the hot springs or lagoni of 
 Tuscany, by evaporating the water. 
 
 B6racite. Borate of magnesia ; an anhydrous compound of magnesia 
 and boracic acid, consisting of 30.2 magnesia and 69.8 boracic acid. It is 
 usually associated with gypsum ; but a compact variety occurs in Germany, 
 forming beds with rock-salt and gypsum. 
 
 Borax. Native borate or bi-borate of soda, found associated with rock- 
 salt in loose crystals in the elay on the shores of certain lakes in Tibet 
 and Nepaul, in South America and in Ceylon. In its rough or impure 
 state it is known as tincal, and from this the pure borax of commerce is 
 derived. It is also made in large quantities from the boracic acid of the 
 Tuscan lagoons. Borax forms the most valuable reagent for blowpipe 
 experiments ; is used in the preparation of fine glass and artificial gems, 
 in medicine, and in South America as a flux for smelting copper. 
 
 Bord. A miner's term for the face of coal parallel to the natural fis- 
 sures, in contradistinction to End, which is at right angles to the natural 
 fissuring. 
 
 Bore. A violent rush of tidal water; the advancing edge or front of 
 the tidal wave as it ascends a river or estuary; e.g., the "bore" of the 
 Hooghly, the Garonne, the Severn, the Tsientang, &c. The bore of the 
 
 114 
 
BOR EOT 
 
 Tsientang is said to advance up that river, at Hangchau, like a wall of 
 water, thirty feet in height, and at the rate of twenty- five miles an hour, 
 sweeping everything before it. 
 
 Boreal (Lat. Boreas, the north wind). Of or belonging to the north; e.g., 
 Boreal Regions, Boreal Fauna, &c. The shells of the " Clyde Beds " re- 
 sembling those of Greenland and other existing arctic seas, these beds are 
 said to have been deposited under cold or " boreal conditions." 
 
 Bornia. Sternberg's term for a genus of Coal-measure plants with ver- 
 ticillate leaves ; the same as the Asteropkyllites equisetiformis of Brongniart 
 and Lindley, which see. 
 
 Bornite. The "purple copper" and "variegated copper" of some 
 mineralogists ; an ore of copper of a reddish pinchbeck colour and pale- 
 blue tarnish ; mostly found massive and disseminated in rocks of various 
 ages, as in the copper-slate of Germany, the crystalline schists of Norway, 
 &c. ; and consisting of about 60 copper, 14 iron, and 26 sulphur. See 
 COPPER. 
 
 Boron. In chemistry, one of the elementary substances ; the indecom- 
 posable base of boracic acid, from which it was obtained by Davy, by the 
 action of the voltaic battery. It occurs in the form of a fine mealy-white 
 powder, and has a weakly bitter taste, but not at all acid. 
 
 Bort or Boort. A kind of diamond, forming from two to ten per cent of 
 the rough diamonds imported from Brazil. "It is generally," says Mr 
 Bristow, "of a spherical shape, and appears to be formed of a confused 
 mass of interlaced and twisted parts, like the knots in a piece of wood. 
 For this reason it cannot be cleaned like ordinary diamonds,' and is only of 
 use as a material for polishing other stones, for which purpose it is broken 
 and reduced to powder in a mortar. Its colour is mostly greyish-white, 
 and its specific gravity exceeds that of ordinary diamonds." 
 
 Bos (Lat.) In zoology, the technical generic term for the Ox kind, of 
 which there are several existing species taurus or common ox, urus or 
 aurock, bison, bubalus or buffalo, grunniens or yak, mosdtatus or musk-ox, 
 &c. The genus occurs fossil, or rather sub-fossil, in the Upper Tertiaries * 
 and Post-Tertiaries of Europe and Asia. See BoviDM. 
 
 Boss (Fr. bosse). A knob or protuberance; a convenient term in geology 
 for rounded masses of rock that have resisted denudation, for sudden 
 mound-like swellings of quaquaversal strata, and for sudden protrusions 
 of trap or other igneous rock. 
 
 Bothrodendron (Gr. lothros, a pit or cavity, and dendron, a tree). A 
 genus of Coal-measure stems with dotted surfaces, and distinguished from 
 sigillaria and stigmaria by two opposite rows of deep oval concavities 
 which appear to have been made by the bases of large cones or seed- 
 bracts ( Fossil Flora,' vol. ii.). In the Ulodendron (which see) the pit-like 
 scars are rounder and more closely placed, while the surface of the stem 
 is covered with tesselated scales like the lepidodendron, and not dotted. 
 
 Botryoidal (Gr. botrys, a bunch of grapes). Applied to certain concre- 
 tionary forms, as those dccurring in the magnesian limestones of Durham, 
 the haematites of Westmoreland, &c., which resemble clusters of grapes. 
 
 Botryolite (Gr. botrys, a bunch of grapes, and lithos, stone). A variety 
 of Datholite, or borate of lime, occurring in small botryoidal or reniform 
 crusts in the magnetic iron-ore of Arendal in Norway. 
 
 Bottle-Track. The name given to the course pursued by bottles which 
 are thrown overboard with a note enclosed of the longitude and latitude 
 
 115 
 
EOT BOV 
 
 where and the date when they are dropped in the ocean. By this means 
 the set-in and velocity of currents are rudely indicated. 
 
 Bottom Beds. A term occasionally employed by English geologists to 
 designate those partially or doubtfully fossiliferous strata which imme- 
 diately underlie the Silurian system in Wales. They constitute the Lower 
 Cambrian formation of Sedgwick, and embrace the Bangor slates, Harlech 
 grits, and Llanberis schists. 
 
 Boulders (Sax.) Any rounded or water- worn blocks of stone, which 
 would not, from their size, be regarded as pebbles or gravel, are termed 
 boulders. The name, however, is usually restricted to the large water- 
 worn and smoothed blocks ("erratic blocks") found imbedded in the 
 clays and gravels of the Drift formation of the Pleistocene epoch, which 
 covers the northern hemisphere, in both worlds, down to the 40th or 42d 
 parallel of latitude. 
 
 Boulder-Clay. A term in frequent use by British geologists to desig- 
 nate those stiff, tenacious, unlaminated clays of the glacial or " Drift " 
 epoch, which are widely spread over Great Britain, and easily distinguish- 
 able from other clays by the numerous boulders and pebbles interspersed 
 throughout their mass. These water-worn blocks have evidently been 
 dropt in deep water from floating ice, and have settled in the clayey silt, 
 without regard to specific gravity, or anj* other arrangement. The clay 
 itself usually partakes of the colour of the formations from whose imme- 
 diate waste it has been derived : red in Old Red Sandstone tracts, dark- 
 blue in Coal-bearing districts, and creamy or chalky white in Oolite and 
 Chalk areas. See DRIFT. 
 
 Bourguetlcrinus (after M. Bourguet). A genus of encrinites occurring 
 in the Chalk and Lower Tertiaries, and much resembling Apiocrinus, under 
 which it was at one time included. 
 
 Bournonite. A plumbo-cupreous sulphuret of antimony, named after 
 Count Bournon, who first discovered it at Endellion in Cornwall, and 
 hence known also as Endellionite. It is of a steel-grey colour, and occurs 
 in thick tabular crystals or massive in granular aggregates, and consists of 
 41.8 lead, 12.9 copper, 26 antimony, and 19.3 sulphur. 
 
 Bourrans. The name given to the fierce snow-storms that blow from 
 the north-east over the steppes of Russia, and which often rage for twenty- 
 four hours at a time. 
 
 Bovey Coal. A local designation for the Tertiary lignite or brown coal 
 which occurs at Bovey in Devonshire, where it is worked for the potteries. 
 There are several beds, varying from two to sixteen feet in thickness, and 
 interstratified with clays the whole forming a local deposit of limited 
 extent. The lignite appears in every degree of purity, from the woody- 
 looking " board coal " of the miner to a soft earthy mass almost undistin- 
 guishable from peat. See LIGNITE. 
 
 B6vidse (Lat. bos, bovis, an ox). -The Ox tribe ; a well-known family 
 of ruminants, whose remains are not known to occur in deposits of older 
 date than the Pliocene and Pleistocene Tertiaries. " At those periods," 
 says Owen, " there existed in Britain a very large species of bison (Bison 
 priscus), and a large species of ox (Bos antiquus) from fresh-water Pliocene 
 beds ; whilst a somewhat smaller but still stupendous wild ox (B. primi- 
 genius) has left its remains in Pleistocene marls, both in England and Scot- 
 land. With this was associated an aboriginal British ox of much smaller 
 stature, and with short horns (B. longifrons), which continued to exist un- 
 
 116 
 
BRA 
 
 til the historical period, and was probably the source of the domesticated 
 cattle of the Celtic races before the Roman invasion. A buffalo not dis- 
 tinguishable from the musk kind (Bubalus moschalus), now confined to the 
 northern latitudes of North America, roamed over similar latitudes of 
 Europe and Asia, in company with the hair-clad elephants (Mammoths) 
 and rhinoceroses." (' British Fossil Mammals.') 
 
 Brachiolites (Gr. Irachion, an arm, and lithos, stone). A fossil zoophyte 
 or bryozoon occurring abundantly in the Chalk of the south of England, 
 presenting a puckered or folded fungiform appearance, and furnished 
 with radical and lateral processes ; whence the name. See Mr Toulmin 
 Smith's 'Memoir on the Ventriculidae.' 
 
 BracMopoda (Gr. Irachion, an arm, and pous, podos, a foot). A numer- 
 ous order of mollusca, including equal and unequal valved genera, and 
 having one shell placed on the back of the animal, and the other in 
 front. They have no special breathing organs, but the mantle performs 
 that office : they take their name from two long, spiral, ciliated arms, de- 
 veloped from the sides of the mouth, which they can uncoil and protrude, 
 and with which they create currents that bring them food e.g., terebratula, 
 spirifer, prodwda, &c. The Brachiopods were more abundant, generally 
 and numerically, iu Palaeozoic than in Neozoic epochs, and have been much 
 studied by palaeontologists. See MOLLUSCA and PALLIOBRANCHIATA. 
 
 Brachy. A Greek word signifying short, and frequently made use of in 
 scientific compounds; as brachyurous, short-tailed; brachypteiyx, short- 
 winged ; brachycera, short-horned, &c. 
 
 Brachycephdlic (Gr. brachys, short; fe^a^, the head). Literally "short- 
 headed ; " applied in scientific descriptions to the form of the head in 
 animals e.g., the brachy cephalic or short-headed tribes of the human 
 family. 
 
 Brachyphyllum (Gr. brachys, short, and phyllum, leaf). A coniferous- 
 looking plant occurring in terminal twigs and branches in the Oolitic 
 formation, and so called from the short, ovate, ribless, scale-like leaves 
 which surround the branches. Judging from its leaves and general aspect, 
 Lindley would ally it with the Araucaria, Callitris, and Dacrydium,. 
 
 Brachyiira (Gr. brachys, short, and oura, tail). A sub-order of the 
 Decapod crustaceans, in which the abdomen is always converted into a 
 short jointed tail, quite destitute of terminal appendages, and bent round 
 so as to fold closely under the breast, as in the common edible crabs. The 
 brachyura are not known in a fossil state earlier than the Lower Cretaceous 
 or Greensand period. 
 
 Bracklesham Beds. A series of Lower Tertiary sands and clays immedi- 
 ately overlying the London Clay, and so called from being well exposed at 
 Bracklesham Bay, near Chichester, in Sussex. They contain the gigantic 
 cerithium, volutes, cowries, bones of fishes, crocodiles, and sea-serpents ; 
 and thus seem to favour the idea of a warm climate having prevailed in 
 these latitudes during the period of their deposit. 
 
 Bradford Clay. A member of the Oolitic system, equivalent with, or 
 immediately overlying, the Great Oolite. It is well developed near Brad- 
 ford, and consists of a pale greyish clay, slightly calcareous, and enclosing 
 thin slabs of tough brownish limestone. It rarely exceeds sixty feet in 
 thickness, and is remarkable for the number of its Apiocrinites, which are 
 consequently sometimes termed the "Bradford Encrinite." 
 
 BrancMa (Gr. a gill). The branchiae or gills are the respiratory organs 
 117 
 
BKA BKE 
 
 of those animals that breathe water instead of air. They vary greatly in 
 their structure and position in different animals. 
 
 Branchidstegal, Branchi6stegous (Gr. Iranchia, gill, and stego, I cover). 
 Gill-covering ; applied to certain bones or bent rays that support the 
 membrane which covers and protects the gills of fishes. The branchiostegal 
 rays are often very beautifully preserved even in Palaeozoic fishes. 
 
 Brard's Process. A method adopted by M. Brard to discover in a short 
 time the relative resistance offered by different kinds of rock to the action 
 of damp and frost, and therefore to determine their durability with re- 
 ference to exposure. It consists in boiling small cubes of the stones to be 
 tested in a saturated solution of sulphate of soda (Glauber's salts), and 
 then suspending them for four or five days in the open air. As they dry 
 they become covered with an efflorescence of crystals, which must be suc- 
 cessively washed off till the efflorescence ceases. If the stone resists the 
 decomposing action of damp and frost, the salt does not force out any 
 portions of the stone with it ; on the other hand, if it yields to this action, 
 small fragments will be perceived to separate themselves, and the cube will 
 gradually lose its angles and sharp edges. The amount of this disinte- 
 gration affords, according to the author of the process, a criterion of what 
 would be produced in course of time by the action of the weather. Ac- 
 cording to other authorities, the expansion of water under frost, and the 
 almost inappreciable expansion of Glauber salt while crystallising, are 
 so very different things, that the one cannot by any means be taken as a 
 test of the effects of the other. 
 
 Brash. " In almost every country," says Sir Charles Lyell, " the allu- 
 vium consists in its upper part of transported materials, but it often passes 
 downwards into a mass of broken and angular fragments, derived from the 
 subjacent rocks. To this mass the provincial name of ' rubble ' or ' brash ' 
 is given in many parts of England. It may be referred to the weathering 
 or disintegration of stone on the spot, the effects of air and water, sun 
 and frost, and chemical decomposition." See CORNBRASH. 
 
 Brattice. In coal-mining, an underground wall or partition made of 
 wood, or faced up with wood, to prevent the escape of gases or water, or 
 to alter the current of ventilation. 
 
 Brannite (in honour of M. Braun of Gotha). An abundant ore of man- 
 ganese, consisting, according to analyses of Indian specimens, of 73.79 
 binoxide of manganese, 12.91 peroxide of iron, 8.30 silica, with magnesia, 
 oxygen, and water. See MANGANESE. 
 
 Brazilian Ruby. The name given by lapidaries to light rose-coloured 
 spinelle, and pink-coloured topaz. 
 
 Brazilian Sapphire. The name given by some authors to light-blue 
 topaz, and by lapidaries to indicolite. 
 
 Brazilian Tourmaline. The name given by lapidaries to Brazilian 
 emerald. 
 
 Breast. A miner's term for the face or front of a coal-seam at which 
 he is working. The term is also applied to the wood en. partition that 
 divides a shaft, from bottom to top, into two compartments the one 
 forming an "upcast " the other a "downcast " current of ventilation. 
 
 Breccia (Ital. a crumb or fragment). A term applied to any rock com- 
 posed of an agglutination of angular fragments, as "volcanic breccia," 
 " osseous breccia," "calcareous breccia," &c. A breccia, or brecciated rock, 
 differs from a conglomerate in having its component fragments irregular 
 
 118 
 
BRE BRO 
 
 and angular, whereas the pebbles of the latter are rounded and water-worn. 
 The origin of many breccias and breccio-conglomerates is extremely 
 puzzling to geologists. Many of them seem to point to the action of frost 
 on exposed rock-surfaces, and to the transporting power of ground and 
 river ice for their deposit in water ; e.g., the Permian Breccias of Devon 
 and Annandale. 
 
 Breeze. The general term for a wind of some briskness, but of limited 
 extent and duration ; less violent than a gale. 
 
 Breithauptite (after Professor Breithaupt of Freyberg). Antimonial 
 nickel ; occurring in the Hartz with ores of cobalt, lead, zinc, and pyrargy- 
 rite ; either crystalline, arborescent, or disseminated ; of a light copper-red, 
 with a violet-blue tarnish ; and consisting of 31.4 nickel, and 68.6 antimony. 
 
 Brewsterite (after Sir D. Brewster). One of the Zeolite family, occur- 
 ring in short prismatic crystals of a greyish white or yellowish colour and 
 vitreous lustre, formed by several vertical prisms, and consisting of 54 
 silica, 17 alumina, 8.7 strontia, 6. 4 baryta with lime, and 13.5 water. 
 
 Brewstoline (after Sir D. Brewster, by whom the first accurate researches 
 were made into the nature of the liquids and gases which occur in the 
 cavities of rock-crystal and other gems). Brewstoline is a transparent, 
 colourless fluid, occurring in the minute cavities of rock-crystal, amethyst, 
 topaz, &c. ; is thirty-two times more expansible than water, and is said to 
 be liquid carbonic acid. See AMETHYSTOLINE. 
 
 Brick-Clay. The familiar term for any clay used in the manufacture of 
 bricks, tiles, and the like. A good brick-clay consists of a tolerably pure 
 silicate of alumina, combined with sand in various proportions, and free 
 from lime and other alkaline earth, of which there ought not to be more 
 than 2 per cent, more than this acting as a flux in the brick-kiln. A 
 little iron is also present in most varieties ; hence the red colour of the 
 bricks as the iron passes into the state of peroxide. Brick-clays are gene- 
 rally superficial deposits, but may also be obtained from any of the strati- 
 fied formations. In geological classification, the term "Brick-clay" is 
 
 frequently used in contradistinction to that of " Boulder-clay " meaning 
 thereby those finely-laminated clays of the Pleistocene epoch which imme- 
 diately overlie the true Boulder-clay, and have evidently been derived from 
 it by the wasting and re-assorting agency of water. 
 
 Bristol-Stone, or Bristol-Diamond. A familiar term for small brilliant 
 crystals of quartz or rock-crystal, occurring in the limestones of Clifton, 
 near Bristol. 
 
 Brittleness. That quality of minerals and other solids by which they 
 admit of being easily broken into fragments. The opposite of tough or 
 tenacious : thus a substance may be hard yet brittle, be soft and yet tenacious. 
 
 Brocatello (Span.) A species of brecciated marble, the component frag- 
 ments of which are of various colours white, grey, yellow, and red. 
 Brocatello is of Tertiary age, and makes a curious rather than an elegant 
 ornamental stone. 
 
 Bromine (Gr. bromos, a stench). One of the non-metallic elements, dis- 
 covered by M. Balard of Montpelier in 1 826. It occurs in the state of a 
 deep-red liquid, having a fetid odour somewhat resembling chlorine, and 
 is usually obtained from the uncrystallisable residuum of sea water called 
 bittern. It is found, however, not only in sea water, but in several salt 
 springs, as well as in certain marine plants and animals. 
 
 Bromite. Bromic- silver, an ore of silver occurring in olive-green grains, 
 119 
 
BEO BKU 
 
 and consisting of 57.5 silver and 42.5 bromine. It is often mixed with 
 carbonate of lead, peroxide of iron, and clay, and is found in the silver 
 mines of Mexico and South America, where it is termed verde plata, or 
 " green silver." 
 
 Br6ngniartin (after Brongniart), known also as Glauberite. A double 
 sulphate of soda and lime a rare salt, occurring in connection with rock- 
 salt and clay. 
 
 Brdntes (Gr. Ironies, a giant). A genus of Devonian trilobites, especially 
 characterised by their broad, radiating, fan-like tail, and so termed from 
 their great size compared with the other genera of the family. Little is 
 known of the true form of the head or disposition of the eyes. 
 
 Brontozoum (Gr. brontes, a giant, and zoon, an animal). A provisional 
 name given by Professor Hitchcock to certain gigantic bird-like footmarks 
 discovered in the New Bed Sandstone of Massachusetts and Connecticut. 
 Some of these footmarks, as those of the B. parallelum, are fully 20 inches 
 in length, with a corresponding breadth or divarication of the toes. 
 (' Silliman's Journal' for 1847.) 
 
 Bronze (Fr.) A well and anciently known alloy of tin and copper the 
 proportions of the admixture varying according to the purposes to which 
 it was to be applied, and the hardness and toughness depending more on 
 the mode of tempering than on the relative quantities of the ingredients. 
 Ancient bronze usually contains from 4 to 15 per cent of tin. Modern 
 bronze, when used for statues, medals, and the like, usually contains a 
 small percentage of zinc and lead ; but that for bells, cannon, and other 
 articles subjected to great strain, is injured by such admixture. The best 
 "gun-metal," it is said, consists of 91 copper and 9 tin; the best "bell- 
 metal," of 78 copper and 22 tin. 
 
 Bronzite. A variety of diallage or schiller-spar, so called from its 
 metallic lustre and pinchbeck or clove-brown colour. It differs from dial- 
 lage and schiller-spar in being less fusible, and also by its greater hardness 
 and specific gravity. See SCHILLER-SPAR. 
 
 Brookite (after Brooke). Same as Analase, which see ; an ore of titan- 
 ium occurring in rhombic prisms of a brownish-yellow or reddish colour, 
 with a brilliant lustre inclining to metallic. Consists of oxide of titanium 
 or titanic acid, with traces of iron peroxide and alumina. 
 
 Brown Coal. Another name for Tertiary lignite, in allusion to its colour, 
 as distinguished from the clear, shining, or crystalline black of true coal. 
 "Wood-coal," "bituminous wood," and " board- coal," are occasional local 
 synonymes. See LIGNITE. 
 
 Brown Spar. Siderite, sphserosiderite, or sparry carbonate of iron ; an 
 abundant ore of iron, consisting generally of from 50 to 60 per cent of iron 
 protoxide, and from 30 to 40 carbonic acid, with traces of lime, manganese, 
 and other minor impurities. The name is also given to the brown crystal- 
 lised varieties of Dolomite, whose colouring matter is derived from a small 
 percentage of iron. See IRON. 
 
 Brucite (after Dr Bruce of New York, by whom it was discovered and 
 described). A native hydrate of magnesia, consisting of 69 magnesia and 
 31 water ; a synonyme also given to C'ondrodite or Chrysolite, which consists 
 of silica, magnesia, fluorine, and iron. 
 
 Bruckmannia (after Bruckmann). Count Sternberg's term for certain 
 closely-jointed stems with verticillate leaves which occur in the Coal-meas- 
 ures, now ranked under the general head ASTEROPHYLLITES. 
 
 120 
 
BEY BUR 
 
 Bryoz6a (Gr. bryos, moss, and zoon, animal). This term embraces all the 
 minute mollusca which inhabit compound structures, and which were 
 formerly regarded as zoophytes or corallines e.g., retepora, fenestella, 
 polypora, kc. The term (introduced by Ehrenberg) has reference to their 
 branched and moss-like aggregation. See POLTZOA. 
 
 Bubalus (Lat. a buffalo). Remains of the Musk-buffalo (B. moschatus), 
 a well-known living inhabitant of arctic regions, have been found in the 
 glacial drift of England, Germany, and other European localities thus 
 indicating the climatal conditions that prevailed over these latitudes 
 during the close of the Tertiary period. See BOVID^E. 
 
 Bucholzite (after Bucholz, the German chemist). Known also as fibro- 
 lite ; a term for the finely-fibrous varieties of Andalusite or Sillimanite, 
 which see. 
 
 Bucking (in mining). Crushing ore. A bucking-iron is the tool (a flattish 
 hammer) with which the ore is crushed by the hand ; a bucking-plate is the 
 plate on which the ore is bucked. 
 
 Biicklandite (after Dr Buckland). A variety of epidote or prismatoidal 
 augite-spar, occurring in small black vitreous crystals in the granitic rocks, 
 and described as a pure iron epidote. 
 
 Buddie (in mining). A pit, trough, or frame filled with water, by means 
 of which ores are separated from earthy substances by washing. 
 
 Blifonite (Lat. bufo, a toad). Literally toad-stone ; a name given to the 
 fossil teeth and palatal bones of fishes belonging to the family of Pycno- 
 donts (thick-teeth), whose remains occur abundantly in the Oolitic and 
 Chalk formations. The term bufonite, like those of " serpent's eyes," 
 " batrachites, " and "crapaudines," by which they are also known, refers 
 to the vulgar notion that those organisms were originally formed in the 
 heads of serpents, frogs, and toads. 
 
 Bumastus (Gr. a bunch of large grapes literally each large as a cow's 
 nipple, bou and mastos). A genus or sub-genus of Silurian trilobites, so 
 called from their oblong-oval or grape-like form, and known to collectors 
 as the "Barr Trilobite," from their plentiful occurrence in the limestone 
 of Barr, in Staffordshire. In bumastus, which may be regarded as a sub- 
 generic form of Ilcenus, the general form is oblong-oval and very convex ; 
 the head, thorax, and abdomen are of nearly equal length ; the head 
 and tail plates much rounded ; the eyes smooth and not granulose ; the 
 thorax of ten narrow segments, in which the trilobation is scarcely discern- 
 ible ; and in most species the crust studded with minute punctures. 
 
 Bunch. A miner's term for an irregular lump of ore more than a stone, 
 and not so much as a continuous vein. A mine is said to be bunchy when 
 the yield is irregular sometimes rich, sometimes poor. 
 
 Bunter (Ger. variegated). The German term for the New Red Sandstone 
 of English geologists, in allusion to its variegated colour; the lowest group 
 of the TRIASSIC SYSTEM, which see. 
 
 Buprestis. A genus of coleopterous insects remarkable for their bril- 
 liant metallic tints ; chiefly inhabitants of warm and intertropical climates, 
 and frequenters of woods and pine-forests. Their elytra or wing-sheaths 
 have been long known in the Oolitic flags of Stonesfield, near Oxford. 
 
 Burdiehouse. About three miles south from Edinburgh, situated on 
 the Lower Coal-measures, and celebrated for its estuary or fresh- water lime- 
 stone, which has yielded many fine fishes (palceoniscus, amblypterus, megal- 
 ichthys, rhizodus, holoptychius, &c.), and beautifully preserved plants, as 
 
 121 
 
BUR CAD 
 
 splienopiens, calamites, aster ophyllites, stigmaria, lepidodendron, lepidostro- 
 bus, &c. See Dr Hibbert's paper in 13th vol. 'Trans. Royal Soc. of Edin- 
 burgh/ and Page in 'Brit. Assoc. Reports' for 1855. 
 
 Burrh or Burr-Stone. A name given to certain siliceous or rather siliceo- 
 calcareous rocks, whose dressed surfaces present a burr or keen-cutting 
 texture ; hence their use as millstones. The most esteemed varieties are 
 obtained from the upper fresh- water beds of the Paris basin, and from the 
 Eocene strata of South America. The French burrhs are porous, or rather 
 vesicular, in texture, and of a whitish or cream colour. They are exten- 
 sively used in this country. 
 
 Byssolite (Gr. byssos, fine flax, and lithos). A somewhat indefinite term 
 applied to fine fibrous varieties of amianthus, tremolite, actinolite, and 
 other filamentous minerals. The Byssolith of Hausmann is a fine, trans- 
 parent, azure-coloured variety of actinolite, consisting, according to Du- 
 frenoy, of 26.98 oxide of zinc, 4.17 oxide of copper, 26.69 lime, and 39.16 
 water and carbonic acid. 
 
 Byssus (Gr. byssos, tine flax). In conchology, the fine silky filaments by 
 which the pinna, mussel, and other bivalves attach themselves to the rocks 
 and sea- bottom. In botany, the silky tufts of mould or fungus-growth 
 which spring from damp and decaying substances. 
 
 Cabocle. The name given in Brazil to a compact brick-red mineral found 
 in the diamond sand of the province of Bahia. It resembles jasper, but con- 
 tains phosphoric acid, alumina, lime, and water. 
 
 Cachalong. A milk or bluish white variety of opal, so called from its 
 being found in great beauty on the borders of the river Cach in Bucharia. 
 In the Kalmuc language, cholong is said to signify a precious stone. Ac- 
 cording to Forchammer, a cachalong from the Faroe Islands yielded 95.32 
 silica, 3.47 water, iron peroxide a trace, .07 potash, .06 soda, .06 lime, .40 
 magnesia. See OPAL. 
 
 Caddis- Worms or Case-Worms. The larvae or grubs of the trichopterous 
 (hairy- winged) insects, and so called because they are enclosed in a case or 
 sheath, composed of agglutinated extraneous substances, such as fragments 
 of straw, twigs, shells, &c. Some pass their larval state under water (e.g., 
 the May-flies), and are thus sometimes found fossil in such masses as to 
 constitute layers of fresh- water limestone. See INDUSIAL LIMESTONE. 
 
 Cadent (Lat.) Falling ; the tenth of the fifteenth series into which Pro- 
 fessor Rogers subdivides the Palaeozoic strata of the Appalachian chain 
 the " Declining Day" of the North American Palaeozoics, and the 
 equivalent of our Lower-Middle Devonian. See tabulations, " GEOLOGICAL 
 SCHEME." 
 
 Cadmium. A bluish-white metal, discovered in 1818 by Stronmeyer and 
 Hermann in several of the ores of zinc, and named from cadmia fossilis, an 
 old term for zinc ore. Cadmium greatly resembles tin in appearance, but 
 it is harder than that metal ; it is ductile and malleable ; melts a little be- 
 
 122 
 
CAE CAL 
 
 low 500 Fahr., or under a red-heat, and is about as volatile as mercury. 
 Its scarcity prevents its use in the arts, but its oxide has been used as a 
 pigment. 
 
 Caen Stone. The French equivalent of our " Great or Bath Oolite," an 
 Oolitic limestone so termed from its being extensively quarried in the neigh- 
 bourhood of Caen in Normandy, where it is developed in thick nearly 
 horizontal beds. As a building-stone it is of admirable quality ; soft in 
 the quarry, of a delicate uniform cream colour, and extreme fineness of 
 texture, but hardens on exposure, and is found to be exceedingly durable. 
 
 Cainozoic <>r Csenozoic (Gr. kainos, recent, and zoe, life). Applied to the 
 upper stratified systems holding recent forms of life, as distinguished from 
 Mesozoic (holding intermediate) and Palaeozoic (holding ancient and extinct 
 forms). As a palseontological division, the Cainozoic embraces the Terti- 
 ary and Post- Tertiary systems of British geologists. See tabulations, 
 " GEOLOGICAL SCHEME." 
 
 Cairngorm. A brownish-yellow or amber-coloured variety of rock- 
 crystal, so called from its being found in great perfection in the Cairngorm 
 Mountains, Aberdeenshire. " It was formerly much valued," says Pro- 
 fessor J. Nicol, " for ornamental purposes, and an Edinburgh lapidary cut 
 nearly 400 worth of jewellery out of a single crystal." See QUARTZ. 
 
 Caithness Flags. A well-known series of dark-coloured bituminous 
 flaggy beds, slightly micaceous and calcareous, of great toughness and 
 durability, and largely employed for paving. They belong to the lower- 
 middle portion of the Old Ked Sandstone as developed in Scotland, and are 
 celebrated for their abundance and variety of fossil fishes as coccosteus, 
 pterichthys, dipterus, diplopterus, cheiracanthus,asterolepis, &c. See Agassiz, 
 ' Poisons Fossils des Vieux Gres Kouge,' and Miller's Old Red Sandstone. ' 
 
 Caking Coal. The name given to certain varieties of bituminous coal, 
 which, like those of the Newcastle coal-field, cake or run together in the 
 act of combustion. See COAL. 
 
 Calaite. A mineralogical term for the turquois, from its being supposed 
 to be the precious stone alluded to by Pliny under the name of Callais. 
 
 Calamine. The common name for the carbonate of zinc, which occurs, 
 massive or crystallised, in beds and veins in the crystalline and transition 
 rocks, and also in the Carboniferous and Oolitic formations. It is most 
 abundant in limestone, and is often associated with calc-spar, quartz, blende, 
 and ores of iron and lead. The name is said to be derived from calamus, 
 a reed, because during the process of smelting it adheres to the bottom of 
 the furnace in the form of reeds. 
 
 Calamites (Lat. calamus^ a reed). A genus of fossil stems occurring 
 abundantly in the Coal-measures, and so termed from their resemblance to 
 gigantic reeds. Their true affinities, however, are not well known, and all 
 that can as yet be said of them is, that they were tall hollow articulated 
 stems, furnished with leaves or branches at the joints, possessing a dis- 
 tinctly separable wood and bark, and readily disarticulating at the nodi. 
 The surface of their wood was marked with numerous parallel furrows, 
 which gives to the fossil stems their striated or channeled appearance ; 
 the leaf or branch scars are observable at all the joints, and their substance 
 seems to have been so soft as to offer little or no resistance to pressure. 
 According to some, they seem analogous to reeds, but this opinion is not 
 well founded. Brongniart would ally them to the equisetums ; but Lindley 
 and others regard their true affinities as yet undiscovered. This much seems 
 
 123 
 
CAL 
 
 certain, that they were both numerically and specifically abundant ; that 
 their habitat was the soft marshy silt of the river edge and estuary ; and 
 that they contributed largely to the formation of our coal-seams. 
 
 Calamodendron (calamus, a reed, and dendron, tree). Literally " reed- 
 tree ;" one of Brongniart's genera of Coal-measure plants, often of consider- 
 able thickness, and having their surfaces or outer barks smooth, their stems 
 solid, and containing a deeply striated, articulated, reed-like pith ; hence 
 the name. Their real nature and affinity to the ordinary catamite are by 
 no means satisfactorily determined. 
 
 Calamophyllia (calamus, a reed, and phyllon, a leaf). A genus of Meso- 
 zoic or Oolitic corals, so called by Milne Edwards from their being com- 
 posed of masses of radiating tubes, with striated reed-like surfaces.' Indi- 
 vidual masses have been found several feet in diameter the progeny, like 
 the existing brain-coral, of a single germ. Known also as EUNOMIA. 
 
 Calcaire Grossier (Fr., literally coarse limestone). An important mem- 
 ber of the Eocene beds of the Paris basin ; usually co-ordinated with the 
 Barton, Bagshot, and Bracklesham beds of the English Tertiaries. 
 
 Calcaire Silicieux. A designation of the French geologists for a compact 
 siliceous limestone of the Paris basin, which sometimes takes the place of 
 the Calcaire Grossier. 
 
 Calcareous (Lat. calx, calcis, lime). Composed of or containing a con- 
 siderable portion of lime. Thus we speak of calcareous spar or Calcite, 
 which is a pure carbonate of lime, and of calcareous shale or calcareous 
 sandstone, which only contain a portion of lime. Geologists also compound 
 the term, as calcareo-argillaceous, calcareo- siliceous, &c. 
 
 Calcariferous. Literally " lime-yielding." A term occasionally applied 
 to springs charged with carbonate of lime, and which on issuing into the 
 air deposit incrustations of calcareous tufa. The "petrifying springs" 
 of ordinary language. 
 
 Calcedony (Lat. calcedonius, found at Calcedon, in Bithynia). A semi- 
 transparent siliceous mineral, of the quartz family, closely allied to the 
 opal and agate, and often found associated with them in geodes and vein- 
 bands. It is usually uncrystallised, of a uniform milky-white or pale 
 yellow, and, when occurring as an incrustation or sinter, has a wavy inter- 
 nal structure and peculiar mammillated surface. 
 
 Calceola (Lat. a little shoe or slipper). A fossil brachiopod, so called 
 from its under or ventral valve, which is flatly conical, or compressed like 
 the point of a shoe, and fitted with an opercular or lid-like upper valve. 
 It is characteristic of the Middle Devonian period, and so abundant in the 
 schists underlying the Eifel limestone, that these are known to German 
 geologists as " Calceola-schiefer." 
 
 Calciferous (Lat. calx, lime, and/ero, I bear). Producing or containing 
 lime ; applied to groups of strata containing subordinate beds of limestone ; 
 e.g., " calciferous grits," " calciferous sandstones" the latter term being 
 usually applied to the Lower Coal-measures in the neighbourhood of Edin- 
 burgh, after Mr C. Maclaren, who first made use of the designation ; the 
 equivalents of the Carboniferous slates of the Irish geologists. 
 
 Calcine (Lat. calx, calcis, lime). To reduce a substance, by heat, to a calx 
 or friable state, by the expulsion of some volatile matter either combined 
 with it or forming its cementing principle, as the carbonic acid from lime- 
 stone, or the water of crystallisation from salts. To oxidise as a metal ; to 
 reduce to a metallic calx. Calcination. The process of reducing any ore 
 
 124 
 
CAL 
 
 or mineral to a calx by the application of heat. Thus chalk by burning is 
 reduced to quicklime, and gypsum to plaster-of- Paris. 
 
 Calcite (Lat. calx, lime). A common mineralogical term for the crystal- 
 lised varieties of carbonate of lime, which are known also as Calcareous or 
 Calc-spars, which see. The calcites are among the most universally diffused 
 of mineral crystals. 
 
 Calcium (Lat. calx, quicklime). The metallic basis of lime, originally 
 discovered by Sir Humphrey Davy in 1808. It is a whiter metal than 
 strontium and barium, and is extremely oxidable, rapidly becoming the 
 protoxide, or quicklime, on exposure to the atmosphere. 
 
 Calc-Sinter (Ger. sintern, to drop). This term is usually applied to 
 compact stalagmitical or stalactitical deposits from calcareous waters. 
 The gradual increment of calc-sinter is usually marked by lines or layers 
 of varying hardness and colour. See SINTER and CALC-TtJFF. 
 
 Calc-Spar or Calcareous Spar. The general term for crystallised car- 
 bonate of lime or calcite, which occurs in a vast variety of forms, and in 
 various degrees of purity from the pure pellucid rhombs of Iceland spar 
 to the confusedly crystalline aggregates of the ordinary marbles. The 
 primitive crystal of calc-spar is rhombohedral, with obtuse angles of 105 8' 
 and 74 52'. The derivative forms and combinations are said to exceed 800 ; 
 they are all easily cleavable, and when irregular are readily distinguished 
 from quartz by being easily scratched, or by effervescing under acids. 
 Calc-spar, in its purest form, consists of 44 carbonic acid and 56 lime ; or 
 40 calcium, 12 carbon, and 48 ^oxygen. See LIMESTONE. 
 
 Calc-Tuff or Calcareous Tufa. A porous or vesicular carbonate of lime, 
 generally deposited near the sources and along the courses of calcareous 
 springs, in crusting and binding together moss, twigs, shells, and other 
 objects that lie in the way. Occasionally, when such springs discharge 
 themselves into lakes and seas, beds of considerable thickness are formed, 
 producing a light calcareous rock like the travertine of Italy. When slowly 
 formed in the open air, compact incrustations are the usual result, and 
 these are known by the name of calc-sinter. In these calcareous springs, 
 commonly known as "petrifying springs," the lime is held in solution by 
 an excess of carbonic acid, or by heat, if it be a hot spring, until the water 
 in issuing from the earth cools or loses part of its acid, and then the cal- 
 careous matter is precipitated in a solid state. See TRAVERTINE. 
 
 Caldera. A Spanish term for the deep caldron-like cavities which 
 occur on the summits of extinct volcanic mountairs and islands, and evi- 
 dently the extinguished craters of ancient volcanoes. 
 
 Caledonite. A mineralogical term for a cupreous sulphato- carbonate of 
 lead, occurring in long prismatic crystals, or in acicular tufts of a fine 
 verdigris or mountain-green; transparent or translucent, and having a 
 resinous lustre ; consists, according to Brooke, of 55.8 sulphate of lead, 
 32.8 carbonate of lead, and 11.4 carbonate of copper. So called by Beudant 
 from its being found at Leadhills in Scotland (Caledonia). 
 
 Calliard (Gr. challis, Fr. caillon, a flinty pebble). A local name for any 
 hard siliceous stone ; often applied by English miners and quarrymen to 
 beds of cherty or siliceous limestone. 
 
 Callimus. The name given to the loose and movable central core of 
 the Aetites, or Eagle-stone, which see. 
 
 Calomel (Gr. kalos, fair ; melas, black or Ethiops mineral). Chloride of 
 mercury (15.1 chlorine and 84.9 mercury), a rare mineral, occurring in the 
 
 125 
 
CAL CAM 
 
 quicksilver mines of Europe in pyramidal crystals or tubercular crusts, of 
 a greyish- white colour, occasionally translucent, and sectile. A prepara- 
 tion of mercury (the submuriate or dichloride), much used in medicine. 
 
 Calp. A provincial Irish term for an impure argillaceous limestone, or 
 rather argillo-ferruginous limestone ; hence the name Calp-slates, adopted 
 by Mr Griffiths for a considerable thickness of shale, argillaceous lime- 
 stone (calp), and flaggy sandstone, which occurs between the two great 
 bands of Carboniferous limestone, as developed in Ireland. The Calp-slates 
 lie above the lower band, the Carbonifemis slates beneath it. 
 
 Calymenfi (Gr. Jcekalymene, concealed, obscure.) A genus of trilobites 
 deriving its name from the obscurity which long hung over the real nature 
 of these crustaceans; the " Dudley Trilobite" or " Dudley Locust" of col- 
 lectors. The genus occurs throughout the Silurian system, but more 
 especially in the Ludlow rocks of England, and is distinguished by its 
 ovate, convex, and deeply-trilobed shell or crust, which is found either 
 expanded or coiled up like the oniscus or wood-louse. The common 
 Calymene Elumenbachii, or " Dudley Trilobite,'' is found from one to five 
 inches in length ; has the head or cephalic shield large, convex, rounded 
 in front with a well-marked border, boldly three-lobed, and having the two 
 compound facetted eyes set widely apart on the sides of the shield ; the 
 thoracic portion consists of thirteen segments, and the pygidium or tail- 
 plate is small and nearly semicircular. 
 
 Cambrian (Cambria, the ancient name for Wales). Belonging to Wales. 
 In geology, a term employed by Professor Sedgwick to designate the lowest 
 fossiliferous rocks as developed in North Wales. As originally employed, 
 the term embraced several series of strata (the Caradoc or May Hill sand- 
 stone, the Llandeilo flags, and the Bala limestone) which have since been 
 ranked as Lower Silurian. As now received by geologists, the " Cambrian 
 System" embraces the Lingula flags of North Wales, the Stiperstones of 
 Shropshire, the lower Greywacke of the south of Scotland, and the lowest 
 fossilferous rocks of Wicklow in Ireland, and is regarded as the equivalent 
 of the ffuronian System of North America, which see. See also tabula- 
 tions, " GEOLOGICAL SCHEME." 
 
 Camelidse (Lat. camelus, a camel). The Camel family, which includes 
 the true camels of the eastern hemisphere and the llamas of the western. 
 They are the only ruminants having incisors in the upper jaw, and are now 
 a limited family, though remains of an extinct species have been found in 
 the Tertiaries of the Siwalik hills in India, and of allied genera, such as 
 Sivatherium from the same deposits, and Macrauchenia from the later 
 Tertiaries of South America. 
 
 Cameo (It. cammeo). A precious stone engraved in relief, as opposed to 
 an intaglio, which is cut into the stone. The earliest cameos appear to 
 have been cut upon the onyx, and subsequently upon the agate. The true 
 cameo is formed upon a stone of two or more layers differing in colour, and 
 the art of the engraver consists in so cutting as to appropriate these differ- 
 ent coloured layers to distinct parts or elevations of the figure to be pro- 
 duced. Porcelain and glass have been employed with indifferent success 
 as a substitute for the natural gems ; and the shells of various mollusca 
 are now chiefly used to produce cheap and not inelegant imitations. 
 
 Campilodiscus (Gr. kampylos, bent, and discos, a quoit or disc). A 
 genus of Tertiary infusorial organisms ; so called from their form, which 
 is that of an oval disc, somewhat incurved or bent inwards upon itself. 
 
 126 
 
CAN CAR 
 
 . Their siliceous shields occur in profusion in the tripoli or polishing-slate 
 of Bohemia and other regions. 
 
 Cancellated (Lat. cancelli, a grating of bars, lattice-work). Latticed; 
 anything which is cross-barred, or marked by lines which cross each other 
 at right angles. This cancellated arrangement is common in leaves, in 
 bones of certain mammals, in the bryozoa, and other organic structures. 
 
 Cangaua (Span.) A South American term for the volcanic mud of the 
 Quitenian Andes. This mud is compact, slightly argillaceous, and more or 
 less saline, and occurs in rock-like masses, yielding very slowly to atmos- 
 pheric agency, or even to running water. 
 
 Canine, Canines (Lat. canis, a dog). Dog-like ; partaking of the nature 
 of, or exhibiting the characteristics of, the Dog tribe. The "canines" or 
 canine teeth in mammals are those strong, sharp-pointed teeth (one on 
 each side in either jaw), inserted between the incisors and premolars ; and 
 are so termed from their well-marked development in the dog, for whom, 
 as for other animals possessed of them, they perform the function of cutting 
 and tearing. See TEETH. 
 
 Cannel Coal. A compact, brittle, jet-like variety of coal, sonorous when 
 struck, breaks with a conchoidal fracture, and does not soil the fingers 
 when handled. It is said to derive its name from the candle-like light it 
 yields when burning ; and is known to the Scotch miners as " parrot-coal," 
 from the crackling, chattering noise it emits when first thrown into the fire. 
 It occurs interstratified in the Coal-measures of certain districts along with 
 ordinary coal, and often forms, in the Scotch coal-fields, the upper portion 
 of a seam of splint-coal, or even of a bed of black-band ironstone. Occa- 
 sionally these ironstones become so bituminous as to pass into a cannel 
 coal more or less pure ; and vice versa, a cannel coal often becomes so 
 ferriferous as to afford an available ironstone. Cannel coal appears to 
 have been formed either by the greater maceration of the vegetable mass, 
 or under such conditions as permitted a more equable and thorough bitu- 
 minisation than in ordinary coal. It is used chiefly in the manufacture of 
 gas, for which it is admirably fitted ; and some of the more lustrous and 
 tougher varieties are worked, like jet, into ornaments and curiosities. 
 
 Canons (Span.) The name given in western America to the profound 
 gorges or river-channels that occur in the region of the Rocky Mountains. 
 Many of these chasms (e.g., those of the Colorado) are wall-sided and cut 
 through stratified rocks as well as granites to the enormous depth of 3000 
 and 4000 feet. 
 
 Cantalite. A variety of pitchstone containing crystals of glassy felspar, 
 of a green colour, slightly translucent, and so named from its occurring in 
 the Cantal. 
 
 Capillary (Lat. capillus, a hair). Hair-like. Applied to amianthus, 
 certain zeolites, and other minerals whose crystals occur in filaments or fine 
 hair-like masses ; also to fine tubes less than the twentieth of an inch in 
 diameter, and capable of sustaining or attracting any liquid considerably 
 above the level at which they may be immersed. This capillary attraction, 
 as it is termed, is a phenomenon which occurs less or more in all porous 
 bodies the minute interstices acting as capillary tubes, and "drawing" 
 or " attracting " any liquid considerably above the level of its mass. 
 
 Caradoc Sandstone. The upper member or series of the " Lower 
 Silurian " formation, as it occurs in the hilly range of Caer Caradoc in 
 Shropshire, from which it takes its name (Caractacus, king of the ancient 
 
 127 
 
CAR 
 
 Britons, corrupted Caradoc). In the typical district, the Caradoc group 
 consists of sandy shales, courses of shelly sandstone occasionally passing 
 into bastard limestone, and light-coloured siliceous sandstones and grits. 
 They are worked as freestones ; and notwithstanding their soft and sectile 
 character, these Caradoc sandstones are laden with a profusion of fossils of 
 the same species as occur in the slaty argillaceous rocks of large tracts of 
 W a i es e.g., Snowdon and Bala. See SILURIAN SYSTEM. 
 
 Carapace (Gr. Tcardbos, a crustaceous animal like the crab and lobster). 
 A general term for the crustaceous and horny coverings of certain classes 
 of animals, which, like the plates of the armadillo, the horny shell of the 
 tortoise, and the calcareous crusts of the crab, protect the internal parts 
 from injury, and become, as it were, a sort of external skeletons. The 
 term, however, is mainly applied to the shields of the tortoises, Crustacea, 
 and infusorial animalcules. 
 
 Carbon (Lat. carbo, the inflammable matter forming charcoal). Carbon 
 is one of the elementary substances, and in its pure form exists only in the 
 diamond. By combustion in oxygen it forms carbonic acid gas. In its 
 impure or mixed forms carbon occurs largely in nature, as in the substance 
 of all wood plants ; in the tissues of animals ; and abundantly in many 
 minerals, as in the coals, bitumens, mineral resins, &c. 
 
 Carbonaceous (Lat. carlo, coal). Coaly ; applied to rocks containing 
 abundant traces of fossil carbon, or vegetable debris ; hence " carbona- 
 ceous shales," "carbonaceous sandstones," &c. 
 
 Carbonate. In chemistry, any compound of carbonic acid with a base ; 
 as carbonate of lime, carbonate of iron, &c. 
 
 Carb6nic Acid. An acid formed by the chemical union of carbon and 
 oxygen. It is the gas given off during the effervescing of soda-water, 
 champagne, and other similar liquids. It occurs largely in nature, being 
 given off by volcanic vents, by fissures in mines, caves, and wells, by many 
 mineral waters, by the respiration of animals, and during the decay of 
 vegetable substances. It is an essential ingredient of all calcareous rock- 
 masses (carbonate of lime), and an active agent of disintegration, whether 
 combined with the atmosphere or with the waters that deeply percolate 
 the rocky strata. 
 
 Carboniferous (Lat. carbo, coal, and fero, I bear). Coal-bearing ; coal- 
 yielding. The term is usually applied to that system of Palaeozoic strata 
 from which our main supplies of coal are obtained, or to the respective 
 groups or members of that system ; hence we speak not only of the " Car- 
 boniferous system," but of the "Carboniferous limestone," the " Carboni- 
 ferous slates," and so forth. 
 
 Carboniferous System. That formation, or system of fossiliferous strata, 
 which, in order of time, succeeds the Old Red Sandstone, and is in turn 
 surmounted by the Permian or New Red Sandstone of the earlier English 
 geologists. As a system, it constitutes the younger or upper portion of 
 the Palaeozoic cycle, and derives its importance from being, in Britain, 
 North America, and other countries, the great repository from which are 
 obtained the chief supplies of COAL, so indispensable to the industrial arts 
 and manufactures of modern civilisation. Lithologically, the system con- 
 sists of alternations of sandstones, shales, clays, limestones, coals, and 
 ironstones, in every degree of admixture and purity, and of every condi- 
 tion of formation terrestrial, fresh-water, estuary, and marine. Palceon- 
 tologically, there have been discovered in its strata representatives of all 
 
 128 
 
CAR 
 
 the great forms of life, with the exception, perhaps, of true dicotyledonous 
 plants in its flora, and of birds and mammals in its fauna. As its name 
 implies, the most striking peculiarity in the formation is the profusion of 
 fossil vegetation, which marks less or more almost every stratum, and 
 which in numerous instances forms thick seams of solid coal. Although 
 this coaly or carbonaceous aspect prevails throughout the whole, it has been 
 found convenient to arrange the system into three groups the Lower Coal- 
 measures or Carboniferous Slates, the Mountain or Carboniferous Lime- 
 stone, and the Upper or True Coal-measures ; or more minutely, as is 
 generally done by British geologists, into 
 
 1. Upper Coal-measures. 
 
 2. Millstone Grit. 
 
 3. Mountain Limestone ; and 
 
 4. Lower Coal-measures. 
 
 Other subdivisions have been attempted according to the local peculiarities 
 of different coal-fields ; but it is enough for the purposes of the general 
 reader to know, that all these minor arrangements can be readily co- 
 ordinated with one or other of the above four series. Thus Sir R. Griffiths, 
 in his Geological Map of Ireland, gives the annexed subdivisions : 
 
 a. Coal-measures, upper and lower, . 1000 to 2200 feet. 
 
 b. Millstone Grit, . . . 350 1800 
 
 c. Mountain Limestone, upper, middle, and 
 
 lower, .... 1200 6400 
 
 d. Carboniferous Slate, . . . 700 1200 
 
 e. Yellow Sandstones (of Mayo, &c.), with 
 
 shales and limestones, . . " 400 2000 
 
 Now, here there is this little difficulty in co-ordinating, as we have first 
 the usual members of the system, a, b, c, and d, and a subjacent series, 
 which lies fairly open to the question whether it is not the equivalent of 
 the " yellow sandstones " which form the uppermost portion of the Old Red 
 Sandstone or Devonian system in other localities. Again, the Carboniferous 
 strata of the south of England (on the Avon near Bristol) are given in the 
 4 Geological Survey's Memoirs' as consisting of: 
 
 a. Millstone Grit here mostly a hard reddish grit- 
 stone, the grains often almost confluent, as in what 
 are called quartzites and quartz-rocks, . . 950 feet. 
 
 I. Alternations of Limestone, red or grey, compact or 
 granular, with shales, red, dark, or grey, and sand- 
 stones. Most of the strata fossiliferous, and Pro- 
 ducta gigantea abundant near the base, . . 400 
 
 c. Scar Limestones grey, reddish, mottled, brown, and 
 
 black ; compact, shelly, crinoidal, and oolitic, in 
 beds varying in thickness, and partially divided by 
 shales, . .... . 1440 
 
 d. Lower Series, enclosing many alternations of lime- 
 
 stones and shales, the former often black, brown, 
 yellowish, sometimes impure, and in one part 
 charged with fish-remains and cyprides in abun- 
 dance, . . . . . . 500 
 
 %.* The upper part of the Old Red shows yellow and grey sandstones 
 and marls. 
 
 In this case there can be no difficulty in at once assigning 6 and c to the 
 great series of the Mountain Limestone ; while d is evidently the equiva- 
 
 129 I 
 
CAR 
 
 lent of the " Lower Coal-measures" of Scotland, with a few of its beds 
 graduating, it may be, into the yellow sandstones of the underlying Devo- 
 nian. In Fifeshire, on the other hand, we have 
 
 a. True Coal-measuresconsisting of numerous alter- 
 nations of coal, shales, sandstones; ironstones, 
 and occasional beds of impure limestone, . 2500 feet. 
 
 J. Several strata of crinoidal and producta limestone, 
 with intervening beds of shale, sandstones, and 
 thin seams of coal, .... 300 ,, 
 
 c. A vast thickness of whitish fine-grained sandstones, 
 bituminous shales, a few thin seams of coal, 
 mussel-bands or shell-limestone, and fresh-water 
 limestones abounding in cyprides, . . 2000 
 
 In this instance there is no development of Millstone Grit the whole 
 system resolving itself, as it does in many other regions, into Upper Coal, 
 Mountain Limestone, and Lower Coal. In Nova Scotia, again, we have in 
 the lower series a vast development of gypseous beds, which look some- 
 what puzzling at first sight to an English geologist ; but which, when 
 taken in connection with the associated shales and coals and fossils, admit 
 of easy co-ordination on the large scale with the main subdivisions estab- 
 lished by British geology. How far these subdivisions may indicate 
 separate life-periods, or only portions of one great epoch, has yet to be de- 
 termined by a more minute and rigorous comparison both of vegetable 
 and animal species. In the mean time, existing evidence rather favours 
 the latter opinion, and geologists are nearly at one in regarding the Car- 
 boniferous system as a great life-period, characterised from all others by 
 many forms of a varied marine and estuary fauna its gigantic sauroid 
 fishes, ci-ustaceans, encrinites, and corals ; but in particular by the vast 
 profusion of its endogenous flora its stigmaria, sigillaria, lepidodendra, 
 favularice, Knorrice, bothrodendra, ulodendra, catamites, aster ophy II rtes, 
 and filicites plants which rose, culminated, and died out with the period, 
 never again to be repeated in the onward phases of vegetable development. 
 
 Carbuncle (Lat. carlunculus, a little coal, from carbo). The name given 
 by jewellers to the variety of precious garnet (Pyrope] which is set en ca- 
 lochon. It is of a deep red colour, with a mixture of scarlet, and when 
 held up to the sun becomes exactly of the colour of a burning coal. 
 
 Carchdrodon (Gr.) Literally "jagged tooth;" a genus of Tertiary 
 sharks, so termed from their notched or jagged teeth, which are often of 
 great size, and indicating dimensions more than double that of the largest 
 existing species. The living genus Carcharias comprises the large sharks 
 with cutting triangular teeth, crenated or notched on their margins, and 
 having a broad base. In the extinct Carcharodon the teeth differ from 
 those of Carcharias in being solid in the centre, while in the latter they 
 are hollow; but in both genera the teeth exhibit the same reticulated 
 structure of medullary and calcigerous tubes. 
 
 Carcharopsis (Gr.) Literally "shark-like;" a genus of Carboniferous 
 shark-like fishes, founded by Agassiz on their teeth the only portions 
 yet discovered. Theso teeth occur in the Carboniferous Limestone ; are 
 compressed, triangular, crenated on the edges, with large plaits or folds in 
 the enamelled surface, towards the base of the crown. 
 
 Cardiglio Marble. A grey, clouded variety of marble obtained for 
 ornamental purposes from the island of Corsica. 
 
 130 
 
CAR CAS 
 
 Cardinal (Lat. cardo, a hinge). A term implying importance, and sug- 
 gestive of the hinge or point on which a thing turns or depends. Thus the 
 cardinal points of the compass are the North, South, East, and West ; the 
 cardinal signs of the zodiac, Aries, Cancer, Libra, and Capricorn. 
 
 Cardiocarpon (Gr. kardia, the heart, and karpos, fruit). A genus of 
 small heart-shaped seeds occurring in groups on the shales of the Coal- 
 measures as if they had grown in clusters. Supposed by Brongniart to be 
 Li/copodiaceous ; by others, to have fallen from some species of Asterophyl- 
 lites; and by Lindley, to have, like other genera of the Coal era, no very 
 positive modern analogy. 
 
 Cardium (Gr. kardia, the heart). The cockle-shell, so named in allu- 
 sion to its heart-like form ; a well-known dimyarian bivalve occurring in 
 many specific forms, both recent and fossil, in almost every sea, and from 
 the Lias upwards. The cockle-like bivalves occurring in palaeozoic forma- 
 tions are Cardiola, Cardiomorpha, and similar provisional genera : Cardita, 
 Cardinia, Cardilia, &c., are chiefly mesozoic and neozoic forms, and be- 
 long to the family CYPRINIDJS. 
 
 Carnelian (Lat. caro, carnis, flesh). Applied originally to a flesh-colour- 
 ed variety of calcedony ; but now a lapidary's term for the more trans- 
 parent varieties, whether brown, blood-red, yellow, white, or almost 
 black. Carnelian is uniform in colour, or it may be less or more clouded, 
 but it is never figured or striped like the agates. The colouring matter 
 seems to be peroxide of iron, which may be acted upon by heat so as to 
 convert specimens originally yellow into a fine deep red, as is done with 
 those found at Cambaya, near Surat. The finest carnelians are found in 
 India, Arabia, Surinam, and Siberia ; but fair specimens are also obtained 
 from Bohemia, Saxony, and Scotland. According to Heintz, a Chinese 
 variety yielded silica, 99.37 ; alumina, .081 ; iron peroxide, .050 ; mag- 
 nesia, .028 ; potash, .004 ; soda, .075 ; carbon, .003 ; and water, .391. 
 
 Carnivora (Lat. caro, carnis, flesh, and voro, I devour). One of Cuvier's 
 orders of the mammalia (hyaena, tiger, &c.), so called from their subsist- 
 ing solely on flesh. Carnivorous. Living on flesh, in contradistinction to 
 herbivorous, frugivorous, &c. See tabulations, " ANIMAL SCHEME." 
 
 Carpolithes (Gr. carpos, fruit, and lithos, stone). The general term for 
 fossil fruits, such as those found in the Tertiary clays of the London basin, 
 in the Coal shales of Newcastle, &c. 
 
 Carrara Marble. A pure white, semi-transparent saccharoid marble 
 obtained from the mountains of Massa Carrara in Italy, and highly valued 
 for statuary purposes. It is an altered or metamorphic limestone of the 
 Oolitic period. 
 
 Cary6caris (Gr. Jcaryon, a nut, and bar is, shrimp). A small crustacean, 
 from the Lower Silurian slates of Skiddaw, having a long, pod-shaped, 
 bivalved carapace, rounded anteriorly, sub-truncate behind, and with the 
 back and front sub-parallel. The surface is smooth, or with only oblique 
 wrinkles near the margins, but with no parallel lines of sculpture. Body, 
 telson, and appendages unknown. 
 
 Caryophyllia (Gr. karyophyllon, a clove). Literally "clove-shaped;" 
 a genus or section of lamellated Anthozoarian corals occurring from the 
 Upper Silurian to the Chalk inclusive. The polyparium or calcareous axis 
 is turbinated or cylindrical, simple or branched, longitudinally striated, 
 fixed at the base ; the cells boldly lamellated. 
 
 Cascade (Fr. from Ital. cascare, to fall). A waterfall ; usually applied in 
 131 
 
CAS CAV 
 
 geography to waterfalls on streams and rivulets, in contradistinction to 
 the falls or cataracts on larger rivers. 
 
 Cascalho (Span.) The name given in Brazil to the auriferous or gold- 
 bearing detritus of the country. " The common cascalho," says Ansted, 
 "is an indurated soil in which gold is contained, and seems to consist of 
 the fragments of veins which have been by some means broken up, rolled 
 about by the action of water, and buried by it among the clays which have 
 composed its bed." The cascalho is also the principal repository of the 
 Brazilian diamonds. 
 
 Cassiterite (Gr. Jcassiteros, tin). A mineralogical term for the oxide of 
 tin, or ordinary tin-ore, which consists of 79 tin and 21 oxygen, but often 
 mixed with impurities of iron peroxide, silica, manganese, and the like. 
 Most of the tin of commerce is derived from this ore. 
 
 Castoroides (Gr. Icastor, beaver, and eidos, like). A large rodent allied 
 to the beaver and capybara, and found, along with the remains of mastodon, 
 in the post-glacial deposits of North America ; e.g., the Castoroides Ohioen- 
 sis of Foster and Wyman. 
 
 Cataclysm (Gr. kataklysmos, inundation). Any violent flood or inun- 
 dation that overspreads or sweeps over a country ; deluge ; debacle. 
 Cataclysmal. Applied to the effects or destructive power of such violent 
 inundations. 
 
 Catenip6ra (Lat. catena, a chain, and pora, cell). Chain-pore coral ; a 
 genus peculiar to palaeozoic strata, and so termed from the chain-like 
 arrangement of its pores or cells in polished specimens. In catenipora the 
 polyparium is hemispherical, composed of vertical anastomosing lamellae ; 
 cells tubular, oval, terminal, and united laterally, so that in transverse 
 sections they present a chain-like arrangement. Often found in hemi- 
 spherical masses more than a foot in diameter. Known also by the Greek 
 synonyme, Halysites, which see. 
 
 Cat's-Eye. A variety of chalcedonic quartz, of a greenish-white or grey, 
 olive-green, red, brown, or yellow colour, and containing parallel fibres of 
 amianthus, which produce a peculiar play of light ; hence the name. For 
 this peculiar play of light the French use the term clurioyant. The finest 
 varieties of this mineral are brought from Ceylon and Malabar. 
 
 Catlinite (after Catlin, the American traveller). A reddish variety of 
 claystone from the C6teau des Prairies, west of the Mississippi, which is 
 carved into tobacco-pipes by the North American Indians. 
 
 Caudal (Lat. canda, the tail). Belonging to or connected with the tail ; 
 as " caudal fin," the tail fin ; " caudal vertebrae," vertebrae of the tail. 
 
 Caudex (Lat. caudex, a stem or stock). In botany, usually applied to 
 the upright stem of ferns, the leaves of which are technically termed 
 fronds, and the root-like or underground stem a rhizome. 
 
 Caulopteris (Gr. kaulos, stem, and pteris, fern). Literally tree-fern ; a 
 genus of stems or trunks found in the Coal-measures, and by Lindley re- 
 garded as decidedly the stems of tree-ferns, in consequence of their shal- 
 low sinuous furrows, and spirally-arranged long oval leaf-scars. 
 
 Caves, Caverns (Lat. cavus, hollow). Caves occur less or more along the 
 rocky shores of all free-flowing seas, and are the results of abrasion by 
 waves laden with gravel, &c., and acting upon pre-existing fissures or the 
 softer portions of the exposed rocks. They occur chiefly in trap-rocks 
 and in limestone strata the former from structural and irregular wasting, 
 the latter from infiltration and chemical erosion. The most celebrated 
 
 132 
 
CAW CEP 
 
 caverns, however, occur in limestone strata, and appear to be the results 
 partly of fissuring by subterranean disturbance, and partly of waste by the 
 percolation and passage of carbonated waters. They are sometimes ar- 
 ranged into four kinds " 1. Those which have arisen from fissures in the 
 rock, and are therefore wedge-shaped crevices, widest at the opening. 2. 
 Those that face the sea-shore, and are merely holes that have been worn 
 out by the dashing of the waves against the cliff. 3. Those which open to 
 the face of an inland cliff, and give egress to water. 4. Those whose en- 
 trances are holes in the ground opening very wide beneath, and having 
 the appearance of water having at one time flowed in from above." (J. E. 
 Woods, 'Geol. Observ. So. Australia.') Some are celebrated for their great 
 extent and subterranean ^waters (Kentucky) ; others for their gorgeous 
 stalactites and stalagmites (Antiparos) ; and many, of late, for their 
 treasures of sub-fossil bones (Kirkdale, Kent's-hole), and consequently 
 known as "Bone Caves," or " Ossiferous Caverns," which see. 
 
 Cawk. A familiar term for heavy-spar or native sulphate of barytes, 
 which see. 
 
 Celestine (Lat. ccelum, the sky). A mineralogical term for sulphate of 
 strontian, in allusion to its colour (sky-blue), which usually ranges from 
 bluish-white to indigo blue, and is rarely reddish or yellow. Celestine 
 occurs in rocks of all ages, but more frequently in the newer formations. 
 Its average composition is 56.5 strontia, 42.5 sulphuric acid; with traces 
 of iron, baryta, lime, and water. 
 
 Cement (Lat. ccementum). In building, literally chips for filling up the 
 interstices between the larger blocks ; now applied to mortar or any simi- 
 lar substance used for uniting other materials, and which ultimately 
 hardens and binds them together. Roman cement, a mortar made of lime 
 and puozzolano (volcanic tufa) ground to fine powder ; hydraulic cement, 
 any mortar that sets rapidly and hardens under water (which see). There 
 are numerous builders' or architects' cements in the market, some for 
 facing walls in imitation of stone, others for setting under water, some 
 for resisting fire, and others for the exclusion of damp (as Gibb's, Parker's, 
 Keene's, Pew's, Martin's, &c.) ; but in all of them lime, silica, and alumina 
 in various proportions, and in different states of calcination, are the prime 
 ingredients. 
 
 Centres of Creation. " When the fauna or flora of a province (we quote 
 the late Edward Forbes) has been thoroughly investigated, the diffusion 
 of the individuals of the characteristic species is found to indicate that 
 the manifestation of the creative energy has not been equal in all parts of 
 the area ; but that in some portion of it, and that usually more or less 
 central, the genesis of new beings has been more intensely exerted than 
 elsewhere. Hence, to represent a province diagrammatically, we might 
 colour a nebulous space, in which the intensity of the hue would be exhi- 
 bited towards the centre, and become fainter and fainter towards the cir- 
 cumference. This feature of zoological and botanical provinces gives rise 
 to the term centres of creation ; and in none, except one centre of creation, 
 do we find the same assemblage of typical species ; in other words, no 
 species has been called forth originally in more areas than one." See 
 SPECIFIC CENTKES. 
 
 Cephalaspis (Gr. Teephale, the head, and aspis, a shield). A fish of the 
 Lower Old Red or Devonian period, so called from having the bones of 
 the head united into a single shield-like case, and terminating posteriorly 
 
 133 
 
CEP 
 
 in three pointed spines or prongs one on each side below, and a third in 
 the mesial or dorsal ridge. The body also seems to have been protected 
 by osseous bands and quadrangular scales, leaving the tail, pectorals, and 
 other fins free as in the living trunk-fish. There are several species, all 
 having the head large in proportion to the body, and none exceeding ten 
 or twelve inches in length. The dentition, and even the position of the 
 mouth, is unknown, though evidently placed beneath the head, and in all 
 likelihood suctorial, as in the living sturgeon. The Cephalaspidce form a 
 very limited family, and embrace such provisional genera as Cepfhala&pis 
 proper, Auchenaspis, Pteraspis, and others of which very little is yet known. 
 Cephaldpoda (Gr. kephale, the head, and pous, podos, foot). The highest 
 class of mollusca, so called from the principal organs of locomotion being 
 attached to the head in the form of muscular arms or tentacles, as in the 
 cuttle-fish and nautilus. In addition to their tentacular organs of motion, 
 many have fin-like processes, and all can propel themselves by the forcible 
 expulsion of water from their respiratory chamber. Of living forms one 
 or two, like the nautilus, have external shells ; all the others, like the 
 cuttle-fish, are "naked" or shell-less, but possess an internal bone or 
 " pen," the representative of the shell. On the other hand, most of the 
 fossil forms, as orihoceratite, ammonite, &c., have external shells, either 
 straight, coiled in a vertical plane, or curved variously; though a large 
 section also of the extinct forms were naked, and possessed internal " pens" 
 or shelly organs which occur abundantly in Secondary strata, and are 
 known as belemnites, belemnoteuthites, and the like. Having numerous 
 organs of prehension, powerful jaws like the mandibles of a parrot, spiny 
 tongues, large eyes, acute senses, active locomotion, and a more concen- 
 trated nervous system than other mollusca, the cephalopods, both now and 
 in former ages, appear to have been the tyrant scavengers of the waters. 
 They are all marine and predatory, living on shellfish, crabs, and fishes. 
 They occur fossil in all formations, and appear to have culminated in 
 point of numbers and power during the Oolitic period each great period 
 having its own peculiar and characteristic forms. It is usual to divide 
 the Cephalopods into two orders the TETBABRANCHIATA and the Di- 
 BKANCHIATA, the former having four branchial plumes, two on each side, 
 and the latter only two branchial plumes, one on each side. The tetra- 
 branchs or Nautiloids form two families, the Nautilidce, and Ammonitidce 
 the former including the existing nautilus (the only living representative 
 of the order), the orthoceratite, lituite, and others having external cham- 
 bered shells with plain partitions, or sutural junctions and siphuncle 
 more or less central; the latter the extinct ammonites, baculites, and 
 others having also external chambered shells, but these with foliaceous 
 complex sutures, and siphuncle dorsal, or on the back of the chambers. 
 The dibranchs or cuttle-fishes, on the other hand, have almost always 
 internal shells or <f pens," which are frequently rudimentary, and when 
 external, or rather pseudo-external, are never chambered. They constitute 
 two main sections 1st, Those with ten tentacular organs (decapoda), such 
 as the Spiralidce or spirulse, the Sepiadce or cuttle-fishes, the Loligidce or 
 squids, and the fossil Belemnitidce or belemnites ; and 2d, Those with 
 eight tentacles (octopoda), such as the Octopodidce or poulpes, and the 
 Argonautidce or paper-nautili, which are provided with a thin fragile 
 pseudo-external shell. To the palaeontologist many of these distinctions 
 are of prime importance, and are curiously indicative of creational pro- 
 
 134 
 
CER 
 
 gress. Thus, in the Palaeozoic genera the sutural junctions are plain and 
 simple, while in the Mesozoic they become foliaceous and complex 
 iiauiilites, goniatites, ceratites, and ammonites, not only indicating generic 
 distinctions, but time and successive formations. So also in Palaeozoic 
 genera their tentacles were void of acetabula or sucking-cups (TENTACUL- 
 IFERA) ; while those of Neozoic periods are almost invariably provided 
 with them (ACETABULIFERA). In like manner the tetrabro.nchs preceded 
 the dibrancJis, and thus, while the former is now represented by a single 
 genus, the latter has representative families and genera in every region of 
 the existing ocean. See tabulations, " ANIMAL SCHEME." 
 
 Ceratiocaris (Gr. Deration, a pod, and kdris, shrimp). An upper Silu- 
 rian crustacean, whose exact affinities are unknown, but whose form 
 apparently connects it with apus and dithyrocaris. It derives its name 
 from its large, finely-striated, pod-like, bivalved carapace (which has fre- 
 quently been mistaken for a bivalve shell) ; and its shrimp-like segmented 
 body, which consists of five or six free segments, terminated by three strong 
 sharp-pointed spines the leptocheles of palaeontologists before they were 
 found in attachment. The finest specimens have been found in the upper 
 Silurians of Lesmahagow. 
 
 Ceratites (Gr. kei-as, a horn curved like a ram's horn). A genus of Am- 
 monitidae, having the lobes of the sutures peculiarly crenulated. The 
 ceratites are characteristic of the Trias (in which upwards of twenty 
 species have been discovered), and ai-e distinguished from the ammonites 
 of the superincumbent Lias and Oolite by the absence of foliaceous sutures 
 the descending lobes terminating in small denticulations, as above 
 described. 
 
 Cerdtodus (Gr. faros, a horn, and odous, tooth). A genus of cestraeiont 
 fish-teeth occurring abundantly in the "Bone-bed," between the Trias and 
 Lias formations, and very puzzling from the variety of shapes they assume. 
 They have in general an uneven or undulating upper surface of dentine 
 and enamel, and an under layer of reticulated osseous tissue ; the several 
 plates or teeth apparently varying in form according to the position they 
 occupied in the pavement-like palates of the cestraeiont. 
 
 Ceratose (Gr. keras, a horn). Horny ; having the texture and consistence 
 of horn. Applied to organic structures that have a horny aspect or con- 
 sistence ; e.g., the sponges, which are usually divided into the "ceratose," 
 "siliceous," and "calcareous," or the horny, flinty, and limy. 
 
 Cerite, Cererite. A siliceous protoxide of cerium, occurring in short 
 six-sided prisms, also massive and granular ; of a dark peach-red or clove- 
 brown colour; very hard, and of dull adamantine or resinous lustre. Con- 
 sists of 64/55 protoxide of cerium, 19.18 silica, 7.28 protoxides of lanthanum 
 and didymium, 1.54 protoxide of iron, 1.35 lime, and 5.71 water. 
 
 CeritMan. A term occasionally applied to certain strata of the Vienna 
 Tertiary basin, from their being charged with several species of the spiral, 
 elongated, gasteropod shell, Cerithium. 
 
 CeritMum (Gr. keration, a small horn). A well-known gasteropod 
 genus, the type of the Cerithiadce. Shell turreted, elongated, many- 
 whorled, with indistinct varices ; aperture small, with a tortuous canal in 
 front ; outer lip expanded ; inner lip thickened. The existing species 
 (about 100) have a world-wide distribution ; the fossil (about 400) range 
 from the Trias upwards, some species being especially characteristic of 
 Tertiary strata. 
 
 135 
 
CEK CHA 
 
 Cerium. One of the rarer metals discovered by Hisinger and Berzelius 
 in 1803, in the mineral named cerite, which consists of silica and protoxide 
 of cerium with minor proportions of iron, lime, and water, together with 
 the less-known metals didymium, and lanthanum. 
 
 Cenissite (Fr. ceruse, white-lead). Carbonate of lead occurring crystal- 
 lised, fine, granular, or earthy ; colourless or white, and often grey or 
 yellowish- white, and consisting of 83.58 protoxide of lead and 16.42 car- 
 bonic acid. It is a common ore of lead, especially in beds or veins with 
 galena (sulphuret of lead), from the decomposition of which it is supposed 
 to be derived ; the liberated sulphuric acid acting on calc-spar, whose car- 
 bonic acid combines with the protoxide of lead. 
 
 Cervical (Lat. cervix, the neck). Belonging to the neck, as the cervical 
 vertebrae, or vertebrae which form the neck. 
 
 Cestracionts, Cestraciontidse (Gr. Jcestra, a pike, a kind of fish, so called 
 from its formidable teeth). The first and oldest sub-family of sharks, 
 beginning, says Buckland in his * Bridgewater Treatise,' with the Transition 
 strata, appearing in every subsequent formation till the commencement 
 of the Tertiary, and having only one living representative viz., the Ces- 
 tracion Philippi, or Port- Jackson shark. The character of the cestracionts 
 is marked by the presence of large polygonal obtuse enamelled teeth, 
 covering the interior of the mouth with a kind of tessellated pavement. 
 In some species not less than sixty of these teeth occupied each jaw. 
 They are rarely found connected together in a fossil state, in consequence 
 of the perishable nature of the cartilaginous bones to which they were 
 attached ; hence the spines and teeth usually afford the only evidence of 
 the former existence of these extinct fossil species. They are dispersed 
 abundantly throughout all strata, from the Carboniferous series to the 
 most recent Chalk ; e.g., psammodus, cladodus, helodus, ceratodus, stropho- 
 dus, acrodus, &c. See tabulations, "ANIMAL SCHEME." 
 
 Cetacea (Gr. Tcetos, a whale). Cuvier's eighth order of mammalia, which 
 includes the whales, dolphins, and other warm-blooded animals inhabiting 
 the ocean. It is now usual to subdivide the order into sections 1st, the 
 CETACEA, including the Balcenidce or northern whales, the Pkysiteridce or 
 sperm whales, and the Delphinidce or dolphins ; and, 2d, the SIRENIA, or 
 herbivorous cetaceans, which embraces the Rhytinidce, and the Manatidce 
 or sea-cows. Remains of cetaceous animals occur only in recent and 
 Tertiary strata ; e.g., Dinotherium (?), zeuglodon, balcenoptera, &c. 
 
 Cetiosaiirus (Gr. ketos, whale, and saurus, lizard). A genus of marine 
 saurians, whose vertebrae and other bones occur in the Oolite and Wealden, 
 and which has been so named by Professor Owen from the presumed 
 general resemblance to the Cetaceans, in the short doubly-concave verte- 
 brae, and the solid bones and natatory character of the extremities. 
 
 Cetotolites (Gr. Jcetos, a whale, and ous, otos, the ear, and litftos}. A term 
 applied by Owen to the fossil petro-tympanics or ear-bones of whales, 
 which occur abundantly in upper Tertiary formations, like the Suffolk and 
 Norfolk "Crag." In general, the peculiar conchoidal-shaped tympanic 
 bone is the only portion preserved. 
 
 Ceylanite. Known also as Candite, from Candy in Ceylon; a dark- 
 coloured variety of spinel, which see. 
 
 Chabasie or Chabasite (Gr. chabos, narrow, compressed). One of the 
 Zeolite family, occurring in compressed, striated, rhombohedral crystals, 
 chiefly in the vesicular cavities and fissures of amygdaloid and other 
 
 136 
 
CHA 
 
 trap-rocks. Its colour is usually white, but sometimes passing into a 
 greyish-yellow or pinkish tinge ; its composition uncertain, analyses giving 
 about 50 silica, 18 alumina, 9 lime, and 10 water, with traces of soda, 
 potash, and iron. 
 
 Chalcedony. More frequently Calcedony, which see. 
 
 Chalcolite (Gr. chalcos, bronze, and lithos).A. combination of uranium 
 with phosphoric acid and copper, forming a cupreo-phosphate of uranium. 
 It occurs in scales of an emerald or verdigris green colour, and is found in 
 metalliferous veins traversing the granitic rocks and crystalline schists. 
 Differs from URANITE (which see) only in containing copper instead of 
 lime. 
 
 Chalcopyrite (Gr. chalcos, copper, and pyrites). Copper pyrites ; a com- 
 mon ore of copper, consisting of 34.78 copper, 30.47 iron, and 34.78 sul- 
 phur. Though a poor ore, nearly one-third of the copper of commerce is 
 said to be obtained from this source. It may be distinguished from iron 
 pyrites by its inferior hardness and deeper yellow colour, and from gold by 
 its brittleness and want of malleability. The fine yellow varieties with a 
 variegated (pavonine) tarnish are esteemed the richest. 
 
 Chalicotherium (Gr. chalix, chalicos, gravel). A genus of fossil pachy- 
 derms (Anisodon of M. Lartet) intermediate between the rhinoceros and 
 anoplothere, and characteristic of the upper Miocene strata of southern 
 Europe and India. So named from its occurrence in the gravelly bed of 
 the Eppelsheim strata. 
 
 Chalk (Lat. calx, Ger. kalk, lime). The familiar as well as technical 
 term for the soft and earthy-looking varieties of limestone. The Chalk of 
 the south of England is well known, both as a rock and as the upper mem- 
 ber of the Cretaceous System, which see. While the white chalk of com- 
 merce is well known as a soft amorphous carbonate of lime, which can be 
 converted into quicklime by calcination, and used for all the purposes of 
 ordinary limestone, it should be borne in mind that the term " chalk" has 
 also been applied to other substances which are in no sense of the word 
 limestones, as Red Chalk, a natural clay containing from 15 to 20 per cent 
 of the protoxide and carbonate of iron ; Brown Chalk, a familiar name for 
 umber ; Black Chalk, a variety of drawing- slate ; and French Chalk, a 
 variety of steatite or soapstone a well-known soft magnesian mineral. 
 See CRETACEOUS SYSTEM. 
 
 Chalybeate (Gr. chalybs, iron or steel). Applied to springs and waters 
 impregnated with iron, or holding iron in solution. Springs, whose active 
 principle is iron, are of two kinds the carbonated, containing carbonate of 
 the protoxide of iron ; and the sulphated, containing the sulphate of iron. 
 
 Chalybite (Gr. chalybs, iron or steel). Sparry or spathose iron, carbon- 
 ate of iron, or siderite. See IRON. The spathose iron-ores are said to 
 afford the best kind of iron, and one which is admirably suited for the 
 manufacturing of steel. "Nearly all the Styrian and Carinthian iron," 
 says Mr Brislow, " is manufactured from chalybite. In those and the ad- 
 joining countries it forms extensive tracts, traversing gneiss, extending 
 along the chain of the Alps on one side into Austria, and on the other into 
 Salzburg. In Britain it occurs chiefly in Cornwall and N. W. of Devonshire 
 and Somersetshire, where considerable quantities are raised on Exmoor 
 and the Brandon Hills." 
 
 Chambered. Usually applied to shells internally divided into chambers 
 or compartments, like the existing nautilus. 
 
 137 
 
CHA CHE 
 
 Channel (Lat. canalis). In geography, the course or excavation in which 
 a river flows ; the deeper part of a strait, bay, or estuary where the princi- 
 pal current flows, whether of tidal or fresh water, and which is most con- 
 venient for navigation. 
 
 Chaos (Gr. chaos, literally an immense void or chasm). Matter without 
 form or arrangement ; according to the poets, the primal condition of the 
 material universe before it was arranged and fashioned into Cosmos. 
 Cha6tic. Confused ; thrown together into a vast heap without any order or 
 arrangement, like the debris resulting from a violent land-flood or debacle. 
 
 Charcoal. The carbonaceous residue of animal, vegetable, and combus- 
 tible mineral substances, when heated to redness in close vessels, or when 
 they undergo smothered combustion. We have thus lamp-black or 
 animal charcoal, derived from oils and fats; wood charcoal, from twigs 
 and faggots ; and coke or mineral charcoal, from ordinary pit-coal. See 
 CARBON. 
 
 Chart (Lat. charta). A hydrographical or marine map, a draught or pro- 
 jection on paper of some part of the earth's superficies, with the coasts, 
 islands, rocks, banks, channels, or entrances into harbours, rivers, and 
 bays, the points of compass, soundings or depth of water, &c., to regulate 
 the courses of ships in their voyages. While the term map is chiefly ap- 
 plied to delineations of terrestrial surfaces, chart on the other hand is 
 applied to those of marine. There are various kinds of charts, plane, globu- 
 lar, &c., according to the mode in which the surface is projected or repre- 
 sented to the eye. 
 
 Chatoyant (Fr.) Changing in lustre like the cat's eye ; a word expres- 
 sive of that changeable lustre exhibited by various minerals, as they are 
 turned less or more to the light ; e.g., cat's-eye opal, Labrador felspar, &c. 
 
 Cheiracanthus (Gr. cfair, the hand, and aJcantha, a thorn). Literally 
 "thorny hand," in allusion to the ichthyodorulite or spine that protects 
 the pectoral fins of this fish. The Cheiracanthus belongs to the Acanthod 
 family ; is found in Devonian strata ; was a small, slim fish, covered with 
 minute, angular, brightly enamelled scales, each having a slight median 
 ridge, and armed in all its fins with defensive spines. 
 
 Cheir61epis (Gr. cheir, the hand, and lepis, a scale). Literally "scaly 
 hand," in allusion to its scaly pectorals ; a genus of Devonian fishes belong- 
 ing to the family Acanthodes, and characterised by the great development 
 of their pectoral and ventral fins, and by the presence only of a small sub- 
 dorsal. In Cheirolepis the scales are lozenge-shaped, and richly adorned 
 with minute waving striae on their posterior margins. 
 
 Cheir6ptera (Gr. cheir, the hand, andpteron, awing). Literally "hand- 
 wings," the Bats ; a well-known order of mammalia, whose fore-feet or 
 hands are so modified as to enable them to exercise the power of flight a 
 power which they alone of all the existing mammalia possess. They are 
 found in all parts of the world, but most abundantly in tropical countries ; 
 are crepuscular and nocturnal in their habits ; and live, some on insects, 
 others on the blood of the larger mammalia, and others again on fruits. 
 Remains of the order occur in Tertiary strata, and also in many of the 
 ossiferous caverns, where they seem to have lodged after the manner of their 
 existing congeners. 
 
 Cheirotherium (Gr. cheir, the hand, and therion, beast). A term applied 
 by Dr Kaup to an unknown quadruped, the hand-like impressions of whose 
 feet are common on the slabs of the Trias or Upper New Red Sandstone. 
 
 138 
 
CHE CHI 
 
 It is supposed by Professor Owen to be one and the same with the batrach- 
 ian or frog-like LABYRINTHODON, which see. 
 
 Cheirtirus (Gr. cheir, hand, and oura, a tail). Literally "hand-tail;" a 
 genus of Lower Silurian trilobites, so termed from their tail or terminal 
 portion presenting four or five finger-like spines or processes. 
 
 Chelae (Gr. chele, a claw). Applied particularly to the bifid claws or 
 pincers of the Crustacea, the scorpion, &c. Fossil chelae (Leptockeles) occur 
 as early as the Upper Silurian epoch. 
 
 Chelichnis (Gr. chelone, a tortoise, and ichnon, footprint). The supposed 
 footprints of tortoises occurring on the slabs of the Permian Sandstones of 
 Corncockle Muir, in Dumfriesshire, and so termed by Sir W. Jardine, who 
 has figured them in his ' Ichnology of Annandale.' 
 
 Chelonia (Gr. chelone, the tortoise). In Cuvier's arrangement, the first 
 order of the Reptilia, including the tortoise, the turtle, &c. , in which the 
 skeleton of the trunk is external, shell-like, and immovable the upper 
 portion being termed the carapace, and the lower or abdominal plate the 
 2)lastron. Chelonian foot-tracks are supposed to have been discovered as 
 early as the Old Red Sandstone period ; but their actual remains have as 
 yet been found only in the Oolite, Chalk, and Tertiary formations. In 
 the Tertiaries of the Siwalik hills Dr Falconer discovered the carapace of 
 the gigantic Testudo Atlas, or Colossochelys, measuring about 20 feet in 
 diameter. 
 
 Cherop6tanms, Chceropotamns (Gr. choiros, a hog, &ndpotamos, river). 
 Literally "river-hog;" a pachydermatous quadruped occurring in the 
 Tertiaries of France and England ; very closely related to the Hog family, 
 and forming, as it were, a link between the extinct anoplothere and the 
 existing peccary. From its geological position, Professor Owen regards it 
 as the earliest representative of the hog tribe on our globe ; and from its 
 dentition, considers it to have been more predacious or carnivorous than 
 any of the existing species. 
 
 Chert (quasi quartz). A mixed siliceous or impure flinty rock, or rather 
 flinty portions occurring in other strata, as in limestone, &c. Resembles 
 some varieties of flint and hornstone, but less conchoidal in the fracture, 
 tougher, and fusible, which latter property is owing to an admixture, less 
 or more, of calcareous matter. A limestone so siliceous as to be worthless 
 for the limekiln, is said to be " cherty." 
 
 Chesil Bank (Ger. kiesel, a pebble). Literally "Pebble bank;" the well- 
 known shifting pebble beach that extends from Portland to Abbotsbury, 
 on the southern coast of England. 
 
 Chessylite. The name given by Brooke and Miller to a fine crystalline 
 variety of the blue carbonate of copper, from its occurring at Chessy, near 
 Lyons. Known also as Chessy Copper. The primary form of Chessylite is 
 an oblique rhombic prism ; its colour from azure to Berlin-blue, and in 
 earthy. varieties, smalt-blue. "It is probably the result," says Bristow, 
 " of the decomposition of other ores of copper. It generally occurs lining 
 cavities in primary and secondary rocks, and associated with malachite 
 and red-copper. It forms a valuable ore of copper when abundant. It is 
 also used when pulverised as a pigment, under the name of Mineral-blue or 
 Mountain-Hue ; but it is not of much value, from its liability to turn 
 green." 
 
 Chiistolite (Gr. chiastos, marked with the letter x, or cleft, and lithos, 
 stone). A crystalline mineral, by some regarded as a variety of Anda- 
 
 139 
 
CHI CHL 
 
 lusite, and by others as a distinct species. It occurs in long four-sided 
 prisms of a pale-grey or greyish-green colour, with a dull vitreous lustre, 
 which present a black or bluish-black crop in their transverse section. It 
 is found imbedded in clay-slate, especially near granitic outbursts. 
 
 China-Clay. A general term for the finer varieties of pottery clay, 
 technically known as Kaolin, which see. 
 
 China-Stone. A familiar term for the decomposed granites which yield 
 the China-clay or Kaolin of commerce. 
 
 Chiton (Gr. chiton, a coat of mail). A well-known gasteropod mollusc 
 (the type of the family Chitonidce), whose elongated flexible covering or 
 shell consists of eight transverse imbricating plates, lodged in a coriaceous 
 mantle, which forms an expanded margin round the body ; e.g., the C. 
 octovalvis of our own shores. Chitons occur fossil from the Silurian 
 upwards. Their detached plates are apt to be mistaken for the patelliform 
 shells of other genera ; but may be distinguished, in good specimens, by 
 their granulated or sculptured surfaces, which are divisible into dorsal and 
 lateral areas, by their processes of attachment on their anterior margins, 
 as well as by their inner surfaces when these can be freed from the matrix. 
 
 Chitonellus (diminutive of chiton). A sub-generic form of chiton, chiefly 
 distinguished, at least in the fossil species, by the form of the plates, which 
 were isolated or placed independently on the mantle, to which they were 
 fixed by much larger processes of attachment than in chiton proper. Chit- 
 onelli occur fossil in several specific forms, the Permian limestones of Dur- 
 ham having as yet yielded the finest specimens. 
 
 Chlorite (Gr. chloros, green). A soft friable mineral, closely allied in 
 character to talc and mica, and so called from its greenish colour. It is 
 generally massive and scaly, or imbedded and interspersed through other 
 rocks. "Chlorite," says Nicol ('Man. of Mineral.'), "is one of the most 
 widely dispersed and geologically important minerals. Externally it re- 
 sembles mica [is flexible but not elastic like mica], and is frequently asso- 
 ciated with, or replaces, it in granite, gneiss, and similar rocks. It is a 
 component of the diabase porphyries and amygdaloids, and then often crys- 
 tallised ; and it is occasionally found in diorite, euphotide, and serpentine ; 
 more rarely in greenstone-porphyry, amygdaloid, basalt, and trachyte. It 
 is most abundant in chlorite slate, or in beds of potstone, intimately mixed 
 with talc, for which it shows a strong affinity. From these it has passed 
 into various sedimentary rocks, which owe to it their green colour. The 
 Alps, Scandinavia, the Ural, the Harz, and many parts of Scotland, are 
 well-known localities of chlorite, both in its crystallised variety and as a 
 constituent of rocks." According to Kobell, a German variety consisted 
 of silica 27.32, alumina 20.69, magnesia 24.89, iron protoxide 15.23, man- 
 ganese protoxide 0.47, water 12.00. The most abundant varieties are com- 
 mon chlorite, chlorite slate (which contains upwards of 40 per cent of 
 magnesia), and foliated chlorite. 
 
 Chloritic Sand (Gr. chloros, green). Any sand coloured green by an 
 admixture of the simple mineral chlorite, which see. The term is generally 
 applied to the " Greensand " of the Chalk formation, which owes its pre- 
 vailing colour to a chloritous silicate of iron. 
 
 Chlorophaeite (Gr. chloros, green, and pJiaios, brown, in allusion to the 
 change of colour produced by exposure). A soft sectile earthy mineral, 
 occurring massive, or disseminated in amygdaloidal trap-rocks ; translu- 
 cent and olive-green when first exposed, but soon changes to blackish - 
 
 140 
 
CHL CHR 
 
 brown, and becomes opaque. Consists of 32.85 silica, 22.08 iron peroxide, 
 3.44 magnesia, and 41.63 water. 
 
 Chlorophane (Gr. chloros, green, arApkaino, I shine). A variety of fluor- 
 spar, so called from its exhibiting a bright-green phosphorescent light 
 when heated. 
 
 Choanites (Gr. choane, a funnel). A genus of spongiform zoophytes 
 occurring in the Chalk formation, and usually converted into flint. They 
 are of a sub-ovate form, and appear to have been composed (according to 
 Dr Mantell, who first described them) of a softer tissue than the ordinary 
 sponges. They have a central funnel-like cavity (whence the name), were 
 fixed at the base by long rootlets, and had their mass traversed by nume- 
 rous channels which opened on the inner surface of the cavity, and which, 
 in transverse sections, gives them the radiating appearance of a sea-ane- 
 mone ; hence the familiar term of " petrified anemones." The choanite is 
 the commonest sponge in the Brighton brooch-pebbles. 
 
 Choke-Damp. A miner's term for carbonic acid gas, as distinct from 
 "fire-damp" or light carburetted hydrogen. See AFTER-DAMP. 
 
 Chondrites (Lat. chondrus, a species of sea- weed). Fossil marine plants 
 of the Chalk and other formations ; so called from their resemblance to the 
 existing Chondrus crispus, or Irish moss of our own shores. The frond is 
 thick, branched, dichotomous, or forking into cylindrical or claviform divi- 
 sions, with a smooth surface, and without tubercles. 
 
 Ch6ndrodite (Gr. chondros, a grain). The hemi-prismatic chrysolite of 
 Haliy. One of the gems occurring in grains in crystalline limestone, &c., 
 of various shades of yellow and red ; transparent ; and consisting of sili- 
 cate of magnesia, with iron, potash, and fluorine. 
 
 Chondropterygii or Cartilaginei (Gr. chondros, cartilage). One of the 
 great Cuvierian sections of fishes. The chondropteryyians are distinguished 
 from the teleosteans, or fishes with true bones, by their cartilaginous skele- 
 tons, and include sharks, sturgeons, rays, and lampreys. 
 
 Cliondr6steiis (Gr.) Literally "cartilage-bone;" a provisional genus of 
 fishes from the Liassic formation, having affinities to the sturgeons in the 
 osseous scutes by which their bodies were protected. 
 
 Chrome, Chromium (Gr. chroma, colour). One of the metals discovered 
 by Vauquelin in 1797, and so named from its property of imparting colour 
 to other bodies in a remarkable degree. Combined with oxygen it forms 
 chromic cwid, and this again, with other substances, forms chromates, as 
 chromate of lead, chromate of iron, &c. In nature, chromium forms the 
 colouring matter of various gems, as the emerald, ruby, &c. ; and in the 
 arts its preparations are extensively used as pigments. 
 
 Chrome Ochre. Oxide of chrome, occurring in loose earthy masses, 
 disseminated or investing, of a fine yellowish-green, but generally so 
 mixed up with the rock in which it occurs as to be separable only by 
 chemical means, and hence termed chrome-stone. 
 
 Chr6mite or Chromate of Iron. A mineral consisting essentially of pro- 
 toxide of iron and oxide of chromium, and occurring generally in serpentine 
 or serpentinous limestones, either in veins, in nests, or disseminated. It 
 is occasionally crystallised in octahedrons, but more frequently massive 
 and disseminated in grains; of an iron-black or brownish-black colour, 
 with a shining sub-metallic lustre. It is used in the preparation of various 
 pigments, as chrome-green, chrome-yellow, &c. 
 
 Chrysoberyl (Gr. chrysos, gold, and beryllion, a gem). A species of cor- 
 
 141 
 
CHR GIN 
 
 undum, of a yellowish or asparagus green, and consisting chiefly of alumina, 
 with glucina and protoxide of iron. When large and transparent it is used 
 as a gem ; the opalescent varieties, named cymophane (floating light), being 
 most esteemed. 
 
 Chrysoc6lla (Gr. chrysos, golden, and colla, glue). A silicate of the pro- 
 toxide of copper, occurring in botryoidal or reniform crusts, of a fine 
 emerald green, and apparently a product from the decomposition of copper 
 ores, which it usually accompanies. Derives its name from the weak 
 resinous lustre and peculiar transparency of its fractured edges. 
 
 Chrysolite (Gr. chrysos, gold, and lithos). A green- coloured mineral 
 occurring in trap and volcanic rocks, and consisting of about 40 silica, 50 
 magnesia, and 9 protoxide of iron, with traces of alumina, manganese, and 
 nickel. The fine green-coloured transparent crystals are known as chryso- 
 lite; the less pellucid granular masses as olivine ; and less-known and 
 duller- coloured varieties as chusite, fazalite, hyalosiderite, &c. 
 
 Chrysoprase (Gr. chrysos, gold, and prasinos, leek-green). A fine apple- 
 green to leek-green variety of calcedony, which owes its colour, according 
 to Klaproth, to a small percentage of oxide of nickel. 
 
 Cidaris, Cidarites (Gr. kidaris, a turban). A genus of the family 
 Echinidea or sea-urchins, characterised by their hemispherical, globular, 
 or sub-oval shape ; parallel ambulacra, that is, diverging equally on all 
 sides from the vent to the mouth ; vent vertical ; mouth beneath and 
 central. Living, and fossil from the Carboniferous Limestone upwards. 
 Many of the cidarites are of large size, and are furnished with long and 
 often curiously ornamented spines. 
 
 Cilia (Lat. cilium, an eyelash). Applied in zoology to a peculiar sort 
 of moving organs, resembling microscopic hairs ; e.g., the hair- like fila- 
 ments that surround the mouths of polypes. Ciliated, furnished or fringed 
 with cilia; ciliary motion, that rapid vibratile motion characteristic of 
 cilia in a state of action. 
 
 Cimoliornis (Gr. Mmolia, a kind of fuller's clay, and ornis, bird). 
 Literally Chalk-marl Bird ; a generic term applied by Professor Owen to 
 certain bones from the Lower Chalk-marls, and considered to be those of 
 birds. It is doubtful, however, whether they do not belong to the Ptero- 
 dactylus compressirostris, and until more is known of the osteology of the 
 Pterodactyles, the name must be received merely as provisional. 
 
 Cimolite. Cimolian earth ; a pure white or greyish-white variety of clay, 
 or hydrous silicate of alumina, so called from its occurring in the island of 
 Cimola (now Argentiera) in the Grecian Archipelago. It is used as a 
 fuller's earth ; and, like kaolin, results from the decomposition of felspar 
 in trachyte or other felspathic rock. 
 
 Cinder-Bed. A stratum of the Upper Purbeck series, almost wholly 
 composed of oyster-shells ; and so named by the quarrymen from its loose 
 incoherent composition. 
 
 Cinnabar (Gr. kinndbari). Sulphuret of mercury, occurring in crystals, 
 disseminated and granular, compact, or earthy, and usually of a fine 
 cochineal-red or vermilion colour. It is found in the crystalline, transi- 
 tion, and secondary strata, in beds or veins, and associated with native 
 mercury, iron-pyrites, and other ores. It is the principal ore of mercury, 
 which is obtained from it by sublimation or distillation. The purer 
 varieties are used as a pigment ; but the vermilion of commerce, which is 
 an artificial cinnabar, is prepared from the crude ore. 
 
 142 
 
CIN CLE 
 
 Cinnamon- Stone. A variety of garnet, belonging to what is termed the 
 " Lime-alumina " division of the family, and so called from its cinnamon or 
 orange-yellow colour. See GARNET. 
 
 Cipolin or Cipollino. An Italian term for a whitish marble, variegated 
 with zones or shadings of green talc or chlorite ; and so called from its 
 resemblance to the alternating green and white coats of an onion 
 (cipollina, a shallot or onion). 
 
 Cirripedes, Cirrhipedia, Cirrh6poda (Gr. kirros, a curl, and pous, podos, 
 a foot). A class of articulated animals, including the barnacles and 
 acorn-shells, which obtain their name (curl-footed) from the many-jointed 
 curled tentacles which terminate their feet. In their adult stage they 
 are furnished with a shelly covering consisting of several pieces, some 
 being sessile, others attached by a long fleshy peduncle. They are found 
 fossil from the Oolite upwards pollicipes, balamis, scalpellum, &c. 
 
 Clathraria (Lat. clathrum, a lattice). A genus of fossil stems, first dis- 
 covered by Dr Mantell in the Wealden of Sussex, and so named from the 
 lattice-like arrangement of the lozenge-shaped leaf-scars which ornament 
 their surface. They are evidently gymnogens, and appear to have the 
 nearest relation to the Cycas family, though certain fruits generally found 
 along with them seem to point to the true Coniferse. 
 
 Clathr6pteris (Lat. clathrum, a lattice, and pteris, fern). Literally 
 " Lattice-fern ; " a genus of gigantic ferns apparently peculiar to the 
 Wealden. The leaf is deeply pinnatifid ; leaflets elongated and traversed 
 by a strong midrib ; secondary veins perpendicular to the midrib, and 
 united by transverse branches, which produce a network of quadrangular 
 meshes ; hence the name. 
 
 Clavate (Lat. dava, a club). Club-shaped ; slender at one extremity, 
 and gradually thickening and terminating obtusely at the other. 
 
 Clay Ironstone. A familiar term for the impure earthy carbonates of 
 iron which occur in nodules, layers, and bands, chiefly in the Coal-forma- 
 tion ; hence clay-band in contradistinction to black-band. See IRONSTONE. 
 
 Claystone. An earthy felspathic rock of the Trap group, occurring in 
 veins as well as in mountain masses, and differing from compact felspar 
 iu being softer, and having the aspect and texture of a baked or indurated 
 clay. It becomes porphyritic by the intermixture of felspar crystals, and 
 is then known as claystone porphyry. The prevailing colours are buffs and 
 reddish-browns, with various tints approaching to purple. 
 
 Cleavage. That peculiar structure in many fine-grained stratified rocks, 
 such as clay- slate, which renders them capable of being split indefinitely 
 into thin plates or laminae, and this in a direction independent of their 
 bedding or stratification. Occasionally the lines of cleavage may coincide 
 with those of bedding when the strata stand at high angles, but for the 
 most part it is transverse, and even often at right angles to the original 
 sedimentary layers. As a superinduced structure occurring among the 
 semi-crystalline or metamorphic strata, its origin has given rise to many 
 hypotheses the chief of which may be regarded as itiechanical or cltemical, 
 according as they are founded on physical or on chemical considerations. 
 Thus, those who regard cleavage as a minute species of jointing, generally 
 running parallel to great axes of elevation, and altogether independent of 
 the strike or dip of the strata through which it passes, adopt the mechani- 
 cal theory of great lines of cosmical uprise and contraction, which pro- 
 duced immense pressure on the irregular particles or interstitial cavities 
 
 143 
 
CLE CLI 
 
 of the cleaved masses ; while those who regard it as a species of crystal- 
 lisation or new molecular arrangement adopt a chemical view, and ascribe 
 the appearances to the long-continued but as yet imperfectly understood 
 operation of electrical or chemical forces. Professor Sedgwick, for 
 instance, who has directed much of his attention to metamorphic pheno- 
 mena, propounds a chemico-electrical hypothesis (founded on the artificial 
 production of cleavage by passing magnetic currents through masses of 
 moistened clay), by which "crystalline or polar forces have rearranged 
 whole mountain-masses, producing a beautiful crystalline cleavage, passing 
 alike through all the strata ; " while Professor Phillips appeals in the main 
 to " mechanical forces compressing the sediment at right angles to the 
 lines of cleavage." On the other hand, Mr Daniel Sharpe attempts to 
 combine with this mechanical theory "the action of some peculiar crystal- 
 line force ; " while Messrs Sorby and Tyndall adopt the purely mechanical 
 view the former maintaining that the flattish unequiaxed particles of the 
 ancient mud and sand greatly aided the compressing force in producing 
 cleavage ; and the latter, that the result was unaided by the shape of the 
 particles, but was caused by the extension under pressure of the minute 
 interstices which must exist in even the most finely levigated mudstones. 
 See METAMORPHISM. 
 
 Cleavelandite (after Professor Cleaveland). One of the Felspar family, 
 and known also as albite, but differs little either in form or composition 
 from ordinary felspar or orthoclase. 
 
 Cleithrolepis (Gr. kleithron, a lock, and lepis, scale). A genus of Pyc- 
 nodont fishes from the Carboniferous rocks of Sydney, New South Wales ; 
 and so called by Sir P. Egerton, from the mode in which the transversely 
 oblong scales are locked by articulating processes into each other. In 
 general aspect Cleithrolepis greatly resembles Platysomus, but differs in 
 the dorsal and anal fins being placed farther back, and in their rays increas- 
 ing in length backward, instead of diminishing ; and also in the tail being 
 less decidedly heterocercal. In Cleithrolepis the cranial bones and scales 
 are also ornamented with fine granulations. ('Geol. Journal' for 1863.) 
 
 Cleveland Ironstone. An important ore of iron obtained from the 
 Cleveland district in Yorkshire, where a stratum, 16 feet thick, of a 
 rusty-looking sandstone (the "Lias Band") crops out from the middle of 
 the Lias formation, and is considered to yield on an average about 30 per 
 cent of iron. "It is chiefly," says Ansted, "a carbonate of the protoxide 
 of iron, with about 30 per cent of impurity, consisting of silica, alumina, 
 lime, and magnesia, and a little water. It is sometimes massive, and 
 sometimes alternates with shaly bands, and is generally oolitic in struc- 
 ture. It extends over a district of some hundreds of square miles, thin- 
 ning out to the south, and capped by sandy shales containing scattered 
 nodules of ironstone. Upwards of a million of tons of ironstone are 
 annually extracted from this deposit, chiefly near Middlesborough." 
 
 Climate (Gr. Mima, an inclination). Originally applied in a technical or 
 astronomical sense to the various belts of the earth as influenced by the 
 length of the day each zone from the equator to the polar circles being 
 measured by half-an-hour's increase on the longest day, and from the 
 polar circles to the poles by the increase of a month. The length of the 
 day at the equator being twelve hours, the first climatic belt extended to 
 the latitude where the longest day was twelve and a half hours long, and 
 so on for every half -hour's increase, there being twenty-four such climes 
 
 144 
 
CLI COA 
 
 between the equator and the polar circles, and six between the polar 
 circles and the poles. The term is now applied to the general weather- 
 conditions of any district, as these may be mild or rigorous, genial or un- 
 genial, salubrious or obnoxious, &c. In a wider sense, when treating of 
 countries geographers speak of insular and continental climates : the for- 
 mer, from their proximity to the sea, being comparatively mild in winter, 
 and cool in summer ; and the latter, cold in winter, but excessively hot in 
 summer. Climatology. The science which treats of the different climates 
 of the earth, their causes, products, and peculiarities. 
 
 Clinker. In mineralogy, the black oxide of iron, readily obtained in 
 scales and globules from red-hot iron while under the hammer of the 
 blacksmith. In familiar language the term is applied to the slaggy ferru- 
 ginous crusts that form on the bars of engine-furnaces, round the taps of 
 iron-furnaces, and the like. 
 
 Clinkstone. A flinty felspathic rock or hornstone, of a greyish-blue 
 colour, having a tendency to divide into slabs, and ringing or "clinking" 
 with a sort of metallic sound when struck by the hammer. Many so-called 
 clinkstones are merely basaltic greenstones, having a shivery or fissile 
 structure the thin slabs ringing under the hammer. When the rock 
 contains disseminated felspar, it is called Clinkstone Porphyry. Same as 
 PHONOLITE, which see. 
 
 Clinoclase (Gr. klino, to incline, and klao, to break). Arseniate of cop- 
 per, so called in allusion to its oblique cleavage. Occurs in the copper 
 mines of Cornwall and other localities in small oblique rhombic prisms of 
 a dark verdigris-green inclining to blue. 
 
 Clinometer (Gr. klino, to lean, and metron, a measure). An instrument, 
 of which there are several sorts, for measuring the dip or angle at which 
 strata incline from the horizon. One of the most commodious and port- 
 able is that formed by attaching a pendule to the pivot of the common 
 field-compass the frame of which being laid to the surface of the stratum 
 the pendule indicates the angle of inclination. 
 
 Clionites. A genus of minute fossil sponges, or rather the silicified casts 
 of these sponges, occurring in perforations of shells found in the Chalk 
 formation. They are named after the existing parasitical sponge cliona, 
 whose perforations often completely riddle the oyster and other shells. 
 
 Chinch. An English provincial term for any tough coarse clay ; applied 
 to certain clays of the Coal-measures, and also to the hard clayey beds of 
 the Gault or Chalk-marl. 
 
 Clymenia (Gr. clymene, a sea-nymph). A genus of nautiloid shells 
 peculiar to Devonian strata, in which upwards of forty species have been 
 detected. In the clymenia, the septa of the chambers are simple or 
 slightly lobed, and the siphuncle is internal, or on the inner side of the 
 whorls; hence the occasional synonyme, Endosiphonites. 
 
 Clypedstridse (Lat. clypeus, a buckler). A family of fossil sea-urchins 
 occurring in the Chalk, and characterised by their oblong or rounded form ; 
 mouth somewhat angular, and furnished with well-developed teeth ; out- 
 let distant from the summit ; tubercles mere granulations, and the spines 
 proportionably small. The group is usually divided into the Galeritidce 
 (helmet-like) and the Clypeidce (buckler-like). 
 
 Coal (Gr. kohle; Fr. houille). In mineralogical systems the COALS con- 
 stitute a limited, but very distinct and highly important family, which 
 embraces such species as graphite, anthracite, common coal, brown-coal or 
 
 145 K 
 
COA 
 
 lignite, and peat. Chemically, their chief constituent is carbon, in com- 
 bination with varying proportions of hydrogen, oxygen, and nitrogen ; and 
 in all there exists a greater or less amount of earthy impurities, which 
 being incombustible, remain, after burning, as ashes. From their com- 
 position, which only differs from vegetable or woody matter in the dimin- 
 ished amount of its gaseous and volatile elements from their internal 
 structure, which, for the most part, exhibits to the naked eye, and almost 
 always to the microscope, abundance of vegetable tissue and from their 
 lithological and other characteristics there can be no doubt of their vege- 
 table origin ; whether occurring as peat and lignite, in which the ligneous 
 structure is still apparent, or as common coal and anthracite, in which, for 
 the most part, mineralisation is so perfect as to have obliterated every ex- 
 ternal trace of their organic origin. We have thus the most satisfactory 
 evidence that COAL, in all its species, is merely mineralised vegetation 
 vegetation which, in part, grew and was submerged in situ as peat-mosses, 
 cypress-swamps, jungles, and forest-growths, and in part was drifted by 
 rivers into the seas of deposit, whose varied strata of sandstones, lime- 
 stones, shales, mudstones, coals, and ironstone, now constitute our avail- 
 able Coal-Fields. Of course, as the operations of nature are uniform and 
 incessant, we have Coals of all periods graphites and anthracites of the 
 Silurian and Devonian, bituminous coals of the Carboniferous and Jurassic, 
 lignites of the Tertiary, and peats of the current epoch the products dif- 
 fering in quality according to the amount of mineralisation and subsequent 
 metamorphism to which they may have been subjected. The available 
 coal of Great Britain is no doubt of Carboniferous age, but many excellent 
 coal-fields in India, America, and other countries, belong to the Jurassic 
 and Chalk periods, while anthracites and graphites may belong to any epoch, 
 just as the original bituminous coal may have been subjected to heat and 
 other metamorphic processes. Like all mixed rocks, common coal pre- 
 sents many varieties and these, according to their structure, texture, 
 and qualities, have received various names, as caking coal, which is soft or 
 "tender" in the mass, like that of Newcastle, and swells and cakes 
 together in burning ; splint or slate coal, which burns free and open, and is 
 hard and slaty in texture ; cannel, which is compact and jet-like in tex- 
 ture, and burns with a clear candle-like flame, and, from its composition, 
 is chiefly used in gas manufacture ; and coarse, foliated, or cubic coal, which 
 is more or less soft, breaks up into large fragments, and contains in gene- 
 ral a large percentage of earthy impurities. Between these there is, of 
 course, every gradation coals so pure as to leave only one or two per cent 
 of ash, others so mixed as to yield from ten to thirty per cent, and many 
 so impure as to be unfit for fuel, and so to pass into shales more or less 
 bituminous. The following analysis exhibits proximately these gradations, 
 but mainly that varying proportion of gaseous elements which marks the 
 passage of wood into peat, peat into coal, and coal into anthracite and 
 graphite : 
 
 Inorganic 
 Ash. 
 
 1 6 
 1-13 
 314 
 1- 7 
 1 7 
 146 
 
 (At 212.) 
 
 Wood 
 Peat 
 
 Carbon. 
 
 4854 
 56 66 
 
 Hydrogen. 
 
 6-10 
 5 9 
 
 Oxygen. 
 
 3545 
 18 33 
 
 Nitrogen. 
 24 
 
 Lignite . 
 
 5670 
 
 3 7 
 
 1327 
 
 10 
 
 Coal. . 
 
 7092 
 
 2 6 
 
 1 8 
 
 02 
 
 Anthracite.... 
 Graphite 
 
 74-94 
 
 8098 
 
 1 4 
 
 3 
 
 trace 
 
COB COG 
 
 According to M. Fremy, the following are the degrees of alteration of 
 woody tissue : 1. Turf and Peat. Characterised by the presence of ulmic 
 acid, and also by the woody fibres or the cellules of the medullary rays, 
 which may be purified or extracted in notable quantities by means of nitric 
 acid or hypochlorites, in which they are insoluble. 2. Fossil Wood or Woody 
 Lignite. This, like the preceding, is partially soluble in alkalies, but its 
 alteration is more advanced, for it is nearly wholly dissolved by nitric acid 
 and hypochlorites. 3. Compact or Perfect Lignite. This substance is char- 
 acterised by its complete solubility in hydrochlorites and in nitric acid. 
 Alkaline solutions do not in general act on perfect lignites. Reagents in 
 this variety show a passage of the organic matter into coal. 4. Coal. 
 Insoluble in alkaline solutions and hydrochlorites. 5. Anthracite. An 
 approximation to Graphite ; resists the reagents which act on the above- 
 mentioned combustibles, and is only acted on by nitric acid with extreme 
 slowness. 
 
 Cob&lt (Ger. Kobold, the demon of German mines). A metal discovered 
 by Brandt in 1733. As an ore it is found chiefly in combination with 
 arsenic as arsenical cobalt or smaltine, or with sulphur and arsenic as grey 
 cobalt ore. As a metal it is white and brittle, unchanged in the air, has a 
 high melting-point, is strongly magnetic, and has a specific gravity of 8.5. 
 It is seldom used in the metallic state, owing to the difficulty of reducing 
 its ores, but these are extensively employed in the arts, as in the produc- 
 tion of pigments, inks, stains, and glazes. The ores of cobalt (smaltine, 
 sulphuret of cobalt, &c.) occur in granitic, crystalline, and secondary for- 
 mations, in connection with ores of silver, copper, &c. ; and being at first 
 mysterious and intractable, received their name from the mysterious 
 Kobold, who is supposed to obstruct the operations of the miners. " The 
 quite recent discovery (says Sir J. Herschel in his 'Physical Geography,' 
 1861) of the exceeding tenacity of metallic cobalt, which is double that of 
 iron, promises to place this metal in the first rank of mechanical utility." 
 
 Cohaltine. Arsenical ore of cobalt, occurring in cubical crystals, and 
 also in arborescent, stalactitic, and amorphous masses. Consists of 13.95 
 cobalt, 11.71 iron, 70.31 arsenic, with traces of nickel, copper, &c. This 
 ore of cobalt and smaltine furnish the greater portion of the smalt of com- 
 merce. It is prepared by roasting the ore, and then melting the oxide of 
 cobalt so produced in certain proportions with pure potash and pounded 
 quartz, which is afterwards ground to powder and carefully washed. 
 
 Coccolite (Gr. kokkos, a berry, and lithos}. Granular sahlite ; a variety 
 or sub-species of augite occurring in the iron-mines of Norway and Sweden 
 in granular or berry-like concretions ; hence the name. 
 
 Cocc6steus (Gr. kokkos, a berry, and osteon, a bone). Literally "berry- 
 bone ; " a fish of the Old Red Sandstone, and so termed from the small 
 berry-like tubercles with which the plates of its cranial buckler and body 
 are thickly studded. In general appearance Coccosteus resembles Pterich- 
 thys, but wants the arm-like appendages, and is usually much larger 
 ranging in the Caithness flagstones from a few inches to two feet in length. 
 In both, the body-plates were similarly arranged and tuberculated ; in both, 
 the tail or terminal portion was covered with scales, and supported a fin 
 or fins ; and both seem to have possessed small bony teeth in either jaw. 
 Hugh Miller and Dr Pander have attempted outlines, but the data are yet 
 insufficient for a satisfactory restoration. It is usual to arrange Coccosteus 
 and Pterichthys under the family Cephalaspidce ; but the group is yet too 
 
 147 
 
COG COL 
 
 little understood for this arrangement, and in the mean time all that can 
 safely be done is to rank them as members of the great order of PLACO- 
 DERMS or PLACOQANOIDS, in allusion to the bony plates which constitute 
 their external covering or skeleton. 
 
 Cochliodus (Gr. Icochlias, a cockle, and odous, tooth). Literally " cockle- 
 like tooth ; " a genus of Cestraciont fish-teeth occurring in the mountain 
 limestone, and so termed from their cockle-shell-like aspect. 
 
 Ccelacdnthi (Gr. koilos, hollow, and acantha, spine). Literally "hollow- 
 spines ; " an extensive group of fossil sauroid fishes, that derive their name 
 from the central cavity in their fin-rays, which, however, may have had 
 originally cartilaginous cores. They occur from the Devonian to the Chalk 
 inclusive, and embrace such genera as ccelacanthus, asterolepis, dendrodiis, 
 holoptychius, rhizodus, mawopoma, &c. 
 
 Coe'lodont (Gr. koilos, hollow, and odous, tooth). Literally "hollow- 
 toothed ; " a term applied to those lacertilians or lizard-like reptiles which 
 have hollow teeth, in contradistinction to the Pleodont or solid-toothed. 
 
 CceloptycMum (Gr. koilos, hollow, and ptyche, a fold or wrinkle). A 
 genus of sponges occurring in the Cretaceous and Lower Tertiary beds near 
 Brunswick in Germany. They are mushroom-shaped organisms mounted 
 on a short tapering stalk the main body or hood being hollow, and more or 
 less lobed and wrinkled at the margin, whence the name "hollow-wrinkle.'' 
 
 Coelorhynclius (Gr. koilos, hollow, and rhynchos, beak). Literally "hollow- 
 beak ; " a genus of sword-fishes whose prolonged premaxillary bones or 
 " swords " have been found in the Upper Chalk and Eocene Tertiaries of 
 England. 
 
 Ccenoe'cium (Gr. Icoinos, common, and oikos, dwelling). The term em- 
 ployed by Professor Allman to designate the plant-like structure or common 
 dermal system of the polyzoa, in contradistinction to the polypary or 
 polypidom of the true polypes. 
 
 Coke. Charcoal; the carbonaceous residue of coal after the volatile 
 matters have been driven off by heat. Formerly coke was prepared by a 
 smothered combustion of the coal in open-air heaps ; now it is prepared in 
 ovens specially constructed for the purpose. 
 
 Cole6ptera (Gr. koleos, a sheath or case, and pteron, wing). Sheath- 
 winged ; an order of insects, like the beetles, furnished with hard crustace- 
 ous sheaths (elytra) which cover and protect their membraneous wings or 
 organs of flight. Coleopterous insects are found fossil from the Coal for- 
 mation upwards. 
 
 Collyweston Slates. Also known as " Colly weston Tilestones ;" a sub- 
 ordinate series of laminated calcareous beds occurring at Collyweston, near 
 Stamford, in Lincolnshire ; and from their position supposed to be the 
 equivalents of the celebrated " Stonesfield Slate." 
 
 Cologne Earth. An earthy, peaty mass of lignite, or partially fossilised 
 wood, of a deep brown colour, occurring in an irregular bed of from 30 to 
 50 feet thick, near Cologne, Lower Rhine. 
 
 Cololites (Gr. Tcolon and lithos). A name given to certain tortuous and 
 convoluted intestinal-like masses and impressions which appear in some 
 instances to be either the petrified intestines of fishes, or the contents of 
 their intestines, still retaining the forms of the tortuous tube in which 
 they were lodged, hence the name ; but which in the majority of cases 
 are undoubted worm-casts, like those of the lob- worm. 
 
 Colossochelys (Gr. kolossos, a statue of enormous size, and chelys, a tor- 
 148 
 
COL COM 
 
 toise). The generic term given by Dr Falconer to the bones and portions 
 of the carapace of a tortoise of gigantic dimensions, discovered by him and 
 Captain Cautley in the Upper Tertiaries of the Siwalik Hills in India. The 
 remains discovered indicate a length of twelve or fourteen feet. 
 
 Colour of Minerals. In describing rocks and minerals, their colours are 
 usually mentioned as a simple and obvious aid to identification. Miner- 
 alogists divide these into the metallic and non-metallic, the latter embrac- 
 ing the ordinary colours, as black, white, red, green, &c. ; or combinations 
 of them, as yellowish-white, reddish-brown, blackish-green, and the like ; or 
 peculiar hues taken from familiar objects, as chest nut-brown, olive-green, 
 sky-blue, and so forth. The metallic colours, on the other hand, are less 
 numerous, and much more decided and peculiar ; hence we have copper-red, 
 the colour of native copper; bronze-yellow, as iron-pyrites ; brass- yellow, 
 copper-pyrites ; gold-yellow ; silver-white ; tin-white ; lead-grey, as galena ; 
 steel-grey ; iron-black, as specular iron-ore ; and a few other shades equally 
 distinct and decided. 
 
 Columbian (Columbia, America). The metal now generally known as 
 Tantalite (which see), but said to have been first discovered in ore found 
 in Connecticut, North America. 
 
 Columnar (Lat. columna, a column). Having the form of columns; 
 arranged in columns. The basalts of Staffa and the Giant's Causeway are 
 said to be columnar, because composed of column-like masses less or more 
 regular in form and arrangement. When the form and arrangement of 
 these masses are indistinct and irregular, the structure is said to be sub- 
 columnar. 
 
 Combe or Coomb (Sax.) A common term in the south of England for 
 an upland valley, generally narrow, and without a stream of water. Dr 
 Buckland remarks, " The term combe is usually applied to that unwatered 
 portion of a valley which forms its continuation beyond and above the most 
 elevated spring that issues into it ; at this point or spring-head the valley 
 ends and the combe begins." 
 
 Combination (Lat. con, together, and bina, two by two). In chemical lan- 
 guage, a combination is not a mere mingling of two substances producing 
 a mixture intermediate between the two, but a union producing a third 
 substance different from either. 
 
 Combustion (Lat. con, together, and uro, I burn). Consumption by fire ; 
 the act of burning. In chemistry, this term is generally applied to the 
 phenomena exhibited by burning bodies, and which depend upon the rapid 
 union of the combustible with the oxygen of the air. The heat and light 
 which accompany ordinary combustion, announce intense chemical action ; 
 and the consequence is that combustion is always attended by the produc- 
 tion of new compounds. Combustible. Susceptible of being burnt ; having 
 the property of catching fire. In mineralogy the combustible or inflam- 
 mable minerals are sulphur, diamond, the coals, bitumens, mineral resins, 
 and the inflammable salts. 
 
 C6mminute (Lat. con, and minuo, I lessen). To reduce to small frag, 
 ments. Comminuted. Reduced to small fragments, like the broken shells 
 (shell-sand) of the sea-shore. 
 
 C6mptonite. Known also as Thomsonite, after the well-known chemist ; 
 one of the Zeolite family, occurring with calc-spar and other zeolitic 
 minerals in cavities, in trap-rocks, and in old lavas. Named after Lord 
 Compton, who brought it from Vesuvius in 1818. 
 
 149 
 
CON 
 
 Conchifera (Gr. conche, a shell, and fero, I bear). An extensive class of 
 acephalous bivalve mollusca, including the oysters, scallops, mussels, and 
 cockles. The conchifera are mostly equivalve, and are usually divided 
 into two orders the Monomyaria, or those having only one muscular im- 
 pression on the valve ; and the Dimyaria, or those having two muscular 
 impressions, and consequently furnished with two adductors. See tabula- 
 tions, " ANIMAL SCHEME." 
 
 Conchitic (Gr. conche, a shell). Composed of shells ; containing shells 
 in abundance. Applied to limestones and marbles in which the remains of 
 shells are a noticeable feature. The simpler terms "shell-limestone" or 
 " shell-marble " are now more frequently employed. 
 
 Conchoidal (Gr. conche and eidos, form). Shell-like ; applied to that 
 peculiar fracture of rocks and minerals which exhibits concave and convex 
 surfaces resembling shells ; thus, when we chip a piece of flint or cannel- 
 coal, the newly-exposed surface exhibits the conchoidal fracture. 
 
 Conchorhynchus (Gr. conchas, a shell, and rhynchos, a beak). De Blain- 
 ville's generic term for the fossil calcareous mandibles of cephalopods, in 
 contradistinction to rhyncholites, which is usually applied to the upper 
 mandible. See RHYNCHOLITES. 
 
 Concrete (Lat. con, together, and cretus, grown). A compact mass, com- 
 posed of coarse pebbles and sand, run or cemented together by lime. 
 Concrete is employed in the foundations of buildings, as a groundwork for 
 causewaying, and occasionally as an arti6cial stone or pavement. About 
 60 parts of pebbles, 25 of river-sand, and 15 of lime, form a good concrete. 
 
 Concretion, Concretionary (Lat. con and cretus, grown together). 
 Nodules like those of chert and ironstone, the grains and spherules of 
 oolite, and the grape-like clusters of the magnesian limestone, are termed 
 " concretions," as formed by a molecular aggregation distinct from crys- 
 tallisation. The concretionary structure is very apparent in certain deposits 
 from calcareous springs (e.g., the pisolite of Carlsbad), in many greenstones, 
 and in other rocks both of ancient and recent formation. 
 
 Confervites. Fossil plants, apparently allied to the aquatic confervse ; 
 occurring chiefly in the Chalk formation. 
 
 Confluence (Lat. con, and/ito, I flow. The point at which two or more 
 streams meet ; the junction of a tributary stream with the main river. 
 
 Conformable. Strata or groups of strata lying one above another in 
 parallel order are said to be conformable; when not in the same plane, 
 or not dipping at the same angle, with those on which they are deposited, 
 they are termed unconformable, which see. 
 
 Congeners. Applied in natural history to plants and animals that be- 
 long to the same genus. 
 
 Congerian. A term occasionally applied to certain strata of the Vienna 
 Tertiary basin, from there being charged with species of the mussel-like 
 shell Congeria, known also as Mytilomya and Dreissena. 
 
 Congldmerate (Lat. con, together, and glomerare, to gather in round 
 heaps). Rocks composed of consolidated gravels, just as sandstones are 
 composed of consolidated sands ; known also as puddingstones, from the 
 resemblance of the pebbles in the mass to the fruit in a plum-pudding. 
 In breccias the fragments are more or less angular ; in conglomerates they 
 are rounded and water- worn, and may vary from pebbles the size of a pea to 
 boulders half a ton in weight. See PUDDINGSTONE. 
 
 Coniferse, Coniferous. Cone-bearing ; applied to the pine tribe, whose 
 150 
 
CON COP 
 
 seeds occur in cones, as the larch, pine, &c. The order includes the firs, 
 pines, yews, junipers, &c., some of which have berry-shaped rather than 
 scaly -coned fruit ; but in all the family resemblance, habit, and woody 
 structure are greatly alike. Structurally considered, the conifers stand 
 intermediate between the endogens and exogens, forming the gymnogens or 
 gymnosperms of the botanist. Undoubted coniferous wood makes its first 
 appearance in the Carboniferous system, and continues upwards through- 
 out all the subsequent formations. See tabulations, "VEGETABLE SCHEME." 
 
 Conodonts. Literally " cone-teeth ;" minute, glistening, slender, conical 
 bodies, hollow at the base, pointed at the end, more or less bent, with 
 sharp opposite margins, and occurring in thousands in the Lower Silurian 
 schists of Russia. They are supposed by Pander to be the horny teeth of 
 cartilaginous fishes ; but this view is opposed by Huxley, Owen, and other 
 naturalists, who regard them as more likely to be the ' ' spines or booklets 
 or denticles of naked molluscs and annelids ''an opinion which has many 
 geological coincidences to support it. 
 
 Contemporaneous (Lat. con, together, and tempus, temporis, time). Ex- 
 isting at the same period ; formed during, or belonging to, the same geo- 
 logical epoch. Contemporaneity. The state of being contemporaneous 
 with; hence we speak of lines and strata of contemporaneity in widely 
 separated portions of the same system. 
 
 Contorted (Lat. con, together, and torsus, twisted). Applied to strata 
 which, like gneiss and mica-schist, exhibit frequent irregular bendings and 
 flexures, as if they had been crumpled and twisted while in a soft and 
 yielding condition. 
 
 Contour (Fr. contour, from con, and tour, a turn). In geography, the 
 outline or horizontal configuration of any portion of the land, as defined 
 by the waters of the ocean that surround it. 
 
 Conul aria (Lat. conulus, a little cone). A genus ofPteropod shells, so 
 called from their tapering conical outline. Conularia is four-sided, straight, 
 tapering, the angles grooved, and the sides striated transversely, as if the 
 thin shell had been divided by numerous septa. Several species are found 
 in the Silurian, Devonian, and Carboniferous formations. 
 
 Copaline. A fossil resin, found in the London and other Tertiary clays. 
 It occurs in irregular pieces of a pale yellowish or dusty brown colour, 
 and is so named from its resemblance to copal -resin in colour, lustre, 
 transparency, hardness, and difficulty of solution in alcohol. It is brittle, 
 yields readily to the knife, and melts easily, giving off a resinous and 
 aromatic odour. 
 
 Cophinus (Gr. kophlnos, a basket). A term applied to curious organic 
 markings, as yet detected only in Silurian shales, but common, in all pro- 
 bability, to all Palaeozoic and Mesozoic mudstones. Their shape is in- 
 versely pyramidal, more or less circular and upright, and having the sides 
 scored with elegant transverse grooves resembling fine wicker-work, whence 
 the name. They are supposed to be impressions made by the stems of 
 encrinites, which, rooted and half-buried in the micaceous mud, have pro- 
 duced, by their wavy and somewhat rotatory motion, the beautiful pattern, 
 every line of which answers to one of the projecting rings of the jointed 
 stem. The funnel-shaped hollow produced in wet soil by the waving of a 
 flower-stem in a windy day is an analogous phenomenon. 
 
 Copper (Lat. cuprum, a corruption of Cyprium, from the island of Cyprus, 
 whence it was anciently brought). One of the most abundant and earliest 
 
 151 
 
- COP 
 
 known metals, being the chief ingredient in domestic utensils and imple- 
 ments of war before the use of iron. It occurs native in the metamorphic 
 and igneous rocks in threads, strings, and arborescent incrustations ; in 
 plates and laminae ; also investing, massive, and disseminated ; but rarely 
 in loose grains or lumps. Occasionally it is found deposited in mines from 
 water containing the sulphate, after the manner of the electrotype pro- 
 cess ; and not unfrequently large anomalous masses, weighing from 1600 to 
 4000 Ib. (like those of Lake Superior and South America), are found in the 
 igneous rocks. More frequently and more abundantly it occurs as an ore 
 in many formations the yellow copper-ores (pyrites), the grey copper- 
 ores, the red copper-ores, and some of the copper salts being the most im- 
 portant and valuable. As a metal it is distinguished by its peculiar red 
 (" copper-red ") colour ; has a hardness of from 2.5 to 3 ; specific gravity, 
 from 8.5 to 8.9 ; is malleable and ductile; and requires a temperature of 
 nearly 2000 Fahr., or that of white heat, to fuse it. It is readily acted on 
 by acids, which form with it blue or green salts ; and as these are poison- 
 ous, hence the necessity of care in the use of copper utensils for culinary 
 and domestic purposes. It is readily detected in solution by the bright 
 blue produced by the addition of liquid ammonia by the brown precipi- 
 tate formed by the ferrocyanate of potash or by its speedily coating a slip 
 of polished iron or steel (a knife-blade, for example) with a thin tilm of 
 metallic copper. Copper is largely employed in the arts and industry of 
 all civilised nations, either alone or as an alloy bronze, brass, bell-metal, 
 and gun-metal being some of its most important admixtures. 
 
 Copperas (Ger. kupfer-wasser). The familiar term for sulphate of iron. 
 The sulphate of copper occurs in blue, and the sulphate of iron in green 
 crystals ; hence apparently the term copperas. It is prepared by moisten- 
 ing the pyritous shales (sulphurets of iron) which are found abundantly in 
 the Coal-measures, &c., and exposing them to the air, when decomposition 
 takes place and the sulphuret is converted into the sulphate of iron, which 
 is subsequenty dissolved and evaporated, to procure it in the crystallised 
 state. It is largely used in dyeing and tanning ; in the manufacture of 
 writing-ink, prussian-blue, sulphuric acid; and in various other arts and 
 
 Copper-Glance. A valuable but rather scarce ore of copper (the disul- 
 phide), occurring most frequently in blackish lead-grey prismatic (six-sided) 
 crystals, but also massive and amorphous. Copper-glance is lamellar in 
 structure, sectile and soft, slightly malleable, and much more easily fusible 
 than copper. Specimens from Cornwall were found to consist of 77.16 
 copper, 20.62 sulphur, and 1.45 iron. 
 
 Copper-Nickel. Known also as nicJceline; a native arseniuret of nickel, 
 generally occurring in veins in the crystalline and transition rocks, associ- 
 ated with cobalt, silver, and other ores. It derives its name from its light 
 copper-red colour, and is used as an ore of nickel in the manufacture of 
 German silver. 
 
 Coprolite (Gr. kopros, dung, and litkos, stone). Petrified excrements or 
 dungstone. Coprolites are found in all the Secondary and Tertiary strata, 
 and appear to be the voidings chiefly of saurians and sauroid fishes. In 
 many instances they contain fragments of scales, shells, &c., the undigested 
 portions of the prey of these voracious creatures. Many specimens exhibit 
 on their surfaces the corrugations and vascular impressions of the intes- 
 tines ; and masses of coprolites have been detected in situ within the ribs 
 
 152 
 
COR 
 
 of liassic ichthyosauri. Coprolites are found in greatest perfection stud- 
 ding the surfaces of certain argillo-calcareous shales in the Lias and Coal- 
 measures ; enclosed as the central nucleus of nodules and balls of ironstone 
 in the Coal-measures ; and in those phosphatic nodules of the Greensand 
 and Lower Chalk now used for manurial purposes. 
 
 Coral (Gr. korallion}. The comprehensive term for all calcareous or 
 stony structures secreted by the marine asteroid polypes or zoophytes. 
 Coralloid. Having the appearance or structure of coral. Coralline. 
 Partaking of the nature of coral. 
 
 Coral Rag. The upper member of the Middle Oolite, so called because 
 it consists, in part, of continuous beds of petrified corals, for the most part 
 retaining the position in which they grew, and sometimes forming masses 
 15 feet thick. See OOLITE. 
 
 Coral-Reef. The term applied by naturalists, as well as by mariners, to 
 any connected mass of coral structures, whether trending away in long 
 partially-submerged ledges, encircling islands like breakwater-barriers, or 
 rising as low ring-shaped islets above the waters of the ocean. Such masses 
 are found studding the Pacific on both sides of the equator to the thirtieth 
 degree of latitude ; abounding in the southern part of the Indian Ocean ; 
 trending for hundreds of miles along the north-east coast of Australia ; and 
 occurring less or more plentifully, in patches, in the Persian, Arabian, Red, 
 and Mediterranean Seas. In the Pacific, where volcanic agency is actively 
 upheaving and submerging, coral-reefs are found forming low circular 
 islands, enclosing lagoons (atolls or lagoon islands) ; surrounding islands of 
 igneous and other origin (fringing or shore reefs) ; crowning others already 
 upheaved (coral ledges) ; or stretching along shore in surf -beaten ridges 
 (the true barrier or encircling reef) of many leagues in length, and from 20 
 to more than 200 feet in thickness. Regarding them as mainly composed 
 of coral, and knowing that the zoophytes can add, unless in some very 
 favourable situations, only a foot or two to the structure during a century, 
 many of these reefs must have been commenced before the dawn of the 
 present epoch ; and looking upon them as consisting essentially of carbon- 
 ate of lime, we have calcareous accumulations now in progress rivalling in 
 magnitude the limestones of the Secondary formations. 
 
 The composition and construction of coral-reefs, though'effected chiefly 
 by lime-secreting zoophytes, seem owing in some measure to the promiscu- 
 ous aggregation of marine debris. The more abundant reef-builders, ac- 
 cording to Darwin, are the madrepores, astrceas, porites, meandrince, and 
 nullipores, at moderate depths, and the milfepores, seriatopores, and other 
 delicate forms, at depths from fifteen to twenty fathoms the great field of 
 coral development thus lying between low water and twenty fathoms. As 
 produced by these minute workers, coral is almost a pure carbonate of 
 lime, soft and porous at first, but gradually becoming so hard and compact 
 as to be used in the South Sea Islands for building. During its formation, 
 however, it encloses shells, fragments of drift-coral, sea-weeds, sponges, 
 star-fishes, sea-urchins, drift-wood, and the like ; and these being cemented 
 in one mass by the growth of new coral, the drift of coral- sand, and the 
 infiltration of carbonate of lime from decomposed coral, the rock presents 
 a brecciated appearance extremely analogous to some older limestones. 
 Again, the sediment deposited in the lagoons and sheltered water-channels, 
 and which arises from the raspings and droppings of the animals which 
 bore into or browse upon it, produces, when dried and consolidated, a 
 
 153 
 
COR 
 
 substance scarcely distinguishable from some earthy varieties of chalk. 
 Further, where reefs have been upheaved by subterranean agency, as the 
 strata of fossil coral on the hills of Tahiti, or enveloped in volcanic tufas, 
 as in the Isle of France, where a bed ten feet thick occurs between two 
 lava currents, the "coral-stone" has a sparry crystalline aspect thus pre- 
 senting the geologist with almost every gradation of limestone, from the 
 soft chalky mass of yesterday's secretion to the compact texture of saccha- 
 roid marble. On the subject of corals and coral-reefs, the reader may 
 consult Darwin ' On the Structure and Distribution of Ccral-Reefs ; ' Dana 
 in the 'Report on the Geology of the United States Exploring Expedi- 
 tion;' Stutchbury in the 'West of England Journal;' Beechey in his 
 'Voyage to the Pacific ; ' and other recent voyagers. 
 
 Coral Zone. In marine zoology, the coral zone, as its name implies, is 
 the region of the calcareous and stronger corals, and extends from 300 to 
 600 feet a depth rarely found in true British seas, but where found, char- 
 acterised by forms of star-fish, cidaris, and brachiopod mollusca, which 
 cannot exist in shallower waters. 
 
 Coralline Zone. That zone of marine life which extends from 90 to about 
 300 feet in depth, and is, in our latitudes, the great theatre of marine life : 
 the common sea- weeds cease, and corallines luxuriate ; the ordinary shore- 
 shells disappear, and buccinum, fusus, trochus, venus, pecten, and the 
 like, abound. 
 
 Corax (Gr., a kind of shark-fish). A genus of shark teeth occurring in 
 the Chalk formation, and differing chiefly from those of the recent genus 
 Galeus, to which the Tope or Grey Shark belongs, in being solid. They 
 are of small size, of triangular form, with a deep concavity on the posterior 
 margin, the base of which is prolonged, and forms three or four -angular 
 points, and have the anterior edge finely serrated. The root of the tooth, 
 as in Notidamis, is a broad bony plate. 
 
 Coriaceous (Lat. corium, a hide). Having a tough leathery consistence ; 
 having the texture of rough skin. Applied to many vegetable and animal 
 substances. 
 
 Cornbrash. A provincial term used by Smith, for a coarse shelly lime- 
 stone of the Upper Oolite. It is said to derive its name from the facility 
 with which it disintegrates and breaks up (brashy) for the purposes of corn- 
 land. See OOLITIC SYSTEM. 
 
 Corncockle Muir, in Dumfriesshire, celebrated for the fossil footprints 
 which occur on the slabs of its Permian sandstones, and which form the 
 subject of Sir W. Jardine's monograph, 'The Ichnology of Annandale.' 
 
 C6rnean (Lat. cornu, a horn). An igneous rock, so called from its 
 tough, compact, and horn-like texture ; known also as Aphanite, which 
 see. 
 
 C6rneous (Lat. cornu, a horn). Horny ; having the colour and texture 
 of horn ; e.g., the operculum and dried epidermis of many shells, the cara- 
 pace of the turtle, &c. 
 
 Cornish. Diamonds. A name given to varieties of rock-crystal found in 
 the Cornish mines, and frequently cut for ornamental purposes. The true 
 Cornish diamond is usually covered with an opaque coating of silica. 
 
 Cornstone. A term usually applied to the reddish and bluish-red con- 
 cretionary limestones which occur in the middle formation of the Old Red 
 Sandstone. In Hereford, Fife, and Forfar, they occur associated with 
 reddish marls and sandstones ; are often irregular in their stratification ; 
 
COR COS 
 
 are frequently too siliceous to be used as limestones ; and are altogether 
 void of fossils. They are said to derive their name from the fertile corn- 
 soil that overlies them in Hereford, as compared with the tenaceous clays 
 which cover the marls and sandstones. 
 
 Cornu A'mmonis (Lat. cornu, a horn). An obsolete term for the ammon- 
 ite, from its fancied resemblance to the horn with which the head of 
 Jupiter Ammon was sculptured. 
 
 Cornulites (Lat. cornu, a horn). A genus of ringed or annulated shelly 
 tubes occurring in Silurian strata, and so called from their shape. At one 
 time supposed to be tentacles or encrinal stems, they are now regarded as 
 the shelly tubes of marine annelids. See TENTACULITES. 
 
 Corroded (Lat. corrodo, I eat or wear away). Eaten away by degrees ; 
 worn away as limestone is by the carbonic acid and moisture of the atmo- 
 sphere. Corrosion, the act or state of being so worn away ; and corrosive, 
 having the power of dissolving and gradually wearing away. 
 
 Corrugated (Lat. con, together ; ruga, a wrinkle). Wrinkled; covered 
 with irregular folds ; having a crumpled and uneven surface. 
 
 Corundum, Corundum Stone (Hindoo, Korund). Crystallised alumina 
 or oxide of aluminum, consisting of from 93 to 95 alumina and 3 water, 
 with traces of lime, silica, and magnesia. It usually occurs in six-sided 
 prisms, and also in obtuse and acute six-sided pyramids, but is likewise 
 found granular and massive. It is generally of a greyish "or greenish- 
 brown tint ; uneven in fracture ; tough when compact ; and the hardest 
 of all known minerals except the diamond. " The name corundum" says 
 Bristow, "is commonly confined to the opaque, rough crystals and cleav- 
 able masses, generally of a dingy colour, and often dark ; while the term 
 emery embraces the more or less impure, massive, granular, and compact 
 kinds ; and sapphire and ruby comprise the transparent, brightly-tinted 
 varieties." It is extensively used for polishing steel and cutting gems. 
 
 Coryphodon (Gr. koryplte, a point, and odous, tooth). A sub-genus of 
 Lophiodont tapir-like pachyderms found in the Eocene and Miocene Terti- 
 aries of France and England ; and so termed by Owen because the angles 
 of the ridges of its molar teeth are developed into points. The broad, 
 ridged, and pointed grinding surface of the tooth indicates its adaptation 
 to comminute the coarser kinds of vegetable substances. 
 
 Cosmical (Gr. kosmos, order natural order, as that of the universe). 
 Relating to the world or universe, as "cosmical laws," or laws of the 
 universe. 
 
 Cosmdgony (Gr. kosmos, world, and gone, origin). Reasoning or specu- 
 lation as to the origin or creation of the universe. Distinct from Geology, 
 whose object is to unfold the history of our globe as far only as fact and 
 observation will permit of sound deduction. 
 
 Cosm6graphy (Gr. kosmos, and grapho, I write). A description of the 
 world or universe ; the science which treats of the several parts of the 
 world, their laws and relations. 
 
 Cosmdlogy (Gr. kosmos, and logos, reasoning). The science which treats 
 of the laws that govern the universe ; the study of the world in general. 
 
 C6smos (Gr. kosmos}. Literally " order ; " natural order, like that pre- 
 vailing in the universe. The whole framework of the material universe ; 
 the world, from the orderly arrangement and symmetry of its component 
 parts, in contradistinction to chaos, the confused and disorderly mass from 
 which it arose. 
 
 155 
 
COS CRA 
 
 Costeaning. In mining, sinking shallow pits at intervals down to the 
 solid rock, and then driving headings at right angles to the general course 
 of the veins in a country, for the purpose of discovering ore. 
 
 Gotham Marble. Known also as Ruin or Landscape Marble. A light- 
 grey argillaceous limestone of the White Lias, occurring in thin layers 
 at Gotham and other places near Bristol. Slices of the stone, taken at 
 right angles to the bedding, exhibit, when polished, fanciful representa- 
 tions of landscapes and ruins ; hence the name. 
 
 Coulees (Fr. couler, to flow as melted metal). In frequent use by geolo- 
 gists for streams of lava, whether in the act of flowing or long since con- 
 solidated into rock-material. 
 
 Courses. Applied in geology to thin regular strata from their being 
 superimposed upon one another like the hewn "courses" of a building; 
 hence we hear such phrases as "alternate courses of limestone and shale." 
 
 Crag (Celt, creggan, shell). Shelly Tertiary deposits of the Pliocene 
 epoch, occurring in Norfolk and Suffolk, and generally subdivided into 
 three members viz., the upper or " Mammal ifero us Crag," the ," Red 
 Crag," and the lower or " Coralline Crag." See TERTIARY SYSTEM. 
 
 Crag and Tail (properly " craig and tail"). Applied to a form of 
 Secondary hills common in Britain, where a bold precipitous front is ex- 
 posed to the west or north-west, and a sloping declivity towards the east. 
 The phenomenon of crag and tail is evidently the result of the currents of 
 the Drift epoch, which in our latitude swept from north-west to north- 
 east, laying bare the opposing heights, but leaving untouched the shel- 
 tered slopes and terraces. 
 
 Cfaigleith Stone. A compact, fine-grained, free-dressing, whitish-grey 
 sandstone quarried at Craigleith, near Edinburgh, and largely used in the 
 Scotch metropolis as a building-stone. It is almost entirely composed of 
 siliceous sand ; the purer beds containing about 98 per cent of silica the 
 admixtures being carbonate of lime, alumina, and iron. 
 
 Crania (Gr. Jcranos, a helmet or head-piece). A genus of small brachio- 
 podous molluscs, which attach themselves to other bodies, and conse- 
 quently have the lower valve flat, and the upper limpet-like or helmet- 
 shaped. They occur from the Lower Silurian to the Chalk inclusive. 
 
 Cranium (Lat.) The skull or brain-case. Cranial. Of or belonging to 
 the skull. In treating of the form of the human skull as a mark of race or 
 tribe, ethnologists are in the habit of speaking of Irachycephalic or short- 
 headed ; dolichocephalic or long-skulled ; acrocephalic, high or pyramidal 
 skulled; and platycephalic or flat-headed. As human remains often occur 
 in prehistoric deposits, these terms are also employed by the palaeon- 
 tologist. 
 
 Crater (Gr. krater, a cup or bowl). The mouth or orifice of a volcano ; 
 so called from its cup or bowl shape. Craters may be central or lateral in 
 the mountain in which they occur ; there may be one principal and several 
 subsidiary ones ; and they may shift their places and become absorbed by 
 subsidence, or be obliterated by eruptions from more active orifices. The 
 craters of active volcanoes have in general one side a little lower, owing to 
 the prevailing winds carrying the greater portion of the light material 
 (scoriae and ashes) to the opposite side. See VOLCANO. 
 
 Crateriform. Applied to hills whose summits present bowl-shaped and 
 other circular depressions that seem to have been the craters of once active 
 volcanoes. We thus speak of the ' ' crateriform hills of Auvergne " hills 
 
 156 
 
CRE 
 
 which were undoubtedly in a state of igneous activity during the Tertiary 
 period. 
 
 Creation, Centres of. See CENTRES OF CREATION. 
 
 Creep. In coal-mining, when the pressure of the superincumbent strata 
 becomes so great as to thrust the " pillars " or masses of coal which are 
 left to support the roofs of the galleries down into the subjacent shales, 
 and thus cause the floors to bulge upwards, this slow bulging is termed 
 a creep, and frequently continues till it reaches the roof and entirely chokes 
 up the gallery. The pressing down of the roof, on the other hand, is 
 known as a thrust or crush, which see. 
 
 Cretaceous or Chalk System (Lat. creta, chalk). The Cretaceous system 
 so called from the chalk beds which form its most notable feature is the 
 last or uppermost of the Secondary formations. As typically developed in 
 the south of England, it is composed of calcareous, argillaceous, and arena- 
 ceous rocks the former predominating in the upper, and the two latter in 
 the lower portion of the system. The calcareous members are generally 
 known as " chalk " and " chalk- marls," the former being applied to the 
 purer beds, and the latter to those that are more earthy and clayey ; the 
 argillaceous strata, which are for the most part stiff blue marly clays, are 
 known by the provincial term "gault" or "golt;" and the sandy beds, 
 being frequently coloured green by the presence of chloritic matter, are 
 distinguished as " greensands." The nodular masses of " flint" that occur 
 in the Chalk consist almost of pure silex, more or less coloured by iron ; 
 and the impure calcareo -siliceous nodules and concretions are spoken of as 
 "chert." The system, as occurring in the south of England, is usually 
 grouped as follows : 
 
 UPPER CHALK. Generally soft white chalk, containing 
 
 numerous flint and chert nodules more or less arranged 
 
 in layers. 
 
 LOWER CHALK. Harder and less white than the upper, 
 CHALK. \ and generally with fewer flints. (Reddish in the north 
 
 of England, and with abundance of flints. ) 
 CHALK MARL. A greyish earthy or yellowish marly 
 
 chalk, sometimes indurated. 
 
 UPPER GREENS AND. Beds of siliceous sand, occasionally 
 indurated to chalky or cherty sandstone (the "fire- 
 stone" of Surrey), of a green or greyish white, with 
 nodules of chert. 
 
 GAULT. A provincial name for a bluish tenacious clay, 
 GREENSAND. sometimes marly, with indurated argillaceous concre- 
 
 tions and layers of greensand. 
 
 LOWER GREENSAND. Beds of green or ferruginous 
 sands, with layers of chert and indurated sandstones, 
 local beds of gault, rocks of chalky or cherty limestone 
 (Kentish rag), and fuller's earth. 
 
 Or, adopting the recent views of palaeontologists respecting the cretaceous 
 affinities of the Wealden, and adding certain Continental beds which are 
 wanting in England, we have then an Upper and a Lower group, compris- 
 ing the following subdivisions : 
 
 UPPER CRETACEOUS. 
 
 1. Maestricht beds and Faxoe limestones. 
 
 2. White chalk, with flints. 
 
 157 
 
CRI 
 
 3. Chalk marl, or grey chalk slightly argillaceous. 
 
 4. Upper greensand, occasionally with beds of chert, and with chloritic 
 
 marl (craie chloritee of French authors) in the upper portion. 
 
 5. Gault, including the Blackdown beds. 
 
 LOWER CRETACEOUS (Neocomiari). 
 
 1. Lower greensand Greensand, ironsand, clay, and occasional beds of 
 
 limestone (Kentish rag). 
 
 2. Wealden beds or Weald clay and Hastings sands. 
 
 Whichever view is adopted, the entire suite of strata with the excep- 
 tion of the fluvio-marine beds of the Weald bear evidence of shifting and 
 widespread seas, and of a climate favourable to the growth of cycads and 
 zamias on land, and of corals, gigantic saurians, and turtles in the waters. 
 Palseontologically, the remains of the Chalk and Greensand are eminently 
 marine, and comprise numerous species of sponges, corals, star-fishes, sea- 
 urchins, shell-fish, Crustacea, fishes, and reptiles. Indications of bird and 
 mammalian remains have also been detected, but these are as yet too 
 scanty and obscure to wai-rant any definite conclusion. On the whole, all 
 the Life-types of the system are strictly Mesozoic, and of the numerous 
 species found in the Trias, Oolite, and Chalk, not one, it is affirmed by 
 palaeontologists, have been detected in Tertiary strata. 
 
 Industrially, the chief products of the system are chalk and flint. 
 Chalk, as an almost pure carbonate of lime, is calcined like ordinary lime- 
 stones, and employed by the bricklayer, plasterer, cement-maker, and 
 farmer; and levigated, it furnishes the well-known "whiting" of the 
 painter. Flint calcined and ground is used in the manufacture of china, 
 porcelain, and flint-glass ; and before the invention of percussion-caps was 
 in universal use for gun-flints. In the south of England flints are exten- 
 sively used as road-material ; and the larger nodules are frequently taken 
 for the building of walls and fences. Beds of fuller's earth are worked in 
 the Greensands, whose indurated strata likewise furnish supplies of not 
 indifferent building-stone and road- material. From the Gault and Upper 
 Greensand of Farnham in Surrey are also obtained those phosphatic nod- 
 ules, now used as a manure by being ground to powder and converted into 
 the superphosphate by the action of sulphuric acid ; as well as that " fire- 
 stone rock," which is said to contain from 30 to 70 per cent of silica 
 soluble in alkalies, and employed in like manner for manurial purposes. 
 
 Crinoids, Crinoidea (Gr. krinon, a lily, and eidos, likeness). Literally, 
 " lily-like animals ;" the Encrinites ; an extensive order chiefly of fossil 
 Echinoderms, so termed from the resemblance which their rayed bodies, 
 surmounted on long slender stalks, have, when closed, to a tulip or lily. 
 In existing seas the Crinoids are represented by the Comatulce or " feather- 
 stars " of our own shores, and by the rare and all but extinct Pentacrinites 
 of the West Indies. The Comatula, though free-floating in its adult state, 
 is attached by a stalk when young ; the marsupite, a fossil form, appears 
 also to have been free in its mature state ; but all the other families were 
 fixed to the sea-bottom or to other objects by their long, slender, many- 
 jointed stems. The characteristics of the order, which is of vast geolo- 
 gical interest, are well exemplified in the Pentacrinus, specimens of which 
 are in the British Museum, the College of Surgeons Museum, London, and 
 in the Hunterian Museum, Glasgow. This animal has a long stem or 
 column, which is composed of calcareous joints or ossicles, articulated to 
 each other by radiated surfaces, and is fixed by the base to a rock or other 
 
 158 
 
CHI CRO 
 
 firm body. The stem, which gives off a number of slender side-branches, 
 supports a vasifonn receptacle or cup, formed of five calcareous plates in 
 close apposition ; and in this receptacle the digestive and other viscera are 
 situated. The upper part of the receptacle is covered by a plated integu- 
 ment in which there is an aperture for the mouth. From the margin or 
 brim of the receptacle, or pelvis as it is sometimes termed, proceed ten 
 many-rayed arms which subdivide into branches of extreme tenuity. On 
 the upper and inner side of the arms are numerous articulated feelers or 
 pinnae capable of expansion and contraction, for the capture of prey. In 
 fact, the pentacrinite may be described, without much error, as a stalked 
 comatula, and this designation of " stalked star-fishes" is more or less ap- 
 propriate to the entire order of Encrinites. The innumerable calcareous 
 joints which constitute the skeleton of the pentacrinite are held in vital 
 union partly by a fleshy investing integument, and partly by the central 
 perforation which connects the stalk and all the other members with the 
 receptacle containing the viscera or body of the animal. Such is the Pen- 
 tacrinus, and such, in general terms, is the whole of the order the main 
 differences lying in the stems, which are round and smooth in the Encrin- 
 ites proper, and pentagonal and ornamented in the Pentacrinites; some 
 having the stem simple, others branched ; some having the joints equal 
 and similar, others having them large and small alternately ; some having 
 the plates of the receptacle larger and more numerous than others ; some 
 having the arms in few bifurcations, others having them in many branches, 
 and armed with innumerable feelers. On these and similar distinctions are 
 founded such families as the /l/n'ocrwiifesorpear-encrinites, the Cyathocrin- 
 ites or cup-encrinites, and others which appear in the usual subdivisions of 
 the order. See ENCRINITES. 
 
 Geologically, the Encrinites range from the Silurian up to the present 
 epoch most abundantly in Palaeozoic and Mesozoic strata, rarely in Cain- 
 ozoic, and now represented only by comatula, and the all but extinct penta- 
 crinus. Like the corals, their function seems to have been, to a great 
 extent, the secretion of lime from the ocean whole strata of limestone, 
 Silurian and Carboniferous, being almost entirely made up of their re- 
 mains. As in other life-forms, each epoch has had its own peculiar genera 
 and species, and thus we rise from the platycrinites, poteriocrinites, cyatho- 
 crinites, and actinocrinites of the Palaeozoic formations, to the pentacrinites, 
 apiocrinites, and marsupites of the Mesozoic, as certainly as we pass from 
 these to the comatula of existing seas. See tabulations, " ANIMAL 
 SCHEME." 
 
 Cri6ceras, Crioceratite (Gr. Lrios, a ram, and Jceras, horn). A genus of 
 the Ammonite family peculiar to the Gault and Greensand, and so named 
 from its shape, the whorls being separate, like the coils of a ram's horn. 
 
 Crocodflia. A well-known group or order of reptiles, represented by the 
 crocodiles, gavials, and alligators of existing rivers. They have their body 
 supported on four partially webbed feet, and encased in an armour of bony 
 plates or scutes, hence they are said to be loricated or mailed. Crocodil- 
 ians occur fossil from the Lias upwards ; but those occurring up to the 
 Chalk inclusive differ from existing genera in the character of their verte- 
 bras, which are either doubly flat, doubly concave (amphiccelian), or convex 
 before and concave behind (opisthoccelian) ; while in recent species, and in 
 those occurring in Tertiary strata, the vertebrae are concave in front and 
 convex behind (proccelian). Besides these differences, the genera having 
 
 159 
 
CRO CRU 
 
 broad muzzles, like the cayman and alligator, are unknown below the Ter- 
 tiary formations all the Secondary genera being referable to the division 
 having elongated beaks, like the recent gavial. Crocodilus, alligator, 
 and gavialis, are recent and Tertiary genera ; goniopholis, teleosaurus 
 steneosanrus, &c., are those found in the Chalk and Oolitic formations. 
 
 Crocoisite (Gr. TcroTcoeis, aurora-yellow). Monochromate of lead, consist- 
 ing, according to Berzelius, of 68.5 oxide of lead and 31.5 chromic acid. 
 Occurs in narrow veins in gneiss and the older crystalline rocks, either 
 crystallised in oblique rhombic prisms, or massive ; colour, various tints of 
 hyacinth red ; streak, orange-yellow. Used as a pigment. 
 
 Crop. The edge of any inclined stratum when it comes to the surface is 
 called the crop or outcrop, which- see. 
 
 Cross-Course. A miner's term for a vein or lode which intersects at 
 right angles (literally crosses) the general direction of productive metalli- 
 ferous veins in any mining district. 
 
 Cross-Cut. In mining, a level driven at right angles to the known direc- 
 tion of a lode with a view to intersect it. 
 
 Cross-Stone. A synonyme of Harmotome or Staurolite, one of the Zeolite 
 family either of which see. 
 
 Crotaldcrinus (Gr. krotalon, a child's rattle). An Upper Silurian encri- 
 nite, so called from its very peculiar shape and structure. In most encri- 
 nites, the arms issue immediately from the edge of the pelvic cup, com- 
 meneing with a single joint, and soon branching into two, three, or four ; 
 the subdivisions varying in different species. But in this genus the sub- 
 divisions commence at the very edge of the cup, and become so numerous 
 as to form a perfect network the five primary reticulate arms overlap- 
 ping each other, and forming, as it were, a convoluted funnel-shaped 
 organism of the finest basket-work, instead of the rayed arrangement of 
 the common encrinite. The stem was made up of close tuberculated joints 
 each tubercle near the root lengthening into tubular processes for 
 attachment to shells and corals. 
 
 Crow-Coal. A miner's term for certain earthy coals which contain very 
 little bitumen and a large percentage of indestructible ash. 
 
 Crush. Applied in mining to any breaking or crushing down of strata 
 by superincumbent pressure, as, for example, the breaking down of the 
 roof of a gallery. The upward bulging of the floor from the same cause is 
 termed a creep, which see. 
 
 Crustacea (Lat. crusta, a hard covering or crust). Literally "crust- 
 clad;" an extensive and varied class of the Articulata or jointed animals, 
 comprising such well-known forms as the crab, crayfish, lobster, shrimp, 
 and prawn. In very general terms they may be described as free animals, 
 having articulated or segmented bodies, jointed limbs, a branchial or gill 
 respiration, a double or complete circulation of blood, which is colourless, 
 a nervous system consisting of chains of ganglions more or less numerous, 
 the sexes distinct, and reproduction by ova or eggs. In many families the 
 crust or covering, to which the class owes its name, is totigh and flexible, 
 and has for its base the peculiar substance termed chitine ; in others it is 
 hard and stony, and consists mainly of carbonate of lime. Such crusts 
 being incapable of expansion so as to accommodate themselves to the in- 
 creasing size of the animals, they are moulted or cast off at stated periods, 
 and this very frequently during the younger stages a circumstance which 
 accounts for the infinite numbers of the exuviae of certain families in the 
 
 160 
 
CRY 
 
 deposits of lakes and estuaries. According to physiologists, the normal 
 number of segments in the Crustacea is twenty-one seven for the head, 
 seven for the thorax, and seven for the abdomen ; but most frequently 
 several of the anterior segments are fused or soldered into a single piece 
 termed the cepluilo-thorax, leaving the abdomen or post-abdomen free, and 
 terminated by a variously compounded tail-plate, telson or pygidium. It 
 is this interfusion of parts which renders the forms of the Crustacean fami- 
 lies so varied ; and the metamorphoses which many of them undergo, from 
 the larval to the adult stage, that render them so difficult of discrimination. 
 This difficulty is further increased by their great variety of habitat some 
 living in the ocean, others in lakes and estuaries ; some chiefly on land, 
 others partly in trees ; some inhabiting the shells and coverings of other 
 animals, and others being parasitic, either for a portion or for the whole of 
 their existence. Their function is also as varied as their habitats most of 
 them being carnivorous, many of them phytophagous, a large portion om- 
 nivorous, while the whole class act less or more as scavengers in clearing 
 away dead and decaying matter. 
 
 For these reasons the classification and arrangement of the Crustacea by 
 different systematists differ according to the point of view from which they 
 have been studied. Thus they are often primarily subdivided into ENTO- 
 MOSTRACA (within shells) and MALACOSTRACA (soft shells) the former 
 embracing those small forms (cypris, nebalia, &c.) which are often par- 
 tially or wholly enclosed in a bivalvular shell-like carapace ; and the latter 
 the larger forms (crayfish, lobster &c.), originally termed " soft-shells," 
 in comparison with the true testacea or shell- fish. Again, viewing them 
 iu reference to their organs of motion, we have such orders as Copepoda 
 (oar-footed), Phyllopoda (leaf-footed), Pcecilopoda (various-footed), and the 
 like, according as these members are more especially fitted for swimming, 
 walking, or prehension. Farther, looking at the position of the eyes in 
 the Malacostraca, we have Podophthalmia (stalk-eyed), and Ednophtkalmia 
 (sessile-eyed) ; at their limbs, and we have Decapoda (ten-footed), Isopoda 
 (equal-footed), and so forth ; or at their caudal terminations, and we have 
 Macrura (long-tailed), like the lobster, Brachyura (short-tailed), like the 
 crab, and Anomura (tailless), like the hermit-crab. These and similar 
 subdivisions show at once the multiplicity and complexity of form in the 
 class a complexity which is greatly increased by the discovery of widely- 
 divergent fossil forms for which new subdivisions and families have had to 
 be erected. 
 
 Geologically, the Crustacea are of prime interest and importance. They 
 occur in the oldest as well as in the most recent formations ; the extinct 
 forms have greatly enlarged our conceptions of vitality ; and their occur- 
 rence in particular strata, and often in inconceivable numbers, enables us 
 to reason on their uniformity of function, even when their forms and 
 organisation appear to be altogether different. The more ancient forms 
 trilobites and eurypterites have now no representatives, and resemble 
 rather the larval than the adult form of any existing genus ; in the Meso- 
 zoic forms glyphcea, &c. we catch a glimpse of the existing long- tailed 
 decapods ; and not till we ascend to upper Mesozoic and Cainozoic strata 
 do we discover the more concentrated structures of the short-tailed crabs 
 and their congeners. For structural and systematic arrangements, see 
 tabulations, " ANIMAL SCHEME." 
 
 Cryolite (Gr. kruos, hoar-frost, and lithos). The double hydrofluate of 
 161 L 
 
CRY 
 
 soda and alumina, a rare mineral found only in the Gneiss of West Green- 
 land, where it occurs in thick veins, massive, and of a lamellar structure. 
 There are two varieties, the snow-white and the rusty-yellow ; and both 
 are now used as the commercial ore of aluminium,. Cryolite melts like 
 ice in the flame of a candle ; hence the name. 
 
 Cryptogamia, Cryptogamic (Gr. kryptos, concealed, and gamos, nuptials). 
 Literally, flowerless ; one of the great divisions of the vegetable kingdom, 
 comprising the mushrooms, lichens, mosses, sea-weeds, and ferns, in 
 which the organs of fructification are concealed or not apparent, as in the 
 Phanerogamia or flowering plants. They are also termed agamous, acoty- 
 ledonous, and cellular plants. Fossil in all formations. See tabulations, 
 "VEGETABLE SCHEME." 
 
 Crystal (Gr. Jcrystallos, ice). Originally applied to transparent gems, 
 but now extended to all minerals having regular geometrical forms. 
 Crystallised. Having the structure of a crystal, as rock-crystal. Crystal- 
 line. Confusedly crystalline, as granite. Sub-crystalline. Indistinctly or 
 faintly crystalline, as some varieties of limestone. See CRYSTALLOGRAPHY. 
 Crystallisation. --The process (natural or artificial) by which the particles 
 of liquid or gaseous bodies are converted into crystals, or solid bodies of a 
 regularly limited form ; e.g., the production of common salt by the evapo- 
 ration of sea-brine, of sugar-candy by the evaporation of syrup. In 
 mineral or unorganised bodies the ultimate or component particles are 
 polygonal solids or crystals ; in- organised bodies they are hollow spherical 
 cells. As in the organic world, therefore, every variety of structure is but 
 the result of modifications of the primitive spherical cell ; so in the inor- 
 ganic world every rock and mineral is composed of original angular solids, 
 or determinate modifications of these. Why calcareous spar should assume 
 one form of crystal, and quartz or rock-crystal another, science cannot tell ; 
 but must, in the mean time, content itself with the determination and 
 description of these curious and multifarious forms. 
 
 Crystall6graphy (Gr. krystallos, and grapho, I write). Literally, a de- 
 scription of crystals ; that sub-science of mineralogy which investigates 
 the relation of crystalline forms, and the origin and structure of crystals. 
 ' ' The word crystal in mineralogy designates a solid body, exhibiting an 
 original (not artificial) more or less regular polyhedric form. It is thus 
 bounded by plane surfaces named faces, which intersect in straight lines 
 or edges, and these again meet in points and form angles, which, when 
 bounded by three or more faces, are named solid angles. The space 
 occupied by a crystal, and bounded by its faces, is often named a form 
 of crystallisation, which is thus merely the mathematical figure regarded 
 as independent of the matter that fills it. Some crystals are bounded by 
 equal and similar faces, and are named simple forms ; whilst those in which 
 the faces are not equal and similar, are named compound forms or combina- 
 tions being regarded as produced by the union or combination of the faces 
 of two or more simple forms. The cube or hexahedron bounded by six 
 equal and similar squares, the octahedral by eight equilateral triangles, 
 and the rhombohedron by six rhombs, are thus simple forms. The axis 
 of a crystal is a line passing through its centre, and terminating either in 
 the middle of two faces, or of two edges, or in two angles ; and axes 
 terminating in similar parts of a crystal are named similar axes. In 
 describing a crystal, one of its axes is supposed to be vertical or upright, 
 and is then named the principal axis. When the axes of the crystals are 
 
 162 
 
CTE CUB 
 
 properly chosen, and placed in a right position, the various faces are 
 observed to group themselves in a regular and beautiful manner around 
 these axes, and to be all so related to them as to compose a connected 
 series produced according to definite laws. It appears that every mineral 
 species is characterised by a certain form of crystal, with axes intersecting 
 at fixed angles, and bearing to each other definite proportions, from which 
 as a primary every other form of crystal observed in that mineral species 
 may be deduced, simply by varying the proportion of these axes. When 
 viewed in this manner, and referred to their simplest forms, it is seen that 
 the innumerable variety of crystals occurring in nature may be all reduced 
 to six distinct groups, or, as they are named, systems of crystallisation. 
 According to Naumann, these systems are the Tesseral, Tetragonal, Hexa- 
 gonal, Rhombic, Monoclinohedric, and Triclinohedric ; and a description 
 of these, with their combinations and derivations, constitutes the main 
 portion of Crystallography. In a description of these systems, the crystals 
 are supposed to be perfect ; that is, the planes smooth and even, and the 
 faces equal and uniform. A perfect crystal can only be produced when 
 during its formation it is completely isolated, so as to have full room to 
 expand on every side. These conditions, however, seldom occur in nature ; 
 hence we have imperfect crystallisation that is, crystals terminating 
 abruptly, having their faces striated, rough, and drusy, their edges 
 curved, and their corners rounded. Amid all these changes and modifica- 
 tions, however, one important element remains unchanged viz., their 
 angular measurement. This is obtained either by the contact, or by the 
 reflecting goniometer" (' Manual of Mineralogy,' passim. ) So far the de- 
 termination of crystalline forms and species is strictly mathematical, and 
 Crystallography, properly speaking, restricts itself to this formation ; but 
 as in nature minerals are often irregularly aggregated, and as the great 
 bulk of the rocks have been formed under conditions that excluded the 
 free development of regular crystallised forms, the mineralogist in his 
 discriminations has to call in the aid of physical characteristics, such 
 as cleavage, fracture, hardness, lustre, and optical properties and even 
 these only assume precision and geological importance when guided by 
 the more exact and satisfactory results of chemical analysis. See MINER- 
 ALOGY. 
 
 Ctenis (Gr. Tcteis, henos, a comb). A provisional genus of Professor 
 Lindley for certain cycadaceous - looking leaves furnished with narrow 
 pointed leaflets (hence their pectinated aspect), but differing from cycads 
 in having their veins bifurcating instead of undivided and parallel. 
 
 Ctenoid, Ctenoidean (Gr. kteis, a comb, and eidos, form). The third 
 order of fishes in Agassiz's arrangement. They are distinguished by their 
 scales, which are jagged or pectinated (like the teeth of a comb) on the 
 posterior margin : these scales are formed of laminae of horn or bone, but 
 have no enamel. The Ctenoideans appear with the Chalk ; the Perch is a 
 familiar example. See ICHTHYOLOGY. 
 
 CtenoptycMus (Gr. kteis, Ictenos, a comb, undptyche, a wrinkle). A genus 
 of palatal fish-teeth belonging to the Cestraciont family, and found chiefly 
 in the Carboniferous limestone. They are readily distinguished by the 
 serrated or comb-like margin of their free-cutting edges. 
 
 Cube-Ore. An arseniate of iron, of an olive-green or pistacio-green 
 colour, and occurring in perfect cubes in the copper-ores of Cornwall and 
 other localities. 
 
 163 
 
CUC CUT 
 
 Cucumites (Lat. cucumis, a cucumber). Fossil fruits from the London 
 Clay, so closely resembling the seeds of various members of the recent 
 genus Cucumis (comprising the gourd, water-melon, &c. ), both in outward 
 form and internal structure, that there is no reasonable doubt of their 
 belonging to plants of the same family; hence the name Cucumites, or 
 fossil cucumbers. 
 
 Culm (Welsh). An impure shaly kind of coal, or anthracitic shale. The 
 culmiferous or- anthracitic shales of North Devon are well known in 
 geology, and are sometimes treated as a lower Carboniferous group under 
 the term " Culm Measures" 
 
 Culmites (Lat. culmus, a stem, like that of corn). A provisional genus of 
 Tertiary articulated stems, with two or more scars at the joints. 
 
 Cumbrian (the ancient Cumbria).. Professor Sedgwick's term for the 
 lowest slaty and partially-fossiliferous beds of Westmoreland and Cumber- 
 land, as indicating an older and earlier system than the SILURIAN of Mur- 
 chison. See CAMBRIAN. 
 
 Cuneiform (Lat. cuneus, a wedge, and forma, likeness). Wedge-shaped ; 
 Cuneate, tapering like a wedge; a form characteristic of many mineral 
 forms, and abruptly terminating stratiform masses. 
 
 Cupressinites (cupressus, the' cypress- tree). A genus of fossil fruits 
 occurring in Tertiary strata, and evidently allied to those of the existing 
 cypress. Known also as Callitrites, Frenilites, and Solenostrobus. 
 
 Cupressites. The generic term employed by Brongniart for all coniferous 
 remains that are nearly allied toj or identical with, the existing cypress. 
 Their leaves are enlarged at the base, sessile, and inserted spirally in six or 
 seven rows ; their fruit consists of peltate scales. They have been found 
 in the Trias, Lias, Oolite, and Wealden. 
 
 Cupriferous (Lat. cuprum, copper, and/jro,. I bear). Applied to veins, 
 rocks, and other matrices containing the ores of copper, or copper in the 
 native or metallic state. 
 
 Cuprite (Lat. cuprum, copper). A mineralogical term for the red oxide 
 of copper, known also as octahedral copper ore, from the form of its crystals, 
 which are usually attached and combined in druses. It also occurs in 
 granular or compact aggregates,, has a metallic-adamantine lustre, a co- 
 chineal or shining red colour-; and consists of 88.5 copper and 11.5 
 oxygen. It is found in beds or veins, in granite, in the crystalline schists 
 and transition rocks, and usually along with other ores of copper, blende, 
 galena, and pyrites. 
 
 Cuproplumbite (Lat. cuprum, copper; plumbum, lead). Literally copper- 
 lead, a massive-granular grey ore with a cubic cleavage, chiefly obtained 
 from Chili, and consisting of 64.9 lead, 19.5 copper, 0.5 silver, and 15.1 
 sulphur. 
 
 Cursores (Lat. curro, I run). Runners or Coursers. An order of birds, 
 so named from the peculiar adaptation of their legs and feet for running. 
 The order includes the ostrich, emu, cassowary, and apteryx, in all of 
 which the wings are merely rudimentary and unfitted for flight. Eemains 
 of gigantic cursorial birds (Dinornis, Epiornis, &c.) have been found 
 in the Upper Tertiary and Newer Pleistocene formations. 
 
 Cuspidate (Lat. cuspis, a spear). Spear-shaped ; tapering abruptly to a 
 stiff short point, in contradistinction to lanceolate, which indicates a slen- 
 der and slowly tapering form. 
 
 Cutters. A quarryman's term for any narrow crack or fissure that cuts 
 164 
 
CYA CYC 
 
 or crosses the strata; hence "backs and cutters," for what is known to 
 geologists as the jointed structure. 
 
 Cyanite (Gr. Jcyanos, azure blue). One of the Garnet family, occurring 
 in broad prismatic crystals, chiefly in mica and talc schists, and so called 
 from its prevailing azure-blue colour. Transparent blue cyanite is often 
 polished and substituted for sapphire, but is easily known from its inferior 
 hardness. 
 
 Cyanose, Cyanosite (Gr. kyanos, azure blue). Sulphate of copper, or 
 blue vitriol, a well-known substance, occurring in nature as a secondary 
 production from copper pyrites, or from iron pyrites containing small 
 quantities of copper, but more frequently prepared artificially either by 
 the roasting and lixiviation of pyrites and other copper ores, by treating 
 these or metallic copper with sulphuric acid, or as a residuary product of 
 metallurgic operations. Used as a pigment and dye-stuff. 
 
 Cyathiform (Gr. cyathos, a cup, and forma, likeness). Oup- shaped ; 
 having the form of a cup, as certain flowers, polypes, corals, &c. 
 
 Cyathophyllum (Gr. cyathos, a cup or goblet, and phyllon, leaf). A 
 genus of cup-corals, having a turbinated polyparium or calcareous axis, 
 simple or compound, and internally lamellated ; the cells polygonal, radi- 
 ated, and depressed or cup-like in the centre ; whence the name. They 
 are extremely abundant in Silurian strata, in the mountain limestone, and 
 in the coral-rag of the Oolite. The simple turbinated forms are often of 
 considerable size (the turbinolia of early authors), and from their shape are 
 known by the familiar term of " petrified ram's-horns." 
 
 Cycadeoidea. Literally cycas-like ; a term which implies merely general 
 resemblance, without hazarding any opinion as to absolute identity. A 
 genus of roundish or oblong stems, covered with densely imbricated scales, 
 and greatly resembling those of the cycas. They are found in the Lias, 
 Oolite, and Wealden strata, and afford evidence of a warm genial climate 
 in the latitudes where they occur. See MANTELLIA. 
 
 Cycadftes. Fossil plants of the younger Secondary epochs Oolite and 
 Chalk apparently allied to the existing cycas. The leaves only are known, 
 and these are pinnated ; leaflets linear, entire, adhering by their whole 
 base, having a single thick midrib and no secondary veins. 
 
 Cyclas (Gr. kuklos, a circle). A genus of fresh- water bivalves, having 
 oval, transverse, equivalved shells, with the hinge-teeth very small ; the 
 substance of the shell thin and fragile. The species occur recent, and in 
 the Tertiary and Wealden formations. In the older formations many 
 organisms formerly regarded as Cyclas are now known to be Estheria, a 
 bivalved entomostracous crustacean, which see. 
 
 Cycle (Gr. kuUos, a circle). Literally a circle of time, like the revolution 
 of the year and seasons ; a periodical or recurrent space of time. Often 
 loosely employed for periods of indefinite duration. 
 
 Cyclocladia (Gr. kuklos, circle, and Mados, branch). A name given to 
 certain Coal-measure plants, consisting of detached whorls of circular 
 leaf-scars, each scar being about half an inch in diameter, and deeply 
 pitted. 
 
 Cycloid, Cycloidean (Gr. JcuUos, a circle, and eidos, form). The fourth 
 order of Fishes in Agassiz's arrangement. They are distinguished by their 
 scales, which are rounded, smooth and simple at the margin, and often 
 ornamented with various figures on the upper surface : these scales are 
 composed of laminae of horn or bone, but have no enamel. The Cycloi- 
 
 165 
 
CYC CYP 
 
 deans are chiefly Tertiary and recent species ; the salmon and herring are 
 examples. See ICHTHYOLOGY. 
 
 Cycl6ne (Gr. kuklos, a circle). A term applied by navigators to those 
 rotatory hurricanes which occur most frequently between the equator and 
 the tropics, and near the equatorial limit of the trade-winds. They sweep 
 round and round with a progressive motion, their course describing a 
 curve, and their violence being greater the narrower the limit of their whirl. 
 In both hemispheres the rotation of a cyclone is contrary to that of the 
 sun ; those in the northern hemisphere moving counter, so to speak, to the 
 motion of a watch-hand, those in the southern following that motion. 
 
 Cycl6pteris (Gr. Icuklos, a circle, and pteris, fern). An extensive genus of 
 fern-like plants, ranging from the Devonian to the Oolite inclusive ; and 
 so called from the rounded or circular shape of their leaflets, which are 
 entire, have no midrib, but are thickly marked with dichotomous veins 
 which radiate from the base to the margin. 
 
 Cymbiform (Lat. cymba, a boat, and forma, likeness). Boat-shaped ; 
 navicular ; having the form of a boat or skiff ; as many shells, the glumes 
 of grasses, &c. 
 
 Cymophane (Gr. Jcuma, a wave, and p/iaino, I appear). The name given 
 to those semi-transparent varieties of chrysoberyl which display a peculiar 
 milky or opalescent appearance. When cut en cabochon they exhibit a 
 white floating band of light ; hence the name. 
 
 Cynochampsa (Gr. Jcyon, dog, and champsai, crocodile). A genus of 
 Crocodilian reptiles, founded by Professor Owen on remains from the sand- 
 stone rocks of Rhenosterberg, South Africa ; and so named from the large 
 carnivorous-looking canines that arm the long slender jaws which termin- 
 ate, as in Teleosaurus, in a single nostril. 
 
 Cyperites (cyperacece, the rush tribe). Long, narrow, ensiform leaves 
 which occur in the Coal-measures, and so called from their general resem- 
 blance to those of the Cyperus. According to Lindley, cyperites, as a genus, 
 is distinguished by the want of a midrib, and by the presence of parallel 
 lateral veins. 
 
 Cyprse'idse (Lat. Cypris, a name of Venus). The Cowry family, including 
 the genera Cyprcea, Erato, and Ovulum. The Cowries or Porcelain shells 
 are carnivorous gasteropods inhabiting the shores of warm seas, and are 
 well known from their convolute, enamelled, and often spotted, barred, 
 and otherwise ornamented shells. In the young the spire is apparent, but 
 in the adult shell it becomes concealed by the last whorl enveloping all the 
 others. They occur fossil from the Chalk upwards, but are not known be- 
 fore that period. 
 
 Cypridina-Schiefer. Slaty bands of limestone occurring, in Belgium and 
 Germany, on the uppermost verge of the Devonian system ; and so termed 
 from their containing as their most characteristic fossil the small crustacean 
 Cypridina serrato-striata. The " Cypridina-Schiefer" is regarded by M. 
 Sandberger and Sir R. Murchison as the typical rock of the Upper 
 Devonians of the Rhine district. 
 
 Cyprinoid (cyprinus, a carp, and eidos, likeness). Carp-like ; applied to 
 many species of small fossil fishes which occur in the fluviatile and lacus- 
 trine deposits of the Tertiary formation, and which, like the living carps, 
 seem to have inhabited fresh waters, or the brackish waters of estuaries. 
 Beautiful specimens are obtained from the Tertiary beds of (Eningen 
 and the marls of Aix the latter locality also yielding vast numbers of 
 
 166 
 
CYP DAM 
 
 Cyprinodonts, the recent species of which are also small fishes, inhabiting 
 the fresh-water lakes of temperate zones. 
 
 Cypris, Cyprididse. A genus and family of minute crustaceans, having 
 two enveloping crusts like those of a bivalve shell, but united by a dorsal 
 fold without hinge. They inhabit the waters of lakes, marshes, and 
 estuaries ; moult or renew their integuments yearly ; and are variously 
 termed and divided by zoologists. Fossil forms under the generic terms of 
 Cypris, Cypridea, Cypridina, Cyprella, and Cypridella, occur in all rocks 
 from the Lower Coal-measures upwards. 
 
 Cystidese (Gr. cystis, a bladder). A family of Silurian echinoderms, so 
 called from their spherical or bladder-like form : the sphceronites of earlier 
 authors. They constituted, in the primeval seas, the representatives of 
 the sea-urchins of the Secondary, Tertiary, and current epochs ; and appear 
 to have been sessile, or furnished with a short jointed foot-stalk, and not 
 to have been free-moving, like the cidaris and echinus. According to E. 
 Forbes, they have affinities with the Crinoids on the one hand (some pos- 
 sessing very perfectly formed arms and tentacles), and with the Sea- 
 urchins on the other ; while others also point out affinities to the Pen- 
 tremites of the mountain limestone. The more frequent genera are 
 JEchinosphcerites, Pseudocrinites, Caryocislites, Hemicosmites, Echino-encrinus, 
 and Cryptocrinites. See CYSTOIDEA. 
 
 Cystiph^Uum (Gr. cystis, a bladder, and phyllon, leaf). A genus of 
 Silurian turbinated corals, externally striated, and internally composed of 
 small bladder-shaped cells, hence the name. 
 
 Cystoidea. Under this title the Cystidece (which see) have been erected 
 by Von Buch and others into a small independent group or " order" of 
 echinoderms. Their leading characteristics are " a globular body covered 
 with close-fitting polygonal plates and attached by a simple jointed stem ; 
 mouth miriute and opposite to the stalk ; close to it is the small anal 
 opening ; and a little more distant the generative orifice, covered by a 
 pyramid of five or six little valves. Some genera, like Pseudocrinus, have 
 two or four tentaculiferous arms, bent down over the body and lodged in 
 grooves to which they are anchylosed ; others, like Sphceronites, have only 
 obscure indications of tentacles situated close to the mouth." 
 
 Cytheridae. A family of Entomostraca, or minute bivalve crustaceans, 
 occurring in every formation ; but most abundantly in the genera Cythere, 
 Cythereis, and Cytherella in the Chalk and older Tertiaries. There are 
 doubts as to the precise affinities of the so-called Palaeozoic species. 
 
 Dad6xylon (Gr. ) Literally "pine or torch- wood;" Endlicher's generic 
 term for fossil wood whose structure is apparently identical with that of 
 the living species of Araucarise; same as A raucarites, which see. Wood 
 of this structure is common in the Lias, Oolite, Wealden, and Chalk. 
 
 Damps. A miner's term for the gaseous products that are eliminated in 
 coal-mines carbonic acid being choke-damp, from its extinguishing life 
 and flame, and light carburetted hydrogen being fire-damp, from its 
 exploding when brought in contact with flame. 
 
 167 
 
DAP DEA 
 
 Dapedius (Gr. dapedon, a pavement). A genus of ganoid fishes peculiar 
 to the Lias, and so named from the arrangement of the rhomboidal scales 
 resembling a tesselated pavement. The Dapedius is a wide, laterally-com- 
 pressed fish, with a rounded head, fins of moderate size, and body rapidly 
 contracting, and terminating in an equally-lobed tail. The mouth is fur- 
 nished with several rows of small conical teeth, crenated at their summits, 
 and has brush-teeth on the palatine bones. 
 
 Darwinite. An arseniate of copper occurring in thin veins in the por- 
 phyritic claystones of Chili and Peru, and named after Darwin in honour 
 of his geological researches in South America. It is found massive, of a 
 dark silver-grey, high metallic lustre, rather brittle, and consists of 88.07 
 copper, 11.69 arsenic, and 0.24 silver. 
 
 Dasyceps (Gr.) Literally "rough-head;" a provisional genus of laby- 
 rinthodont reptiles occurring in the Bunter Sandstein or Permian forma- 
 tion of Warwickshire. Beyond the cranium and teeth nothing further is 
 yet known of the genus. 
 
 Dasypus (Gr. dasys, hairy or rough, and pous, a foot). The zoological 
 term for the Armadilloes, in allusion to the common character of their 
 feet, the soles of which are covered with strong hairs, and on which they 
 walk, with their claws expanded. The armadilloes are edentate, that is, 
 possess only grinders ; are covered with a cuirass composed of strong 
 horny rings ; are nocturnal, live in burrows, and prey alike on animal and 
 vegetable substances. They inhabit the warmer parts of South America, 
 in the Upper Tertiaries of which are found the remains of the Glyptodon, 
 and other extinct congeners. 
 
 Datholite or Datolite. A siliceous borate of lime, forming one of the 
 Fluor-spar family, and occurring in various formations, in druses and in 
 coarse granular masses. It consists of 38.3 silica, 21.5 boracic acid, 34.6 
 lime, and 5.6 water. 
 
 Dank or Dawk. A mining and quarry term for bands and beds of 
 tough, compact, sandy clay. See DOUK. 
 
 Davite. In honour of Sir Humphrey Davy. A native sulphate of alu- 
 mina, of a yellow or greenish-yellow colour, and nauseous and highly as- 
 tringent taste. It occurs as a deposit from certain thermal springs, con- 
 taining free sulphuric acid, near Bogota in the Columbian Andes. 
 
 Davy-Lamp. A form of lamp invented by Sir Humphrey Davy, and now 
 extensively used in coal-mines subject to explosions of fire-damp. The 
 principles involved in this invention are first, that no mixture of fire-damp 
 with common air, however dangerous, conveys an explosion through tubes 
 or openings, the diameter of which is less than about one-eighth of an inch ; 
 and secondly, that these explosive mixtures need a much stronger heat 
 for their explosion than mixtures of common inflammable gas, since neither 
 charcoal nor iron at a red-heat will produce this effect, which requires, 
 indeed, that iron be raised to a white heat. Proceeding upon these prin- 
 ciples, the light of a lamp is surrounded by wire-gauze, the meshes of 
 which are from & to ^V of an inch ; and through these, any explosions that 
 may take place inside the lamp are not communicated to the outside, so 
 that the miner can pursue his calling with the light of a " Davy " in 
 workings which would otherwise be unapproachable. There are several 
 modifications of the Davy -lamp ; but in all, the fundamental principles 
 are the same. 
 
 Deads. In mining, any vein-stone or mine-stuff, broken underground, 
 163 
 
DEB DEI 
 
 that does not contain enough of ore to make it worth removing for dress- 
 ing ; mine waste ; mine rubbish. 
 
 Debacle (Fr. deader, to unbar). A term originally signifying the 
 breaking-up of the ice on a river a freshet ; but now applied to any sud- 
 den flood or rush of water which breaks down opposing barriers, and 
 hurls forward and disperses blocks of stone and other debris. 
 
 Debris (Fr., wreck or waste). A convenient term, adopted from the 
 French, for any accumulation of loose material arising from the waste of 
 rocks ; also for drifted accumulations of vegetable or animal matter. 
 
 Decapoda (Gr. deJca, ten, and pous, podos, foot). Literally ten-footed ; 
 the highest order of Crustacea, including all the stalk-eyed families, in 
 which the whole of the thoracic segments are united with those of the 
 head into a single piece (the cephalo'thor.ax), encased in a common crust, 
 with no traces of segmentary division (the carapace) ; and which have the 
 branchial organs enclosed within a cavity on each side the cephalo-thorax. 
 The true thoracic legs are almost always ten in number, whence the name 
 of the order. The order includes three subdivisions the Macrura, or long- 
 tailed, such as the crayfish ; the Brachyura, or short-tailed, as the common 
 crab ; and the Anomura, or tailless, as the hermit-crab. 
 * Decomposition (Lat.) Literally " set free from composition : " the reso- 
 lution of compounds into their elements, or the alteration of their chemical 
 constitution in such a manner that new products are formed. Thus, we 
 speak of decomposing granite, when its particles of quartz, felspar, and 
 mica fall asunder under the action of the atmosphere ; and of the further 
 decomposition of the felspar when it becomes converted into clay, and the 
 soda, potash, and iron with which the clay was combined are set free. 
 
 Dec6rticated (Lat. de, from off, and cortex, the bark). Having the bark, 
 skin, husk, or other integument removed or stripped off. Thus, many 
 fossil plants have their bark converted into a thin pellicle of coal, and 
 accordingly their leaf-scars or external sculptures present very different 
 aspects according as the specimens retain their bark or are decorticated. 
 
 Decrepitate (Lat. de, and crepito, to make a crackling noise). To fly in 
 particles with a crackling noise when exposed to heat, as common salt and 
 many other mineral substances do when they thus part with their water 
 of crystallisation. 
 
 Deflagration (Lat. de, from, and flagro, to burn vehemently). The 
 sudden combustion of any substance for the purpose of producing some 
 change in its composition by the joint action of heat and oxygen. The 
 process is commonly performed by projecting into a red-hot crucible, in 
 small quantities at a time, a mixture of about equal parts of nitre and the 
 body to be oxidised. 
 
 Degradation (Lat. de, down, and gradus, step). Kemoving or wasting 
 down step by step. The degradation of hills and cliffs is caused by atmos- 
 pheric and aqueous agency ; hence water is said to exert a degrading in- 
 fluence on the earth's crust ; waves and tidal currents a degrading action 
 on certain sea-shores. It is usual to arrange degrading causes or agencies 
 into three sets the atmospheric, or those connected with the atmosphere ; 
 the fluviatile, or those depending on rivers ; and the oceanic, or those in 
 which the ocean is the immediate agent. 
 
 Dein6rnis, Dinornis (Gr. deinos, terrible or monstrous, and ornis, bird). 
 A gigantic cursorial bird, whose remains (fragments of eggs as well as 
 numerous bones) have been discovered, in a sub-fossil state, in the river- 
 
DEI DEL 
 
 silts of New Zealand. The affinities of the Dinornis, or Moa of the natives, 
 are not yet clearly defined, though, according to Owen and Mantell, it has 
 evidently been a wingless cursorial bird of great size and strength varying 
 from ten to fourteen feet in height, or considerably larger than the existing 
 ostrich, and occurring in several well-marked species. The epoch of the 
 Dinornis is strictly Post-Tertiary, and the traditions of the natives would 
 indicate its contemporaneity with the Apteryx and Notornis wingless 
 birds which still inhabit these islands. The Palapteryx, Aptornis, &c., 
 are sub-fossil congeners, found in the same deposits. See Mantell's ' Petri- 
 factions and their Teachings ; ' and Owen in ' Zoological Transactions' for 
 1844-1850. 
 
 Deinosaiirians, Dinosaur (Gr. deinos, monstrous; saurus, lizard). Liter- 
 ally " fearfully -great lizards ; " a term employed by Professor Owen to desig- 
 nate an order of terrestrial reptiles peculiar to the upper Secondary for- 
 mations, and comprising the Iguanodon, Megalosaurus, and Hylceosaurvs, 
 which see. As an order, the Dinosauria are characterised by their free 
 vertebrae being flat at both ends, but in some species the cervical become 
 convex in front and concave behind. The limbs are ambulatory, strong, 
 long, and unguiculate ; and the femur has, in some, a third trochanter. 
 The species are of great bulk, and eminently fitted for terrestrial life 
 some being vegetable-feeders, like iguanodon, and others, like megalosaur, 
 being carnivorous. ('British Association Report on Fossil Reptiles,' 1841 
 and 1859 ; Dr Mantell's various works.) 
 
 Deinotherium (Gr. deinos, terrible, and therium, wild beast). A huge 
 proboscidean mammal found in the Miocene Tertiaries of Europe and 
 Asia. The zoological position of the dinothere (of which there seem to be 
 several species) is not yet distinctly ascertained the skull, molar teeth, 
 scapular bone, and pelvis being the only portions yet discovered. From 
 these it appears that the animal was furnished with a short proboscis like 
 the tapirs ; lived on vegetable food, like the tapirs and lamantins ; and had 
 the lower jaw armed with two enormous tusks, depressed downwards, and 
 gently curved inwards. Professor Kaup regards the Dinothere as inter- 
 mediate between the mastodons and tapirs, and truly terrestrial ; MM. 
 Blainville and Pictet consider it a herbivorous cetacean which inhabited 
 the embouchures of great rivers, and uprooted with its tusks the marsh 
 and aquatic plants which constituted its food ; while M. Solaro, who has 
 recently discovered the pelvis of the animal (nearly 6 feet in diameter, by 
 4 feet 3 inches in height) in the deposits of the Haute Garonne, believes it 
 to have been marsupial and of true terrestrial habits. "The adult denti- 
 tion of Deinotherium (according to Dr Falconer) is characterised by two 
 vertically succeeding premolars, and three true molars five teeth in all, 
 with transverse crenulated ridges closely resembling those of the tapir ; 
 and by two huge inferior recurved incisors, implanted in an enormously 
 thickened and deflected beak, or prolongation of the symphasis of the 
 lower jaw." 
 
 Delesserites. A genus of fossil Algse (chiefly Tertiary), so named by 
 Sternberg from their resemblance to the existing Delesseria, which has 
 thin, flat or undulated, smooth, membraneous fronds, with a median rib. 
 
 Deliquescence (Lat. deliquesco, to melt away, to become liquid). The 
 property of certain salts, acids, and alkalies, to become liquid by their 
 gradual absorption of moisture from the atmosphere. Such salts, &c., are 
 said to be deliquescent. 
 
 170 
 
DEL DEN 
 
 Delphinidse (Lat. delphinus, a dolphin). The Dolphin family; a tribe of 
 cetaceans distinguished from the true whales chiefly by the more propor- 
 tionate size of the head, which in general is about one-seventh of the 
 entire length of the animal. The family includes the dolphins proper, 
 with long slender snouts and numerous conical teeth ; the porpoises ; the 
 narwhal, &c. Found fossil in the later Tertiary and Post-Tertiary strata. 
 
 Delta. The alluvial land formed at the mouth of a river, such as that 
 of the Nile, which received this name from the resemblance of the space 
 enclosed by the two main branches of the river to the Greek letter A, 
 delta. The deltas of many existing rivers, such as the Mississippi, Niger, 
 Ganges, &c., present the inquirer with the most instructive, perhaps, of 
 geological phenomena exhibiting in their magnitude, the variety of their 
 composition, alternation of their beds, and the entombment of plants and 
 animals, the perfect analogues of many of the older formations. Deltic. 
 Of or belonging to a delta. Deltoid. In the form of the Greek letter A ; 
 resembling a delta. 
 
 Dendrachate (Gr. dendron, tree, and achates, agate). Arborescent agate ; 
 moss-agate ; agate exhibiting in its sections the forms or figures of vege- 
 table growths. 
 
 Dendrerpeton (Gr. dendron, a tree, and erpeton, a lizard). A small 
 lizard-like reptile, discovered by Mr Dawson and Sir C. Lyell in the 
 Lower Coal-measures of Nova Scotia ; so named from its being found in the 
 interior of a fossil trunk, and thence supposed to have been cf arboreal 
 habits. 
 
 Dendritic (Gr. dendron, a tree). Applied to certain branching moss-like 
 appearances which occur on the surfaces of the fissures and joints in rocks. 
 They are apt to be mistaken for fossil vegetation, but are strictly inor- 
 ganic, and of chemical origin as much so as the dendritic frost-work of a 
 winter's night on the surface of a window-pane. 
 
 Dendrodonts (Gr. dendron, a tree, and odous, tooth). An extinct family 
 of fishes, characteristic of the Old Red Sandstone or Devonian system ; 
 and so called from the section of their seemingly simple conical teeth, 
 which presents numerous fissures radiating or spreading like the branches 
 of a tree from a central mass of " vasodentme," or vascular uncalcified 
 tissue. 
 
 Dendrolite (Gr. dendron, tree, and lithos, stone). Fossil wood ; a gene- 
 ral term for any fossil stem, branch, or other fragment of a tree. 
 
 Density (Lat. densus, thick, set close). That property of bodies which 
 relates to the comparative compactness or closeness of their component 
 particles or molecules bulk for bulk, the denser being the heavier. As 
 gravity is thus in proportion to density, the specific gravity of bodies is 
 taken as the measure of their densities. See GRAVITY, SPECIFIC. 
 
 Dental Formula. A notation now generally used by zoologists to denote 
 the number and kind of teeth of a mammiferous animal the teeth forming 
 one of the elements in its generic character. Thus, the dental formula of 
 Man is, incisors f ; canine }, { ; premolars, f , \ ; molars, f , f = 32 ; or 
 placing them as they occur on each side of the incisors, f, f, 1, |, }, |> 
 which signifies that there are 4 incisors in either jaw, with 1 canine, 2 
 premolars or false molars, and ft molars on either side of these incisors, 
 both in the upper and in the lower jaw. In other words, the incisors 
 being taken as the centre, the upper figures refer to the upper jaw in either 
 side, and the lower figures to the lower jaw. See TEETH. 
 
 171 
 
DEN DES 
 
 Dentine (Lat. dens, tooth). The tissues that compose the teeth inverte- 
 brate animals are arranged by anatomists into dentine, which forms the 
 body of the tooth ; cement, which forms the outer crust ; and enamel, which 
 (when present) is situated between the dentine and cement. 
 
 Dentition (Lat. dens, a tooth). The period at which the teeth of mam- 
 malia makes their first appearance through the gums ; also the character 
 and arrangement of the teeth in different families, which becomes a most 
 important aid to the paleontologist in the discrimination of fossil species. 
 Denudation (Lat. de, down, and nudus, naked). Laying bare by re- 
 moval. The removal of superficial matter, so as to lay bare the subjacent 
 strata, is an act of denudation ; so also the removal by water of any for- 
 mation, or part of a formation. We thus speak of denuded rock-surfaces, 
 and of strata destroyed or removed by denudation. Before a current of 
 water can lay down a quantity of matter in one place, it must manifestly 
 take it up from another ; hence, as a geological operation, denudation 
 must accompany and precede deposition. 
 
 Deoxidised, Deoxidated. Literally, " deprived of oxygen;" disunited 
 from oxygen. 
 
 Deposit (Lat. de, down, and positus, placed). Applied to matter which 
 has settled down from suspension in water. Mud, sand, &c., are deposits, 
 so also are the shales, sandstones, &c., of older date. Deposits are usually 
 distinguished by the positions in which they occur, or by the agencies con- 
 cerned in their formation, as fluviatile, lacustrine, estuary, marine, &c. 
 The deposition of rock-matter is going forward less or more rapidly in all 
 waters on the surface of the globe. 
 
 Derby-Spar. A familiar name for fluate of lime or fluor-spar, from its 
 occurring abundantly in the Derbyshire limestones^ See FLUOR-SPAR. 
 
 Dercetis (Gr., a sea-god, so termed from his glittering scales). A ganoid, 
 eel -like fish of the Chalk formation, belonging to the family of Plectognathi, 
 and known to the quarrymen as "petrified eel." In Dercetis the body is 
 very elongated (often two and three feet long) ; the head short, with a 
 pointed beak, the upper jaw being a little longer than the lower ; and both 
 jaws armed with long, conical, elevated teeth, and several rows of very 
 small ones. On each side of the fish there are three rows of osseous scutes 
 like those of the sturgeon the rest of the body being also covered with 
 small scales. 
 
 Dermal (Gr. derma, the skin). Belonging to the skin ; hence we speak 
 of the dermal or enveloping integuments of plants and animals. 
 
 Dermo-Skeleton (Gr. derma, the skin). The hard integument which 
 covers and affords protection to most invertebrate, and also to many verte- 
 brate animals ; the external or " exo-skeleton," in contradiction to the in- 
 ternal or true bony skeleton of the higher animals. It makes its appear- 
 ance as a tough coriaceous membrane, as shell, crust, scales, horny scutes, 
 &c. ; but never as true bone. 
 
 Desert. In geography, applied somewhat loosely to any waste and un- 
 inhabited tract of land ; but strictly and more especially to wide, open, 
 and comparatively barren tracts, as the Deserts of Africa, Arabia, and 
 Central Asia, which are arid, sandy, and shingly ; the desert steppes of 
 Northern Asia, which are partly barren and partly covered with rough 
 grasses ; and the desert plains of Australia, which are scrubby and waterless. 
 Desiccation, Desiccation Cracks (Lat. de, and siccus, dry). The drying 
 of solid bodies by the evaporation of whatever moisture they may contain. 
 
 172 
 
DET DIA 
 
 Thus clay and clayey beds are desiccated by the sun's heat, and as they be- 
 come dry they shrink and crack in all directions. Were such beds to be 
 overlaid by a new deposit of mud or other soft matter, portions of it would, 
 enter these cracks, and the two strata, on being separated (after consolida- 
 tion) would present the lower the "mould," and the upper the "casts" 
 of these fissures. Such appearances are frequent among the strata of all 
 formations, are known as desiccation cracks, and. are not to be confounded 
 with "joints," "cleavage," and similar phenomena. 
 
 Detritus (Lat. de, down, and tritus, rubbed or worn). An appropriate 
 term for accumulations arising from the waste or disintegration of exposed 
 rock-surfaces. Detrital matter may thus consist of clay, sand, gravel, 
 rubbly fragments, or of any admixture of these, according to the nature 
 of the rocks and the amount of attrition to which their particles have been 
 subjected. 
 
 Devil's Toe-nails. A familiar term in some districts of England for the 
 Liassic shell, Gryphcea incurva, whose form somewhat resembles a distorted 
 toe-nail. 
 
 Devonian. A common, but not always appropriate synonyme of the 
 Old Red Sandstone, portions of which are extensively developed in Devon- 
 shire. The term was introduced by Sir R. Murchison (and harmonises 
 with his " Silurian," " Permian," &c.), "because the strata of that age in 
 Devonshire lithologically very unlike the Old Red Sandstone of Scotland, 
 Hereford, and the South Welsh counties contain a much more copious 
 and rich fossil fauna, and were shown to occupy the same intermediate 
 position "between the Silurian and Carboniferous rocks." See OLD RED 
 SANDSTONE. 
 
 Devonite. A name given by Dr Thomson to Wavellite, a phosphate of 
 alumina originally discovered by DrWavel in the north of Devonshire. 
 See WAVELLITE. 
 
 Dextral (Lat. dexter, belonging to the right hand right-handed). This 
 term is usually applied to spiral shells whose whorls, when the mouth is 
 placed towards the observer, turn from left to right ; and this is the general 
 course in nature. Sinistral or reversed shells are those whose spires turn 
 from right to left. In other words, when spiral shells are placed vertically 
 with the spires uppermost, and the mouth towards the observer, the aper- 
 ture in dextral shells is towards the rigkt ; in sinistral it is towards the left. 
 
 Diabase. A term adopted from the French, and occasionally applied to 
 those greenstones whose constituents are hornblende and felspar; same 
 as Diorile. 
 
 Diaclasite (Gr. dia and Jdao, to cleave through). A laminated or bladed 
 mineral with the pale colours of diallage passing into brass yellow, but in 
 composition intermediate between diallage and hypersthene. 
 
 Diallage (Gr. diallage, interchange). A siliceo-magnesian mineral, hav- 
 ing a laminated or bladed cleavage, and so called from its changeable colour 
 forms diallage rock, and enters into the composition of serpentine. 
 Closely related to Schiller-spar, which see. 
 
 Diallogite. Manganese spai*, or red manganese; a carbonate of man- 
 ganese, occurring in crystallised druses, in columnar aggregates, or in 
 granular masses ; having a rose-red or flesh-red colour, and glassy pearly 
 lustre. It is found in various formations, but chiefly in veins in gneiss and 
 porphyry along with silver, galena, blende, haematite, and other ores. 
 
 Diamond (Gr. adamus, unsubdued). The diamond ; so called in allusion 
 173 
 
DIA 
 
 to its unparalleled hardness. The diamond is the most precious of known 
 gems ; and, chemically speaking, is carbon or charcoal in its pure and crys- 
 tallised form. This form is primarily that of a regular octahedron, but 
 of this there are numerous modifications ; and the crystals having often 
 curved faces, they more or less approximate to spheres. They occur loose 
 in alluvial sands and gravel ; or singly imbedded in a matrix of sandstone 
 in India, and of mica-slate in Brazil and South America. Geologically, 
 they have been found chiefly in India and Borneo, and the Brazils ; more 
 sparingly and in minor crystals in the Urals, in the Carolinas, and in 
 Mexico. The "Diamond Sandstone" of India, and which furnishes the 
 detritus in which most of the specimens are found, is apparently of Ter- 
 tiary or recent origin ; the age of the micaceous schists which yield the 
 diamonds of Brazil and the Urals is unknown. Diamonds are found of all 
 colours ; those which are colourless, or which have some very decided tint, 
 are most esteemed ; those slightly discoloured are the least valuable. 
 Diamonds are cut and polished only by their own dust or powder an art 
 known from remote antiquity in the East, but introduced into Europe only 
 about the end of the fifteenth century. They are cut chiefly into three 
 forms table, rose, and brilliant; the latter having the finest effect, but 
 requiring a greater sacrifice of bulk some crystals being reduced nearly 
 one half in weight by the operation. 
 
 Respecting the origin of the diamond, neither chemistry nor geology has 
 thrown much light on the subject. We know that it consists of carbon in 
 its purest and most concentrated form ; but whether this carbon is of 
 vegetable or of animal origin, or whether it may not be a purely chemical 
 elimination altogether apart from organic growth, science has not yet de- 
 termined. It is true that some observers have thought they detected traces 
 of vegetable structure in the ashes of the diamond, but their observations 
 have not been confirmed ; and none of the specimens containing foreign 
 matter have as yet given any hint of their origin. It has been remarked 
 that their occurrence in mica-slate does not favour the idea of their 
 immediate vegetable origin ; nor does their occurrence in a soft quartzose 
 sandstone indicate the operation of excessive heat. Indeed, their com- 
 bustible nature forbids the idea of intense heat in connection with their 
 formation ; and yet high heat under pressure, or a long- continued low heat 
 manifesting itself in chemical change, may have effected the crystallisation 
 of carbon in decaying organic matter. Unlike amber, however, diamonds 
 are never found in connection with vegetable or animal substances ; so 
 that the primary source of their carbon, as well as the cause of its subse- 
 quent crystallisation, remains a mystery. 
 
 Diamond Spar. A familiar term for corundum, which next to diamond 
 is the hardest known mineral. 
 
 Diaphanous (Gr. dia, through, and pkano, I appear). Applied to gems 
 and minerals that may be seen through ; transparent ; pellucid. 
 
 Diatoms, Diotomdcese (Gr. dia, through, and temno, to cut asunder). 
 In botany, a group of microscopic organisms, referred by Ehrenberg to 
 the animalcules, but by most naturalists of the present day to the algte ; 
 and so named from the genus dialonta, whose frustules are connected to- 
 gether by the angles so as to form a zigzag chain, which looks like a stem 
 cut into several portions. These frustules consist of a single cell, and 
 are invested with a siliceous epidermis ; hence deposits of these minute 
 
 174 
 
DIG 
 
 growths, or " microphytal earths," are siliceous, and unlike those of the 
 foraminifera, which are calcareous. See TKIPOLI, MICROPHYTES, &c. 
 
 Diceras (Gr. di, two, and Jceras, horn). A massive bivalve of the Upper 
 and Middle Oolites; belonging to the Chamidce or Clam-shells; and so 
 termed from its prominent umbones or beaks, which are twisted backward 
 in ram's-horn fashion, and furrowed externally by ligamental grooves. 
 There are several species in which the beaks are more or less spiral and 
 horn -like, and the valves less or more unequal. Diceras Limestone. A 
 division of the Oolite in the Alps, regarded by most geologists as the equi- 
 valent of the English "coral rag," and so called from its containing abun- 
 dantly the shells of the diceras. 
 
 Dichobune (Gr. dicha, divided in two, and bounos, a ridge). A genus of 
 anoplotheroid quadrupeds whose remains occur chiefly in the Eocene or 
 Lower Tertiaries of Europe ; so called from the deeply-cleft ridges of the 
 upper molars. 
 
 Dichodon (Gr. dicha, in two parts, and odous, odontos, a tooth). A Middle 
 Tertiary artiodactyle (even-toed) mammal, showing affinities, according to 
 Owen, to the Hog tribe among the non-ruminant section, and to the Camel 
 tribe among the ruminants; so called from the double crescent-shaped 
 lines of enamel on the upper surface of its true molars. 
 
 Dichroism (Gr. dis, twice; chroa, colour). The property by which a 
 crystallised body assumes two or more colours, according to the direction 
 in which light is transmitted through it ; hence the Dichroiie of Cordier, 
 a silicate of alumina and magnesia which exhibits three or more colours 
 along its chief axis. 
 
 Dicotyledonous (Gr. dis, double, and cotyledon, seed-lobe). A grand divi- 
 sion of the vegetable kingdom, comprising all those plants whose seeds 
 are composed of two lobes or seed-leaves. They are exogenous, or in- 
 crease by external layers of growth, and the venation of their leaves is 
 reticulated or net-like, and not in parallel order, as in monocotyledonous 
 endogens. See tabulations, "VEGETABLE SCHEME." 
 
 Dictyophyllum (Gr. dictyon, a net, and phyllon, leaf). Literally "net- 
 leaf ; " a provisional genus erected for the reception of all unknown fossil 
 dicotyledonous leaves which exhibit the common reticulated structure. 
 Dictyophylla have been found as low as the Trias and Permian. 
 
 Dicty6pteris (Gr. dictyon, net ; pteris, fern). A genus of Carboniferous 
 ferns established by Gutbier, for those forms possessing the general habit 
 of Neuropteris, but differing from it in having a somewhat radiate-retwi- 
 lile venation and no distinct midrib. 
 
 Dictyopyge (Gr. diktyon, net, andpyge, anus). A genus of ganoid fishes, 
 with smooth rhomboidal scales, heterocercal tails, and broad flowing fins, 
 from the Triassic coal-field of Virginia, and so named by Sir P. Egerton 
 from the net-like appearance of the large anal fin. The species vary from 
 four to six or eight inches in length. 
 
 Dicynodon (Gr. di, two; cyon, dog; and odous, tooth). Literally "two 
 canine teeth ;" a provisional genus of very peculiar reptiles occurring in a 
 sandstone, supposed to be of Triassic age, in Southern Africa. The princi- 
 pal remains yet found are the bones of the head, which seem to indicate a 
 gigantic type between the lizards and turtles. The eye orbits are very 
 large, the cranium flat, with nostrils divided as in lizards ; and the jaws 
 toothless, with the exception that the upper jaw possesses a pair of long 
 
 175 
 
DID DIM 
 
 tusks, implanted in sockets and turned downwards like those of the walrus 
 hence the name dicynodon. 
 
 Didelphys, Didelphidse (Gr. dis, two, and delphys, womb). The opos- 
 sum family, so termed from their external abdominal pouch or marsupium, 
 in which the foetus is placed after a very short period of uterine gestation, 
 and where it remains (as if in a second womb), suspended to the nipple by 
 its mouth until sufficiently matured to come forth to the open air. Re- 
 mains of didelphine animals occur as early as the Oolitic if not Triassic 
 formation. 
 
 Did^mium. One of the rarer metals, of whose properties little is yet 
 known, found along with lanthanum, in the ores of Cerium, which see. 
 
 Didymograpsus (Gr. didymos, twin or double, and grapsus). The twin 
 or double graptolite ; a common form in the Silurians of Wales and Scot- 
 land, having the stems or axes united in pairs. The cells are arranged in 
 single rows as in the common graptolite, but the axes are in twins, or two- 
 branched. 
 
 Die-Earth. A local term at Coalbrook Dale for the Wenlock shale, 
 because this stratum lies beneath all the mining ground of the district 
 the minerals " dying out," as it were, at this stage of descent. 
 
 Differentiate, Differentiation. In zoology, the vital functions are said 
 to be more and more "differentiated," when, instead of several functions 
 being performed by the same organ, each function is performed by an 
 organ specially devoted to it. " Differentiation " is, therefore, a mark of 
 higher organisation the higher the animal in the scale of being, the more 
 specialised is its organisation. 
 
 Digitate (Lat. digitus, a finger). Finger-shaped. Applied to bodies 
 whose parts expand in finger-like process ; e.g., the alcyonia, or " dead- 
 men's-fingers" of the sea-shore; the scorpion strombus, whose outer lip is 
 armed with strong finger-like spines ; the leaves of the horse-chestnut, &c. 
 
 Digitigrada (Lat. digitus, the toe, and gradus, a step). An extensive 
 tribe of the Carnivorous animals, as the lion, tiger, cat, weasel, &c., whose 
 feet are constructed for walking on the toes, and therefore capable of a 
 swift bounding motion, as compared with the slow shuffling walk of the 
 Plantigrades (bear, badger, &c.), that set down the entire phalanges of 
 the foot. 
 
 Diluvium, Diluvial (Lat. dis, asunder, and luere, to wash). Alluvium 
 (which see) has been described as the term usually applied to matter 
 brought together by the ordinary operations of water ; diluvium, on the 
 other hand, is regarded as implying the extraordinary action of water. 
 In this sense it was at one time restricted to those accumulations of gravel, 
 &c., supposed to have been the result of the Noachian deluge ; but it has 
 now a wider signification in geology, being applied to all masses apparent- 
 ly the result of powerful aqueous agency. 
 
 Diluvialists. Theorists who regard the boulder-clay, abraded and 
 polished rock-surfaces, ossiferous gravels, and similar superficial pheno- 
 mena, as the result of the Noachian deluge ; in other words, those who 
 ascribe to a universal deluge such superficial results as they cannot readily 
 reconcile with the ordinary operations of water now going on around 
 them. 
 
 Dimorphism (Gr. dis, two, and morplte, form). "It is sometimes sup- 
 posed," says Nicol ('Manual of Mineralogy'), "that each particular sub- 
 stance can crystallise only in one particular form or series of forms. 
 
 176 
 
DIM DIP 
 
 Mitscherlich has, however, shown that this is only partially true, and 
 that sulphur, for instance, which usually crystallises in the rhombic 
 system, when melted, may form monoclinohedric crystals. This property 
 is named dimorphism, and has been explained by its discoverer on the 
 principle that the form, and with it the other physical characters of a 
 body, depend not merely on the chemical nature of the atoms, but also on 
 their relative position. Hence the same chemical substance may form two, 
 or even more, distinct bodies or mineral species. Thus carbon in one 
 form is the diamond, in another, graphite ; and carbonate of lime appears 
 as calc-spar or as arragonite. Even the temperature at which a substance 
 crystallises influences its forms, and so far its composition, as seen in 
 arragonite, Glauber salt, borax, &c." 
 
 Dimyaria (Gr. dis, twice, and mus, a muscle). That division of the con- 
 ch if erous bivalves whose shells are closed by two adductor muscles, as the 
 common edible mussel. See CONCHIPERA. 
 
 Diopside (Gr. did, through, and opsis, appearance ; in allusion to its oc- 
 casional transparency). A variety or sub-species of augite, occurring in 
 various shades of greyish-green, and crystallised in broad columnar or 
 concentric lamellar aggregates. A similarly crystallised body has been pro- 
 duced by fusing silica, lime, and magnesia in due proportion. See AUQITE. 
 
 Dioptase (Gr. , capable of being seen through, in allusion to the natural 
 joints being visible by transmitted light). Emerald copper, or rhombo- 
 hedral emerald malachite ; occurring in fine emerald-green, transparent, or 
 translucent crystals, and consisting of 38.7 silica, 50 copper protoxide, 
 and 11.3 water. It is found in limestone veins in Tartary, and when first 
 brought to Europe was sold as emerald ; but may be distinguished by its 
 inferior hardness, and greater specific gravity. 
 
 Diorite (Gr. dioros, a clear distinction). A variety of greenstone, com- 
 posed of hornblende and felspar, and of a dark colour in consequence of 
 the disseminated plates of hornblende. It receives its name from being 
 unmistakable, in contradistinction to dolerite. 
 
 Dip. The inclination or angle at which strata slope or dip downwards 
 into the earth. This angle is measured, of course, from the plane of the 
 horizon or level, and may be readily ascertained by the common spirit- 
 level and plummet, or, as is usual among geologists, by a small pocket 
 instrument called the clinometer (which see). The opposite of dip is the 
 term rise; and either may be used, according to the position of the 
 observer. Thus, standing on the surface, we speak of a bed of coal dipping 
 to the south-; while at the bottom of the pit, the miner, looking at the 
 same bed, would say that it rose to the north. It is usual, on geological 
 maps, to indicate the direction of the dip by an arrow, and the line of 
 outcrop or strike of a stratum by a bold line the one being at right angles 
 to the other. See STRIKE. 
 
 Diplograpsus. Literally " double graptolite." That section of grapto- 
 lites in which the cells are arranged in two rows one on each side the 
 central axis, like the feathers on a quill. The diplograptolites have a 
 foliaceous appearance, and are presumed to resemble the existing Pen- 
 natula and Virgularia. See GRAPTOLITE. 
 
 Diplostylus (Gr.) Literally "double tail ;" a genus of small shrimp-like 
 crustaceans, from the Coal formation of Nova Scotia, and so named by Mr 
 Salter from the two pairs of appendages to the last segment, telson, or 
 tail-plate. 
 
 177 M 
 
DIP DIS 
 
 Diprion (Gr. dis, two, and prion, a saw). Literally "double saw." A 
 synonyme of diplograpsusthe serrated cells on each side the central axis 
 giving the organism the appearance of a double saw. 
 
 Dipr6todon (Gr. dis, two ; protos, first ; and odous, tooth). A gigantic 
 pachydermoid marsupial mammal from the Pleistocence or Upper Tertiary 
 beds of Australia ; and so termed from the large scalpriform character of 
 its incisors or front teeth. The head of a specimen now in the British 
 Museum measures three feet in length, and gives some idea of the immense 
 size of the creature, which, while nearly related to the kangaroo, has, 
 according to Owen, "osculant relationship with the herbivorous wombats." 
 The hind limbs are shorter and stronger, and the front limbs are longer 
 and stronger than those of the existing kangaroos. 
 
 Dipyre (Gr. dis, andpyr, fire). One of the Scapolite family, usually im- 
 bedded in slate or limestone, and occurring in rounded eight-sided prisms. 
 Consists of 55.5 silica, 24.8 alumina, 9.6 lime, and 9.5 soda; and is said 
 to derive its name "from its twofold susceptibility to the action of fire. 
 When heated before the blow-pipe it first becomes phosphorescent, and 
 then fuses." 
 
 Dirt-Beds. The name given to certain dark-coloured loam-like beds that 
 occur interstratified with the Oolitic limestones and sandstones of Port- 
 land evidently the soils in which grew the cycads, zamias, and other plants 
 of the period. " At the distance of two feet," says Mr Bakewell, lt we 
 find an entire change from marine strata to strata once supporting terres- 
 trial plants ; and should any doubt arise respecting the original place and 
 position of these plants, there is over the lower dirt-bed a stratum of fresh- 
 water limestone, and upon this a thick dirt-bed, containing not only 
 cycadese, but stumps of trees from three to seven feet in height, in an erect 
 position, with their roots extending beneath them. Stems of trees are 
 found prostrate upon the same stratum, some of them from twenty to 
 twenty-five feet in length, and from one to two feet in diameter." 
 
 Discous, Discoid (Gr. discos, a quoit, and eidos, likeness). Quoit- 
 shaped; in the form of a disc ; e.g., the shell of the planorbis. 
 
 Discrase, Discrasite (Gr. dis, twofold, and krasis, admixture). Antimon- 
 ide of silver, a rare ore, consisting of 76 silver and 24 antimony, and so 
 called in allusion to its composition. It occurs in hexagonal prisms, radiat- 
 ed forms, massive, disseminated, and in grains ; is of a silver and tin- white 
 colour ; metallic lustre, lamellar, brittle, but slightly malleable. It is 
 found in veins in the granitic and crystalline rocks, along with galena, 
 silver, iron-pyrites, and other ores. 
 
 Disintegration (Lat. dis, asunder, and integer, whole). The breaking 
 asunder of any whole or solid matter. The disintegration of rocks is caused 
 chiefly by the slow action of frosts, rains, and other atmospheric influences ; 
 and the facility with which some kinds are acted upon by these influences 
 depends partly on their chemical composition, partly on the aggregation 
 of their particles, and partly on the readiness with which they absorb 
 moisture. 
 
 Dislocation (Lat. dis, asunder, and locus, place or position). A general 
 term for any displacement of the stratified rocks from their original hori- 
 zontal or sedimentary position. Slips, Faults, and the like, are " dislo- 
 cations." 
 
 Disrupting (Lat. dis, asunder, and ruptus, rent or broken). When 
 igneous matter forces its way through the stratified rocks, and fills up the 
 
 178 
 
DIT DOD 
 
 rents and fissures so made, it is termed disrupting ; when, having passed 
 through the strata, it spreads over their surface in sheet-like masses, it is 
 said to be overlying ; and when these discharges have taken place at the 
 bottom of the sea, and have been in turn covered over by new deposits of 
 sediment, they then appear as interstratified. 
 
 Dithyr6caris (Gr. dithyros, having two valves, and cam, shrimp). A 
 genus of phyllopod crustaceans, first discovered by Dr Scouler in the coal 
 shales of Lanarkshire, and so named from its being enclosed, like the 
 existing genus apus, in a thin flattish bivalved carapace. The abdominal 
 portion, which is not enclosed in the carapace, consists of five or six 
 segments, and terminates, in a trifid tail like Ceratiocaris. 
 
 Divaricating (Lat. dis, asunder, and varico, I stride). Applied to roots, 
 branches, and other members that spread widely and decidedly from each 
 other. 
 
 Divining-Rod, Known also in Cornwall and Wales as the Do^osing-Rod. 
 A hazel-rod by the aid of which some persons pretend to be able to tell 
 where water and minerals lie below the surface by a process of divination. 
 The rod is balanced in the hands of the diviner in a peculiar way, and is 
 supposed to indicate the position of the substance sought, by turning 
 towards it with a slow rotatory motion. This superstition is occasionally 
 still practised, and passes under the learned names of Metalloscopy, 
 Hydroscopy, or JRhabdomancy the last of which see. 
 
 Divisional Planes. A technical term for those lines of separation which 
 traverse rock-masses, and divide them into blocks or fragments, more or 
 less regular. It is usual to speak of them as congenital, or those which, 
 like lamination and stratification, are formed at the same time as the rocks 
 themselves ; resultant, or those arising, like joints, from consolidation and 
 contraction ; accidental, such as fissures, faults, and veins ; and superin- 
 duced, or those which, like cleavage and foliation, are accompanied by a 
 change in the internal structure of the rocks themselves. 
 
 Doab. The name given in India to the tongue of land that lies between 
 the confluence of two or more rivers, as the doabs of the Punjab, or plains 
 that lie between the rivers of that region. 
 
 Dodo. An extinct gigantic bird belonging, as has been shown by MM. 
 Strickland and Melville in their monograph 'The Dodo and its Kindred' 
 to the order Columbse or Pigeons, and constituting the type of a new 
 family (the Dididce), to which several fossil species have been ascribed. 
 At the discovery of the island of Mauritius in 1598, the Dodo was still 
 abundant there, and formed a principal portion of the food of the inhabit- 
 ants ; but in the course of a few years it was completely extirpated by the 
 sailors, and its bones are now found only in the silt and tufaceous deposits 
 of that island. A few specimens were, however, brought to Europe in the 
 period which intervened between its discovery and its final destruction, 
 and from these several paintings were made, which, with two heads, a 
 foot, and a few feathers, are now the only proofs of the existence of a large 
 bird which was certainly living within the last two hundred years. The 
 Dodo is described as having been considerably larger than a swan, weighing 
 sometimes fifty pounds ; of a very bulky and heavy form ; having a strong 
 predaceous bill, hooked at the tip ; face or front of the head covered with 
 a naked skin ; feet short and stout, but resembling those of a pigeon ; 
 wings short, incapable of flight, and composed of soft tufty plumes like 
 those of the ostrich. The Solitaire, and other kindred species said to have 
 
 179 
 
DOG DRE 
 
 recently existed in the islands of the Mauritius, are in like manner extinct ; 
 and the nearest living approach to the family now known is the little 
 Didunculus of the Navigators' Islands. 
 
 Dog's-tooth. Spar. A familiar name given to to certain crystals of cal- 
 cite or calc-spar, from their fanciful resemblance to the tooth of a dog. 
 
 Doldrums. A sailor's term for the tropical zones of calms and variables 
 belts in which they are often detained for weeks by baffling calms, 
 storms, and rains. 
 
 Dolerite (Gr. doleros, deceptive). A variety of greenstone, composed of 
 felspar and augite ; so called from the difficulty of discriminating these 
 compounds. See DIORITE. 
 
 Dolichocephalic (Gr. dolichos, long, and Jcephak, the head). Long-headed ; 
 e.g., the dolichocephalic or long-skulled tribes of the human family. 
 
 Dolichosaurus (Gr.) Literally "long lizard;" a snake-like reptilian, 
 whose remains, found in the Chalk formation, indicate a creature from two 
 to three feet in length, and probably of aquatic habits. According to Pro- 
 fessor Owen, the Dolichosaurus presents somewhat of the ophidian charac- 
 ter in the number and size of its cervical vertebrae, in the size and shape of 
 its ribs, and in the slender proportions of its trunk and head ; but with 
 these partial exceptions, its affinities are truly lacertian. 
 
 Dolomite (after the French geologist Dolomieu). A crystalline, or 
 granule-crystalline, variety of magnesian limestone, occurring largely in 
 many Secondary formations, and often in the vicinity of igneous rocks, 
 whose heat seems, in most instances, to have been the proximate cause of 
 the superinduced crystalline texture. Ordinary magnesian limestone, 
 though occurring in all stages of compactness, is void of this crystalline 
 texture. See MAGNESIAN LIMESTONE. 
 
 Domite. A granular arenaceous-looking variety of trachyte found in 
 the Puy de Dome, Auvergne : hence the name. 
 
 Dorsal (Lat. dorsum, the back). Appertaining to the back; as the 
 dorsal vertebrae, or vertebra? of the back ; the dorsal fin, or back-fin, &c. 
 
 Douk, Dank, or Daugh (Sax. deaggan, to knead). Applied in mining to 
 beds or bands of hard, tough clay or clayey admixture ; generally without 
 lamination, and more or less compact and homogeneous, hence the idea of 
 daugh or dough. 
 
 Downs (Brit, dune, a hillock). Applied in the south of England to the 
 rounded, dry, and unwooded chalk hills of Kent, Surrey, Sussex, and ad- 
 jacent counties. These " downs " are described as " covered with a sweet, 
 short herbage, forming excellent sheep-pasture, generally bare of trees, 
 and singularly dry even in the valleys that wind for miles between them." 
 Applied also to the low hills of blown sand which skirt the shores of many 
 countries. 
 
 Dragons' Skin. A familiar term among miners and quarrymen for the 
 stems of Lepidodendron, whose rhomboidal leaf-scars somewhat resemble 
 the scales of reptiles in their form and arrangement. 
 
 Dreelite (after the Marquis de Dree). One of the heavy spars, generally 
 occurring as a whitish crystallised gangue or vein-stone in the lead-mines 
 of the mountain-limestone, and consisting essentially of sulphate of barytes 
 and sulphate of lime. According to Dufrenoy, a specimen from the lead- 
 mines of Nassiere yielded 61.73 sulphate of barytes, 14.27 sulphate of lime, 
 8.05 carbonate of lime, and 9.71 silica, with alumina and water. 
 
 Dressing. In mining, the " dressing of ores" consists in breaking, 
 180 
 
DRI DYK 
 
 stamping, and washing them so as to separate as much as possible of the 
 stony matrix from the metallic ore. 
 
 Drift. Literally, "that which is driven ;" as sand-drift, sand driven and 
 accumulated by the wind; drift-wood, wood carried down by rivers and 
 driven by tides and currents to distant shores. In geology the word is 
 frequently used as an abbreviated term for the "Glacial Drift," "North- 
 ern Drift," or " Dilluvial Drift" of the Pleistocene epoch. See GLACIAL 
 DRIFT. 
 
 Drift-Currents. The name given to oceanic currents which mainly de- 
 pend on the winds. The monsoons which prevail in the Indian Ocean give 
 rise to drift-currents, which set alternately in one direction and then in 
 another, according to the season of these winds. 
 
 Dromatherium (Gr. dromaios, swift- running, and therion, beast). The 
 name given to a small mammal, teeth, jaws, and detached bones of which 
 have been discovered by Mr Emmons in the Red Sandstones of Virginia 
 and North Carolina strata which, by some, are regarded as Triassic, and 
 by others as the equivalents of our European Permians. Supposed to be, 
 like amphitherium and phascolotherium, of marsupial affinity. 
 
 Drosdmeter (Gr. drosos, dew; metron, measure). Laterally "dew-meas- 
 urer ; " any apparatus or instrument for determining the amount of dew 
 deposited during a single night. "The most simple process," says Pro- 
 fessor Kaemtz, ' l consists in exposing to the open air bodied whose exact 
 weight is known, and then weighing them afresh after they are covered 
 with dew. According to Dr Wells, locks of wool, weighing five deci- 
 grammes, are to be preferred, which are to be divided into spherical 
 masses, of the diameter of about five centimetres." 
 
 Druse (Gr. drosos, dew). A mineralogical term for any hollow space in 
 veins of ore, or vesicular cavity in igneous rocks, like amygdaloid, that is 
 lined or studded with crystals literally " dewy with crystals ; " hence we 
 speak of drusy and sparry cavities. 
 
 Dryopithecus (Gr. dryos, a wood, and pithekos, ape). Literally "tree- 
 monkey ;" the generic term applied by M. Lartet (1856) to a large species 
 of monkey found in the Miocene beds of the south of France, and appa- 
 rently related to the modern long-armed apes (hylobates). It is supposed 
 to have been a frigivoreus, tree-climbing ape, equalling Man in stature. 
 
 Ductility (Lat. ductus, drawn out). The property which certain metals 
 possess of being drawn out into wire or thread-like filaments more or less 
 slender. Platinum, gold, and silver, are the most ductile of the metals 
 a single grain of gold being capable of being drawn into a wire nearly 600 
 feet in length ! 
 
 Dune (Brit., a hillock). Usually applied to hillocks of blown sand. 
 Sand-dunes, sand-drift, like that which, in so many places, skirts the 
 shores of our own island, Holland, and other countries. 
 
 Dunstone. A local term for certain magnesian limestones of a yellow- 
 ish dun or cream colour, occurring in the valley of the Derwent, near 
 Matlock, in Derbyshire. They are of a granular texture, extremely hard, 
 and rich in lead and calamine, for which they have been extensively 
 mined. 
 
 Dyke (Scot., a wall or fence). Applied to those wall-like intrusions of 
 igneous rock which fill up rents and fissures in the stratified systems. In 
 general they burst through and displace the strata, though occasionally 
 they merely fill up pre-existing rents and fissures. In dykes composed of 
 
 181 
 
DYS EAR 
 
 basalt and basaltic greenstone, the columnar structure is horizontal or at 
 right angles to the stratified walls of the rent or fissure which they occupy. 
 When the matter of the dyke is harder than the intersected strata, and 
 these have been subjected to waste and denudation, the igneous wall-like 
 mass may be traced for miles across a country ; and, on the other hand, 
 where the rock-matter of the dyke has been softer, its course may also be 
 traced by narrow wall-sided fissures and linear ditch-like depressions. 
 Both phenomena are well exhibited in the island of Arran. 
 
 Dysodile (Gr. dysodes, fetid, and ilys, mud). The name given to a bitu- 
 minous shale or Tertiary mud of a greenish-grey colour, composed of thin 
 papery laminae, and frequently containing the impressions of fish and 
 dicotyledonous leaves. Its bitumen is evidently of animal origin ; it burns 
 slowly with much smoke and flame, and emits a highly fetid odour ; hence 
 the name. 
 
 E 
 
 Eagle-Stone. The celites lapis of the ancients, fabled to have been 
 hatched in the nest of the eagle. A variety of nodular argillaceous iron- 
 ore, having a concentric structure, and occasionally so decomposed within 
 as to have a loose kernel which rattles on being shaken. This kernel was 
 known by the name of callimus, and was supposed to be the young in the 
 womb of the parent nodule ; hence the fable of the cetites bringing forth 
 young. When there is no internal kernel the nodule becomes simply a 
 geode, which see. 
 
 Ear-Bones. The tympanic or petro- tympanic bones of the higher osseous 
 and cartilaginous fishes, as well as those of whales, are of frequent occur- 
 rence in a fossil state in the Crag of Norfolk, and other Tertiary strata. 
 They are termed otolithes or otolites, that is, "ear-stones;" and though 
 varying greatly in size and configuration, are readily distinguished from 
 other bones by their greater density and smooth unattached forms. See 
 OTOLITES. 
 
 Earth. In chemistry, a solid, opaque, friable substance, without lustre, 
 and incombustible ; it is thus distinguished from metals on the one hand, 
 and from carbon and other combustible substances on the other. The 
 primitive earths are thus said to be baryta, strontia, lime, magnesia, 
 alumina, glucina, zirconia, yttria, donaria, and thorina. The first four are 
 termed alkaline earths, from their partial solubility in water, their alkaline 
 taste, and their action on vegetable colours ; the remainder constitute the 
 earths proper, are insoluble in water, and only imperfectly neutralise the 
 acids. In geology, as well as in familiar language, the word EARTH is 
 often loosely employed the earths of the agriculturist being the soils he 
 cultivates, while fuller's earth (an absorbent clay), bone-earth (phosphate of 
 lime), and the like, are everyday terms. The epithet earthy refers more 
 strictly to the character and consistency of a rock, as an ' earthy lime- 
 stone, " meaning thereby that it is soft, friable, and non-crystalline. In 
 geography, the distinctive name for our planet, as associated with the Sun, 
 
 182 
 
EAR 
 
 Moon, and other bodies of the solar system ; hence such phrases as the 
 " Earth's mass," " Earth's orbit,'' " Earth's axis of rotation," and so 
 forth. 
 
 Earth's Crust. That external rind or shell of our planet which is acces- 
 sible to human investigation ; in contradistinction to the internal mass, of 
 which we can know nothing by direct observation ; the Erd-rinde of the 
 German geologist. See TEMPERATURE OF THE EARTH. 
 
 Earth of Bone. A phosphate of lime, sometimes termed " bone phos- 
 phate," existing in bones after calcination. 
 
 Earth-Foam. A fine, light, scaly variety of calcite or calc-spar, techni- 
 cally known as aphrite, which see. 
 
 Earthquake. The familiar as well as technical term for any shaking or 
 tremor of the earth's crust produced by subterranean agency. As the 
 name implies, an earthquake consists of an agitation of some particular 
 portion of the earth the shock or convulsion being less or more violent, 
 and extending over a less or greater area, according to the intensity of the 
 motive power, and according to conditions of internal structure, with which 
 we are but slenderly acquainted. The conditions accompanying earth- 
 quakes are by no means uniform, and though science has recorded a great 
 many facts in connection with their occurrence, it is by no means in a 
 position to enunciate any law either as regards their premonitory warnings, 
 their intensity, their duration, or the direction of their movements. In 
 some instances they are preceded by an unusual stillness of the air, by an 
 unnatural agitation of the waters, and by hollow subterranean rumblings. 
 In others, the shock comes on at once with or without noise the earth is 
 violently agitated by perpendicular lifts or heaves rolls from side to side 
 or undulates with uneasy motion as if it were floating away from beneath 
 the feet of the observer. The single shock of an earthquake seldom lasts 
 more than a minute often for a few seconds only ; but they frequently 
 follow each other after short intervals, and for a considerable length of 
 time, and these paroxysms occur at certain periods more intensely than at 
 others. Of course such movements of a solid, unelastic, and variously 
 composed mass like the earth's crust as if it were extensively cavernous 
 or floated on a sea of molten matter must be followed by fractures, fis- 
 sures, and chasms ; by upheavals and depressions ; by elevations of the 
 sea's bed into dry land, and the submergence of dry land beneath the 
 waters of the ocean. Of all these we have abundant evidence and record 
 within the historical period ; and the further testimony, that these fissures 
 often emit smoke and flame, and more frequently discharge fragments of 
 stone and torrents of water. 
 
 From these and similar circumstances, as well as from their greater 
 frequency in volcanic districts, there can be little doubt that earthquakes 
 are intimately associated with volcanoes in fact, are but varied expres- 
 sions of the same primal agency. They produce modifications of the earth's 
 crust chiefly by fracture, subsidence, and elevation. During their convul- 
 sions the level plain may be thrown into abrupt heights or rent by chasms 
 and ravines ; lakes may disappear and rivers change their courses ; islands 
 may be submerged or elevated and joined to the mainland ; and maritime 
 tracts may be sunk beneath the waters, or the adjacent sea-bed raised 
 into dry land. Their geological function is therefore, like that of vol- 
 canoes, to diversify the surface of the globe, and to render irregular what 
 aqueous agency is perpetually striving to render smooth and uniform. 
 
 183 
 
EAR ECH 
 
 Presuming on the uniformity of nature's operations, in subordination to 
 the higher law of Creational Progress, the effects of earthquakes must 
 have been similar in all time past, and to them, therefore, must be 
 ascribed many of the fractures, dislocations, and contortions, so prevalent 
 among the earlier rock-formations of the globe. See SEISMOGRAPHY. 
 
 Earthquake- Waves. The name given to those huge and sudden waves, 
 or rather walls of water, which during earthquake convulsions are some- 
 times thrown with tremendous impetus upon the land. That rolled in upon 
 the coasts of Portugal, during the great Lisbon earthquake in 1755, was 
 estimated at 60 feet high. 
 
 Eboulement (Fr. fouler, to tumble down). A term adopted from the 
 French for sudden rock-falls and earth-slips in mountainous regions. 
 
 Ebullition (Lat. ebullitio, a boiling or bubbling-up). The boiling or bub- 
 bling-up of liquids after they have been heated to the boiling-point, which 
 varies, of course, according to the altitude of the situation above the level 
 of the sea. Many thermal springs are in a state of constant ebullition. 
 See BOILING POINT. 
 
 Ecculioinphalus (Gr., unrolled navel). An obscure Lower Silurian shell, 
 thin, curved or discoidal, with a few widely- separate whorls, slightly un- 
 symmetrical and keeled. Usually placed among the Gasteropods, but by 
 some regarded as a peculiar form of Pteropod. 
 
 Echinida, EcMnoidea (Gr. echinos, the sea-urchin). A well-known 
 family of the Radiata, comprehending those marine animals commonly 
 known by the name of sea-eggs or sea-urchins, and constituting, according 
 to zoologists, the third order of the class Echinodermata, which see. The 
 Echinida are found fossil in all formations, but are most abundant and 
 beautifully preserved in the Chalk. 
 
 E'chinite. The general palseontological term for any fossil, sea-urchin, 
 or cidaris, or portion thereof. Echinites are common in many formations, 
 and wherever they occur give evidence of true marine conditions. 
 
 EcMnobrissus (Gr. echinos, sea-urchin ; brissos, sea-urchin). An echino- 
 derm of the Oolite and Chalk periods, so called from its closer resemblance 
 to the. existing sea-urchin in the form and arrangement of its spines. 
 
 Echinocyamus (Gr. echinos, and kyamos, bean). A minute echinoderm 
 of the Pleiocene period, so termed from the bean-shaped form of its crust 
 or shell. 
 
 Echinodermata (Gr. echinos, and derma, the skin). A numerous class, 
 recent and fossil, of Radiata like the star-fish and sea-urchin all less or 
 more covered with a firm coriaceous or crustaceous integument, which in 
 many instances is densely armed with spines. It embraces, according to 
 recent zoological arrangements, the following orders : 
 
 1. The Crinoida, or those species, almost exclusively fossil, which are 
 fixed by a long jointed stalk, and have branching articulated tentacula 
 extending from around the abdominal cavity, as in the common encrinite. 
 
 2. The Asterida or Stellerida, comprising the free, flexible, and star- 
 shaped species, which are destitute of stalk or peduncle, as the common 
 star-fish (asteria). The asterida are recent as well as fossil hi all forma- 
 tions. 
 
 3. Echinida, in which the body is inflexible, and composed of a solid 
 articulated crust, the exterior surface of which is covered with movable 
 calcareous spines, as in echinus. Recent as well as fossil in all formations. 
 
 4. The Holothurida, in which the axis of the body is placed horizontallv, 
 
 184 
 
ECH EFF 
 
 and there is a soft coriaceous skin, seldom protected with spines, as in 
 /toio^iria. Found in the glacial clays of the Clyde. 
 
 Or including fossil genera, we have the further subdivisions given in the 
 preliminary tabulations, "ANIMAL SCHEME." 
 
 Echinosphaerites (Gr. echinos, and sphaira, a ball). Literally "prickly 
 ball ; " a genus of echinoderms characterised by their small size and globular 
 form, and restricted apparently to the Lower Silurian and Upper Cambrian 
 periods. 
 
 Echinostdchys (Gr. echinos, and stachys, a head of flowers). A term 
 applied to a singular fossil occurring in the New Ked Sandstone ; ap- 
 parently a spike of inflorescence, beset on all sides with sessile, contiguous, 
 sub-conical flowers or fruits. Supposed to be akin to the Typhacece or 
 reed-maces. 
 
 E'clogite (Gr., select). The name given to a coarse or fine grained mix- 
 ture of green smeragdite with red garnet a rock apparently of metamor- 
 phic origin. Some varieties take a good polish, and are coming into use as 
 ornamental stones. 
 
 Ecume de Mer, or Meerschaum. Literally " foam of the sea ; " a light 
 white earthy silicate of magnesia, much esteemed for the bowls of 
 tobacco-pipes. See MEERSCHAUM. 
 
 Eddphodon (Gr.) Literally "pavement- tooth ; " a genus of Lower Ter- 
 tiary fishes, founded chiefly on the jaws and dental apparatus, which resem- 
 ble those of the existing chimcera, but yet differ so much as to have induced 
 Professor Owen to erect the Edaphodonts (JEdaphodontidee) into a separate 
 family. Known also as Passalodon (peg-tooth), and Psittaeodon (parrot- 
 tooth). 
 
 Eddy (Sax. ed, water, and ea, backwards). Any rotatory motion of 
 water caused by the meeting of opposing currents. Eddies generally occur 
 in estuaries where the tide meets the current of the river ; and in seas 
 where currents from different quarters meet, or where tidal currents are 
 thrown back on themselves by opposing obstacles. See WHIRLPOOL. 
 
 Edentata (Lat. edentula, toothless). The sixth order of mammalia in 
 Cuvier's arrangement, or quadrupeds agreeing in the unimportant charac- 
 ter of being destitute of front or incisive teeth. It comprehends the Eden- 
 tata proper viz., ant-eaters, armadilloes, &c. and the Tardigrada or 
 sloths. Many of the huge Tertiary mammals of South America belong 
 to the Edentate order. See tabulations, "ANTMAL SCHEME." 
 
 Edingtonite. So called after its discoverer. A member of the Zeolite 
 family, found implanted in minute crystals on Thomsonite in the Kilpat- 
 rick Hills, but very rare. 
 
 Edriophthalmous (Gr. edraios, sessile, and ophthalmos, the eye). Applied 
 to those crustaceans which, like the sandhopper and woodlouse, have im- 
 movable sessile eyes ; in contradistinction to those which, like the crab 
 and lobster, are stalk-eyed or podophthalmous. The group Edriophihalma 
 comprises the amphipods, leemidopods, and isopods. See tabulations, 
 "ANIMAL SCHEME." 
 
 Effervescence (Lat. effervesce, I boil or bubble up). The bubbling, hiss- 
 ing commotion which takes place in fluids when gas is generated and given 
 off with rapidity. The effervescence of a Seidlitz powder, and of limestone 
 under the action of muriatic acid, are familiar examples. 
 
 Efflorescence (Lat. effloresce, I put forth flowers). Applied in mineral- 
 ogy to those saline excrescences which cover certain minerals, like alum- 
 
 185 
 
EGG ELE 
 
 shale, sulphuret of iron, &c., when exposed to the action of the atmosphere 
 the air decomposing the saline crystals and abstracting their water of 
 crystallisation. Efflorescence is caused by the removal of moisture, just as 
 deliquescence is caused by the absorption of it. 
 
 Eggs, Fossil. The eggs of turtles occur in a sub-fossil, or rather in a 
 petrified state in the shore-deposits of Ascension and other islands ; those 
 of snakes in fresh-water limestones of comparatively recent origin in Ger- 
 many ; those of birds (dinornis and epiornis) in the ancient river-silts of 
 New Zealand and Madagascar; and those of unknown animals (birds, 
 pterodactyles, or other reptiles) so early as the Oolitic formation. Such 
 remains are termed Oolithes and Ovulites, which see. 
 
 Egyptian Jasper, Egyptian Pebble. "A variety of jasper occurring in 
 roundish pieces, scattered over the surface of the desert between Cairo and 
 . the Red Sea. The surface of these masses is rough, and of a yellowish 
 chestnut-brown colour, but internally the brown colour forms irregular 
 concentric zones, between which are black spots and small black dendritic 
 markings in a base of pale yellowish-brown colour " (Bristow). When cut 
 and polished these jaspers are used as gem-stones. 
 
 Eifel. A district on the Lower Rhine, celebrated in geology for its re- 
 cent volcanic rocks, its brown-coal, and other Tertiary deposits, as well as 
 for its highly fossiliferous Devonian and Silurian strata. The subject of 
 papers in the geological journals by Lyell, Scrope, Homer, Hibbert, Ham- 
 ilton, and others, as to its Tertiary phenomena ; and the fertile field of 
 research to Sandberger, Rb'emer, Von Dechen, and others, in its Paleo- 
 zoic aspects. 
 
 Eisleben in Saxony ; a locality well known for its finely-preserved palceo- 
 nisci, and other fishes peculiar to the Carboniferous and Permian formations. 
 
 Elaeolite (Gr. elaion, oil; lithos, stone). A mineral of the Scapolite family, 
 having a dull opalescent or fatty resinous lustre ; the Fetistein or fatstone 
 of Werner. Composition, 45 silica, 32 alumina, 15 soda, 5 potash, and 
 traces of lime, magnesia, and iron peroxide. 
 
 Elaterite. Known also as elastic " mineral pitch " and " mineral 
 caoutchouc." A variet} 7 of bitumen possessing a certain degree of elas- 
 ticity, and generally found in the crevices of Carboniferous limestone, as in 
 Derbyshire and Fifeshire. On exposure to the atmosphere, elaterite gra- 
 dually loses its elasticity, and becomes hard and brittle like asphalt. 
 According to Johnston, it consists of about 85 carbon and 13 hydrogen, 
 with traces of oxygen and nitrogen. 
 
 E'lberseuth, near Bareuth, in the N.E. of Bavaria; celebrated for its 
 Devonian strata, which abound in the shells of Clymenia upwards of 
 thirty species having been found there, and the greater number of them 
 peculiar to the locality. 
 
 Electrum. A term of the ancients for argentiferous gold-ore, and still 
 applied to those varieties which contain more than 20 per cent of silver, 
 and of a light brass or bronze-yellow colour. 
 
 Element. A simple substance; one which chemistry cannot resolve 
 into other component substances. Iron, for example, is a simple substance 
 or elementary body ; rust of iron, a compound, consisting of metallic iron 
 and oxygen. Elements are spoken of as proximate or intermediate, and ulti- 
 mate. Thus, limestone consists of lime and carbonic acid these are its 
 intermediate elements ; but the lime is still further resolvable into calcium 
 and oxygen, and the carbonic acid into carbon and oxygen the calcium, 
 
 186 
 
ELE EME 
 
 oxygen, and carbon being ultimate elements. Upwards of sixty elemen- 
 tary substances are known to the chemist, and of these all the countless 
 combinations and matters in the mineral, vegetable, and animal world are 
 composed. See CHEMISTRY, and tabulations, "CHEMICAL SCHEME." 
 
 Elevating Causes. Under this head are comprehended those agencies 
 which refer to the operation of volcanoes, earthquakes, and gradually 
 elevating forces. The operations of the volcano and earthquake are 
 sudden and violent, and depend proximately on the presence of subter- 
 ranean heat ; gradual elevation, on the other hand, may arise from slow 
 secular movements in the earth's crust, with the proximate causes of which 
 geologists are yet unacquainted. The elevatory power of the volcano is 
 seen partly in the upheaval of portions of the earth's crust into mountain 
 chains and ridges, and partly in the accumulation round some centre of 
 eruption of ejected lava, scoriae, and other materials. The power of the 
 earthquake is manifested both by subsidence and elevation subsidence, as 
 in the sinking of the Allah Bund at the mouth of the Indus in 1819 ; and 
 elevation, as in the uprise of the coast of Chili in 1822. Gradual elevation 
 manifests itself in such uprises as those of the Scandinavian peninsula (to 
 the extent of some three or four feet in a century), and appears to depend 
 on movements in the earth's mass with which we are yet unacquainted. 
 
 Elie Euby. A variety of pyrope found in small garnet-like grains in the 
 trap-tuff of Kincraig Point, near Elie, in Fifeshire. 
 
 Elutriation (Lat. eluere, to wash out or cleanse). In chemistry and 
 metallurgy, the process of washing by which the lighter earthy parts are 
 separated from the heavier and metallic. 
 
 Elvan, Elvan Courses. A Cornish name for a felspathic rock or porphyry 
 occurring in dykes in the mining districts of that county. 
 
 Elytra (Gr. elytron, a sheath). The hard crustaceous case or sheath 
 which covers the membraneous wings of coleopterous insects like the 
 beetle ; the wing-sheath. The elytra of beetles are found fossil from the 
 Coal formation upwards. 
 
 Embouchure (Fr.) The mouth of a river, or that part where it dis- 
 charges itself into a lake or sea. 
 
 Emerald (Fr. emeraude; Ital. emeraldo ; Lat. smaragdus). One of the 
 gems, and generally of a rich deep-green colour ; the less brilliant and 
 colourless varieties being known as beryls. The crystals occur in hexa- 
 gonal prisms, rarely in columnar aggregates, and usually marked with 
 vertical strise. The emerald is found either imbedded or in druses in some 
 countries in the crystalline schists, but in the most celebrated modern 
 locality (Muzo, in New Grenada), in a Secondary limestone abounding in 
 ammonites. The finest specimens are brought from South America, but 
 fair varieties have been found in Bavaria, India, and Siberia. According 
 to Vauquelin, vrho, in analysing the emerald, first discovered the earth 
 glucina, the purest specimens consist of 65 silica, 14 alumina, 13 glucina, 
 2.56 lime, and 3.50 oxide of chromium, to which last the gem was supposed 
 to owe its fine green colour. According to the more recent researches of 
 M. Levy, however, the colouring matter is considered to be a carburet of 
 hydrogen, and of animal origin a supposition to which the fossiliferous 
 limestone of Muzo gives great support. The colour of the emerald can 
 easily be destroyed by heat a circumstance which does not occur in those 
 gems that are coloured by oxide of chromium. See BERYL. 
 Emergence, Emergent (Lat. emergo). Rising out of that by which it was 
 187 
 
EME END 
 
 covered ; applied to islands and shores gradually rising from the ocean. 
 Emergence and Subsidence are contradistinguishing terms. 
 
 Emery. A massive, nearly opaque, greyish-black, or indigo-coloured 
 variety of rhombohedral corundum, consisting of alumina, with a small 
 percentage of silica and peroxide of iron. It occurs in Spain, the Greek 
 Islands, and other localities, and derives its name from Cape Emeri, in the 
 island of Naxos, from which most of the emery of commerce is derived, 
 and where it occurs in large blocks in the soil, and sometimes in white 
 marble. Triturated, sifted, and attached to paper or cloth, it forms the 
 emery-paper and emery-cloth of the polisher. 
 
 Einmonite (after Professor Emmons of Massachusetts). A snow-white 
 variety of Strontianite, with an obscurely foliated structure, and a scaly 
 appearance not unlike some varieties of gypsum. Consists of 82.7 car- 
 bonate of strontia and 12.5 carbonate of lime. 
 
 E'mydse (Gr. emys, the fresh-water turtle). Fresh-water turtles or mud- 
 tortoises; a family of chelonian reptiles intermediate between the marine 
 turtles and the land -tortoises. In form they are flatter than the land- 
 tortoises ; their toes are longer and webbed, but not so long as those of the 
 marine turtles. Fossil species have been found in the Wealden and Terti- 
 ary strata. See REPTILIA in preliminary tabulations, "ANIMAL SCHEME." 
 
 Enaliosaiiria (Gr. enalios, marine, and sauros, lizard). Literally sea- 
 saurians ; a group of fossil reptilians, including the aquatic forms 
 ichthyosaurus, pliosaurus, plesiosaurus, &c. See SAURIANS. 
 
 Enamel. In anatomy, the smooth, hard, glossy substance which in 
 various forms constitutes the outer surface of the teeth ; seen also on*the 
 scales of the fossil ganoid or enamelled- scale fishes. 
 
 Encephalous (Gr. en, in, and kephale, the head). Applied to those mol- 
 lusca which, like the limpet and periwinkle, have a distinct head. The 
 division JEncephala comprehends the cephalopods, gasteropods, and ptero- 
 pods in other words, all the univalves. See ACEPHALOUS. 
 
 E'ncrinite, Encrinites (Gr. krinon,a, lily). The original and general term 
 for the Crinoidea or lily-like echinoderms an extensive and chiefly fossil 
 class, characterised by their long many -jointed stalks, surmounted by lily- 
 shaped bodies or receptacles, which were furnished with numerous finger- 
 like rays capable of closing and expanding. The internal calcareous skele- 
 tons of the encrinites (in scattered joints and fragments) are so abundant 
 in some Carboniferous limestones as to compose the greater portion of the 
 mass ; hence the term encrinal or encrinital limestone. The minuter joints 
 of the fingers and rays are usually termed entrochi or wheel-stones, and 
 these, when abounding in certain limestones, confer on them the title en- 
 trochal limestones. The stalk having been perforated by a canal which 
 kept the whole in vital union, the separated joints present a bead-like 
 appearance ; hence such familiar terms as " St Cuthbert's beads " and 
 " wheel-stones " for the solid pieces ; and "pulley-stones" and "screw- 
 stones " for their hollow casts in limestones. It is usual, in a general 
 way, to apply the term ENCRINITES to the genera having rounded stalks, 
 and PENTACRINITES to those which are angular or pentangular. See 
 CRINOIDEA. 
 
 Endo (Gr. endon, within). A common prefix in geology, as well as in 
 other of the natural sciences ; as endogens, plants increasing in growth 
 from within ; endosiphonites, a genus of fossil cephalopods having the 
 siphuncle placed at the inner side of the whorls, &c. 
 
 188 
 
END ENT 
 
 E'ndocarp (Gr. endon, within, and Jcarpos, fruit). The stone or shell 
 which, in fruits like the peach and cherry, encloses the embryo or kernel ; 
 the outer skin being the epicarp, and the fleshy edible substance the 
 sarcocarp. 
 
 E'ndogens (Gr. endon, within ; ginomai, I am formed). That division of 
 the vegetable kingdom palms, grasses, rushes, and liliaceous plants 
 whose growth takes place from within, and not by external concentric 
 layers as in the Exogens.QQ MONOCOTYLEDONOUS, and tabulations, 
 " VEGETABLE SCHEME." 
 
 Endogenites. Fossil stems and fragments exhibiting the endogenous 
 structure are so termed. " It is merely," says Brongniart, "a provisional 
 assemblage of objects to be further examined." 
 
 Endosiphonites {Gr. endon, within). A synonyme of Prof. Ansted's for 
 the nautiloid shell clymenia, whose siphuncle is on the inner side of the 
 whorls, therein differing from the ammonite, whose siphuncle is on the 
 outer side or dorsal, and from the nautilus, in which it is central. 
 
 Engis, Engihoul. The caverns of Engis and Engihoul the former on 
 the left bank, and the latter on the right bank, of the Meuse, about eight 
 miles from Liege have become celebrated in the question of man's an- 
 tiquity, from their containing human remains imbedded in the same muds 
 and breccias with those of mammoth, rhinoceros, cave-bear, reindeer, and 
 other mammalia now extinct in Europe. 
 
 Enhydrous, Enhydrite (Gr. en, within, and hydor, water). The name 
 given to crystals and minerals containing water ; the opposite of an- 
 hydrous. 
 
 E'nsiform (Lat. ensis, sword, and forma, likeness). Sword-shaped ; 
 straight, flat, and pointed, like the leaf of the iris ; slender and more 
 tapering forms being lanceolate; and those less or more recurved, falciform. 
 
 Ent6molite (Gr. entoma, insects, and lithos, stone). The general term for 
 a fossil insect, or any part or fragment thereof. 
 
 Entomolithus Paradoxus (Gr. entoma, insects). The term given by the 
 earlier palaeontologists to the trilobite, which was long confounded with 
 insects in consequence of the segmented aspect of its body. 
 
 Entomology (Gr. entoma, insects, and logos, reasoning). The science 
 of insects ; that branch of natural history that treats of the history and 
 habits of insects. Entomological. Pertaining to the science of insects. 
 Entomologist. One devoted to the study of insects. 
 
 Entom6phagous (Gr. entoma, insects, andphago, I devour). Insect-eat- 
 ing ; applied to those animals which chiefly subsist on insects. Same as 
 Insectivorous, which see. 
 
 Entom6straca (Gr. entomon, insect, and ostrdkon, shell). Literally 
 " shelled insect ; " an extensive sub-class of Crustacea, generally of small 
 size, covered with a delicate skin, and usually protected by a broad shield 
 or sort of bivalve shell. The branchiae, when present, are attached to the 
 feet, which, with the antennae, are generally furnished with bristles that 
 render them efficient organs of locomotion. Occur recent, and fossil in all 
 formations, as cypris, ceratiocaris, dithyrocaris, &c. See CRUSTACEA in pre- 
 liminary tabulations. 
 
 E'ntrochi, Entrochites, and Trochftse (Lat. trochus, a wheel). Names 
 given to the wheel-like joints of the encrinite, which are frequently scattered 
 in great profusion through certain limestones ; hence entrochal marble. 
 See SCREW-STONES, PULLET-STONES, and ST CUTHBERT'S BEADS. 
 
 189 
 
ENV EPI 
 
 Envelope (Fr. envelopper, to roll or wrap up). A wrapper ; a cover ; any 
 investing integument ; applied to superficial soils, clays, and gravels that 
 mask or cover up the subjacent rocky strata. 
 
 Eocene (Gr. eos, the dawn, and kainos, recent). A term introduced by 
 Sir Charles Lyell to designate the Lower Tertiary strata, from the idea that 
 the very small percentage of living testacea contained in these strata (ac- 
 cording to Deshayes only 3g per cent) indicates what may be regarded as 
 the dawn or commencement of the existing or current condition of creation. 
 See TERTIARY SYSTEM. 
 
 Eolian (Eolus, the god of wind). A term given by Nelson to loose 
 material (sand and the like) drifted and arranged by the wind. As we 
 have aqueous formations, so we may have eolian or sub-aerial, which is the 
 term most frequently employed. 
 
 Eosaiirus (Gr. eos, dawn, and sauros). A provisional genus of Enaliosau- 
 rians, occurring in the Nova Scotian Coal formation, and founded on some 
 vertebrae which indicate, according to Mr Marsh their discoverer, " a rep- 
 tile of large size, air-breathing, carnivorous, and aquatic, probably marine." 
 
 Eozoic (Gr. eos, dawn; zoe, life). A term recently introduced to express 
 the oldest fossiliferous rocks, such as the Laurentian and Huronian of 
 Canada, from their containing the first or earliest traces of life in the 
 stratified systems. In this case Eozoic signifies older than the Palaeozoic, 
 and takes the place of Azoic and Hypozoic, which were formerly applied to 
 such metamorphic strata. 
 
 Eozodn (Gr. eos, dawn, and zoon, animal). A foraminiferal organism 
 occurring in the Laurentian limestones of Canada, and so named by Prin- 
 cipal Dawson from its position in the oldest stratified rocks yet known to 
 geology. It is found in large sessile patches, after the manner of Carpen- 
 teria ; and though greatly mineralised, yet reveals to the microscope a 
 structure resemoling that of other foraminiferal forms. According to 
 Drs Carpenter and Dawson, its affinities are towards the Nummuliiie 
 group. 
 
 Epi (Gr. epi, upon). A prefix adopted from the Greek, and having, as 
 the case may be, the signification of upon, over, outer, all through, besides. 
 
 Epicarp (Gr. epi, and karpos, fruit). The outer skin or husk of certain 
 fruits ; the fleshy or edible portion being the sarcocarp, and the stone the 
 endocarp. 
 
 Epidermis (Gr. epi, and derma, the skin). The outer skin, scarf-skin, or 
 cuticle. Used in many branches of natural history, as in conchology, to 
 the membranaceous horny cuticle that covers many shells ; in botany, to 
 the membrane or outer bark that covers the stems of plants ; and in zoo- 
 logy, to the pellicle or scarf-skin that covers the true skin of animals. In 
 general the epidermis can be peeled or rubbed off without injury to the 
 underlying parts, and in many instances it peels and falls off with the in- 
 creasing size and age of the plant or animal. 
 
 E'pidote (Gr. epi, and didomai, I give or add to). A member of the Gar- 
 net family, known also as prismatic augite-spar, pistacite, and Arendhal- 
 ite ; and said to derive its name from its crystals, which always appear 
 horizontal-prismatic, but are prolonged (or added to, epididomai) at the 
 base of the prism in one direction. It is generally of a green or greyish 
 colour, and occurs regularly crystallised in druses, or in granular, pris- 
 matic, and fibrous concretions. It is found in granite, diorite, and other 
 crystalline rocks, and has many sub-species or -varieties, as zoisite, Thallite, 
 
 190 
 
EPI EQU 
 
 Bucklandite, manganese-epidote, &c. It consists of 38 silica, 28 alumina, 
 14 lime, 17 peroxide of iron, and traces of manganese and magnesia. 
 
 Epigastric (Gr. epi, and gaster, the belly). Belonging to the upper por- 
 tion of the belly, or epigastric region. 
 
 Epimera (Gr. epi, and meros, a part or portion). Those parts of the seg- 
 ment of an articulate animal which lie immediately above the joint of the 
 limb ; e.g., the epimera or side-segments of the lobster. 
 
 Epiornis. A gigantic extinct bird of Madagascar. See JEriORNis. 
 
 Epiphyte (Gr. epi, and pliylon, a plant or shoot). A term for those 
 plants which grow upon others, adhering to their bark, and rooting among 
 the decaying portions of their epidermis. Generally restricted to those 
 orchids that grow upon trees. 
 
 Epoch (Gr. epoclie, a pause in the reckoning of time). A term literally 
 signifying a stop or fixed point of time from which succeeding years are 
 numbered, but somewhat loosely used in geology as synonymous with age 
 or era ; as the " Silurian epoch," "epoch of gigantic reptilians." 
 
 E'psomite, Epsom Salt. Sulphate of magnesia, consisting of 16.26 mag- 
 nesia, 32.523 sulphuric acid, and 51.22 water. It occurs in botryoidal 
 masses and capillary efflorescences in many mines, veins, and old coal- 
 workings, and is a common ingredient in many mineral waters, like those 
 of Epsom and Surrey. The greater portion of the Epsom salts of com- 
 merce, however, is manufactured from magnesian limestone. 
 
 Equator (Lat. aquus, equal). The great circle on the earth's surface, 
 every point of which is equally distant from the poles ; such a circle cuts 
 the globe into two equal parts or halves, in other words, into hemispheres 
 viz., the Northern and Southern. When the sun is in the line of the 
 equator, day and night are of equal duration, hence it is also termed the 
 equinoctial line (nox, the night). Equat6rial. Belonging to, or in the 
 region of the equator; as the "equatorial diameter" of the earth, the 
 "equatorial current" of the Atlantic. 
 
 Equatorial Current. That great current which manifests itself within 
 the equatorial region of the Atlantic, Pacific, and Indian Oceans. In either 
 ocean it has a decided westerly flow, is warmer by several degrees than the 
 adjacent waters, and spreads over many degrees of latitude. It is influ- 
 enced in its course and character partly by the trade-winds, and partly by 
 the earth's rotation, and being unobstructed by islands is most decidedly 
 felt in the Atlantic. In the Atlantic, as it strikes the South American 
 shores it bifurcates into the Brazil and Guiana currents ; in the Pacific, 
 as it nears the Asiatic islands it separates into the Australian and Japan 
 currents ; and in the Indian Ocean, as it impinges on the African coast 
 it is mainly deflected southward into the strong flow of the Mozambique 
 current. 
 
 Equi (Lat. cequus, equal). A common prefix in scientific terminology 
 signifying equal or alike ; as equidistant, equally distant ; equilateral 
 equal- sided ; equivalved, having both valves alike. 
 
 E'quidse (Lat. equus, a horse). The Horse tribe ; the family of solidun- 
 gulous pachyderms, having only one apparent toe and a single hoof to each 
 foot. It includes the horse, ass, zebra, &c.; and members of the family, 
 differing slightly from the existing species, occur fossil in the middle and 
 upper Tertiaries. 
 
 Equine (Lat. eqmts, a horse). Pertaining to the horse ; belonging to the 
 Horse family. 
 
 191 
 
EQU EKI 
 
 Equisetacese (Lat. equus, a horse, and seta, a hair or bristle ; whence the 
 English name horsetail). An extensive order of marsh or boggy crypto- 
 gams or flowerless plants, well represented by the common "horsetail" of 
 our bogs and ditches. They occur in every region from Lapland to the 
 equator, but acquire their greatest magnitude and abundance in moist 
 warm regions. They are also found fossil in all formations, the most gi- 
 gantic specimens occurring in Carboniferous and Oolitic strata. The 
 equisetums are readily distinguished by their erect hollow stems, which 
 are striated and jointed, frequently with whorls of small attenuated leaves 
 at the joints, and all less or more rough from the quantity of silex con- 
 tained in their cuticle. 
 
 Equisetites (Lat. equisetum, the plant horsetail). Fossil plants resem- 
 bling the equisetum of our pools and marshes, and found in all formations 
 from the Devonian upwards. In equisetum the stems are jointed, and sur- 
 rounded by closely-fitting cylindrical sheaths, which are regularly tooth - 
 letted, and which leave their impress on the stems ; but the stems are not 
 channeled throughout as in Catamites, for which they are apt to be mis- 
 taken. See CALAMITES. 
 
 Equivalent. A term freqiiently employed by geologists to designate 
 strata or series of strata that have been formed contemporaneously in 
 distant regions, or which, palseontologically speaking, are characterised 
 by similar suites of fossils. Thus the "Ketiper" of Germany, and the 
 " Marnes Irishes" of France, are said to be the equivalents of the saliferous 
 and gypseous sandstone and marls of Cheshire ; the " Calcaire de Caen," 
 or celebrated building-stone of Caen, the equivalent of our Great or Bath 
 Oolite. See Table of Contemporary or Equivalent Strata, in preliminary 
 tabulations, " GEOLOGICAL SCHEME." 
 
 Era (Lat.) In chronology, a fixed point of time, at which the computa- 
 tion of ensuing years is commenced, as the "Christian era." In geology 
 the term is somewhat loosely employed, not only to denote the commence- 
 ment of a new "system " or " formation," but the entire duration of that 
 system or formation ; as " the plants of the Carboniferous era," "the era 
 of gigantic reptiles." 
 
 Erbium. One of the rarer metals, of which very little is known. Ac- 
 cording to Mossander, the earth called yttria is a mixture of the oxides of 
 three metals yttrium, erbium, and terbium, which differ in the character 
 of their salts, and some other particulars. 
 
 Eremacausis (Gr. ereme, slow, and Icausis, burning). Slow- burning ; 
 decay. Liebig's term for that slow chemical change brought about by the 
 action of the oxygen of the atmosphere on moist organic bodies, by which 
 they are consumed or burnt without any sensible increase of temperature ; 
 e.g., the conversion of vegetable substances into humus. 
 
 E'rinite (Erin, the ancient name of Ireland). The name given by Haid- 
 inger to a beautiful green arseniate of copper (59.5 protoxide of copper, 
 33.5 arsenic acid, 5 water, and 2 alumina), from its being found in the 
 county of Limerick, in Ireland, where it occurs in mammillary crystalline 
 groups. Also the name given by Thomson to a dull brownish-red variety 
 of bole found in the amygdaloid of Antrim, and which consists of 47 
 silica, 18.5 alumina, 6.5 iron peroxide, 25 water, with traces of lime, salt, 
 and magnesia. 
 
 Erismacanthus (Gr. erisma, subject of dispute, and acantha).A. provi- 
 sional genus of fish-spines belonging to the Coal period, and so called from 
 
 192 
 
ERO ESO 
 
 their doubtful character that is, whether a distinct genus or merely a 
 species of ctenacanthus. 
 
 Er6sion (Lat. erosus, gnawed or worn away). The act of gradually 
 wearing away; the state of being gradually worn away; e.g., "Valleys 
 of erosion," or those valleys which have been gradually cut out of the 
 solid strata by the long-continued action of the river or rivers that flow 
 through them. Most of the ravines and glens and river- channels in the 
 British Islands are the result of erosion; for, whatever inequalities of 
 surface may have originally directed the waters into their channels, all the 
 subsequent deepening, and scooping out, and widening of the valleys, 
 have been owing to the erosive force of running water laden with sand, 
 gravel, and other triturating debris. 
 
 Erpet6logy (Gr. erpetos, reptile, and logos, reasoning). That branch of 
 natural science which treats of the structure, habits, and history of reptiles. 
 
 Erratic Block Group. A synonyme of the Boulder Clay, so called from 
 the large transported blocks which are thickly strewn through it. See 
 PLEISTOCENE and DRIFT FORMATION. 
 
 Erratic Blocks, Erratics. A term frequently applied to those large 
 water-worn and ice-borne blocks of stone (boulders) which are scattered so 
 generally over the higher and middle latitudes of the northern hemisphere. 
 
 Eructation (Lat. eructatio), A violent bursting forth of gaseous and 
 liquid matter from any orifice or opening, as from the crater of a volcano 
 or geyser. 
 
 Eruption (Lat. e, out of, and ruptus, burst forth). A violent and for- 
 cible breaking out of enclosed matters ; as the outburst of lava, ashes, 
 mud, hot water, or steam from an opening in the earth's crust. Erupted. 
 Forcibly thrown forth, as stones, scoriae, &c., from the crater of a volcano. 
 Eruptive. Applied to such igneous rocks as have evidently burst through 
 the sedimentary strata, in contradistinction to those which have gently 
 overflowed, and become inter stratified. 
 
 Erythrine (Gr. eruthros, red). The name given to cobalt-bloom, which 
 occurs in small botryoidal masses and acicular diverging crystals, generally 
 of a fine carmine or peach-red colour. As an arseniate of cobalt, its normal 
 composition is 38.43 arsenic acid, 37.55 oxide of cobalt, and 24.02 water; 
 but most specimens contain oxide of nickel and protoxide of iron. 
 
 Erythrite (Gr. eruthros, red). A flesh-coloured variety of felspar, oc- 
 curring in the amygdaloid of the Kilpatrick Hills, and so named by Thom- 
 son from its colour. 
 
 Escarpment (Fr. escarper, to cut steep). The abrupt face or cliff of a 
 ridge or hill-range. 
 
 EsMrs or Escars. The name given in Ireland to the elongated and often 
 flat-topped mounds of post-glacial gravel which occur abundantly in the 
 greater river- valleys of that country. Known as Kaims in Scotland and 
 Osars in Sweden, which see. 
 
 Es6cidse (Lat. esox, the pike). The Pike family; represented by the 
 well-known fresh- water fish of that name. The pikes are extremely vora- 
 cious fishes, and for this purpose have their mouths abundantly armed 
 with formidable teeth. Fossil species are said to occur from the Chalk 
 period upwards. 
 
 Esdphagus or (Esophagus (Gr. olo, oiso, I carry, and phago, I eat). The 
 canal through which the food passes (or is carried) from the mouth to the 
 stomach. 
 
 193 N 
 
EST EUK 
 
 E'stuary (Lat. cestuscestuo, I boil the tide ; so called from the troubled 
 boiling- up of the water-line, which marks its approach in river-mouths). 
 Estuaries are, properly speaking, tidal river-mouths, like those of the 
 Thames, Severn, Solway, &c. ; whose fauna and flora are mixed fresh-water 
 and marine, or composed of such species as are peculiar to brackish waters. 
 From these peculiarities, the geologist is enabled to determine that cer- 
 tain formations, such as the Wealden, have been deposited in estuaries, 
 and not in fresh-water lakes, nor in the open ocean ; and hence also the 
 frequent use of such phraseology as " estuary limestones," " estuary mud- 
 stones," and the like. 
 
 Etesian (Gr. etesios, annual). The Etesian Wind of Europe is a northerly, 
 or rather north-easterly wind, that prevails in early spring all over the 
 continent. The word is applied, in Greek and Koman authors, to the 
 periodical winds in the Mediterranean, from whatever quarter they blow. 
 
 Ethmoid (Gr. ethmos, a sieve, and eidos, like). Sieve-like; perforated like 
 a sieve. Generally applied to the bone of the nose, which is perforated 
 like a sieve, for the passage of the olfactory nerves. 
 
 Ethn6grapliy (Gr. eihnos, a race, and graphe, a description). An account 
 or description of the origin, dispersion, connection, and characteristics of 
 the various races of mankind. Ethnology. The science of races, in all that 
 relates to physical features, language, manners, religion, and other charac- 
 teristics. 
 
 Etiolate (Fr. etioler). In gardening, to grow up long-shanked and 
 colourless ; to blanch or make white, by concealment from the light. The 
 inner leaves of lettuce and cabbages become etiolated by exclusion from 
 the light ; and the blanching or etiolation of celery is produced by earthing 
 up, so as to exclude the actinic or colouring effect of the sun's light. 
 
 Euchroite (Gr. eu, beautiful, and chroa, colour). A rare arseniate of 
 copper of a fine green colour ; hence the name. 
 
 Euclase (Gr. eu, easily, and klasis, fracture). The prismatic emerald of 
 Mohs ; a very rare mineral, found chiefly in Brazil and Peru, in trans- 
 parent crystals of a pale bright green colour. It consists, according to 
 Berzelius, of 43.22 silica, 30.56 alumina, 21.78 glucina, with the oxides of 
 iron and tin. Its form is an oblique prism, variously modified. It is 
 characterised by great brittleness (whence its name), the facility with 
 which it becomes electric by heat, and the length of time it retains this 
 property. These characters distinguish it from the true emerald and 
 beryl ; and its brittleness prevents its being employed as a gem. 
 
 Eiidialite (Gr. eu, easily, and dialyo, I dissolve). The rhombohedric 
 almandine-spar of Mohs, one of the Haloid family, and so named from its 
 easy solubility in acids. A rare mineral from Greenland, occurring in 
 octahedral crystals of a soft reddish-lilac or hyacinthine colour, and con- 
 taining zircon with silica and soda. It much resembles almandine or noble 
 garnet, but is distinguished by its crystalline form, its lower specific 
 gravity, inferior hardness, and action under the blow-pipe. 
 
 Euelephas (Gr. eu, well, and elephas). Founding chiefly on their denti- 
 tion, Dr Falconer proposes to divide the Elephants into three sub-generic 
 groups the Stegodons, the Loxodons, and the Euelephants the latter 
 term having reference to the typical elephants most familiarly known. 
 
 Eukairite (Gr. euJkairos, convenient, well-situated). A cupreous seleni- 
 uret of copper, found disseminated in the calcareous rocks of Smoland in 
 Sweden. Consists of 39 silver, 26 selenium, 23 copper, and 8 alumina. 
 
 194 
 
EUN EUR 
 
 Eunotia (Gr. eu, well, and notos, back). A genus of Diatoms or micro- 
 scopic plant-growths, having a siliceous simple or bivalve shield, flat 
 below, and convex, and often richly dentated above ; whence the name. 
 Occurs in the mountain-meal of St Fiora, and in similar accumulations. 
 
 Euomphalus (Gr. eu, well, and omplialos, navel). A whorled discoidal 
 shell, ranging from the Lower Silurian to the Trias inclusive, but specially 
 abundant in the Carboniferous limestone. In the euomphalus, which be- 
 longs to the family Turbinidae and order Gasteropoda, the whorls are 
 angular or coronated, the aperture polygonal, the umbilicus very large, and 
 the shell frequently of gigantic dimensions. 
 
 Euosmite (Gr. eu, well, and osmos, odour). The name givem by Dr 
 G umbel to a fossil resin occurring in thelignites of the Upper Palatinate, 
 Bavaria ; and so termed from its strong, peculiar, and pleasant odour. 
 The miners give it the name of "Kampferharz," its odour resembling that 
 of camphor, and at the same time partaking of that of rosemary. It occurs 
 either in semi- pulverulent masses of a brownish-yellow, or firm, and of the 
 colour of cherry-gum. It is brittle, electric when rubbed, dissolves readily 
 in alcohol or ether, and consists of 81.89 carbon, 11.73 hydrogen, and 6.38 
 oxygen. It is evidently the produce of the coniferous trees which con- 
 stitute the bulk of the lignite. 
 
 Euphorbites. Artis's term for the Sigillaria pachyderma, from its sup- 
 posed affinity to the Euphorbias. 
 
 Eiiphotide (Gr. eu, well, and pfios, photos, light). A crystalline rock 
 consisting essentially of Labrador felspar and diallage, with subordinate 
 intermixtures of hornblende or augite. So called from irridescent lustre 
 or quality of reflecting light. The Gabbro of the Italian artists. 
 
 Elirite. The whitestone or weiss-stein of Werner. A term of the 
 French mineralogists for a variety of granite in which felspar predominates 
 so as to give it a uniform white colour ; generally small-grained, with a few 
 crystals of quartz, and occasional scales of white silvery mica ; sometimes 
 porphyritic from the interspersion of larger crystals of felspar. 
 
 Euryndtus (Gr. euros, breadth, and notos, the back). Literally "broad 
 back ; " a genus of Lepidoid fishes'occurring in the Carboniferous forma- 
 tion, and differing from Palceoniscus, with which they were at one time 
 united, in their high bream-like back, stronger crenulated scales, and 
 generally larger size. 
 
 Eurypterite. A convenient Anglicised term for any of the Eurypterus 
 family, or for any undetermined portion or specimen thereof. Introduced 
 to harmonise with Trilobite ; hence we speak of the trilobites of the 
 Silurian and the eurypterites of the Devonian epoch. 
 
 Eurypterus, Eurypteridae (Gr. euros, breadth, and pteron, wing or fin). 
 A genus and family of extinct crustaceans, ranging from the Upper Silu- 
 rians to the Lower Coal-measures inclusive, and so termed in allusion to 
 their broad oar-like swimming feet. The family embraces eurypterus 
 proper, pterygotus, and others all characterised by their long lobster-like 
 forms, which consist (in the dorsal aspect) of an oblong-oval cephalo- 
 thorax or carapace, with marginal or sub-central eyes ; eleven abdominal 
 or thoracico-abdominal segments, free and devoid of appendages ; and a 
 telson or tail-plate more or less elongated, and usually pointed. The 
 carapace (in the oral or ventral aspect) is furnished with three pairs of 
 five- or six-jointed members the two first variously formed in the different 
 genera (some furnished with spines, others with prehensile pincers), and 
 
 195 
 
EUR EXO 
 
 the posterior forming the broad swimming feet which give name to the 
 family. The oral apparatus consists, as in the King-crab, of the serrated 
 basal joints of the limbs, and is protected by a broad heart-shaped meta- 
 stome or mouthpiece. In all the genera the exterior crust is ornamented 
 with a peculiar scale-like sculpture, which becomes bolder and stronger on 
 the free or exposed margins. The relations of the Eurypteridse to other 
 crustacean families are by no means well determined, and geologists must 
 in the mean time rest satisfied with mere hints as to affinities with Copepods, 
 Pcecilipods, and other existing orders. See PTERYGOTUS, CRUSTACEA, and 
 tabulations, " ANIMAL SCHEME." 
 
 Eurytherium (Gr.) Literally "broad beast;" a provisional genus of 
 mammalia, apparently pachyderm and aquatic, from the Eocene and Mio- 
 cene Tertiaries of Europe. Allied to Halitherium, which see. 
 
 Euthacanthus (Gr. euthys, straight, acantka, spine). A genus of fishes 
 (apparently placoid) occurring in the Lower Old Ked of Forfarshire, rang- 
 ing from seven to eighteen inches in length, and thus characterised by 
 its discoverer, Mr Powrie : Head small, rather compressed ; body rather 
 elongated ; branchial arches numerous and exposed ; tail heterocercal ; 
 fins membranous, preceded by conical spines two dorsals, two pectorals, 
 two ventrals, one anal ; several pairs of intermediate dermal scutes ; spines 
 straight, and ridged longitudinally ; scales smooth and minute. 
 
 Evaporation (Lat. evaporo, I send off in vapour). The act of convert- 
 ing into vapour such liquids as water, either by natural or by artificial 
 means, the former being termed ' ' spontaneous evaporation." Heat is the 
 grand evaporating agent in nature, and its effects are greatly facilitated 
 by the removal of the vapour as soon as it is formed either by currents of 
 wind, by absorption, or by other analogous means. See VAPOUR. 
 
 Excavation (Lat. ex, out of, and cavus, hollow). Any cavity or hollow, 
 whether natural or artificial. Eocks are excavated naturally by the action 
 of waves, by subterranean springs, by rivers, and other currents of water. 
 
 E'xcrement (Lat. ezcrementuni).Tha,t which is separated from the food 
 after digestion, and ejected from the body of animals by the intestinal 
 canal. Excrementitious or fsecal matter is found abundantly in a fossil 
 state, and known as coprolite, which see. 
 
 Excrescence (Lat. ex, out of, and cresco, I grow). Any body or sub- 
 stance growing upon or out of another in an unusual manner ; any pre- 
 ternatural growth of a substance, mineral or organic. 
 
 Excretion (Lat. excretus, thrown out of, separted). The act of separat- 
 ing or voiding excrementitious matter from the blood and food ; also the 
 substances excreted, as perspiration, fsecal matter, &c. 
 
 Exfdliate (Lat. ex, from off, &&& folium, a leaf). To separate or fall off 
 in laminse or scales. Exfoliation, by weathering, is very perceptible in 
 some varieties of greenstone which disintegrate, coating after coating (leaf 
 after leaf), till the whole of the rock-face looks like a pile of concentric 
 concretions in various stages of decay. 
 
 Exhalation (Lat. exhalatio, a breathing out of). Any vapour or gaseous 
 matter arising from substances or surfaces exposed to the atmosphere ; as 
 the (< sulphurous exhalations" from a volcanic crater, the "poisonous ex- 
 halations " or miasm from a putrid bog or fen. 
 
 Exogenites. Any fragment of fossil wood exhibiting the exogenous 
 structure, and otherwise of unknown affinity, is so termed. 
 
 E'xogens (Gr. exo, without, and ginomai, I am formed). That division 
 196 
 
EXO EYE 
 
 of the vegetable kingdom whose growth takes place by external concentric 
 layers of annual increment, like the beech, ash, elm, &c., in contradistinc- 
 tion to the Endogens, or those whose growth is not indicated by concentric 
 layers. All the trees in cold climates, and most of those in hot latitudes, 
 are exogenous, and are easily distinguished from the endogenous by the 
 reticulated venation of their leaves. See DICOTYLEDONOUS. 
 
 Exogyra (Gr. exo, outward, and gyros, a twist or turn). The sub-generic 
 term employed by Sowerby and others to designate the Chama-shaped 
 species of Gryphcea having the umbones sub-spiral, and turned outwards 
 or towards the posterior side. These shells are now usually included in 
 the wider genus Gryphsea, though some still retain gryphcea and exogyra as 
 sub-genera of the more typical genus Ostrea or oyster. 
 
 Exotic (Gr. exotikos, thence, from a strange country). Applied to plants 
 and animals, but chiefly to the former, that have been introduced into a 
 country from other regions that is, from without. Used in contradistinc- 
 tion to indigenous, or naturally belonging to a region, which see. 
 
 Expansion (Lat. expansus, spread out). The increased bulk which bodies 
 assume when heated. All substances, solid as well as liquid, when chemi- 
 cal change does not take place, expand by heat and contract by cold. 
 Water presents an apparent exception to this rule, inasmuch as it attains 
 its minimum volume at 40, expands and is converted into steam above 
 this temperature, and also expands as it falls below it, till converted at 32 
 into ice, a solid crystalline mass, which being lighter (or occupying a 
 larger volume) floats on the surface. Clay also, from its losing its water 
 of plasticity, shrinks or contracts by heat ; but such contraction applies to 
 the compound mass only not to separate substances per se. 
 
 Explosion (Lat. explosio). The sudden and violent expansion of any 
 object, by which its constituent parts are burst asunder. Explosion differs 
 from expansion inasmuch as it is always sudden and of momentary dura- 
 tion, whereas the latter is gradual, and more or less continuous. Explosion 
 is also for the most part accompanied by chemical change ; expansion, on 
 the other hand, is mainly mechanical. Explosion has reference chiefly to 
 gaseous substances ; expansion, to solids and liquids. 
 
 Exsiccation (Lat. ex, out of, and siccus, dried up). The drying up of solid 
 bodies ; the expulsion of moisture from their structure by heat, by pres- 
 sure, or by any other means. 
 
 Extracririus. A sub-genus of Pentacrinus, and separated from that 
 genus by Major Austin, in consequence of the more frequent bifurcation 
 or subdivision of its tentacular arms. It occurs in tangled masses, forming 
 beds of considerable extent in the Lower Lias of Dorset, Gloucestershire, 
 and Yorkshire. "This Crinoid," says Lyell, "with its innumerable ten- 
 tacular arms, appears to have been frequently attached to the drift-wood 
 of the Liassic Sea, in the same manner as barnacles float about at the 
 present day." 
 
 Exuviae (Lat., cast clothes). In zoology this term is applied to the 
 moulted or cast-off coverings of animals, such as the skin of the snake, 
 the crust of the crab, &c. ; but in geology it has a wider sense, and ap- 
 plies to all fossil animal matter or fragments of whatever description. 
 
 Eye-Stone. The name given to those varieties of circle-agate which show, 
 in the centre, a spot or spots more highly coloured than the concentric 
 layers. Also given to varieties of stalactite which, when cut across, show 
 a dark-coloured or hollow central portion, fancifully resembling an eye. 
 
 197 
 
FAB FAL 
 
 Faboidea (Lat. faba, a bean). A term applied by Mr Bowerbank to 
 certain bean-shaped leguminous seeds found in the London, or Lower Ter- 
 tiary, clays of the Isle of Sheppey. 
 
 Face. In crystallography, one of the planes which form the surface of 
 a regular solid. A cube has six such " faces," or plane surfaces. 
 
 Facet (Fr. facette, a little face). Applied to the small terminal faces of 
 crystals and cut gems. Precious stones cut into numerous faces are said 
 to be facetted, in contradistinction to being polished into rounded forms, 
 or cut, as lapidaries term it, " en cobochon." 
 
 Fades (Lat.) A convenient term in natural history, introduced to ex- 
 press any common resemblance or aspect among the rocks, plants, ani- 
 mals, or fossils of any area or epoch. Thus we speak of the " facies of the 
 Carboniferous flora " as distinct from the floras of other epochs ; and of the 
 " facies of the Australian fauna " as distinguished from the animals of other 
 regions by their common marsupial characteristics. 
 
 Factitious (Lat. factus, made). Made or fashioned by art, in contradis- 
 tinction to that formed by nature. We have thus factitious waters and fac- 
 titious stones made to resemble the natural products. 
 
 Faeces, Faecal (Lat. fcex, pi. fceces, excrement, worthless sediment). 
 The fossil faeces of fishes, saurians, &c., are known as coprolites ; the hard- 
 ened excrement of dogs and wolves, album grcecum, ; that of mice, album 
 nigrum. The preservation of faecal matter is common in all the geological 
 formations. 
 
 Fahlore, Fahlerz (Ger. falil, ash-coloured, and erz, ore). The mineral- 
 ogical term for ' ' grey copper-ore," and the type of a family of minerals 
 containing that important metal. See tabulations, " MINERAL SCHEME." 
 
 Fdhlunite. A sub-species of octahedral corundum, found in talcose rocks 
 at Fahlun in Sweden, hence the name. See AUTOMALITE. 
 
 Fahrenheit. Fahrenheit's thermometer is that arrangement of the ther- 
 mometrical scale in which the space between the freezing and the boiling 
 points of water, under a medium pressure of the atmosphere, is divided 
 into 180 ; the freezing point being marked 32, and the boiling 212. See 
 THERMOMETER. 
 
 Faikes or Fakes. A Scotch miner's term for fissile sandy shales, or 
 shaly sandstones, as distinct from the dark bituminous shales known as 
 "blaes" or "blaize." 
 
 Fairy-Stone. A name given by the peasantry in the south of England to 
 the flinty fossil sea-urchins found in the Chalk ; also a term used by geolo- 
 gists for recent concretions of hardened clay or clay-ironstone occurring 
 near the sources of certain chalybeate springs. In some districts the term 
 " Fairy loaves " is that most frequently applied to the Chalk ananchyles. 
 
 Falcate, Falcated (Lat. falx,f aids, a reaping-hook). Sickle-shaped, bent, 
 or shaped like a reaping-hook. 
 
 Falciform (Lat. falx, a reaping-hook, and forma). Shaped like a scythe 
 or reaping-hook ; e.g., certain bivalves and fish-spines. 
 
 198 
 
FAL FAT 
 
 Falling-Stones. A familiar term for aerolites or meteoric stones, which 
 see. 
 
 Faluns. A French provincial term for the shelly Tertiary (Upper 
 Miocene) strata of Touraine and the Loire, which resemble the " Crag " of 
 Norfolk and Suffolk. Though generally composed of shelly sand and marl, 
 in some districts they form a soft building-stone, chiefly composed of an 
 aggregate of broken shells, bryozoa, corals, and echinoderms, united by a 
 calcareous cement. 
 
 Family. In natural history classifications this term denotes the group 
 next in value and comprehensiveness above the genus. As species con- 
 stitute a genus, so genera constitute a family. The word, however, is 
 often used in a loose and general way, as equivalent to kind, tribe, or 
 group. 
 
 Farewell Rock. The familiar term in the South Welsh coal-field for the 
 Millsto'iie Grit, because on striking it the miner bids farewell to all workable 
 seams of coal. In Wales, some beds of this grit possess the valuable pro- 
 perty of resisting, for a long time, the action of the most intense heat, and 
 are therefore used for the " hearths " of iron furnaces. 
 
 Farina (Lat. far, corn). Meal or flour, obtained by grinding and sifting 
 wheat or other corn. Fossil Farina. A mealy-looking infusorial or micro- 
 phytal earth the Berg-mahl of the Swedes and Laplanders. 
 
 Farnham Beds. A portion of the Upper Greensand, near Farnham in 
 Surrey, which yields phosphate of lime in such abundance as to be largely 
 used by agriculturists as a fertiliser. " It is doubtless of animal origin," 
 says Lyell, " and partly coprolitic, derived from the excrement offish and 
 reptiles." See COPROLITES. 
 
 Fascicular (L&t. fasciculus, a little bundle). United or growing together 
 in bundles or tufts, as the needle-shaped crystals of some of the zeolites, 
 or the leaflets of the larch, pine, and other coniferse. 
 
 Fascicularia (Lat. fasciculus, a cluster or little bundle). A genus of 
 polyzoa occurring in the Coralline Crag of Suffolk, and so named from its 
 clustered or globular form. It belongs to the family of Tubuliporidce. 
 
 Fasciolaria (Lat. fasciola, a swathing band or stripe). A genus of 
 gasteropods belonging to the family Muricidce, and so termed from the 
 smooth band-like surface of their windings. They are thus distinguished 
 from Murex, whose windings are rough with '* varices" or wrinkle-like 
 swellings, and from Fusus by their spirally-plaited columella. The exist- 
 ing species are found chiefly in warm and southern seas ; the fossil occur in 
 the Chalk and Upper Tertiaries. 
 
 Fassaite. A variety or sub-species of augite, occurring in fine sharp 
 crystals of high lustre, and dark or pistacio-green colour, in traps, altered 
 limestones, and magnetic ores. It derives its name from Fassathal, in the 
 Tyrol, where it is found in great perfection. 
 
 Fata Morgana. The phenomenon of the mirage at sea. It arises from 
 two currents of air of different density or temperature coming suddenly in 
 contact ; and as at sea the upper is generally the warmer and the lower the 
 colder, the former becomes condensed at the place of contact, and forms, 
 as it were, a mirror for the objects which are in the lower current, so that 
 their images are inversely reflected. As the surface of separation is not 
 level throughout, various refractions and distortions result, which often 
 impart to the whole a singular and fantastic appearance. On land, where 
 the warmer current of air is on the surface of the ground, the aerial mirror 
 
 199 
 
FAU FEL 
 
 is formed beneath the eye of the observer, by which the same phenomenon 
 is produced that results from the reflection of objects on the surface of the 
 water. The name is said to be of Breton origin mor, sea, and gana, fine 
 lady the fairy mermaid of our popular legends. See MIRAGE. 
 
 Fault. The term for any fissure accompanied by a displacement of the 
 strata on either side. On one side the strata may be thrown down many 
 fathoms, on the other, thrown up; and at the same time may be altered 
 in their dip or inclination. Strata so fissured and displaced are said to be 
 "faulted." blip, slide, shift, heave, hitch, throw, trouble, and the like, are 
 familiar and synonymous terms. See THROW. 
 
 Fauna (Lat. rural deities). A convenient term for the animals of any 
 given epoch or area ; e.g., the " fauna of South America," the " fauna of 
 the Permian Era." As the Animals of an area or epoch constitute its 
 FAUNA, so the plants constitute its FLORA. 
 
 Favosites (Lat. favus, a honeycomb). A genus of sessile-spreading 
 corals common to the Silurian, Devonian, and Carboniferous systems ; and 
 so called from the regular polygonal arrangement of their pore-cells. 
 
 Favularia (Lat. favosus, honeycombed). A genus of Coal-measure stems, 
 so called from the aspect of their leaf-scars, which resemble in closeness 
 and regularity the arrangement of a honeycomb. The Favularia have 
 furrowed stems, with square-shaped leaf-scars on the ridges the scars 
 being of a breadth with the ridges. The stems seem to have been clothed 
 with a densely imbricated foliage, the leaves running in parallel rows, 
 which were separated by narrow intermediate furrows. 
 
 Felidse (Lat. felis, a cat). The Cat kind; a family of carnivorous mam- 
 malia, characterised, like the lion, tiger, cat, &c., by their short powerful 
 jaws, retractile claws, and the peculiar adaptation of their teeth for cutting 
 (trenchant). Geologically, the Felidse are of recent origin, their remains 
 not occurring prior to the Pleistocene cave-period ; e.g., the Machairodus. 
 See tabulations, " ANIMAL SCHEME." 
 
 Felspar (Ger. feldspath, rock-spar). An important rock-constituent or 
 simple mineral, consisting essentially of silica and alumina, with potash or 
 soda, and traces of lime, magnesia, and peroxide of iron. It is the 
 representative of a family the Felspar family whose species enter 
 largely into the composition of all igneous rocks granite, porphyry, 
 greenstone, and trachyte. It occurs crystallised, disseminated, massive, or 
 amorphous ; is colourless, but usually of shades of greyish- white, reddish, 
 yellow, or green ; when crystallised, breaks into rhomboidal fragments, 
 whose flat surfaces have a peculiar pearly- vitreous or resino-vitreous lustre ; 
 and its crystals have a hardness about 6, with a specific gravity varying 
 from 2.5 to 2.75. In ordinary granite it is readily distinguished from the 
 quartz, with whioh it is associated, by its flat lustrous fracture, and by 
 its being scratched by the knife while the quartz resists it. The more 
 abundant and better-known species are Orthodase or potash-felspar, with 
 its varieties adularia, common felspar, glassy-felspar, and felstone or 
 compact felspar ; Albite or soda- felspar, known also as Cleavelandite ; La- 
 bradorite; Oligodase ; and Amorphous felspar, with its varieties obsidian, 
 pumice, pearlstone, and pitchstone all of which are noticed under their 
 respective names. Mineralogically and geologically, the felspars are most 
 important minerals, and industrially they have also their value some, as 
 adularia, being used by the lapidary ; others, as common felspar, for enamels, 
 artificial teeth, and the like ; and the decomposable varieties yielding in 
 
 200 
 
FEL FER 
 
 nature the finest kaolin, or china clay, to the potter. Mineralogically, 
 the interchanges of soda, potash, and lime in the several varieties, 
 are curious and instructive ; and geologically, the fact that potash abounds 
 in the more siliceous felspars of the older Plutonic rocks, whereas soda and 
 lime prevail in the less siliceous or volcanic, is not without its significance 
 and value. The following exhibits their range of composition, and conse- 
 quently accounts for their varying external or physical characteristics : 
 
 Silica. Alumina. Potash. Soda. 
 
 Lime. 
 
 Iron. 
 
 Orthoclase... 
 
 64-70 
 
 1520 
 
 714 
 
 1-4 
 
 13 
 
 12 
 
 Felstone ... 
 
 7180 
 
 11-15 
 
 47 
 
 
 01 
 
 12 
 
 Albite 
 
 6771 
 
 1420 
 
 14 
 
 7-11 
 
 1-3 
 
 0-1 
 
 Labradorite . 
 
 4855 
 
 2630 
 
 01 
 
 14 
 
 912 
 
 13 
 
 Anorthite ... 
 
 4246 
 
 3237 
 
 01 
 
 01 
 
 1018 
 
 01 
 
 Oligoclase ... 
 
 6064 
 
 1824 
 
 1-3 
 
 2-10 
 
 25 
 
 0-1 
 
 Obsidian ... 
 
 7284 
 
 411 
 
 610 
 
 3-5 
 
 14 
 
 13 
 
 Pumice 
 
 7077 
 
 1218 
 
 0-4 
 
 04 
 
 24 
 
 14 
 
 Pitchstone... 6676 814 
 
 26 
 
 2-5 14 
 
 Felspathic. Of the nature of felspar ; containing felspar. Any mineral 
 or rock in which felspar greatly predominates is said to be felspathic ; as, 
 " felspathic claystone," " felspathic greenstone," &c. 
 
 Felstone. The term now generally employed by geologists to designate 
 compact felspar which occurs in amorphous rock-masses, and used in con- 
 tradistinction to felspar proper which occurs in more or less definite crys- 
 tallised forms. The term Felsite was at one time employed for the same 
 purpose, but is now all but obsolete. 
 
 Fen (Sax.) In geography, low land overflowed, or covered wholly or 
 partially with water, but producing reeds, sedges, coarse grasses, and 
 other aquatic plants ; low marshy tracts like the fens of Lincolnshire, 
 Kent, and Cambridgeshire. 
 
 Fenestella (Lat., a little window). An extensive genus of polyzoans, 
 resembling the retepora or flustra of existing shores, and found in all the 
 Palaeozoic strata, from the Silurian upwards. In fenestella the cells are 
 very small, indistinct externally, with minute prominent openings ; and 
 the polypary or coenoecium composed of branches which unite by growth 
 and form a cup. 
 
 Fermentation (Lat. fermentatio). The spontaneous decomposition of the 
 proximate principles of organic bodies, under the joint influence of warmth, 
 air, and moisture, and the reunion of their elements forming new com- 
 pounds ; e.g., the conversion of the expressed juice of the grape into wine, 
 or a solution of malt into alcohol or spirit. The simplest case of fermenta- 
 tion is that of must, or the expressed juice of the grape, which, when ex- 
 posed, either in close or open vessels, to a temperature of about 70, soon 
 begins to give off carbonic acid, and to become turbid and frothy ; after 
 a time a scum collects upon the surface, and a sediment is deposited ; the 
 liquor, which had grown warm, gradually cools and clears, loses its sweet 
 taste, and is converted into wine. This is the " vinous fermentation ; " 
 but if the wine be further exposed to air, and a due temperature, a second 
 fermentation ensues, which is called the "acetous fermentation," and which 
 terminates in the production of vinegar or acetic acid. In other words, the 
 oxygen of the air converts the hydrogen of the alcohol alcohol consisting 
 theoretically of carbon, water, and hydrogen into water, and leaves in 
 the acetic acid an indestructible or permanent residue of carbon and water 
 
 201 
 
PER FIG 
 
 only. Fermentation } or putrefaction, thus differs from eremacausis, or decay, 
 in being limited to changes occurring in and beneath the surface of water, 
 the effect being a mere transposition of elements or a metamorphosis of 
 the organic body. Eremacausis, on the other hand, refers to the decom- 
 position of moist organic matter, when freely exposed to the air, by the 
 oxygen of which it is gradually burned and destroyed, without any sensible 
 elevation of temperature. In the economy of nature as well as in the arts 
 of life, fermentation or putrefaction is an agency of the highest interest 
 and importance. "Like the labours of a scavenger," says Dr Cooley, 
 from whom we abridge, " it speedily removes from the surface of our globe 
 those matters which would otherwise remain for some time without under- 
 going decomposition. It either dissipates in air, or reduces to more fixed 
 and useful forms of matter, those organic substances which by their 
 presence would prove noxious, or at all events useless, to the animal and 
 vegetable kingdoms. It is the great power that cleans the Augean stable 
 of nature, at the same time that it provides some of the most esteemed 
 articles of utility and luxury (the fermented liquors, &c.) for the wellbeing 
 and enjoyment of man." 
 
 Ferricalcite (Lat. ferrum, iron, calx, calcis, lime). A term occasionally 
 applied to those varieties of limestone which contain a notable percentage 
 of iron, from seven per cent and upwards. 
 
 Ferriferous (Lat. ferrum, and fe.ro, I yield). Applied to veins, strata, 
 and other matrices that yield or contain iron. 
 
 Ferruginous (Lat. ferrum, iron). Impregnated or coated with oxide of 
 iron ; rusty-looking. 
 
 Ferruginous Quartz, or Iron Flint. A variety of quartz occurring in 
 various formations ; containing from 4 to 7 per cent of iron as an admix- 
 ture, and forming the transition into jasper. Very hard. 
 
 Fettstein (Ger., fat-stone). Same as elcnolile (oil-stone) or nepheline. 
 One of the Scapolite family, so called from its fatty or resinous lustre. 
 Consists of silica 45, alumina 32, soda 15, and potash 5, with traces of 
 lime, magnesia, iron, and water. 
 
 Fibrolite. A term occasionally applied to the fine fibrous varieties of 
 Andalusite. They consist of from 38 to 46 silica, 50 to 58 alumina ; and 
 .75 to 2.5 iron peroxide ; and are known also by the name of Buchohite. 
 See ANDALUSITE. 
 
 Fibrous (Lat. fibra, a thread or fibre). Applied in geology and miner- 
 alogy to rock and mineral textures which consist of or resemble fibres, as 
 amianthus or asbestos. 
 
 Fichtelite. A fossil resin occurring chiefly in the form of yellowish 
 transparent scales between the annual rings of growth of a species of pine 
 which have separated from each other in the process of decay. So named 
 from being found in the turf -beds of the Fichtelgebirge, North Bavaria. 
 
 Ficoidltes (fig-like). The generic term used by Artis, in his 'Antedilu- 
 vian Phytology,' for the Stigmariaficoides, which see. 
 
 Figuline (Lat. figidus, a potter, from Jingo, I fashion). A term occasion- 
 ally applied by mineralogists to potter's clay. See CLAY. 
 
 Figure-Stone. A variety of talc-mica or steatite ; known also as Agal- 
 matholite. Its usual colour is white or red, or both colours intermingled 
 in bands and patches. The finest are brought from China, where it is cut 
 into various figures, pagodas, &c. ; hence the names figure-stone, pagodite, 
 and the like. 
 
 202 
 
FIL FIS 
 
 Piles. A familiar term among the peasantry of the south of England 
 for the striated and tuberculated spines of Cidaris. 
 
 Pilices (Lat. filix, a fern). In botany, the Fern tribe the Filicales or 
 Filical Alliance of Lindley. See tabulations, "VEGETABLE SCHEME." 
 
 Pilicites (Lat. filix, a fern). Sclotheim's generic term for the fern-like 
 plants now called neuropteris and pecopteris ; used also as a general term 
 for any fossil fern or filicoid plant. 
 
 Filicoid (Lat. filix, fern, and eidos, likeness). Applied to plants, recent 
 or fossil, which resemble or partake of the nature of the fern tribe. 
 
 Filiform (Lat. filum, a thread). Thread-like ; slender as a thread. 
 
 Filtration (Lat. filtrum, an instrument for straining liquids). The separ- 
 ation of liquids from substances mechanically suspended in them, by pass- 
 ing them through the pores of media sufficiently fine to keep back the 
 particles of solid matter. Gravel, sand, sandstone, and other porous strata, 
 are the great filtering media in nature. 
 
 Fiorite. Pearl-sinter ; a variety of siliceous sinter found incrusting vol- 
 canic tufa at Santa Fiora in Tuscany, whence the name. It is not un- 
 common in the vicinity of hot springs and volcanoes, and consists chiefly 
 of silex, with a little alumina, iron-peroxide, and water. 
 
 Fire-Clay. Any clay capable of resisting a great heat without slagging 
 or vitrifying. This property arises from the absence of any alkaline earth 
 to act as a flux. Fire-clays abound in the Coal-measures of Great Britain, 
 and are largely employed in the manufacture of furnace and grate bricks, 
 retorts, chimney-flues, and the like. The celebrated Stourbridge clay 
 (Worcestershire) is said to consist of about 64 silica, 24 alumina, and 2.0 
 oxide of iron the rest being water and traces of carbonaceous matter. 
 
 Fire-Damp. A miner's term for light carburetted hydrogen, which, when 
 diffused in the atmosphere of the coal-workings to the amount of one-thir- 
 teenth by volume, becomes explosive. The most explosive mixture is 
 said to be seven volumes of air to one of fire-damp. When the proportions 
 vary considerably either above or below that of seven to one, the mixture 
 is not explosive. See AFTER-DAMP and CHOKE-DAMP. 
 
 Fire-Opal, or Girasol. A fine lustrous variety of opal, which see. 
 
 Fire-Stone. Any stone that stands heat without injury ; generally ap- 
 plied to certain Cretaceous and Oolitic sandstones employed in the con- 
 struction of glass-furnaces. In geological classification, a calcareo-aren- 
 aceous member of the Upper Greensand, so called from its yielding stone 
 of this description. 
 
 Fissile (Lat. fissilis). Capable of being split; applied to rocks which, 
 like clay- slate, can be split or divided in the direction of the grain or 
 cleavage. Fissility. The quality or characteristic of admitting to be split 
 in thin leaves or laminae. 
 
 Fissiparous (Lat. fissus, split or divided, and pario, I produce). Gen- 
 eration, or rather multiplication, by the self-division of the individual into 
 two or more parts, each of which becomes a perfect creature similar to 
 its parent-original. Generation may thus be fissiparous (by division), 
 gemmiparous (by buds), oviparous (by eggs), or viviparous (by living young). 
 Fissiparism is confined, of course, to the lower vegetable and animal forms. 
 
 Fissure (Lat. fissus, split asunder). A crack, rent, or open crevice in 
 rocks ; strata or rock-masses so rent are said to be fissured. 
 
 Fistnlous, Fistular (Lat. fistula, & pipe). Hollow like a pipe; tube-like. 
 Applied to the stems of grasses, umbelliferous plants like the hemlock, &c. 
 
 203 
 
FIX FLI 
 
 Fixed Air. A name formerly given by chemists to carbonic acid gas, 
 from its being the air or gas fixed, as it were, in lime, magnesia, and the 
 alkalies. 
 
 Flabellaria (Lat. flabellum, a fan). A provisional genus intended to em- 
 brace all those broad, flabelliforin, palm-like leaves which occur particu- 
 larly in the Coal formation and Tertiary lignites. 
 
 Flabelliform (Lat. ftabellum, a fan, and forma, likeness). Fan-shaped ; 
 applied to the broad spreading leaves of certain palms, such leaves being 
 found in many lignites as well as in the older Coal formations. 
 
 Flagstone. A quarryman's term for any fissile sandstone which " beds," 
 or splits up into flags, like the Arbroath and Caithness paving-stone. 
 Flaggy. Applied to the laminar strata capable of being split up. 
 
 Flenu Coal. A peculiar variety of bituminous coal occurring abundantly 
 in the Belgian coal-fields. It burns rapidly with much flame and smoke, 
 not giving out an intense heat, and having a somewhat disagreeable odour. 
 It resembles some of the seams found at Swansea in Wales. See COAL 
 FAMILY. 
 
 Flexible Sandstone. A fissile variety of sandstone, thin slabs of which 
 have a certain amount of flexibility. This property, 'in some instances, 
 arises from the dissemination of minute scales of mica, and in others from 
 a peculiar arrangement of the particles, which stand apart as if some in- 
 gredient had been removed by percolation. 
 
 Flint Implements. The general term for spear -heads, arrow-heads, 
 knife-like flakes, and other implements, whether for war, the chase, or 
 domestic purposes, which are formed of flint, and are used or have been 
 used by rude tribes unacquainted with the use of the metals. In Europe 
 these implements are found abundantly in Post- Tertiary or Upper Pleisto- 
 cene drifts and caverns, and belong to what is termed the " stone age " 
 of archaeology ; and in some instances, as at Abbeville (which see), seem 
 to have been imbedded contemporaneously with the bones of Mammoth, 
 Irish Elk, and other extinct mammalia thus bespeaking a vast antiquity 
 for the people who fashioned them. 
 
 Flints (Sax.) The familiar as well as technical term for those siliceous 
 nodules and concretions which occur so abundantly in the white chalk of 
 England, in many limestones, and other calcareous strata. Flints are com- 
 posed almost entirely of silex, with traces of iron, clay, and lime ; and 
 where lime is present in any notable proportion, or when limestones be- 
 come so siliceous as to be incapable of conversion into quicklime, the admix- 
 ture is known as Chert. In the Chalk formation, flints are usually aggre- 
 gated round some nucleus of sponge, shell, coral, or other organism ; and 
 there is little difficulty in conceiving the silex to have been originally in 
 solution in the waters of deposit, and subsequently segregated by some 
 chemical process into layers and nodules as we now behold it. Being so 
 frequently collected round spongiform organisms, it has been ingeniously 
 surmised by Dr Bowerbank, " that the geological office of the Sponges in 
 creation is that of inducing the deposit of siliceous matter held in solution 
 in the ocean, just as the corals assist in the consolidation of the calcareous 
 matter." Economically, fliut is of considerable importance, being largely 
 used (when calcined and ground) in the manufacture of china, porcelain, 
 flint-glass, and the like. It is also employed, in absence of other material, 
 as a building-stone ; and before the invention of percussion-caps and lucifer- 
 matches, was in universal use for gun-flints and fire-production. 
 
 204 
 
FLO FOH 
 
 Float-Stone (Ger. Schwimmslein}. A variety of earthy silica, of a coarse 
 porous aspect, soft and often friable, and of a yellow or greyish-white 
 colour. Being porous, it swims on water till saturated ; hence the name, 
 float-stone or spongiform quartz. According to Ehrenberg it consists chiefly 
 of the siliceous coverings of infusoria, and is thus closely related to tri- 
 poli, polishing-slate, and other earthy silicas. An analysis by Schaffgotsch 
 gives 85.9 silica, 0.7 alumina, 9.1 carbonate of lime, and 3.3 water. 
 
 Flocculent (Lat. floccus, a lock of wool). Applied to solutions or mechan- 
 ical suspensions of impalpable mineral matter the particles aggregating 
 in light cloudy " flocks " during the act of deposition. 
 
 Flookan or Flucan. A miner's term for a soft clayey substance occa- 
 sionally found in cross-courses and slides ; a cross-course or transverse 
 vein composed of clay. A cross-floolan is a slide or fissure filled with clay 
 which runs across a lode and heaves it. 
 
 Flora (Lat., the goddess of flowers). A convenient term for the vegeta- 
 tion of any given epoch or area as " the flora of the Coal-measures " 
 " the flora of South America." As the plants of a country or epoch con- 
 stitute its FLORA, so the animals constitute its FAUNA. 
 
 Flos-Ferri (literally, flower-of-iron). A fine radiated or corralloid variety 
 of arragonite, common in the iron mines of Styria, and also in some lime- 
 stone beds. Known also as Needle-spar; and differs from Satin-spar, which 
 is a fine fibrous silky variety of the same mineral. See ARRAGONITE. 
 
 Flbtz (Ger., a layer). A term applied by Werner to the Secondary strata, 
 because they were flotz, or flat-lying, compared with the Primary and 
 Transition rocks. 
 
 Fluor-Spar (Lat. fluere, to flow ; so called from being used as a flux). 
 Fluate of lime, or fluoride of calcium, consisting of 67.75 lime, and 33.25 
 fluoric acid. It occurs chiefly in veins either crystallised in cubes, foliated, 
 in granular crystalline masses, or compact and earthy. Its colours are 
 various, the more common being violet-blue, honey -yellow, green, and 
 purplish-blue passing into red. Beautiful crystals are found in the lead 
 mines of Alston Moor and Derbyshire, and the concretionary crystalline 
 masses of Castleton in Derbyshire (known as Blue- John or Derbyshire spar) 
 are wrought into various ornamental articles. 
 
 Fliiviatile (Lat. flumus, a running river). Belonging to a river ; pro- 
 duced by river action ; growing or living in fresh-water rivers. 
 
 Fluvio-Marine (Lat. fluvius, a river, and marc, the sea). Applied to stra- 
 tified deposits which seem to own a mixed river and sea origin ; in other 
 words, to deposits brought into the sea by river-currents, loaded with the 
 detritus of the land : hence the occurrence in the same beds of terrestrial, 
 fresh-water, and marine remains. 
 
 Flux (Lat. fluere, to flow). In chemistry and metallurgy, any substance 
 added to facilitate the fusion of metals or minerals. Alkaline fluxes are 
 generally employed ; they render the earthy mixture fusible by converting 
 it into glass. Salts of potash and soda, lime, borax, and the like, are well- 
 known fluxes. In hydrography, the flow of the tidal wave the Flux 
 being the rise, the Reflux the ebb of the tide. 
 
 Flysch. A provincial Swiss term for a series of Tertiary strata consist- 
 ing of dark-coloured slates, marls, and fucoidal sandstones immediately 
 overlying the nummulitic limestone. According to Lyell, the flysch occu- 
 pies a middle place in the Eocene or older Tertiaries. 
 Fohn. The name given in Switzerland to the hot southerly winds of 
 205 
 
FOL FOU 
 
 summer (the sirocco), which, arising from the northern tracts of Africa, 
 cross the Mediterranean, and impinge on the snow-clad Alps, thereby 
 annually causing a rapid diminution of the lower glaciers. " Were the 
 desert tracts of Africa again covered, as they once were, by the ocean," 
 says Prof. Phillips, "the wind would lose its excessive dissolving power, 
 snows would gather on the Alps above, and glaciers extend below to levels 
 and distances now quite unattainable without some great physical change." 
 
 Foliated (Lat. folium, a leaf). Resembling a leaf; composed of thin 
 leaf-like layers. Thus certain shells are said to be foliated, when their 
 surfaces are covered with leaf-like projections, as the rose-bush murex ; the 
 substance of a shell is also said to be foliated when composed of thin flat 
 layers overlapping each other, as in the oyster ; and we speak of foliated 
 gypsum, when the texture is scaly or leafy, and not granular or compact. 
 
 Foliation (Lat. folium, a leaf). In botany, the manner in which the 
 young leaves of plants are arranged in the leaf-bud ; synonymous with 
 vernation. In geology, the laminae or plates into which gneiss, mica- 
 schist, and other crystalline rocks are divided. " Cleavage" says Mr 
 Darwin, " may be applied to those divisional planes which render a rock 
 fissile, although it may appear to the eye quite or nearly homogenous ; 
 foliation may be used for those alternating layers or plates of different 
 mineralogical nature, of which gneiss and other metamorphic schists are 
 composed." The subject of foliation has given rise to a great deal of 
 unsatisfactory speculation and hypothesis, some associating the pheno- 
 menon with cleavage, contending that the planes of both are generally 
 coincident, and attempting to account for both by the same metamorphic 
 process ; while others maintain that foliation is identical with the lines 
 of bedding, and is a structure conferred on stratified rocks by their 
 original deposition. While leaning to the latter hypothesis, Sir Charles 
 Lyell, at the same time, " fully admits that the alternate layers of quartz, 
 or of mica and quartz, of felspar, or of mica and felspar, or of carbonate 
 of lime, are more distinct in certain metamorphic rocks than the ingre- 
 dients composing alternate layers in most sedimentary deposits, so that 
 similar particles must be supposed to have exerted a molecular attraction 
 for each other, and to have congregated together in layers more distinct 
 in mineral composition than before they were crystallised." 
 
 Foralites (Lat. foro, I bore). Applied to certain tube-like markings 
 which occur in sandstones and other strata, and which seem to have been 
 the burrows of annelids having the habits of the common lob- worm. 
 
 Foraminifera (Lat. foramen, an orifice, and fero, I bear). The name 
 given by D'Orbigny to a group of minute, many-chambered shells, or 
 rather many-celled organisms the calcareous cells (loculi) of which are 
 pierced, like a sieve, with numerous pores or foramina. The Foraminifera 
 were supposed by D'Orbigny to be cephalopods, but more recent observa- 
 tion (Dujardin) has shown that they are not mollusca, but compound Pro- 
 tozoa, whose cellular aggregation produces the many-chambered aspect in 
 question the numerous pores being for the protrusion of their delicate 
 filaments. Physiologically speaking, and according to Owen, a Foramin- 
 ifera may be regarded either as a series of individuals organically united ; 
 or as a simple aggregate-being, compounded according to the law of vege- 
 tative repetition. They occur in rocks of all formations, from the Lauren - 
 tian upwards their microscopic remains constituting the greater bulk of 
 the Chalk and Tertiary limestones. See RHIZOPODA and POLTTHALAMIA. 
 
 206 
 
FOR FRA 
 
 Forest-Bed. The name given by English geologists to a stratum which 
 underlies the Glacial Drift at Cromer in Norfolk, because it imbeds abun- 
 dant stumps, trunks, and branches of trees. This bed can be traced for 
 miles between high and low water mark, and contains numerous erect 
 stumps and prostrate trunks of trees, such as the Scotch fir, spruce, yew, 
 alder, oak, &c., together with remains of elephant, rhinoceros, hippopo- 
 tamus, horse, pig, and other mammals. The whole, in fact, exhibits both 
 the flora and fauna of a forest of the preglacial era. 
 
 Forest Marble. An argillaceous laminated shelly limestone, alternating 
 with clays and calcareous sandstones, and forming one of the upper por- 
 tions of the Lower Oolite. It derives its name from Whichwood Forest in 
 Oxfordshire, where the finer bands are quarried as a marble. See OOLITE. 
 
 Formation. "The term formation," says Lyell, " expresses in geology 
 any assemblage of rocks which have some character in common, whether 
 of origin, age, or composition. Thus, we speak of stratified and unstrati- 
 fied, fresh-water and marine, aqueous and volcanic, ancient and modern, 
 metalliferous and non-metalliferous formations." In this wide sense, how- 
 ever, the word is often loosely and inaccurately used ; and when speaking 
 of the stratified rocks, it is better to restrict the term to such an assem- 
 blage of strata as are connected by mineral composition, by unbroken 
 succession in point of time, and by continuity of fossil species. In this 
 sense we have such assemblages as the "Chalk formation," "Coal forma- 
 tion," &c., whose members, though differing in minor particulars, have evi- 
 dently been formed or deposited under a continuance of similar conditions. 
 
 Fossil (Lat. fossus, dug up). Literally anything dug out of the earth ; 
 hence the earlier geologists spoke of native fossils or minerals, and extra- 
 neous fossils or the bodies of plants and animals accidentally buried in the 
 earth. The term is now generally restricted to "organic remains," or the 
 remains of plants and animals imbedded in the earth's crust, and more or 
 less altered in structure and composition by mechanical and chemical 
 agencies. When these remains are only partially petrified, and occur in 
 superficial or recent deposits, the term sub-fossil is employed. 
 
 Fossiliferoas (Lat. fossilis, and/ero, I bear). Applied to rocks and rock- 
 systems containing organic remains, in contradistinction to non-fossil- 
 iferous, or those which contain no such relics. 
 
 Fossilisation, Fossilised, &c. The conversion of vegetable and animal 
 remains into fossils, by impregnation with mineral or metallic matter. 
 See PETRIFACTION. 
 
 Fossil-Paper, Fossil-Wool, Fossil-Flax, Fossil-Cork, &c. Familiar terms 
 applied to certain varieties of amianthus, according as these appear in 
 thin papery flakes, in flax-like fibres, in loose woolly floes, or in tough cork- 
 like fragments. See ASBESTOS. 
 
 Fracture (Lat. fractus, broken). When a mineral breaks up into deter- 
 minate forms with smooth regular surfaces, such surfaces are said to con- 
 stitute its cleavage; but when a rock or mineral breaks up irregularly 
 under a blow of the hammer, the appearance of the fresh surface so 
 exposed is termed its fracture. Thus the fracture is said to be even when 
 it forms a face or plane of some extent ; uneven, when the surface is rough 
 and unequal ; conehoidal, or shell-like, when concave on one side and 
 convex on the other ; splintery, when the surface presents the appearance 
 of numerous thin-edged scales ; and hackly, when covered with numerous 
 sharp points or inequalities. 
 
 207 
 
FRA FRO 
 
 Fragmentary (Lat. fragmentum, a chip or portion broken off, from 
 frango, I break). Applied in geology to rock-masses composed of the 
 fragments or debris of other rocks ; rocks not homogeneous in texture ; 
 nearly synonymous with breccias or breccio-conglomerates, which see. 
 
 Frangibility. In geology, the degree of facility with which a rock 
 yields to the hammer. 
 
 Franklinite (after Benjamin Franklin). An ore of iron occurring in 
 grains or in granular masses of an iron-black colour and metallic lustre, 
 and found in veins, often of great thickness, as those of New Jersey in the 
 United States. It consists of from 56 to 66 peroxide of iron, the remainder 
 being composed of peroxide of manganese and oxide of zinc in varying 
 proportions. The oxides of manganese and zinc are said to exercise a very 
 favourable influence upon the iron manufactured from this ore, increasing 
 its tenacity, rendering it less liable to rust, and fitting it for easy conver- 
 sion into the finest steel. 
 
 Freestone. Any rock which admits of being freely cut and dressed by 
 the builder ; generally applied in Scotland to the varieties of sandstone. 
 
 French Chalk. A white or greyish- white variety of steatite, used for 
 removing stains from silk, for slate-pencils, and, in powder, for lessening 
 friction. 
 
 Freshet. A river-flood or inundation, occasioned by the sudden melting 
 of the ice and snow in spring ; the predominance of fresh water in tidal 
 estuaries, during periodical rainfalls and land-floods. 
 
 Friable (Lat./rt'o, I grind or crumble). Easily broken into small pieces; 
 easily crumbled or reduced to powder. The opposite of tough or tenacious. 
 
 Fringing-Reefs. A class of coral-reefs, known also as " shore-reefs," 
 from their fringing or encircling islands at a moderate distance from 
 shore. "They differ from barrier-reefs," says Darwin, "in not lying so 
 far from shore, and in not having within a broad channel of deep water." 
 The reefs which fringe the island of Mauritius form a good example of the 
 class. See CORAL-REEFS. 
 
 Frith, Firth (Lat. /return). An arm of the sea, as the Frith of Forth, 
 the Frith of Tay, &c. Originally applied to any strait narrow passage, 
 or inlet. 
 
 Frond (Lat. frons, a branch). In botany, the term applied to the foli- 
 aceous or leaf-like part of ferns and other flowerless plants. The frond 
 differs from a true leaf both in structure and function, and combines as it 
 were branch, leaf, and fructification in one organ. 
 
 Frost (Sax.) In meteorology, the freezing, or conversion into ice, of 
 water and watery vapours by the influence of cold. In ordinary circum- 
 stances water passes into ice when the temperature of the air falls to 32 
 of Fahrenheit ; but as the cold increases the frost becomes more intense, 
 and substances (such as oils, mercury, &c.) which remained liquid at 32, 
 gradually lose their caloric and pass into the solid state. As a geological 
 agent, frost exerts a purely mechanical influence, but this influence is of 
 prime importance in disintegrating rocks and soils, moulding the contour 
 of mountains, and assisting in the dispersion of boulders and other debris, 
 not only from higher to lower levels, but from the land over the bottom 
 of the ocean. Thus, the rain and moisture that enter the fissures of cliffs, 
 and between the particles of all rocky matter, are often frozen during 
 winter, and in this state of ice expand and force apart these rocks and 
 particles. When thaw comes, the particles, having lost their cohesion, fall 
 
 208 
 
FUG FUN 
 
 asunder ; and thus, under all latitudes and at all altitudes, where frost 
 occurs, vast waste is every winter effected and this in proportion to the 
 intensity of the cold, which may range from freezing to 60 below freezing, 
 and according to the rapidity and frequency of the alternations from fresh 
 to freezing. It is also by the action of frost that avalanches, glaciers, and 
 icebergs are formed on mountains above the snow-line and in arctic 
 regions : the avalanche of snow and ice, which, losing its coherence, is 
 launched from the mountain-side, carrying masses of rock and soil and 
 trees before it the glacier, or ice-lake, that gathers in the mountain-glen 
 above, and slowly grinds its way to the valley below, smoothing the rocks 
 in its passage, and leaving as it melts away its lateral and terminal ridges 
 of gravel and debris, technically termed "moraines" and the iceberg, 
 detached by fracture from the projecting glacier of some arctic shore, that 
 floats its burden of rock and gravel to warmer latitudes, there to drop 
 them as it melts away on the bottom of the ocean. In the study of frost- 
 operations, whether among the cliffs and gorges of mountains like the 
 Alps and Himalayas, or along the shores of the Arctic Ocean, the observer 
 discovers at once an important cause of present change and a key to the 
 solution of some of the most interesting of geological problems. See ICE, 
 ICEBERG, &c. 
 
 Fucivorous (Lat. fucus, sea- weed, and wro, I devour). Literally "fucus- 
 eating;" applied to animals that subsist on sea- weeds, e.^.,the "fuci- 
 vorous mollusca," the " fucivorous cetaceans," &c. 
 
 Fucoides (fucus, sea- weed, and eidos, likeness). The generic term for any 
 fossil fucus or fucus-like organism of unknown affinity. 
 
 Fucoids (fuciis, sea- weed, and eidos, likeness). Fucoids, or fucus-like 
 impressions, occur in strata of every epoch, from the Lower Silurians 
 to the Upper Tertiaries. Such terms, therefore, as " fucoidal sandstones," 
 fi fucoidal shales," &c., are not unfrequent in geological descriptions. 
 
 Fulgurite, Fiilgorite (Lat. fulgur, lightning). Any rocky substance 
 that has been fused or vitrified by lightning. More strictly applied to a 
 bore or tube produced by the passage of lightning into a sandy soil, which 
 it sometimes penetrates to a depth of twenty feet, fusing and vitrifying 
 the sand and gravel in its downward progress. Fulgorites are occasionally 
 dug up in the sandy plains of Silesia and Eastern Prussia. 
 
 Fuller's Earth. A term applied to certain soft unctuous clays (hydrous 
 silicates of alumina) of the Oolite and Chalk systems, from their being 
 employed in the fulling of woollens. Good fuller's earth is usually mas- 
 sive, opaque, soft, dull, with a greasy feel and an earthy fracture ; scarcely 
 adheres to the tongue, and when placed in water falls down to an impalp- 
 able powder without forming a paste with it. So important at one time 
 was this earth to the woollen manufacture of England that its exportation 
 was prohibited by act of Parliament. Its place is now mainly supplied by 
 soap and other detergents, though considerable quantities are still dug and 
 prepared for the fuller in Surrey and Bedfordshire. In geological classifi- 
 cation the term is applied to an argillaceous stratum ("the Fuller's 
 Earth") which lies between the Great and Inferior Oolites, near Bath. 
 
 Fumarole (Ital. fumare, to smoke). An opening or orifice, in a volcanic 
 district, from which smoke and other gaseous fumes are emitted. 
 
 Fungia, Fungida. A genus and family of single lamellated corals, so 
 called from the resemblance of their stony' structure to that of a fungus or 
 mushroom. They are of a depressed form, have the under surface scab- 
 
 209 o 
 
FUN GAD 
 
 rous, and are divided above by numerous lamellae or plates, which radiate 
 from a central oblong depression. The original genus Fungia of Goldfuss 
 is now broken up into micrabacia, a form peculiar to the Chalk and Green- 
 sand, anabacia to the Oolite, and palceocyclus to the Silurian system. 
 
 Fungoid, Fungiform (Lat. fungus, a mushroom, and eidos, likeness V 
 Applied to nodular excrescences and petrifactions which resemble the 
 clustering tubercular growth of the fungus ; also to single structures (e. </., 
 certain corals) which resemble the mushroom in form. 
 
 Funiform (Lat. funis, a cord or cable). Cord-like ; rope-like ; resem- 
 bling a cord or cable in appearance. 
 
 Fusible Metal. An alloy of eight parts of bismuth, five of lead, and 
 three of tin, which melts at the boiling-point of water (212 F.), and may 
 be fused over a candle in a piece of stiff paper, without burning the paper. 
 
 Fusible Quartz. A term occasionally applied by the older mineralogists 
 to obsidian, which see. 
 
 Fusiform (Lat. fusus, a spindle, and forma, likeness). Spindle-shaped ; 
 thickest in the middle, and tapering towards the extremities ; e. g. , shells 
 of the genus Fusiis or "spindle-shell." 
 
 Fusion (Lat. fusus, melted, from fundo, I pour out). The state of 
 melting. Solid substances, as iron, basalt, &c., when rendered fluid by the 
 application of heat, are said to be in a state of fusion. Substances which 
 admit of being melted are termed fusible ; those which resist the action of 
 fire are termed refractory. 
 
 Fusulina (Lat., a little spindle). A genus of foraminiferous organisms, 
 occurring in the Carboniferous formation, and so termed from their fusi- 
 form shells, which are elongated transversely the cells being divided in- 
 ternally by constrictions. Regarded as the earliest and most ancient type 
 of the Foraminifera yet known. 
 
 Fusus (Lat., a spindle). An extensive genus of gasteropods belonging 
 to the Muricidce or Murex family, having a world-wide distribution, and 
 occurring also in a fossil state from the Oolite upwards. The spindle-shell, 
 red-whelk or buckie of our own shores, may be taken as a type. They 
 inhabit sandy or muddy bottoms, and have a range from 5 to 70 fathoms. 
 
 G 
 
 Gabbro. An Italian term for a rock consisting essentially of diallage 
 and felspar ; the euphotide of French geologists, and the Verde di Corsica 
 duro of artists. 
 
 Gad. In mining, a pointed wedge of a peculiar form, much used in 
 Cornwall for underground purposes; hence the title "Pick and Gad" 
 at one time adopted for a mining periodical. 
 
 Gadolinite. A greenish-black mineral, occurring massive, and in gran- 
 ular and prismatic concretions, in granitic and felspathic rocks. It is 
 named after the Russian chemist Gadolin, who, in 1794, discovered the 
 earth yttria in specimens obtained from Ytterby in Sweden. According 
 
 210 
 
GAH GAN 
 
 to Berzelius, it consists of 45.93 yttria, 24.16 silica, 16.90 protoxide of 
 cerium, 11.34 protoxide of iron, with traces of magnesia, lime, and glucina. 
 When heated, Gadolinite becomes incandescent, but undergoes no change 
 in weight a property which Rose ascribes to the liberation of specific heat, 
 the quantity in the mineral before and after ignition being different. 
 
 Gahnite. Known also as Automalite ; a native aluminate of zinc, named 
 after its discoverer, Gahn. 
 
 Galecynus (Gr. gale, weasel, and kyon, dog). A term applied by Owen 
 to the remains of a viverrine fox, from the fresh- water Tertiary (Miocene) 
 deposits of CEningen the characters of the bones indicating a genus inter- 
 mediate between the polecats and dogs that is, viverra and canis. 
 
 Galena (Gr. galeo, I shine). Native protosulphide of lead ; lead -glance. 
 So called from its bluish-grey colour and metallic lustre. Galena is the 
 chief ore of lead in this country, occasionally occurring in crystals, but 
 most frequently massive, and disseminated in granular, compact, or lam- 
 inar aggregates. It is found in veins in the crystalline rocks, and abund- 
 antly in the Carboniferous limestone. It usually contains a small proportion 
 of silica, varying from 1.03 to .06 per cent, and very rarely amounting to 
 1 per cent. Small percentages of antimony, iron, zinc, and the like, occur 
 in most British ores. 
 
 Galeocerdo (Gr.) Literally "fish-fox ;" a genus of sharks, whose broad- 
 based, sharp, serrated teeth occur from the Lower Tertiaries upwards. 
 
 Galerites, Galerltidae (Lat. galea, a helmet). A genus and family of sub- 
 conical, helmet-shaped sea-urchins abounding in the Chalk formation, and 
 from their shape popularly known in Kent and Sussex as "sugar-loaves." 
 In the Oaleritidce the shell is high and much inflated, more or less conical 
 above, and oblong-oval at the base, narrowing towards the hinder part. 
 The ambulacra are simple, never petalloid ; the poriferous zones extend 
 from the summit to the mouth, which is situated in the centre of the base ; 
 the outlet near the posterior margin. One of the most abundant species 
 is the albo-galerus, so termed from its fanciful resemblance to the white 
 conical caps of the priests of Jupiter. 
 
 Galesaiirus (Gr. gale, polecat, and sanrus, lizard). A provisional genus 
 of Crocodilians, founded on an entire cranium and lower jaw, from the 
 sandstone rocks of Rhenosterberg, South Africa ; and so named by Pro- 
 fessor Owen from the resemblance of its dentition (which is quite of a 
 mammalian character) to that of the weasels and polecats. This peculia- 
 rity of dentition is regarded by its describer as "a singular and suggestive 
 approach to the mammalian class." 
 
 Galionella (Lat., a small helmet). AIJ abundant genus of Diatoms or 
 microscopic plant- growths, so called from the cylindrical, globular, or helm 
 shape of their siliceous shields. They are free, but usually occur in chains ; 
 and abound in pools and lakes, as well as in Tertiary marls and other mi- 
 crophytal earths. 
 
 Gallery. In mining, a working drift or level from which the mineral 
 has been excavated. 
 
 Gang, Gangue. The German term for a vein or lode ; literally a 
 course or passage. Gangue, the veinstone, vein-stuff, or matrix in which 
 the metallic ore occurs. t 
 
 Ginglioneura (Gr. ganglion, a knot, and neuron, nerve). Literally 
 " knotted nerves ; " a name applied by Rudolphi to the articulate and 
 molluscous divisions of the animal kingdom, because characterised by a 
 
 211 
 
GAN GAR 
 
 ganglionic type of the nervous system. In the Articulata the ganglia arc 
 always disposed symmetrically along the middle line of the body, and 
 brought into communication by a double chord ; whence these have been 
 termed Homogangliata. In the Mollusca, on the other hand, the ganglia 
 are dispersed and placed at a distance from each other, and from the 
 mesial line, and are frequently unsymmetrical in their arrangement; hence 
 these have been termed Heterogangliata. 
 
 Ganister, Gannister. The local name for a fine hard-grained grit 
 which occurs under certain coal-beds in Derbyshire, Yorkshire, and the 
 north of England. 
 
 Ganocephala (Gr. ganos, lustre, and Icepliale, the head). One of the 
 orders into which Professor Owen proposes to arrange the Reptilia, living 
 and extinct. The term has reference to the sculptured and externally 
 polished or ganoid bony plates with which the entire head is defended. 
 The order embraces the Archcegosaurus and other allied palaeozoic forms, 
 which, in addition to the peculiar bones of the head, are characterised by 
 the absence of occipital condyles, by the persistence of the notochord (the 
 vertebral arches and peripheral elements being ossified), by small natatory 
 pectoral and pelvic limbs, by large median and lateral throat-plates, by 
 their small, narrow, and sub-ganoid scutes, and, in some, by traces of 
 branchial arches. 
 
 Ganoid, Ganoidean (Gr. ganos, splendour, and eidos, likeness). The 
 second order of fishes in Agassiz's arrangement. They have angular 
 scales regularly arranged, and composed of horny or bony plates, covered 
 with a strong shining enamel. The Ganoideans are chiefly palaeozoic and 
 extinct forms: the bony pike of Canada and the sturgeon are living 
 examples. 
 
 Garnet (Fr. grenat, Ital. grenato, quasi granum, a grain). In modern 
 systems of mineralogy the garnets constitute an extensive but extremely 
 variable family, according as alumina, iron, lime, magnesia, or similar 
 bases, are associated with the silica, which composes about half the mineral. 
 They are all, in fact, silicates of one or more of these bases, and are usually 
 arranged into six sections viz.', lime-garnets, magnesia-garnets, iron- 
 garnets, manganese-garnets, iron-lime-garnets, and lime-chrome-garnets. 
 They occur chiefly in mica-schist and other crystalline strata, but are 
 found also in granite, trap, and other igneous rocks. The garnet proper 
 appears in dodecahedral crystals and druses, in grains, occasionally in thin 
 subordinate bands, or so thickly studding portions of the gneiss and mica- 
 schist that millstones have been made from the mass. The colour of the 
 garnet is usually a deep amber-red, reddish-brown, or black, but occasion- 
 ally olive-green passing into yellow ; its lustre is vitreous or resinous ; and 
 it is transparent in all degrees. Of the better-known varieties we may 
 mention the Almandine or noble garnet, of a beautiful columbine-red ; the 
 Grossular or olive-green ; the Hessonite or Cinnamon- stone ; the Colophonite 
 or resinous garnet ; the Pyrope or, fire-garnet ; the Topazolite, and the 
 common iron-garnets so abundant in most localities. 
 
 Garua. The local term for dense sea-fogs that occur periodically along 
 the Pacific coast of South America. During the Garua, it is said, the 
 atmosphere loses its transparency, and the sun is obscured for months to- 
 gether. The vapours of the Garua of Lima are so thick that the sun, seen 
 through them with the naked eye, assumes the appearance of the moon's 
 disc. They commence in the morning, and extend over the plains in the 
 
 212 
 
GAS GAY 
 
 form of refreshing fogs, which disappear soon after mid-day, and are fol- 
 lowed by heavy dews, which are precipitated during the night. 
 
 Gaseous (Teut. gas, air or breath). In the form of gas ; consisting of 
 gas gas being the term applied to all permanently elastic or aeriform 
 fluids, except the atmosphere, which is an admixture of two or more gases. 
 In nature the gases play an important part, and geologically speaking, are 
 of vast significance. Some, like oxygen and carbonic acid, are continually 
 corroding, wasting, and forming new compounds; others, like carbonic 
 acid, sulphuretted hydrogen, and carburetted hydrogen, are largely disen- 
 gaged from the crust of the earth by volcanic vents, springs, mines, and 
 other openings ; some again, as oxygen, carbonic acid, and nitrogen, are 
 indispensable to vegetable and animal life ; while others, as oxygen and 
 hydrogen, form permanent combinations, as in the rocks of the crust, the 
 atmosphere that surrounds it, and the waters which cover so large a por- 
 tion of its surface. 
 
 Gaster6poda (Gr. gaster, the belly, and pous, podos, a foot). An exten- 
 sive class of mollusca which, like the periwinkle and garden-snail, have a 
 distinct head, and move by means of a muscular foot attached to the 
 lower part of the body; hence the term "belly-footed." Representatives 
 of the class occur in all formations, from the Silurian upwards ; but both 
 genera and species increase in ascending order. See tabulations, "ANIMAL 
 SCHEME." 
 
 Gast6rnis (Gaston, after M. Gaston Plante, the discoverer, and ornis, 
 bird). A provisional generic term applied to certain bird-remains from 
 the Eocene Tertiaries of Meudon, near Paris. The leg and thigh bones are 
 the only portions yet discovered, and these indicate a bird as large as an 
 ostrich, but more robust, and having affinities to wading and aquatic 
 orders that is, of an extinct genus intermediate between the grallatores 
 and cursor es. 
 
 Gault, Golt. A provincial term, and now adopted in geology, for that 
 series of dark-blue marls or calcareous clays which occur between the 
 upper and lower greensands of the Chalk formation, as developed in the 
 south of England. It is sometimes known as FolJcstone Marl ; ranges from 
 100 to 150, or even occasionally to 200 feet in thickness ; and abounds in 
 marine shells ammonites, hamites, scaphites, belemnites, inocerami, &c., 
 often in a beautiful state of preservation. When decomposed, it forms a 
 strong fertile soil ; and, according to Mr Austin, is the main repository 
 of those " phosphatic nodules " now so highly prized by the agriculturist. 
 
 Gavial. The Gavial or Gangetic Crocodile ; an existing genus and 
 species of crocodile, characterised by its prolonged, slender snout, which 
 terminates in a cartilaginous protuberance, in which the nostrils are 
 situated by its numerous teeth, of nearly equal size throughout the whole 
 of the jaws and by its hind feet, which are palmated to the extremities of 
 the toes. Slender-snouted crocodiles of closely allied forms teleosaunis, 
 steneosaurus, &c. occur in the Lias, Oolite, and Wealden. 
 
 Gaylenreuth. A village of Franconia in Germany, celebrated for its 
 Bone-Cave, which lies to the north-west of the village, on the left bank of 
 the Wiesent, which has cut its channel through the limestone. According 
 to Cuvier, who examined large collections of the bones, three-fourths of 
 them belonged to bears (ursus spelaeus, and prisons); and the remaining 
 portion to hyenas, tigers, wolves, foxes, gluttons, and other small carnivora. 
 
 Gay-lussite (after the French chemist, Gay Lussac). Hydrated carbon- 
 213 
 
GEH GEO 
 
 ate of lime and soda ; a mineral occurring in the natron beds of South 
 America, in long nail-like transparent prisms, and consisting of 34.5 car- 
 bonate of soda 33.6 carbonate of lime, and 30.4 water. It is slowly and 
 partially soluble in water. 
 
 Gehlenite. One of the Scapolite family ; a mineral occurring in small 
 greenish or greyish-brown four-sided prisms, along with calc-spar, in Mount 
 Monzoni in the Fassa Valley, and so named after Gehlen the chemist. It 
 is a ferro-silicate of alumina and lime, and closely allied to Hiimloldtilite. 
 
 Gem (Lat. gemma). A general term for any precious stone. In miner- 
 alogy the " Gems," which include the ruby, sapphire, topaz, emerald, &c., 
 are usually erected into a separate family, and, as Professor Nicol observes, 
 " notwithstanding their diverse chemical composition, must ever appear a 
 highly natural one, when regarded as individual objects. Their great 
 hardness, tenacity, high specific gravity without the metallic aspect, their 
 brilliant lustre, transparent purity, and vivid colours, all mark them out 
 as a peculiar distinct family. Only the diamond, which might naturally 
 seem to take the chief place in this class, differs so much, not only in 
 elementary composition, but in physical properties, that it must be 
 assigned to a diverse place in the system." Gems are usually arranged 
 into real gems the diamond, sapphire, ruby, spinelle, &c., which have great 
 hardness, lustre, and colour and precious stones, which have the same 
 characters as the real gems, but only possess them in a less degree. The 
 term Oriental is applied as a mark of excellence, whether coming from the 
 East or not. Gems are also spoken of as natural and artificial ; the latter 
 being composed of vitreous "pastes," coloured by different metallic oxides. 
 
 Gemmiparous (Lat. gemma, a bud, and pario, I bring forth). In phy- 
 siology, reproducing by buds on the body, which mature and fall off, and 
 then become independent animals, as in many of the infusoria. 
 
 Genus (Lat., kind or kindred). In natural history, the word genus has 
 often wide, and not well-defined limits, but is generally regarded as 
 embracing such members of a Family or larger group as possess some 
 common properties, more marked in them than in the other members of 
 the family. Thus the Canidse or Dog family embraces the dog, wolf, 
 jackal, fox, &c. ; but the dog, wolf, and jackal are regarded as one genus, 
 Canis, while the foxes are separated into another genus, Vulpes, the points 
 of agreement between the dog and wolf being more numerous and intimate 
 than between the dog and fox. The other permanent differences between 
 the individuals of the same genus constitute a species; and the accidental 
 differences found among the species give rise to varieties. 
 
 Geodes (Gr. geodes, earthy). Originally applied to nodules of indurated 
 clay or ironstone, hollow within, filled with soft earthy ochre, or having a 
 free nucleus or kernel, which rattled when the nodule was shaken ; the 
 cetites, or eagle-stone, of the ancients. The term is now generally employed 
 to denote all rounded nodules having internal cavities, whether empty, 
 nucleated, or lined with crystals. Locally and familiarly known as "potato- 
 stones," "cat-heads," and similar fanciful terms. 
 
 Geognosy (Gr. ge, the earth, and gnosis, knowledge). A term invented 
 to express absolute knowledge of the earth, in contradistinction to Geology, 
 which embraces both the facts and our reasonings respecting them. The 
 term, however, is seldom used by British geologists. 
 
 Geogony (Gr. ge, the earth, and gonos, generation). Like cosmogony, 
 geogony consists in abstract speculations regarding the original formation 
 
 214 
 
GEO GEY 
 
 of the earth, and is altogether distinct from the definite and intelligible 
 science of geology. 
 
 Ge6logy (Gr. ye, the earth, and logos, doctrine). Embraces all that can 
 be known of the constitution and history of our planet. Its object is to 
 examine the various rock-materials of which our planet is composed, to 
 describe their appearance and relative positions, to investigate their nature 
 and mode of formation, and generally to discover the laws which seem to 
 regulate their arrangement. As thus denned, the science may be viewed 
 in three great aspects Descriptive, Theoretical, and Practical : Descrip- 
 tive Geology being that which restricts itself to a consideration of facts and 
 appearances as presented in the rocky crust; Theoretical, that which 
 attempts to account for the phenomena, and arrange them into a con- 
 nected world-history ; and Practical, that which, guided in its researches 
 by the other two, treats of the mineral products of the globe, the methods 
 of obtaining them, and their application to industrial or economic purposes. 
 
 Geosaiirus (Gr. ge, the earth, andsawros, a lizard). A gigantic terrestrial 
 reptile of the Oolitic epoch. 
 
 Geoteuthis (Gr. ge, the earth that is, fossil and teuthis, a squid). A 
 genus of fossil squids or calajnaries, whose short broad pens, pointed 
 behind, and truncated in front, with lateral wings shorter than the shaft, 
 occur abundantly and in many species in the clays of the Lias and Oolite. 
 Besides the pens of this calamary, the ink-bag, the muscular mantle, and 
 the bases of the arms, are preserved in the Oxford clay. Some of the 
 ink-bags found in the Lias are nearly a foot in length, and are invested 
 with a brilliant nacreous layer ; the ink, like that of the recent analogues, 
 forming excellent sepia. It is difficult to understand how these ink-bags 
 were preserved, as the existing calamaries "spill their ink" on the 
 slightest alarm ; unless we suppose, with Dr Buckland, that their pos- 
 sessors were instantaneously enveloped in the muddy deposit that now 
 entombs them. 
 
 Gervillia (dedicated to M. Gerville, a French naturalist). A genus of 
 the Aviculidse, or wing-shells, found fossil in many species, from the Car- 
 boniferous system to the Chalk inclusive. Shell like avicula ; elongated, 
 anterior ear small, posterior ear wing-like ; area long and flat, cartilage 
 pits several wide apart ; hinge-teeth obscure, diverging posteriorly. 
 
 Geyser (literally "rager" or "roarer "). An Icelandic term for the inter- 
 mittent boiling-springs, or spouting fountains, which occur in connection 
 with the volcanic phenomena of that island. "These intermittent hot 
 springs occur in a district situated in the south-western division of Iceland, 
 where nearly one hundred of them are said to break out within a circle of 
 two miles. They rise through a thick covering of lava, which may perhaps 
 have flowed from Mount Hecla, the summit of thatvolcano being seen from 
 the spot, at the distance of more than thirty miles. In this district the 
 rushing of water is sometimes heard in chasms beneath the surface ; for 
 here, as on Etna, rivers flow in subterranean channels through the porous 
 and cavernous lavas. It has more than once happened, after earthquakes, 
 that some of the boiling fountains have increased or diminished in violence 
 and volume, or entirely ceased, or that new ones have made their appear- 
 ance changes which may be explained by the opening of new rents, and 
 the closing of pre-existing fissures. Few of the geysers play longer than 
 five or six minutes at a time, and the intervals between their eruptions are 
 for the most part very irregular. The Great Geyser rises out of a spacious 
 
 215 
 
GEY GHA. 
 
 basin at the summit of a circular mound, composed of siliceous incrusta- 
 tions, deposited from the spray of its waters. The diameter of this basin 
 in one direction is fifty-six feet, and forty-six in another. In the centre is 
 a pipe seventy-eight feet in perpendicular depth, and from eight to ten 
 feet in diameter, but gradually widening as it rises into the basin. The 
 inside of the basin is whitish, consisting of a siliceous crust, and perfectly 
 smooth, as are likewise two small channels on the sides of the mound, 
 down which the water escapes when the bowl is filled to the margin. 
 The circular basin is sometimes empty, but it is usually filled with beauti- 
 fully transparent water in a state of ebullition. During the rise of the 
 boiling water in the pipe, especially when the ebullition is most violent, and 
 when the water is thrown up in jets, subterranean noises are heard, like the 
 distant firing of cannon, and the earth is slightly shaken. The sound then 
 increases, and the motion becomes more violent, till at length a column of 
 water is thrown up, with loud explosions, to fhe height of one or two 
 hundred feet. After playing for a time like an artificial fountain, and 
 giving off great clouds of vapour, the pipe or tube is emptied, and a 
 column of steam rushing up with amazing force, and a thundering noise, 
 terminates the eruption. If stones are j^hrown into the crater, they are 
 instantly ejected ; and such is the explosive force, that very hard rocks 
 are sometimes shivered by it into small pieces. Henderson found that, 
 by throwing a great quantity of large stones into the pipe of Strockr (churn), 
 one of the geysers, he could bring on an eruption in a few minutes. The 
 fragments of stone, as well as the boiling water, were thrown in that case 
 to a much greater height than usual. After the water had been ejected, a 
 column of steam continued to rush up with a deafening roar for nearly an 
 hour ; but the geyser, as if exhausted by this effort, did not send out a 
 fresh eruption when its usual interval of rest had elapsed." (Lyell's 'Prin- 
 ciples,' as condensed from Barrow, Henderson, Mackenzie, and others who 
 have visited Iceland.) Various theories have been proposed to account for 
 the phenomena of the geysers, but that proposed by Sir G. Mackenzie, 
 and which connects the intermittent eruptions of steam and water with 
 the formation and expansion of steam in caverns and fissures in the lava 
 beneath, is that which is generally accepted. It is obvious, if fissures and 
 caverns exist, that steam of a very high pressure must be found in them 
 by the passage of the boiling waters along the subterranean channels ; and 
 as the pressure increases, the steam will force itself forward, and escape 
 by the nearest opening. Once discharged, it will require some time before 
 another supply can be formed of the requisite pressure and temperature. 
 According to Mr Roberts, all the waters issuing from these springs are 
 highly charged with silica ; hence siliceous incrustations and deposits 
 cover the adjacent country to the extent of four leagues, and the streams 
 proceeding from the springs often resemble milk in appearance, owing to 
 the argillaceous bole they take up in their passage among the siliceous 
 concretions (palagonite tufa) and accumulations. 
 
 Geyserite. The name given to a loose, porous, hydrated form of silica 
 deposited in concretionary, cauliflower -like masses around such hot 
 springs as the geysers of Iceland, those of the Sierra Nevada in California, 
 and other regions. 
 
 Ghauts. A term applied originally to the narrow and difficult passes in 
 the mountains of Central Hindostan, but has been gradually extended to 
 the mountains themselves viz., the Eastern and Western Ghauts, which 
 
 216 
 
GIB GLA 
 
 consist of two great chains, stretching along the east and west coasts of 
 the Deccan or Indian Peninsula. 
 
 Gibbous (Lat. gibbus, bunched, humped). Applied to forms that have 
 a suddenly convex, or hump-like external surface. Bossed ; abruptly pro- 
 tuberant, like the upper surface of the cyprcea gilbosa or hump-backed 
 cowry. 
 
 Giraffe. The tallest of known quadrupeds, and now restricted to the 
 deserts of Africa, was once a native of Europe and Asia, for fossil bones of 
 a species of this remarkable ruminant have been found in the Upper Ter- 
 tiaries of Issoudun in France, at Pikermi in Greece, and in the Siwalik 
 Hills in Hindostan, associated with varieties of the Elk, Deer, &c. 
 
 Girasol, Gyrasole (Lat. gyro, I turn, and sol, the sun). Known also as 
 fo-e-opal ; a transparent variety of opal, having a brilliant vitreous lustre, 
 and of a bright hyacinth red, particularly when turned towards the sun, 
 or any bright light : hence the name. The finest specimens are strongly 
 translucent, and show a faint bluish light, coming as it were from the in- 
 terior of the stone. 
 
 Glacier (Lat. glacies, ice). Applied to those accumulations of ice, or of 
 snow and ice, which collect in the valleys and ravines of snowy mountains 
 like the Alps, and which move downward with a peculiar creeping motion, 
 smoothing the rocks over which they pass, and leaving mounds of debris 
 (moraines), lateral and terminal, as they melt away. According to Saussure, 
 glaciers are of two kinds those formed in valleys and following the wind- 
 ings of their courses (the ice-river), and those formed in the slopes and 
 higher peaks of the mountains in sheet-like masses. In both, the mode of 
 action is almost identical ; and, combined with the avalanche and iceberg, 
 the glacier is now, as it has been in ages past, one of the most important 
 of geological agents. The evidence of glaciers in any country, during 
 former epochs, consists partly in the polished and grooved surfaces of the 
 rocks over which they slid with their impacted boulders and shingle (these 
 scratching and^grooving in the direction of that movement) ; and partly 
 by the peculiar contour and composition of the moraines, which differ ma- 
 terially from beds of debris brought down by torrents and other currents 
 of water. As glaciers can only be formed above the line of perpetual con- 
 gelation, and melt when they descend to and below that level, important 
 inferences as to climate can often be drawn from the occurrence of moraines, 
 rock-groovings, and other kindred phenomena. 
 
 Glacier-Table. The name given in Alpine regions to large table-like 
 blocks of stone lying on the surface of glaciers, and more or less elevated 
 on pedestals of ice these pedestals being protected from the sun's rays 
 by the superincumbent stone-blocks while the surrounding ice has been 
 melted down to a lower level. 
 
 Glacis (Fr.) A slope in fortification; applied to easy insensible slopes 
 like those of a harbour-breakwater, or the shingle piled on the shore by 
 the force of the waves ; less steep than a talus. 
 
 Glance (literally, splendour). A frequent term of the earlier miner- 
 alogists, and applied to such minerals as exhibited a glancing or pseudo- 
 metallic lustre, as lead-glance, iron-glance, glance-coal, &c. The term is 
 now seldom employed. 
 
 Glance-Coal. A familiar term for anthracite (which see), in allusion to 
 its semi-metallic lustre. 
 
 Glaserite. A sulphate of potash, occurring in delicate white or yellow- 
 217 
 
GLA GLE 
 
 ish-white crystallisations, and in crusts and masses, sublimed around the 
 fumeroles of active volcanoes. It has a semi-resinous lustre, is more or less 
 translucent, and has a saline and bitter taste. Specimens from Vesuvius 
 contained 71.4 sulphate of potash, 18.6 sulphate of soda, 4.6 chloride of 
 sodium, and 5.4 chloride of ammonium, copper and iron. 
 
 Glass. The well-known silicates of potash and soda (quartz-sand fused 
 with one or other of these alkalies) ; "but which are variously compounded 
 to give them colour, transparency, toughness, &c. Thus green or bottle 
 (jlass consists of the silicates of alumina, of the oxides of iron, magnesia, 
 and potash, or soda ; flint-glass, a silicate of potash and lead ; window- 
 glass, a silicate of soda and lime ; and plate-glass, silicate of potash and 
 lime. In mineralogy, the term glass is applied to several substances hav- 
 ing a glassy appearance, as Muscovy-glass or mica, tin-glass or bismuth, 
 glass of antimony or sulphuret of antimony. 
 
 Glaiiberite. A rare crystallised salt, occurring in oblique four-sided 
 prisms, and consisting of 51 parts sulphate of soda and 49 sulphate of 
 lime. It is found associated with rock-salt in Spain, South America, and 
 other localities, and is so named from containing a large amount of Glau- 
 ber-salt. 
 
 Glauber-Salt (after Glauber, a German chemist). Native sulphate of 
 soda ; the sal-mirabile of the older chemists. It occurs chiefly as an efflor- 
 escence in quarries and on old walls, as in the salt-mines of Austria, Spain, 
 and other countries ; it is deposited in great abundance from the hot 
 springs at Carlsbad, and is found in many other mineral waters ; and is 
 likewise procured from salt springs, and forms a crust or efflorescence on 
 the borders of salt lakes in Egypt, Southern Russia, and other countries. 
 
 Glaiicolite (Gr. glaucos, bluish-green, sea-green, and lithos).A. pale- 
 blue or greenish variety of Labrador felspar, from Lake Baikal in Siberia. 
 
 Glauc6nie, Glauccmie Crayense. The French term for certain strata 
 (bluish chalky marls and greensands) which appear to be on the same 
 horizon'with, and in part the equivalents of, our Upper Greensand and 
 Gault. See CRETACEOUS SYSTEM. 
 
 Glaiiconite (Gr. glaucos, bluish-green). A mineral forming small round 
 grains in the greensand of England, France, Germany, and North America, 
 and very similar in colour, &c., to green-earth, but seems essentially a 
 hydrous silicate of iron protoxide and potash. In green-earth, the iron is 
 in the state of peroxide. 
 
 Glen Roy, Parallel Roads of." Glen Roy," says Sir Charles Lyell in his 
 ' Antiquity of Man,' is situated in the Western Highlands, about ten miles 
 north of Fort William, near the western end of the great glen of Scotland, 
 or Caledonian Canal, and near the foot of the highest of the Grampians, 
 Ben Nevis. Throughout nearly its whole length a distance of more than 
 ten miles three parallel roads or shelves are traced along the steep sides 
 of the mountains, each maintaining a perfect horizontality, and continuing 
 at exactly the same level on the opposite side of the glen. Seen at a dis- 
 tance, they appear like ledges or roads cut artificially out of the sides of 
 the hills ; but when we are upon them, we scarcely recognise their exist- 
 ence, so uneven is their surface and so covered with boulders. They are 
 from ten to sixty feet broad, and merely differ from the side of the moun- 
 tain in being somewhat less steep. On closer inspection we found that 
 these terraces are stratified in the ordinary manner of alluvial or littoral 
 deposits. . . . Numerous and diverse theories have been proposed 
 
 218 
 
GLI GLY 
 
 to account for these ' roads ' or shelves ; but on one point they are all 
 agreed namely, that they are ancient beaches, or littoral formations, ac- 
 cumulated round the edges of one or more sheets of water which once 
 stood for a long time successively at the level of the several shelves." 
 
 Glimmer. The term applied by Werner to the several varieties of mica ; 
 by Haidinger and Hausmann to the variety called muscovite; and also 
 occasionally vfted to designate talcose and micaceous compounds. 
 
 Globigerina (Lat. glolus, a sphere, and gero, I carry). A genus of fora- 
 miniferous organisms, whose many-celled shell is turbinated, cells sphe- 
 roidal, and the last or terminal one furnished with a semicircular aperture 
 at the umbilical angle. Several fossil species abound in the Chalk and in 
 Tertiary deposits ; and many species still swarm in our seas. Indeed, a 
 large proportion of the oaze or calcareous mud brought up during the 
 soundings of the Atlantic telegraph route consisted of Globigerinse, partly 
 in the living state, but chiefly in fragments, which formed a mud almost of 
 the consistency of putty, and which, when dried, was scarcely distinguish- 
 able from a mass of soft, yellowish chalk. 
 
 Gl6bular (Lat. globus, a ball). Round ; applied to forms more or less 
 spherical. Globule, any minute rounded particle. 
 
 Glossopetra (Gr.glosse, the tongue, andjpefr-a, stone). Literally "tongue- 
 stone ; " an early term for the flattened tongue-shaped shark's teeth, so 
 abundant in many of the Upper Secondary and earlier Tertiary for- 
 mations. Known also as Lamiodontes or throat-teeth, and Odontopetrce or 
 teeth-stones. 
 
 Gloss6pteris (Gr. glosse, tongue, and pteris, fern). A genus of Oolitic 
 ferns, so called from their tongue-shaped leaves (which were four-parted), 
 and now known as Sagenopteris, which see. 
 
 Gl6ttalite (Lat. Glotta, the Clyde, and lithos).A. variety of analcime 
 occurring in small aggregated and irregular white or colourless crystals in 
 the trap walls near Port-Glasgow on the river Clyde, whence the name. 
 
 Glucina (Gr. glucos, sweet). A rare earth, discovered by Vauquelin in 
 1798, and constituting nearly 14 per cent of the emerald and beryl, which 
 owe to it their fine green colour. It combines with all the acids, and 
 forms, with them, sweetish salts : hence its name. According to Sir H. 
 Davy, it is an oxide of glucinum a metallic basis not yet obtained in a 
 separate state. 
 
 Glyphsea (Gr. glyphe, sculpture). A genus of small lobster-like crus- 
 taceans (Astacidce), whose carapaces occur in the Oolite of England ; and 
 so termed from the sculptured ornamentation of their outer surfaces. 
 
 Glypt6crinus (Gr. glyptos, sculptured). A genus of Lower Silurian en- 
 crinites, characterised by their highly-ornamented basal plates ; whence 
 the name. 
 
 Gl^ptodon (Gr. glyptos, sculptured, and odous, tooth). So named from 
 the deeply-grooved teeth ; a gigantic edentate animal from the Upper 
 Tertiaries of South America ; allied to the armadilloes (Dasypince), and 
 furnished with a carapace or coat of mail, formed of polygonal bony plates, 
 united by sutures, which constituted an impenetrable covering for the 
 upper part of the body. The plates of this bony integument were not 
 disposed in rings as in the armadillo, but were articulated to each other 
 and formed a tessellated cuirass ; the tail was enclosed in a case of this 
 kind, like a sword in its scabbard. See DASYPUS. 
 
 Glypt6strobus (Gr.) Literally "carved cone;' 1 a genus of coniferous 
 219 
 
GME GOL 
 
 fruits occurring in the Upper Miocene beds of CEningen, and so named 
 from their resemblance to the Japanese G. heteropliyllwn, now common in 
 our shrubberies. 
 
 Gmelinite (after Gmelin, the German chemist). A soda - chabasite, 
 occurring in amygdaloidal trap-rocks in flat six-sided prisms, terminated 
 at both extremities by truncated six-sided pyramids ; of a white or yellow- 
 ish-white colour ; vitreous lustre ; translucent ; and having the surface of 
 the prisms striated horizontally. 
 
 Gneiss. Originally a German term for a peculiar granitic-looking rock 
 occurring at the very base of the so-called " Primary strata ; " but now 
 applied not only to the rock properly so-called, but to the whole suite of 
 hard crystalline granitoid schists which constitute the lowest portion of 
 the metam orphic or non-fossiliferous strata. As a rock, it occurs in three 
 main varieties viz., Gneiss Proper an aggregate of quartz, felspar, and 
 mica, occasionally garnetiferous ; Porphyritc Gneiss the same as pre- 
 ceding, with large irregular macles of felspar or quartz ; and Syenitic 
 Gneiss of quartz, felspar, and hornblende. As a suite, or portion of the 
 metamorphic system, it consists of irregularly interstratified schists 
 gneiss, mica-schist, quartz-rock, crystalline limestones, &e. all of which 
 have been subjected to less or greater intensity of metamorphic action, 
 though originally deposited as muds, clays, and sands. In whatever state 
 of aggregation the particles of Gneiss may have been when originally de- 
 posited, we know that it is now a hard, tough, crystalline rock, exhibit- 
 ing curved and flexured lines of stratification, and composed in the main 
 of quartz, felspar, mica, and hornblende. Mineralogically speaking, it 
 differs from the granitic rocks with which it is associated chiefly in this, 
 that while the crystals of quartz, felspar, &c., are distinct and entire 
 in granite, in gneiss they are indistinct, and confusedly aggregated, 
 There is also this essential distinction, even where the mineral aspects of 
 the two rocks are most alike, that the gneiss never sends out dykes and 
 veins, like the granite, into contiguous strata ; nor does it ever assume 
 the tabular or sub-columnar structure so frequent in granite a structure 
 peculiar to rocks which are the products of cooling and consolidation from 
 a state of igneous fusion. In the most granitoid masses of gneiss, the 
 stratified disposition is never wholly obliterated ; hence their fissility in 
 one direction as compared with the indeterminate and hackly fracture of 
 the true igneous granites. Though GNEISS is thus (generally speaking) 
 the oldest or lowest of the Primary strata, it may occur in any system, 
 just as the strata of that system may have been subjected to the necessary 
 metamorphic agency of heat and other mineralising conditions ; and so it 
 happens that many of the Secondary strata of the Alps are as highly 
 crystalline as the Primary schists of the Grampians. 
 
 Gneissic, Gneissose. Having the aspect of gneiss; partaking of the 
 qualities of gneiss; exhibiting the crystalline texture and foliated and 
 flexured structure of gneiss. 
 
 Goaf, Gob. In mining, the waste or empty space left by the extrac- 
 tion of a seam of coal. It is in this " Goaf " that the most destructive 
 accumulations of fire-damp generally occur. 
 
 Gohbin, Goaffin. A miner's term for the refuse of a coal mine which 
 is thrown into the " Goaf" or worked-out portion, to assist in supporting 
 the roof. 
 
 Gold (Ger.) The most valuable and longest known of the metals. It 
 220 
 
GOM GON 
 
 generally occurs native in capillary, thread-like, arborescent, and moss-like 
 aggregates ; in scales and grains (granos) ; and in rolled masses known as 
 pepitas and nuggets. Very frequently it is found disseminated in minute 
 microscopic particles or imperfectly formed crystals throughout the quartz 
 or vein-stone in which it occurs. Geologically, it is distributed in veins, 
 nests, and lodes in the Primary and Palaeozoic schists, but is most fre- 
 quently found in the sands, gravels, and debris which have arisen from the 
 waste and disintegration of these schists during the later Tertiary and 
 Post-tertiary periods. Thus, though worked in the vein-mines of Mexico, 
 South America, the Rocky Mountains, and Australia, the main commercial 
 supply is obtained from the auriferous sands and gravels of the Ural, 
 Hungary, Africa, California, Brazil, Australia, and other gold-yielding 
 districts the drift-workings being inexhaustible, though capriciously 
 fertile, while the veins and lodes are said to become poorer the deeper they 
 are followed. Gold is one of the most widely-disseminated metals, being 
 found in every known region ; but rarely in such local abundance as to 
 pay for its search, collection, and preparation. It is also frequently found 
 in combination with other metals, as palladium, rhodium, and silver ; and 
 sometimes also in minute quantities in the metallic sulphides, as galena, 
 iron and copper pyrites ; but generally so disseminated as to require 
 skilful and expensive methods of extraction and purification. Gold is said 
 to occur most abundantly in mountain-ranges having a meridional direc- 
 tion ; and, according to the observations of M. Laur in California, it is 
 still in course of being deposited from hot siliceous springs along with iron, 
 copper, and other metals the gold being metallic or native, while the 
 other metals are in the state of ores. 
 
 As a metal, it is characterised by its yellow colour ; its extreme per- 
 manence in air and fire being little tarnished by any amount of exposure, 
 and melting at 2016 Fahr.; its usual hardness is about 2.6 ; its density or 
 specific gravity from 18 to 19.4 ; its malleability is such that it may be 
 beaten into leaves not more than snW of an inch in thickness ; and its 
 ductility so great that one grain is capable of being drawn out into 500 
 feet of wire. It readily forms alloys with other metals ; and in coinage as 
 well as in the arts it is generally so alloyed (with copper, silver, &c.) to 
 improve its hardness, and so render it better able to resist the tear and 
 wear of circulation, handling, and cleaning. Gold is not acted upon by 
 the common acids ; but chlorine and nitro-muriatic acid corrode and dis- 
 solve it, forming a chloride of gold, which is soluble in water. 
 
 G6mpliolite (Gr. gomphos, nail, and lithos). A term applied by Bron- 
 gniart to certain sandy conglomerates of the Middle Tertiary epoch which 
 occur in vast thickness at the foot of the Alps in the great Swiss valley, 
 where they are known as Nagelflue, which see. 
 
 Gonidster (Gr. gonia, an angle, and aster, star). A genus of fossil star- 
 fishes occurring in the Greensand, Chalk, and older Tertiaries, and popu- 
 larly known as Cushion-stars. They are characterised by their solid pent- 
 angular bodies, which in some species are obtuse at the angles, and in 
 others more or less pointed and arm-like. The ossicles of the disc are 
 generally punctuated, and the margins are provided with a double series 
 of larger plates bearing granules or short spines. 
 
 Goniatites (Gr. gonia, an angle). A genus of the Ammonite family, so 
 called from the angular or zigzag lines which mark the junctions or 
 sutures of its chambers. In the goniatite, which ranges from the Devonian 
 
 221 
 
GON ' GRA 
 
 to the Trias, and of which there are about 150 species, the shell is dis- 
 coidal, sutures lobed, lobes simply angulated, siphuncle dorsal. 
 
 Gonidmeter (Gr. gonia, a corner, and metron, a measure). An instru- 
 ment for measuring angles, particularly those of crystals. Two instru- 
 ments have been specially used for this purpose the common or contact 
 goniometer invented by Carangeau, and the reflecting goniometer of Dr 
 Wollaston. 
 
 Goniopholis (Gr. gonia, corner or angle, and pholis, scale or scute). 
 Literally "angle-scute;" a genus of Crocodilians whose teeth, bones, and 
 dermal scutes occur in the Purbeck and Wealden strata. So termed from 
 the angular shape of its scutes, many of which are furnished with a lateral 
 projection, which fits into a corresponding depression of the adjoining 
 scute, thus connecting and giving great strength to the dermal cuirass. 
 Popularly known as the "Swanage Crocodile," from the fine specimen now 
 in the British Museum, having been discovered in the Purbeck beds of 
 that locality in 1835. 
 
 Gorgonia, Gorgoniidse (Gorgones, fabled personages whose heads bristled 
 with serpents instead of hairs). A genus of Anthozoan corals, so called 
 from their branching flexible axes ; and popularly known as " Venus's 
 fans" and " Sea-fans," from their spreading fan-like forms. The Gor- 
 gonise are attached by a root ; have a shrub-like growth ; consist of a horny, 
 flexible axis or central portion, which is covered by a calcareous cell-crust, 
 like the bark of a tree, and often appear in elegant fan-shaped or flabel- 
 lated forms. A few fossil species have been discovered in the Upper Chalk 
 of Maestricht and in Tertiary strata. 
 
 Goslarite (Goslar in the Harz Mountains). Sulphate of zinc, consisting of 
 28.2 oxide of zinc, 27.5 sulphuric acid, and 44.3 water. Generally occurs 
 in old mines and workings as a decomposition from zinc-blende (sulphuret 
 of zinc), and appears in greyish and greenish-white efflorescences, also 
 massive stalactitic, botryoidal, and incrusting. See WHITE VITRIOL. 
 
 Gossan (in Cornish mining). "A peculiar ferruginous condition," says 
 Ansted, " of the top of a lode near its outcrop, considered to be very 
 strongly indicative of the lode below. Some gossans are simply ferrugin- 
 ous quartz, but others are solid iron ore. Gossans are seldom found so 
 deep as 30 fathoms. They not unfrequently have a strong decomposed or 
 ochreous appearance, and sometimes contain gold." 
 
 Gower Caves. The ossiferous caverns of the peninsula of Gower, in 
 Glamorganshire, which have yielded in large abundance the remains of 
 mammoth, tichorine rhinoceros, hippopotamus major, reindeer, and other 
 extinct mammals, associated with species still living in Europe, such as the 
 badger, fox, and wolf, together with flint knives and other rude imple- 
 ments of human workmanship. From the position of these implements, 
 Colonel Wood and the late Dr Falconer, who examined the caverns, con- 
 sider them to have been unmistakably coeval with the extinct mammalia. 
 Grallat6res (Lat., "walkers on stilts"). The Waders or Stilt-birds; 
 a well-known order of aquatic birds frequenting marshes and shallow 
 waters, and so named from their being raised on their long legs as on 
 stilts. The order comprises the rails, snipes, coots, herons, stilts, cranes, 
 &c.; and is represented in the Tertiary strata by remains having affinity 
 to the curlew, rail, heron, and other grallatorial congeners. 
 
 Grammysia (Gr. gramme, a line of writing, and mys, a mussel -shell). 
 A mussel-like bivalve occurring in Upper Silurian strata, and so named 
 
 222 
 
GRA 
 
 by De Verneuil from the strong transverse lines or furrows which cross its 
 valves from the umbones to the middle of the ventral margin. Regarded 
 as a sub-generic form of the fossil genus Myaciles. 
 
 Granite (Lat. granum, a grain). This well-known rock is so termed from 
 its granular-crystalline composition and aspect. The typical granite is a 
 compound of quartz, felspar, and mica, arranged in distinct grains or 
 crystals ; and all rocks partaking of the character and appearance of 
 granite are termed granitic. The epithets granitoid and granitiform are, on 
 the other hand, applied to rocks having some resemblance to granite, 
 though not decidedly of granitic nature, nor even, it may be, of true 
 igneous origin. The granitic rocks, properly so called, are all highly crys- 
 talline ; none of their crystals are rounded or water-worn ; they present 
 no traces of deposition or stratification ; they occur in the crust as moun- 
 tain masses and veins, bursting through and displacing the sedimentary 
 rocks ; and they indurate and otherwise alter (as all heated masses do) the 
 strata with which they come in contact. From these circumstances they 
 are held to be of igneous origin ; and as far as geologists have been able to 
 discover, they are the most deeply-seated of all rocks forming, as it were, 
 the floor or foundation for all the superincumbent formations. As the 
 earliest of igneous rocks, they are generally found associated with primary 
 and transition strata, tilting them up on their edges, bursting through 
 them in dykes and veins, and variously altering their positions and mineral 
 character. Though occuring most abundantly among primitive strata, 
 granitic outbursts may be found among rocks of all ages, but certainly not 
 as a marked and general feature of the period the great epoch of granitic 
 intensity being that which terminated with the deposition of the Silurian 
 strata. 
 
 Whether occurring in veins or mountain -masses, the structure of granite 
 is irregular and amorphous. In its texture it varies from a close-grained 
 compact rock to a coarse and loose aggregation of primary crystals. In 
 the composition of granitic rocks there is also considerable variety. Thus, 
 ordinary granite is composed of crystals of felspar, quartz, and mica ; when 
 the dark glassy mineral called hornblende takes the place of the mica, the 
 rock is known by the name of syenite (from Syene in Upper Egypt) ; and 
 when both mica and hornblende are present, the compound is known as a 
 syenitic granite. Occasionally talc supplants the mica, and then the ad- 
 mixture of felspar, quartz, and talc, is known by the name of protogine 
 (literally, first-formed) a term by no means happily chosen, as many of 
 these talcose granites (like those of the Alps) occur in connection with 
 rocks of secondary formation. The term hypersthenic granite is applied to 
 an admixture of quartz and hypersthene, with scattered flakes of mica ; 
 and graphic granite is a binary compound of felspar and quartz the quartz 
 being disposed through the felspar matrix like the lines of Arabic writing 
 hence the name. Another fine-grained compound of felspar and quartz, 
 with minute scales of mica, is known by the name of pegmatite (pegma, 
 compacted) ; and porphyritic granite is the term employed when, in addi- 
 tion to the crystals composing the general mass of the rock, there are 
 indiscriminately mingled through it larger and independent crystals of 
 felspar. 
 
 Besides the preceding there are other granitic compounds, in all of 
 which felspar, quartz, mica, hornblende, and hypersthene are the princi- 
 pal ingredients, and talc, steatite, chlorite, schorl, and actynolite the 
 
 223 
 
GRA 
 
 accidental or modifying minerals. It is customary, on this account, to 
 speak of granites as binary, ternary, and quaternary, according to the 
 number of simple minerals that enter into their composition. Thus graphic 
 granite, as composed of felspar and quartz, is a binary ; ordinary granite, 
 of felspar, quartz, and mica, is a ternary ; and syenitic granite, of felspar, 
 quartz, hornblende, and mica, is a quaternary compound. (See GRANIT- 
 ELLE, &c.) There are, however, many blendings of these, one into the 
 other ; and in the same hill, or even in the same quarry, we may find some 
 half-dozen varieties of granite, if distinctions are to be founded upon the 
 greater or less abundance of any one constituent mineral. However com- 
 plicated the mineral admixtures of granitic rocks, and however varied 
 their aspects, there are several features which they preserve in common, 
 and which serve to distinguish them from the later igneous rocks. For 
 instance, they are more crystalline, or rather granular-crystalline, than 
 any other variety of igneous rock ; they are never vesicular, cellular, or 
 porous, like trap and volcanic lavas ; they exhibit less structure than trap- 
 pean rocks, being generally massive or cuboidal, and void of that columnar 
 structure so common in basalts and greenstones ; they are never amygda- 
 loidal like traps, conglomerated or brecciated like trap-tuffs, or scoriaceous 
 like volcanic tufa. They seem to have been formed at greater depths or 
 under greater pressure than either traps or lavas ; hence they are spoken 
 of as plidonic, in contradistinction to volcanic, which may be originated 
 under the open air. 
 
 Industrially, granitic rocks are of prime importance the hard and 
 close-grained yielding the most durable building-stone for heavy struc- 
 tures ; the soft and decomposable the finest kaolin, or china-clay ; the 
 veins and vein-stones such accidental minerals as felspar, apatite, mica, 
 meerschaum, asbestos, rock-crystal, tourmaline, beryl, and other precious 
 stones. 
 
 Granitelle. A term employed by Kirwan to designate a binary granite, 
 or granular aggregate of two ingredients. Thus a compound of quartz 
 and felspar is a granitelle; of quartz, felspar, and mica, an ordinary or 
 normal granite; of any other three ingredients than those constituting 
 granite, as felspar, quartz, and schorl, or quartz, mica, and schorl, a 
 granitine ; and a compound of more than three ingredients, a granilite. 
 The terms are rarely used by modern geologists. 
 
 Granitic. Composed of granite ; having some of the characteristics of 
 granite ; belonging to the granitic series, which comprehends such rocks 
 as granite proper, graphic granite, syenite, protogine, pegmatite, eurite, 
 and many analogous porphyritic compounds. 
 
 Granitoid (Gr. eidos, likeness). Applied to such rocks as have the gran- 
 ular-crystalline aspect of granite. Thus we speak of the "granitoid 
 schists," meaning thereby such rocks as gneiss, hornblende-schist, por- 
 phyritic gneiss, and the like, which have much the aspect of granite with- 
 out being so in reality. 
 
 Granulation (Lat. granum, a grain). The reduction of metals into grains, 
 drops, or coarse powder generally accomplished by pouring them in the 
 melted state into water. 
 
 Graphic Granite (Gr. grapho, I write). Literally "written granite;" a 
 binary compound of felspar and quartz the quartz being disposed through 
 the felspar matrix like lines of Arabic writing : hence the name. 
 
 Graphite (Gr. grapho, I write, and lithos, stone). Literally " writing- 
 224 
 
GRA . 
 
 stone ; " and so called from its use in making writing-pencils. Known also 
 as plumbago and blacklead from its appearance, though lead does not at 
 all enter into its composition. It consists almost entirely of pure carbon, 
 with a small proportion of iron as an admixture, but not in chemical 
 union the amount being from 5 to 9 per cent. It occurs chiefly in pri- 
 mary formations, but occasionally in later strata in the neighbourhood of 
 igneous irruptions. When crystallised it appears in six-sided tabular and 
 short prismatic crystals, but generally it is compact and massive, foliated 
 or scaly, and disseminated or occurring in vein-like nests and patches. It 
 is found in many localities the purest in Britain being that of Borrowdale 
 in Cumberland, where it is included in a bed of trap subordinate to the 
 clay-slate of the district. It is largely used for making writing-pencils, in 
 the fabrication of fire-proof crucibles, as a polishing material, &c. ; and 
 has been artificially produced by placing an excess of charcoal in contact 
 with fused cast-iron. See COAL FAMILY. 
 
 Graphularia. A genus of coralloid organisms, with a horny axis of sub- 
 angular or cylindrical form, occurring in septarian nodules in the London 
 Clay, and by some regarded as an extinct form of Pennatula. 
 
 Graptolites (Gr. graptos, written, and lithos, stone). Characteristic Sil- 
 urian zoophytes, akin to the virgularia or sea-pen of modern seas ; hence 
 the name. They consist of sessile polpye cells, arranged in one or two 
 rows on a flexible stem, and have been subdivided into three groups - 
 1. Graptolites proper, or those having a single row of cells united together 
 at the base ; 2. Rastrites, those having the cells placed not united, but 
 placed at wide intervals along the axis ; and 3. Diplograpsus, or those hav- 
 ing two rows of united cells arranged along the axis, and presenting a 
 foliaceous appearance. The two first groups seem related to the Sertula- 
 ridce, the last to the Pennatula and Virgularia of the present day. There 
 are also others having twin branches, to which the name Didymograpsus 
 is applied ; and the whole group of these slender serrated fossils is usually 
 distinguished by zoologists as the GRAPTOLITHINA. 
 
 Graptopora (Gr. grapho, I write, and pora). A rare form of zoophyte 
 occurring in Lower Silurian rocks, and interesting as showing a probable 
 connection between the Fenestellidse and Graptolites. It is of horny tex- 
 ture, and appears in leaf-like bundles of fine lines radiating from numerous 
 central pores ; hence the name. See PHYLLOGRAPSUS. 
 
 Grave- Wax. A familiar term for adipocere, because occasionally found 
 in grave-yards. See ADIPOCERE. 
 
 Gravel. The familiar as well as technical term for accumulations of 
 water- worn rock-fragments, where the pebbles vary from the size of a pea 
 to that of a hen's egg. It is generally composed of the fragments of the 
 harder and more siliceous rocks those longest resisting the process of 
 attrition. Accumulations of finer detritus, whose particles are less than a 
 pea, are known as sands ; those whose fragments are larger than a hen's 
 egg are generally termed shingle. 
 
 Gravity, Gravitation (Lat. gravis, heavy). The mutual tendency which 
 all bodies in nature have to approach each other, with forces which are 
 directly as their masses and inversely proportional to the squares of their 
 distances. As a force it is altogether independent of the nature of the 
 substances on which it acts, and influences alike the particles of a fragment 
 of rock, and the spheres which constitute the systems of the universe. 
 This mutual tendency of all the particles of matter to each other is called 
 
 225 P 
 
GRA 
 
 the attraction of gravitation ; in reference to any particular body, the 
 aggregate attraction of all its particles is usually called simply its gravity 
 or weight. It is owing to this force that all heavy bodies, when unsup- 
 ported, fall towards the earth, and that in a direction perpendicular to the 
 level surface of water ; or in other words, in the direction of the plumb- 
 line, which always points towards the centre of the earth the attraction 
 of a sphere (as demonstrated by Newton) acting in the same manner as if 
 all its matter were condensed into a single point at its centre. The phe- 
 nomena of gravity, as manifested on and within the earth, is usually spoken 
 of as terrestrial gravitation ; that which has reference to the mutual action 
 and reaction of the planetary bodies is denominated universal gravitation. 
 Thus the oscillations of the pendulum, and the perpetual tendency of 
 water to fall or seek towards a lower level, depend on terrestrial gravita- 
 tion ; the bi-diurnal rise and fall of the tides, and the regular revolutions 
 of the planets, are sustained by the force of universal gravitation. Owing 
 to the oblate or spheroidal figure of the earth, which makes the distance 
 between the earth's surface and the centre less by some 13 miles at the 
 poles than at the equator, the gravity of a body slightly increases as we 
 approach either pole. Thus, according to Newton, a body weighing 
 194 Ib. at the equator, would weigh, if transferred to the pole, 195 and 
 proportionally at all intermediate distances ; so that the attraction of 
 gravity becomes not only a measure of weight, but a means of determining 
 the earth's figure, by ascertaining the intensity of gravitation at different 
 latitudes. 
 
 Gravity, Specific. The Specific Gravity of a body is the ratio of its 
 weight to the weight of an equal volume of some other body assumed as a 
 conventional standard. In Britain, the standard usually adopted for solids 
 and liquids is distilled water at the temperature of 60 Fahr., and for gases 
 or aeriform bodies, the ordinary air of the atmosphere. In either case the 
 standard is regarded as unity, or equal to 1. The following list exhibits 
 the specific gravities of some of the more important and abundant rocks, 
 minerals, and metals : 
 
 Agate 2.590 Diamond, Coloured 3.550 
 
 Alum 1.714 Brazilian 3.444 
 
 Amber 1.064 to 1.100 Dolomite 2.540 to 2.830 
 
 Amethyst, Common 2.750 Emerald 2.600 2.770 
 
 Oriental 3.391 Felspar 2.450 2.700 
 
 Amianthus 0.315 to 1.000 Galena 6.565 ,, 7.786 
 
 Arragonite 2.900 Glass, crown 2.520 
 
 Asphalt 0.905 to 1.220 green 2.642 
 
 Azure-stone 2.850 flint 2.760 to 3.000 
 
 Barytes, Sulphate of 4.550 Graphite 1.987,, 2.400 
 
 Carbonate of 4.600 Gypsum, Compact ...1.870 2.288 
 
 Basalt 2.421 to 3.000 Crystallised 2.311 2.-900 
 
 Beryl 3.549 Heliotrope 2.629,, 3.000 
 
 Borax 1.714 Honeystone Mellite 1.650 
 
 Calcedony 2.600 to 2.650 Hornblende 3.250 to 3.830 
 
 Carnelian 2.615 Hornstone 2.555 2.810 
 
 Chalk 2.000 to 2.255 Hyacinth 4.000 4.780 
 
 Chrysolite 3.400 Ironstone 3.000 3.575 
 
 Coals 1.025 to 1.350 Jasper 2.358,, 2.820 
 
 Coral 2.500 ,,2.800 Jet 1.300 
 
 Corundum 3.710 Limestone 2.386 to 3.000 
 
 Diamond, Oriental 3. 521 Magnesia, Carbonate 2. 240 
 
 226 
 
GRE 
 
 Malachite 3.572 to 3.994 
 
 Marble 2.500 2.700 
 
 Melanite 3.600 3.800 
 
 METALS 
 
 Antimony 6.702 
 
 Arsenic 5.765 
 
 Bismuth 9.880 
 
 Brass- 7.809 to 8.400 
 
 Cadmium 8.600 
 
 Chromium 5.900 
 
 Cobalt 8.600 
 
 Columbium 5.600 
 
 Copper 8.900 
 
 Gold, cast 19.258 
 
 ,, hammered 19.361 
 
 Iridium, 23.000 
 
 Iron, cast 7.248 
 
 forged 7.788 
 
 Lead 11.352 
 
 Manganese 8.000 
 
 Mercury 13.598 
 
 Molybdenum 8.600 
 
 Nickel, cast 8.279 
 
 forged 8.666 
 
 Osmium-iridium 19. 500 
 
 Palladium 11.800 
 
 Platina, forged 20.336 
 
 wire 21.042 
 
 plate 22.069 
 
 Potassium 0.865 
 
 Rhodium 11.000 
 
 Selenium 4.300 
 
 Silver 10.474 
 
 ,, hammered 10.510 
 
 Sodium 0.972 
 
 Steel, soft 7.833 
 
 Steel, tempered 7.825 
 
 Tellurium 5.700 to 6.110 
 
 Tin .. ....7.295 
 
 METALS, continued 
 
 Tungstein 17.400 
 
 Uranium 9.000 
 
 Zinc 6.200 to 7.200 
 
 Mica 2.650 2.934 
 
 Mineral Tallow 0.780 
 
 Naphtha 0.700 to 0.840 
 
 Nitre 1.900 
 
 Obsidian 2.370 
 
 Oolite 2.100 to 2.600 
 
 Opal 1.958 ,,2.110 
 
 Pearlstone 2.340 
 
 Pitchstone 2.000 to 2.700 
 
 Porphyry 2.450 2.950 
 
 Pumice.'. 0.752 0.914 
 
 Quartz 2.624 3.750 
 
 Rock-Crystal 2.580 2.888 
 
 Ruby, Oriental 4.285 
 
 Sandstone, Craigleith 2.250 
 
 Fife 2.100 
 
 Glasgow 2.156 
 
 Derbyshire 2.628 
 
 Newcastle 2.229 
 
 Sapphire, Oriental 4.200 
 
 Schorl 2.922 to 3.450 
 
 Serpentine 2.264 3.000 
 
 Slate 2.000,, 2.200 
 
 Spar, Fluor 3.090 3.790 
 
 Calc 2.510 2.830 
 
 Sulphur, native 2.033 
 
 fused 1.990 
 
 Talc 2.000 to 3.000 
 
 Topaz 4.000 ,,4.066 
 
 Tourmaline 3.000 3.680 
 
 Turquoise 2.500 3.000 
 
 Ultramarine 2.360 
 
 Woodstone 2.000 to 2.674 
 
 Zeolite 2.075 2.718 
 
 Zircon 4.385 4.700 
 
 Atmospheric Air 1.000 
 
 Carbonic Acid 1 527 
 
 Chlorine 2.500 
 
 Hydrogen 0.069 
 
 Carburetted 0.972 
 
 GASES. 
 
 Hydrogen, Sub-carburetted ...0.555 
 
 Sulphuretted 1.180 
 
 Nitrogen 1.041 
 
 Oxygen 1.111 
 
 Great Oolite. The "Grand Oolithe" of the French; a frequent 
 synonyme of the Bath Oolite, from the great development of its Oolitic 
 limestones and freestones as compared with other members of the system. 
 It belongs to the lower section of the system having the Stonesfield slate 
 for its base, and being overlaid by the Forest Marble and Cornbrash. 
 
 Green-Earth. An earthy variety of chlorite, occurring in various shades 
 of green, having a greasy feel, and faint lustre when rubbed with the nail. 
 It is common in the trap-rocks, occasionally massive, but more frequently 
 filling amygdaloidal cavities, coating agate nodules, or colouring the 
 sides of fissures, &c., with a thin streaky glaze. The finer varieties fur- 
 nish the mountain-green of the colourman and artist. See GLAUCONITE. 
 
 227 
 
GEE 
 
 GreenocMte. Sulphuret of cadmium ; one of the blendes, consisting of 
 77.3 cadmium, and 22.4 sulphur. It occurs in deep- yellow, hexagonal, 
 translucent crystals with dissimilar terminations in porphyritic amyg- 
 daloid, near Bishoptown in Kenfrewshire, and is named after its discoverer, 
 Lord Greenock, now Earl Cathcart. 
 
 Greensand. The lower portion of the Cretaceous or Chalk system as 
 developed in the south of England, and so named from its greenish colour, 
 which it owes to a chloritous silicate of iron. These sands, however, are 
 not uniformly green, but partake of ochraceous and yellow tints ; present 
 various degrees of fineness, from compact sands to coarse nodular grits; 
 and not unfrequently imbed cherty bands, nodular sandstones, and irre- 
 gular deposits of fuller's earth, fossil wood, and ochre. In England the 
 greensand is usually divided into Lower and Upper, because of the stiff 
 blue marly clays (gault) which occur about the middle of the group ; but 
 otherwise there is a great lithological similarity throughout its entire 
 thickness, which rarely exceeds 400 or 500 feet. The gault or golt (a local 
 term) is not of great thickness, nor very regular in its occurrence. It is 
 a bluish chalky clay, which effervesces strongly on the application of acids ; 
 is interstratified with layers of greensand ; and in some localities holds 
 irregular balls of argillaceous ironstone, collected round ammonites and 
 other shells. In some districts the gault assumes a reddish tint, from the 
 iron it contains ; but in other respects its composition is very persistent, 
 and it rarely exceeds 80 or 100 feet in thickness. These three members 
 the Upper Greensand, the Gault, and the Lower Greensand constitute 
 the Cenomanien, the Aptien, and Neocomien (in part) of French geolo- 
 gists. See CRETACEOUS SYSTEM. 
 
 Greenstone. A general designation for the hard granular-crystalline 
 varieties of trap, consisting mainly of felspar and hornblende, felspar and 
 augite, or felspar and hypersthene. The term has reference to their green- 
 ish or blackish-green colours, and though not very precise, these shades 
 very largely prevail. Compared with the Basalts, the Greenstones (whin- 
 stones of Scotland) are less compact, more granular, exhibit distinctly their 
 component crystals, often contain sulphuret of iron, and are usually mas- 
 sive or tabular in their structure. It is customary to speak of them as 
 hypersthenic greenstones, augitic greenstones, &c., according to the pre- 
 dominating mineral ; and as many of them are porphyritic in their texture, 
 we have greenstone porphyries, or porphyritic greenstones. Adopting Conti- 
 nental nomenclature, those exclusively composed of hornblende and fel- 
 spar are termed diorites ; those of augite and felspar, dolerites. On the 
 whole, though the trap-rocks often differ little in composition, the texture 
 of the Greenstone is always more granular or granitic than the basalts, 
 never earthy like the tuffs and wackes, vesicular like the amygdaloids, nor 
 glassy like the obsidians and pitchstones. 
 
 Grenatite (Fr. grenat, a garnet). Prismatoidal garnet ; known also as 
 Stauroiite or Cross-stone, from the peculiar combination of its prisms. 
 
 Gres Bigarre (Fr.) Literally " variegated sandstone;" the equivalent 
 of the Bunter Sandstein of Germany, and the Variegated Sandstones or Lower 
 Trias of England. 
 
 Gres de Vosges. The lowest member of the Trias or Upper New Eed 
 Sandstone of France, as extensively developed in the Vosges. 
 
 Greystone. A variety of trachyte, of a lead-grey or greenish colour, 
 and composed of felspar and augite the felspar being more than 75 per 
 
 228 
 
GRE GRY 
 
 cent of the admixture. " Greystone lavas," says Lyell, " are intermediate 
 between basaltic and trachytic lavas." 
 
 Greywacke (Ger. grauwacke) . A German term originally employed to 
 designate the grey-coloured argillo-arenaceous beds, or coarse slaty strata 
 of the Transition rocks, and subsequently as a name for the entire transi- 
 tion series. It is now seldom employed in this sense the "transition" 
 rocks having been resolved mainly into the Silurian, and partly into the 
 Cambrian and Hypozoic systems. It is still, however, used to designate 
 the hard, gritty, brecciated, or breccio-conglomerate beds which occur in 
 these formations ; and, as a mere lithological term for these ancient grits 
 and breccias, is by no means without its convenience. 
 
 Grey Wethers. Known also as Sarsen Stones and Druid Stones; the 
 name given in the south of England to the weather-worn and half- rounded 
 blocks of grey sandstone which are scattered over the surface of the Lower 
 Downs and adjacent districts, and which are evidently the remains of the 
 Eocene sands and sandstones that have been removed by denudation. 
 
 Griffithides. One of the three genera of small trilobites (Phillipsia, 
 Griflithides, and Brachymetopus), the only examples yet discovered in the 
 Carboniferous formation. Named after Sir R. Griffiths, the original 
 expounder of the ' ' Carboniferous slates " of Ireland. 
 
 Grit. Any hard sandstone in which the component grains of quartz are 
 less rounded or "sharper" than in ordinary sandstones, is technically 
 termed a grit as millstone grit, grindstone grit. 
 
 Grossular, Grossulaire (Lat. grossula, a gooseberry). The name given 
 by mineralogists to the pale gooseberry-green varieties of translucent lime- 
 alumina garnet. See GARNET. 
 
 Ground Ice. In northern countries, when the streams are reduced nearly 
 to the freezing-point, congelation begins frequently at the bottom ; the 
 reason being, according to Arago, that the current is slowest there, and the 
 gravel and large stones, having parted with much of their heat by radiation, 
 acquire a temperature below the average of the main body of the river. It 
 is therefore when the water is clear, and the sky free from clouds, that 
 ground ice forms most readily, and oftener on pebbly than on muddy bot- 
 toms. Sheets of such ice rising occasionally to the surface, bring up with 
 them gravel and even large stones, and in this way become a means of 
 transport where the ordinary current of the stream would be unavailing. 
 
 Ground-Swell The name given to those long heavy waves which occa- 
 sionally set in-shore when there is no wind, these having been produced 
 by storms far out at sea. Geologically, the ground-swell is one of the most 
 destructive forms that the wind- wave assumes. 
 
 Group. An assemblage of objects having some resemblance or charac- 
 ter in common ; hence we speak of groups of strata, of minerals, of plants, 
 and of animals. 
 
 Growan. A mining term for decomposed granite. "The word," says 
 Ansted, "is old Cornish, and appears to have originally meant a rock of 
 uneven composition, whether a conglomerate, a mere gravel, a decomposed 
 porphyritic rock, or solid granite." The expression soft growan is some- 
 times applied when the mineral is sandy. 
 
 Grypnsea, Gryphite (Lat. gryps, a griffin). A sub-genus of the Oyster 
 family, abounding in the Lias, Oolite, and Chalk formations. It derives 
 its name from the beak-like incurved umbo of its left or larger valve ; the 
 right being small, opercular-like, and concave. 
 
 229 
 
GUY GUL 
 
 Gryphite Limestone. A term occasionally applied to the limestones of 
 the Lias, from the marked predominance of the shells of the gryphcea. 
 
 Gudno. A Peruvian term for the well-known manure obtained from the 
 rocks and islets of the Pacific, and other rainless regions, favourable to the 
 retention of the ammoniacal salts which constitute its principal value. It 
 consists mainly of the droppings of countless sea-fowl, intermingled with 
 their skeletons and eggs, the decomposed bodies and bones of fishes, seals, 
 sea-lions, and other marine creatures frequenting these islands. Consider- 
 ing the immense thickness of some guano deposits (40, 60, and 80 feet), 
 and their necessarily slow accumulation, the lower beds must be of vast 
 antiquity carrying us back to the very verge of the current era. 
 
 Gulf Stream. One of the most important and influential of ascertained 
 ocean-currents. It is generally considered as " taking its rise in the Gulf 
 of Mexico (whence its name), though it may be regarded as a continuation 
 of the mighty equatorial current, which sets out from the western coast 
 of Africa, and, after a course of four thousand miles, enters the Carribbean 
 Sea. Absorbing the sun's rays as it advances, it passes into that magnifi- 
 cent indentation in the Mexican coast which serves as a caldron ; for 
 there its waters are raised to the temperature of 86. It then sweeps 
 through the Pass of Florida its heat being 9 more than the ocean can lay 
 claim to, by reason of its latitude and skirts the shores of North America, 
 until it takes that remarkable bend off Nova Scotia and Newfoundland, 
 which throws its waters towards the coasts of Europe. One branch curves 
 downwards and flits past the Azores to the south ; the other glides north- 
 ward in the direction of the British Islands and the Polar Sea. This 
 magnificent ocean-river is supposed to be equal in volume to three thou- 
 sand Mississippis. Its length, reckoning from its Mexican head to the 
 Azores, is upwards of three thousand miles. Its velocity in the Gulf of 
 Florida is about 78 miles a-day, but its current dwindles down to a sober 
 flow of 10 before it reaches the Azores. Its average velocity is about 
 38 miles in the four-and-twenty hours. There are many peculiarities 
 attached to this noble current. The colour of its waters is an indigo - 
 blue as far as the coast of the Carolines. Its margins, especially the 
 left, are generally well-defined ; so that the voyager knows when he dips 
 into its flood the edge being made manifest by the ripplings which 
 mark the line of division, as well as by other visible traits. It would 
 appear, too, that this current actually runs up-hill, for the thermometer 
 shows that the under part, in flowing from Cape Hatteras to the Capes of 
 Virginia, makes an ascent of six hundred feet, being a gradient of five or 
 six feet to the mile. It is noticeable, also, that the surface of this ocean- 
 river slopes from the centre towards the margins, like the curve of a 
 causeway, and thus boats and other objects, if left to themselves, naturally 
 drift towards the edges. It is in this way that the Sargasso Sea (the 
 expanse permanently covered with the fucus natans) has been formed 
 the weeds, like the drift on an eddy, floating always towards the still and 
 lower level." 
 
 The great function of the Gulf Stream seems to be the equalisation of 
 the superficial temperature of the globe. Acquiring in its fountain-head 
 a temperature of 86, and losing only some 13 or 14 in its progress, it 
 diffuses a perennial supply of warmth, not only among the waters of the 
 oceans, but throughout the atmosphere which passes over it, and over the 
 countries along whose shores it travels. Thus, as its velocity slackens 
 
 230 
 
GUM GYP 
 
 about mid Atlantic, it begins to diffuse itself over a wider area, and so 
 counteracts the cold brought down by the Arctic Current. So perceptible 
 is this, that while the sea beyond its influence is little above freezing, 
 navigators, on fairly entering its waters, find the ocean gradually rise to 
 50 above freezing. As it diffuses itself, in virtue of its diminished velocity, 
 it spreads over a wider area, and thus renders more genial a broader 
 expanse of ocean ; while the winds passing over it are tempered, and bear 
 their balmier influences to wider regions. It is to the Gulf Stream that 
 western Europe, and Britain in particular, owes a higher mean tempera- 
 ture than other places in the same parallels of latitude ; and so, also, while 
 modifying the rigours of our European winters, it sends its surplus warmth 
 to Arctic regions and the Polar seas. Cosmically, it is thus a great modifier 
 and regulator of the Life of the ocean, as well as of the countries against 
 which its genial current impinges conferring on regions which are geo- 
 graphically sub-temperate, a truly temperate flora and fauna. Geologi- 
 cally, it gives us vast insight into those modifications of former climate which 
 may have been brought about by other distributions of land and sea than 
 those at present existing, and that without at all calling in the aid of those 
 abnormal conditions of "internal heat," "change of earth's axis," and the 
 like, under which the slenderly informed theorist too often takes shelter. 
 See Maury's ' Physical Geography of the Ocean.' 
 
 Gum-Lead. The familiar term for plumlo-resinite (which see), from its 
 appearance to gum-arabic. 
 
 Gurt (Sax. ) In mining, a gutter or channel for water, usually hewn out 
 of the "pavement" or bottom of a working drift. 
 
 Guydquillite. A mineral resin occurring in friable amorphous masses of 
 a pale-yellow colour, and melting at 157 Fahrenheit. It is found at 
 Guyaquil in South America, on the site of ancient resiniferous forests, and, 
 like amber, is evidently of vegetable origin. See MINERAL RESINS. 
 
 Gymnodonts (Gr. gymnos, naked, and odous, tooth). A family of fishes 
 belonging to the order Plectognathi (soldered jaws), and including the 
 globe-fish, trunk-fish, &c., in which the jaws are covered with a substance 
 resembling ivory arranged in small plates, representing united teeth. The 
 gymnodonts appear only in the Chalk and Tertiary formations. 
 
 Gymnosperms (Gr. gymnos, naked, and sperma, seed). Flowering plants 
 with naked seeds (that is, whose ovules are not enclosed in a pericarp), and 
 so called in contradistinction to the Angiosperms, whose seeds are enclosed. 
 The gymnosperms, or gymnogens, as they are also termed, differ only in 
 this respect from the Exogens, and consequently have their wood arranged 
 in concentric layers ; e.g., the Coniferce or Pine tribe. 
 
 Gypseous. Kesembling or partaking of the nature of gypsum, as "gyp- 
 seous marls." Gypsiferous. Containing or producing gypsum, as " gypsi- 
 ferous limestones." 
 
 Gypsum. Sulphate of lime, plaster -of -Paris, or stucco -stone. The 
 Greek word gypsos signifies lime in general, and seems to be derived from 
 ge, the earth, and epso, I boil, in allusion to the heat given off when burnt 
 lime is slacked with water. Gypsum is found in crystals, in fibrous masses, 
 and in granular-compact beds, often of great extent. Its normal composition 
 is 46.47 sulphuric acid, 32.65 lime, and 20.88 water. " It is a very common 
 mineral," says Nicol, " especially in the more recent sedimentary forma- 
 tions, and is even now forming, either as a deposit from water holding it in 
 solution, or from the decomposition of iron-pyrites, when the sulphuric 
 
 231 
 
GYK 
 
 acid combines with lime, or from the action of sulphurous vapours in 
 volcanic regions on calcareous rocks. It is often imbedded in nests or 
 reniform masses in clay or marl, more rarely makes part of mineral veins, 
 but seldom or never forms veins by itself. The transparent crystals are 
 termed selenite, and fine specimens occur in the salt mines of Bex in 
 Switzerland, in those of the Tyrol, Salzburg, and Bohemia, in the sulphur 
 mines of Sicily, at Lockport in New York, and other places in North 
 America, in the clay of Shotover Hill near Oxford, at Chatley near Bath, 
 and many other localities. Fibrous gypsum (satin-spar) occurs of remark- 
 able beauty at Ilfeld in the Harz, in the compact gypsum of northern 
 Germany, and at Matlock in Derbyshire. Compact white gypsum or 
 alabaster is found in great beauty at Volterra in Tuscany, and also in the 
 Harz. Massive or compact gypsum forms whole beds in the Trias and 
 Permian Red Sandstones of many parts of Germany, France, Italy, and 
 England, and is often associated with rock-salt. In Nova Scotia it occurs 
 with similar beds in the Lower Carboniferous formations. The fine varie- 
 ties are cut into various ornamental articles, as vases, and the so-called 
 Roman pearls, chiefly distinguished from the true pearl by their specific 
 gravity. Plaster-of- Paris, used for casts and other works of art, is formed 
 by calcining the mineral and grinding it down to a fine powder, which 
 forms a paste that soon hardens by absorbing the water driven off by the 
 heat. It, however, loses this property when exposed to a temperature 
 above 300 Fahrenheit, when it becomes similar to Anhydrite. Gypsum is 
 also used for glazing porcelain, and the formation of potters' moulds ; in 
 the manufacture of glass ; as mortar, and as manure, especially as a top- 
 dressing for meadows." 
 
 Gyracanthus (Gr. gyros, a circle or spire, and acantha, a spine). Liter- 
 ally "spiral or twisted spine;" a genus of cestraciont fin-spines or ich- 
 thyodorulites occurring in the Carboniferous and Permian formations, often 
 from ten to eighteen inches in length, and so termed from the sculptured 
 ridges with which they are ornamented, and which run in a spiral or 
 twisted-like manner, from the base upwards. 
 
 Gyration (Gr. gyros, a circle). The act of revolving; a revolution. 
 Gyratory. Having a revolving and twisting motion. 
 
 Gyrodus (Gr. gyros, a circle, and odous, tooth). Literally " circle 
 tooth ; " a genus of pycnodont fishes, occurring in the Oolite and Chalk, 
 and so termed from their circular grinding teeth, which are disposed in rows 
 on the bones composing the roof, floor, and sides of the mouth. The fishes 
 of this genus have the body large, flat, and elevated ; the dorsal and anal 
 fins long ; the tail forked with unequal lobes ; and the scales laterally con- 
 nected by strong processes, as in Lepidotus. 
 
 Gyrogonites (Gr. gyros, twisted, and gone, seed). The spiral seed-vessels 
 of plants allied to the chara, and found fossil in fresh-water Tertiaries. 
 "The Cliarce" says Lyell, "inhabit the bottom of lakes and ponds, and 
 flourish mostly where the water is charged with carbonate of lime. Their 
 seed-vessels are covered with a very tough integument, capable of resisting 
 decomposition, to which circumstance we may attribute their abundance 
 in a fossil state." 
 
 Gyrolite (Gr. gyros, a circle, and lithos, stone). A hydrous silicate of 
 alumina occurring in spherical lamellar radiations within the cavities of 
 basalt and greenstone. White and vitreous when fresh, but becomes pearly 
 on exposure to the air. 
 
 232 
 
HAA KJF. 
 
 Haarkies (Ger. haar, hair). A German term for the native sulphate of 
 nickel, or MUlerite, which occurs in very fine acicular and capillary crystals. 
 It is known also as Capillary Pyrites, and consists of 64.76 nickel and 
 35.24 sulphur. 
 
 Habitat. Applied in botany and zoology to the country or district in 
 which a plant or animal is indigenous; the tract or range to which it 
 seems limited by external conditions of soil, climate, &c. More properly, 
 the term station, is applied to plants, and habitat to animals. 
 
 Hackly. Having the surface rough with irregular protruding points ; a 
 term applied to the fracture of rocks and minerals when they break up 
 with a rough irregular surface, as certain greenstones and granites. 
 
 Hade, Hading. A miner's term for the inclination or slope of any slip, 
 fault, vein, or lode- The amount of deviation from the vertical is spoken 
 of as the trading ; and a fault or vein so sloping is said to hade. 
 
 Hadrosaurus (Gr. kadros, mighty, and sauros, lizard). The name given 
 by Dr Leidy of Philadelphia to a huge herbivorous reptile whose remains 
 were discovered, in 1858, in the Chalk marls of Haddenfield, New Jersey. 
 The remains comprised nearly the entire skeleton, and gave ample indica- 
 tion of a genus closely allied to, but larger than the iguanodon of the 
 English Weald. Dr Leidy thinks the creature was most probably amphi- 
 bious ; and, from the greatly disproportioned size of the fore and back 
 parts of the skeleton, suspects that it may have been in the habit of brows- 
 ing, kangaroo -like, in an erect position, sustaining itself on the hinder ex- 
 tremities and tail; or if it retained the ordinary prostrate condition, it 
 must have progressed in the manner of the batrachians. Calculating from 
 the remains now preserved, the Hadrosaur must have been about 25 feet 
 in length, from snout to tail, and in height from 9 to 10 feet upon the 
 haunches. 
 
 Haematite, Hematite (Gr. haima, blood). Native oxide of iron, so 
 named from its prevailing reddish colour and blood-like streak. It is 
 customary to speak of the red haematite and the brown haematite the one 
 being an anhydrous (70 iron, 30 oxygen), the other a hydrated peroxide 
 of iron (85.6 peroxide of iron, and 14.4 water). The red haematite is an 
 abundant ore, occurring in veins and beds in the older crystalline rocks, 
 and passing from a state of sparry crystallisation (specular iron), through 
 concentric kidney-shaped concretions (fibrous red iron), and compact or 
 ochrey masses (hcematite proper), to a soft earthy variety known as reddle 
 or red-chalk. The brown haematite, often termed Limonite, occurs in 
 beds, veins, and nests, in rocks of all ages, and also presents several varie- 
 ties, as the fibrous^ compact, and ochrey. It is frequently mixed with other 
 mineral substances, such admixtures forming umber, yellow-ochre, bog-iron, 
 and other well-known substances. See IRON. 
 
 Hsematocrya (Gr. haima, blood, and kruos, cold). Literally "cold- 
 blooded ; " a term applied by Professor Owen to the cold-blooded verte- 
 brates (fishes and reptiles), in contradistinction from the Hcematotlierma 
 
 233 
 
1LE HAM 
 
 or warm-blooded birds and mammals. Considering the linking and blend- 
 ing of the fishes with the reptiles, he regards the Hcematocrya as a wider 
 group possessed of great naturality of character. 
 
 Hsematotherma (Gr. ha-ima, blood, and thermos, heat). Literally "warm- 
 blooded ; " a term applied by Professor Owen to the warm-blooded verte- 
 brates (birds and mammals), in contradistinction from the Hcematocrya or 
 cold-blooded fishes and reptiles. 
 
 Haidingerite (after Haidinger, the mineralogist). A name given to two 
 totally different minerals the Haidingerite of Turner being a hydrous 
 arseniate of lime (85.68 arseniate of lime, and 14.32 water) ; and that of 
 Berthier being an ore of antimony, consisting of sulphuret of antimony 
 and sulphuret of iron in varying proportions. 
 
 Hail (Sax., so called from the rough, broken form of the hailstones). 
 Rain or other moisture that has been suddenly frozen in its downward 
 course by passing through a stratum of air below the temperature of 32. 
 Hail pellets are of various forms round, angular, or flat ; and though 
 generally about a quarter of an inch in diameter, have yet been found two 
 and three inches in diameter, especially during thunder-storms and in tro- 
 pical countries. The phenomena attending the formation and fall of hail 
 are not well understood, though sudden cold winds seem to be the chief 
 promoters. The electricity usually accompanying hail-storms is an effect 
 rather than a cause the electric fluid being an accompaniment of the 
 passage of water from a liquid to a solid state. 
 
 Hair-Salt. A familiar term for native sulphate of magnesia, from its 
 frequent occurrence as a fine capillary incrustation on the walls of damp 
 cellars and new buildings. 
 
 Halcy6rnis (Gr. halcyon, the kingfisher, and ornis, bird). An extinct 
 bird, whose remains occur in the Eocene beds of the isle of Sheppey ; and 
 so termed from its apparent affinities to the existing kingfisher. 
 
 Halecopsis (Gr.) Literally "herring or sprat-like;" a genus of fishes 
 founded by Agassiz on some remains from the London Clay of the isle of 
 Sheppey, and so named from their fusiform, sprat-like appearance. 
 
 Halitherium (Gr. hals, halos, the sea, and t/wrion, beast). Literally " sea- 
 beast ; " a Tertiary cetacean having evident affinities to the phytophagous 
 family of the Manatidce or sea-cows. 
 
 Halogene (Gr. hals, salt, and gennao, I produce). A term employed by 
 Berzelius to denote bodies which form salts with metals, as chlorine, brom- 
 ine, iodine, fluorine, and cyanogen. The salts thus produced are termed 
 haloids. 
 
 Haloid Salts (Gr. hals, salt, and eidos, resemblance). Salt-like com- 
 pounds consisting of a metal on the one hand, and of chlorine, iodine, and 
 the radicals of the hydracids in general, excepting sulphur, on the other. 
 
 Hal6nia. A genus of fossil stems apparently intermediate between the 
 Lycopods and Conifers, and so called from its affinity, being nearest with 
 Halonia. "It comprehends," according to Lindley, "all stems in which, 
 to the surface of lepidodendron, is added the mode of branching of certain 
 coniferse." According to others, Halonia is merely the branches of Knorria, 
 and is described as "stem not furrowed, branched, covered with indistinct 
 rhomboidal marks, and tubercular projections disposed in quincunx order." 
 
 Halysites (Gr. halusis, a chain). Chain-pore coral ; a genus peculiar to 
 Palaeozoic strata, and better known as Catenipora, which see. 
 
 Hamite (Lat. hamus, a hook). A genus of the Ammonite family peculiar 
 234 
 
HAR HAT 
 
 to the Chalk and Greensand, and so named from the shell, which is hook- 
 shaped, or bent upon itself more than once the courses being separate. 
 D'Orbigny separates the Greensand from the Chalk species, and erects them 
 into a distinct genus under the title Hamulina. 
 
 Hardness of Minerals and Bocks. In discriminating rocks and minerals, 
 their hardness is one of the physical properties almost invariably made use 
 of by the geologist and mineralogist. In mineralogy, it is estimated by 
 a conventional scale of ten degrees, invented by Mohs, who assumed talc 
 to be the lowest in the scale, and diamond the highest, thus: 
 
 Talc, 1 
 
 Rock-salt, 2 
 
 Calc-spar, 
 
 Fluor-spar, 4 
 
 Apatite, 5 
 
 Adularia felspar, ............ < 
 
 Rock-crystal, .................. 7 
 
 Topaz, 
 
 Corundum, ..................... 9 
 
 Diamond, ..................... 10 
 
 If, for example, a mineral can be scratched by rock-crystal, but can in 
 turn scratch felspar, it is evident its hardness lies between 6 and 7 of the 
 scale, and may be expressed by 6.3 or 6.8, just as it seems to approach 
 felspar on the one hand, or rock-crystal on the other. The hardness of 
 minerals may also be tested by the application of a file or steel point ; and 
 thus it is customary to say that talc can be scratched with the nail of the 
 finger, that felspar yields to the knife, while rock-crystal resists it. In 
 treating of rocks it is impossible to determine their hardness with the 
 same precision, though quartz-rock may be regarded as standing at one 
 end of the scale, and ordinary white chalk at the other. A very good test 
 of the hardness and compactness of a rock is the sound that it emits when 
 struck by the hammer the harder yielding a sharp ringing sound, the 
 softer a dull and heavy. It is thus that the French quarrymen estimate the 
 quality of the celebrated Caen stone, their scale of hardness being indi- 
 cated by the expressive sounds pif, pof, pouf- the pif being the hard and 
 compact, the pouf the soft and friable. 
 
 Hare. Remains of the hare and rabbit have not yet been detected in 
 deposits of older date than the Pleistocene bone-caverns of England and 
 the south of Europe. 
 
 Harmatome (Gr. karmos, a joint, and tome, a section). One of the Zeolite 
 family, consisting of 48.3 silica, 17.8 alumina, 19.9 baryta, and 14 water, 
 with traces of lime and potash. It is known also as Cross-stone, and 
 derives its name from the joint-like intersection of its rhombic crystals. 
 Associated with zeolite, &c., in the older metalliferous veins. 
 
 Harmattan. The name given in Guinea and Senegambia to the simoom 
 or hot dry wind which blows from the great African desert during the 
 months of December, January, and February. See SIMOOM. 
 
 Hartite. A fossil resin occurring in the brown coal of Oberhart, in 
 Lower Austria, either in transparent clearable masses, in angular frag- 
 ments, or in small tables with six faces. Resembles wax in appearance ; 
 colourless or greyish white, with a somewhat greasy lustre ; translucent ; 
 brittle ; melts at 165 Fahr., and consists of 87.5 carbon, 12.05 hydrogen. 
 
 Hatchetine (after Mr Hatchett, the mineralogist). Mineral tallow ; a 
 waxy or spermaceti-like substance of a greenish -yellow colour, faint pearly 
 lustre, and translucent. Occurs in thin flaky veins in the ironstone of 
 Merthyr-Tydvil and other localities ; consists of 86 carbon and 14 hydro- 
 gen ; and is fusible, according to variety, at 115 to 160 Fahr. See 
 RESINS, MINERAL. 
 
 235 
 
HAU HEL 
 
 Haiismannite (after the mineralogist Hausmann). Pyramidal mangan- 
 ese ore, occurring, with other manganese ores, either as a protoxide or as 
 a peroxide of that metal. 
 
 Hauyne (after the mineralogist Haiiy). One of the Haloid minerals, of 
 a fine azure-blue colour, and occurring in crystalline grains, in lava and 
 other volcanic rocks. Its average composition seems to be 34.8 silica, 28.9 
 alumina, 17.2 soda, 7.9 lime, and 11.2 sulphuric acid. 
 
 Hayesine (after Hayes). Borate of lime, occurring in globular, mammil- 
 lated or reniform masses, from the size of a marble to that of a potato, on 
 the dry plains of.Iquique in Peru; in incrustations near the lagoons of 
 Tuscany ; and in narrow veins in gypsum in Nova Scotia. On being broken 
 the masses present the appearance of interwoven silky fibres of a snow- 
 white colour ; are opaque, tasteless, but with a peculiar odour, and consist 
 of 52 boracic acid, 11.5 lime, and 35 water, with traces of soda, sulphuric 
 acid, and chlorine. Imported from Peru under the name of Tiza, which 
 see. 
 
 Heading. In mining, a small gallery driven in advance of a gate-road 
 or larger gallery ; or, it may be, driven for some temporary purpose. 
 
 Headland. Any projection of the land into the sea ; generally applied 
 to a cape, ness, or promontory, of some boldness and elevation. 
 
 Heart-wood. A familiar term for the hard and matured interior portion 
 of exogenous stems or timber-trees, in contradistinction to the sap-ioood, or 
 soft, unmatured, exterior layers. Technically, the former is termed dura- 
 men, the latter alburnum. 
 
 Heave (in mining). The displacement of a vein or bed by the inter- 
 section of another vein or fault. When the intersected vein is thrown up, 
 it is said to be a heave, and when thrown down a slide. Heave and slide 
 are thus merely relative terms, according to the position from which they 
 are viewed. See FAULT and DISLOCATION. 
 
 Heavy-Spar. A term often loosely applied to the carbonate as well as 
 to the sulphate of baryta, and not un frequently also to the carbonate and 
 sulphate of strontia. Properly speaking, the " heavy-spar "" of the mineralo- 
 gist is the sulphate of baryta, occurring in veins massive, fibrous, lamellar, 
 and in prismatic crystals. The rhomboidal carbonate is better known as 
 Witherite, the carbonate of strontia as Strontianite, and the sulphate of 
 strontia as Celestineall of which see. 
 
 Hedenbergite. An important variety of lime-iron augite, of a black or 
 blackish-green colour, named after Hedenberg, the Swedish chemist. 
 
 Helianthoida (Gr. helios, the sun, and anthos, flower). Literally "sun- 
 flowers ; " the actiniform zoophytes, which constitute an extensive order of 
 the Anthozoa, and of which the actiniae or sea-anemones may be taken as 
 the type. The Helianthoids, except in the free species, as the Actinia, 
 have a lamellated calcareous polypidom, the plates of which radiate (flower- 
 like) from the centre ; and these stony structures enter largely into the 
 composition of coral-reefs, recent as well as fossil. 
 
 Helicidse (Lat. helix, a coil). The land-snails ; a well-known family of 
 vegetable-eating gasteropods, having a light, variously coloured, more or 
 less turbinated shell, and of which the garden-snail may be taken as the 
 type. The Helicida3, of which there are upwards of 1200 living species, 
 have a world-wide range; the extinct species, about 50 in number, are 
 found only in Tertiary and recent formations. 
 
 Helidceras, Helioceratite (Gr. helix, a spiral, and faros, horn). A genus 
 236 
 
HEL HEP 
 
 of the Ammonite family, ranging from the inferior Oolite to the Chalk in- 
 clusive, and so named from the spiral arrangement of its chambered 
 whorls. 
 
 Heliolites (Gr. hellos, the sun, and lithos, stone). An extensive genus 
 of Silurian and Devonian corals, belonging to the family Milleporidce ; and 
 so called from the central-radiating or sun-like aspect of the septa of their 
 pores, compared with those of the Astrcea or star-corals. 
 
 Heliotrope (Gr. helios, the sun, and trope, turning). Bloodstone ; a 
 variety of calcedony of a dark-green colour, and sprinkled with deep 
 red spots. The name is also applied by lapidaries to stones, some of which 
 are agates and others jaspers the agate-bloodstones being in greater 
 part translucent, the jasper-bloodstones, on the contrary, being mainly 
 opaque. 
 
 Helminthites (Gr. helminthos, a worm). Applied to those long sinuous 
 tracks so common on the surfaces of many flaggy sandstones, and which 
 are usually considered as worm-trails. 
 
 Helodus (Gr. helos, a stud, and odous, tooth). Literally " stud-tooth;" 
 a genus of cestraciont fish-teeth, occurring abundantly in the Carboniferous 
 Limestone, and so termed from the stud-like aspect of their crushing 
 crowns. 
 
 Helladothe'riuin (Gr. Hellas, Greece, and therion).An extinct pachy- 
 derm of Upper Tertiary, or perhaps Miocene, age, from the Pikermi beds 
 at the foot of Mount Pentelicus, in Greece ; whence the name. 
 
 Hematite, more frequently HAEMATITE, which see. 
 
 Hemi. A Greek word frequently employed as a prefix to denote half, 
 and synonymous with the Latin semi ; as hemisphere, half a sphere ; hemi- 
 ptera, half-winged, &c. 
 
 Hemicidaris (Gr. hemi, half, and cidaris). A genus of turban-echinites 
 characteristic of the Upper Jura Limestone of Switzerland, and distin- 
 guished by its depressed form (hemi), and long sub-cylindrical spines. It 
 occurs abundantly in the Oolites of England. 
 
 Hemicosmites (Gr.) Literally "half-sphere." A Lower Silurian cysti- 
 dean, characterised by its spherical form, composed of numerous hexagonal 
 and pentagonal plates ; central, proboscidiform mouth ; and absence of 
 tentacles or arms. Originally known as Echinosphcerites. 
 
 Hemipneustis (Gr. hemi, half, and pneustis, blown). M. Agassiz's generic 
 term for the fossil sea-urchin Spatangus, in allusion to its flattened or 
 half-inflated shape. See SPATANGID^B. 
 
 Hemipristis (Gr. pristis, a saw). A provisional genus of shark's teeth 
 occurring in the Chalk and Tertiary formations. They are distinguished 
 by their serrated edges, that do not extend to the summit, which is sharply 
 pointed. 
 
 Hemitelites (Gr. hemiteles, half-finished, incomplete). A term employed 
 by Goeppert to designate certain Oolitic ferns, because of their abruptly 
 terminating (incomplete-looking) pinnules. The J^hlebopteris of Professor 
 Lindley, which see. 
 
 Hepatic (Gr. hepar, the liver). Applied in mineralogy to various sub- 
 stances of a liver-like cdlour and consistency ; as Hepatic pyrites, a variety 
 of prismatic iron pyrites which, on exposure to the atmosphere, is gradually 
 converted from a yellow sulphuret to a liver-brown compact oxide of iron, 
 still retaining the original crystallised form ; Hepatic cinnabar, a variety 
 of cinnabar of a dark liver colour, passing into steel-grey. 
 
 237 
 
HEP HEU 
 
 Hepatite (Gr. hepar, the liver). A dark-grey variety of heavy-spar or 
 sulphate of baryta, which, when rubbed, emits a fetid odour like sulphu- 
 retted hydrogen. It seems a mere mixture of barytes with carbonaceous 
 matter. 
 
 Herbaceous. Applied in botany to stems that die down annually, in 
 contradistinction to ligneous, or woody, persistent stems. 
 
 Herbivorous (Lat. herba, herb, and voro, I devour). Herb-eating ; sub- 
 sisting on vegetable food ; in contradistinction to carnivorous. 
 
 Hermetically Sealed. Sealing or closing-up by fusion, as the closing 
 of a glass tube by melting the ends. Said to be derived from the Egyptian 
 Hermes, the fabled father of chemistry. 
 
 Herpetichnus (Gr. herpeton, a reptile, and ichtion, footprint). A pro- 
 visional term employed by Sir W. Jardine for certain small lizard-like 
 footsteps occurring on the New Red Sandstone slabs of Corncockle Muir, 
 Dumfriesshire, of Storeton, Cheshire, and similar localities. 
 
 Herpet6logy (Gr. lierpeton, reptile, and logos, discourse). That branch 
 of zoology which treats of the structure, habits, history, and arrangement 
 of reptiles. 
 
 Hervidero (Span, hervir, to boil). The name given in Central America 
 to .the mud -volcanoes which occur in that and the contiguous districts of 
 Mexico. The hervideros consist of mounds more or less conical, with a 
 crater at top, in which a clayey fetid mud of various colours and consis- 
 tency is kept in continual ebullition, and which is occasionally thrown up 
 in pasty flakes that fall around and form the conical mounds in question. 
 The vapours that escape from these hervideros are chiefly steam, sulphu- 
 retted hydrogen, and sulphuric acid ; and in the fetid mud, as it cools and 
 hardens, are detected numerous incipient cubes of iron-pyrites and flakes 
 of selenite or crystallised gypsum. 
 
 Hetero (Gr. heteros, the other, not the same). A term often employed 
 in composition to denote difference or dissimilarity, as Iwmo indicates 
 sameness or similarity. Thus heterogeneous, composed of different ma- 
 terials ; Jielerocercal, having unequal lobes, like the tail of the dog-fish, &c. 
 
 Heterocercal (Gr. heteros, other, not the same, and kerkos, tail). A term 
 applied by Agassiz to fishes having unequally-lobed tails, that is, where 
 the rays are principally developed on the under side, and the vertebrae 
 are produced far beyond, forming an upper and prominent lobe, as in the 
 sharks and dog-fishes. Existing fishes have chiefly homocercal, or equally- 
 lobed tails, as the herring, cod, salmon, &c.; several have undivided or 
 single and rounded tails, as the wrasse; while the unequally-lobed or 
 heterocercal tail is found only in the sharks, sturgeons, lepidosteus, and a 
 few others. In the Palaeozoic periods, however, the heterocercal form 
 alone prevailed, no fish with a true homocercal tail occurring below the 
 Triassic formation. 
 
 Heteroclite (Gr. heteros, other, not alike, and Uylos, notable). Irregular ; 
 notably diverse ; dissimilar in parts. Thus Cuvier designates the Plesio- 
 saurus as the most fwterodite animal that is, made of the most unexpected 
 combination of parts that had come under his knowledge. To the head 
 of a lizard it united the teeth of a crocodile ; a neck of enormous length, 
 resembling the body of a serpent ; the trunk and tail having the propor- 
 tions of an ordinary quadruped ; the ribs resembling those of a chameleon ; 
 and the paddles being like those of the whale. 
 
 Heulandite (after Mr Heuland, the English mineralogist). Foliated or 
 238 
 
HEX HIP 
 
 tabular zeolite ; the Stilbite of Haiiy. Occurs chiefly in amygdaloid and 
 other trap rocks ; is generally white, but often of reddish or hair-brown 
 colour; and consists of 58.1 silica, 18.4 alumina, 7.5 lime, and 16 water. 
 
 Hexagon (Gr. hex, six, and gonia, an angle). A figure with six angles, 
 and consequently having six sides. 
 
 Hexagonal (Gr. hex, six, and gonia, an angle). Applied to figures 
 having six angles, and consequently six sides, more or less regular. Basalt 
 occasionally appears in hexagonal or six-sided columns. 
 
 Hexapro'todon (Gr.) Literally "six-front-teeth ;" the generic term for 
 a large pachyderm whose remains occur in the Pliocene and Miocene 
 Tertiaries of Asia. It was, according to Owen, " essentially a hippopo- 
 tamus, with six incisor teeth, instead oifour, in each jaw." 
 
 Highgate Resin. A familiar term for a spepies of fossil gum-resin or co- 
 pal found in nodular masses in the Tertiary Clay at Highgate, near London. 
 
 High-Level Gravels. A recent designation for those sands and gravels, 
 consisting largely of rolled chalk-flints, which cover so much of the higher 
 grounds in the south of England and north of France. It is believed that 
 this deposit was spread over the surface before the formation of the exist- 
 ing valleys. No fossils have been found in the high-level gravels, and Mr 
 Godwin Austen supposes that they may be of any age between that of 
 the uppermost Eocenes and the Crag. 
 
 Hils-Conglomerat,Hils-Thon. In Germany and Brunswick respectively, 
 the equivalents of the Lower Greensand of England. See tabulations, 
 "GEOLOGICAL SCHEME." 
 
 Hippopodium (Gr. hippos, horse; pom, podos, foot). Literally "horse- 
 foot ; " a large heavy bivalve, allied to Cypricardia, and characteristic of 
 the Lower Lias shales of England. 
 
 Hippopotamus (Gr. hippos, horse, and potamos, river). A well-known 
 amphibious pachyderm, now restricted to the rivers and swampy lakes of 
 Africa, but whose remains are found abundantly in the Pleistocene or 
 uppermost Tertiaries of England, France, Germany, and Italy. These 
 remains, which occur in Pliocene, Pleistocene, and Recent deposits, seem 
 to indicate the existence of several species, and some of these of more 
 gigantic dimensions than the living animal. 
 
 Hippotherium (Gr. hippos, horse, and therion, wild beast). A mammal 
 of the Miocene Tertiaries, so called from its close resemblance to the Horse 
 family. Remains from the Siwalik Hills indicated a size about that of the 
 fallow-deer, with extreme length and slenderness of limb. 
 
 Hippurite (Gr. hippos, horse). A massive horsehoof-like bivalve of the 
 Chalk formation, having a deep conical or sub-cyndrical under-valve, with 
 a flattish lid or upper-valve. As a family the Hippuritidce have no living 
 analogues ; hence the diversity of opinion that has been expressed as to 
 their true relations. The family embraces the hippurites, radiolites, capri- 
 nella, caprina, caprotina, &c. all very peculiar in form, and highly 
 characteristic of the Lower Chalk both in Europe, Northern Africa, and 
 America ; hence the occasional Continental term of the " Hippurite lime- 
 stone " for the calcareous beds of that formation. For the structure and 
 affinities of the Hippuritidse, see S. P. Woodward in the llth vol. of the 
 * Geological Journal.' 
 
 Hippurites. A genus of Coal-measure plants, so called from their close 
 resemblance to the common hippuris vulgaris, or mare's-tail of our marshes. 
 If they grew in the same relative proportions as the existing hippuris, 
 
 239 
 
HIS HOL 
 
 many of the fragments found would indicate a height of eighteen or 
 twenty feet. Very little, however, is known of their habits or true affi- 
 nities. 
 
 Histology (Gr. histos, a tissue, and logos, a discourse). The doctrine of 
 the tissues which enter into the formation of the various organs of any 
 living being ; that department of natural science which is specially con- 
 nected with the investigation (by the microscope) of the minuter structures 
 of organic life. 
 
 Hog's Backs. The name given by geologists to the ridgy structure of 
 certain districts, which consists of alternate ridges and ravines, occasioned 
 either by the sharp undulations of the subjacent rocks, or more frequently 
 by the erosive action of mountain-torrents that cut out the ravines and 
 leave the ridges or " hog's backs " standing between. This structure 
 occurs most abundantly on the lower slopes and flanks of mountain-ranges. 
 
 Holaster (Gr. holos, entire, and astron, star). A genus of Spatangidse 
 (which see) established by Agassizfor those ecbinites that are heart-shaped, 
 with simple ambulacra converging towards the summit. The mouth is 
 elongated transversely, and the vent is on the posterior face. The species 
 are common in the Lower Chalk and Chalk-marl of England. 
 
 Holectypus (Gr. holos, entire, wholly, and ektypos, moulded or embossed). 
 " In certain kinds ofGfalerites (fossil sea-urchins) the shell is strengthened 
 internally," says Mantell, " by five strong ribs or projections, which of 
 course leave corresponding deep furrows or channels on the flint casts 
 moulded in them ; " hence the name. These echinites have been erected by 
 M. Desor into the genus Holectypus, the characteristics of which are shell 
 hemispherical and circular ; the base flat ; the tubercles disposed in series ; 
 the inside of the case supported by five lamellae or ribs. 
 
 Holing. In coal-mining, cutting under a seam of coal for a certain dis- 
 tance, so as to deprive it of support, and thus facilitate its falling down 
 when cut away at the sides of the gallery or when wedges are driven in at 
 the roof. This " holing," which is one of the most laborious parts of coal- 
 mining (inasmuch as it is frequently performed by the miner lying on his 
 side), has been recently performed by an under-cutting machine, propelled 
 by compressed air, and which, from its rapidity and greater depth of stroke, 
 bids fair to come into very general operation. 
 
 Holopea(Gr. holos, entire, and ope, opening). Literally, "entire-mouth;" 
 an obscure genus of Lower Silurian Gasteropods ; periwinkle-like in con- 
 tour, and hence formerly regarded as a form of Littorina. Outer lip situ- 
 ated near the base. 
 
 Holopella. Another obscure genus of Silurian Gasteropods ; turritella- 
 like in form, and hence originally ranked under that genus. Peristome 
 entire, not produced in front. 
 
 HoloptycMns (Gr. holos, entire, and ptyche, wrinkle). Literally " all- 
 wrinkle ; " a genus of sauroid fishes belonging to the Devonian and Car- 
 boniferous periods, and so called from the corrugated or wrinkled surfaces 
 of their enamelled scales. They belong to the Ccelacanthi or hollow-spines ; 
 and judging from the bones of the head and the dorsal and fulcral scales, 
 which are often from three to five inches in width, many of them must 
 have been of great size from eight to ten or even twelve feet in length. 
 In some species the wrinkles or furrows on the scales are disposed in laby- 
 rinthine fashion ; in others they radiate in dichotomising lines from the 
 anterior to the posterior margin ; and in others, again, they are arranged in 
 
 240 
 
HOL HOM 
 
 somewhat concentric order. Besides being armed with numerous sharp- 
 pointed fish-teeth, their jaws were furnished with larger reptilian teeth of 
 conical form placed at intervals in either jaw, evidently for the purpose of 
 seizing and cutting up their bulkier prey. In the Carboniferous genus 
 Rhizodus, which has been separated from the Holoptychii, the teeth are 
 larger, compressed laterally, and more trenchant in form, while the scales 
 also are larger and stronger, and covered with irregular granular corruga- 
 tions. As yet the chief localities for Holoptychius have been the middle 
 and upper Devonian sandstones of Elgin, of the Carse of Gowrie, and of 
 Dura Den in Fife ; and the lower Carboniferous strata of Fife, Mid-Lothian, 
 and Lanark in Scotland, and of Armagh in Ireland. Though remains are 
 abundant enough, much yet remains to be done for the rigid determination 
 of the so-called species. 
 
 Holothurioidea. The sea -cucumbers; an order of echinoderms, of 
 which the common ffolothuria, or sea-cucumber of our own shores, has 
 been taken as the type. They are characterised by their vermiform body, 
 which is covered by a tough flexible integument with scattered reticu- 
 late calcareous corpuscles, or beset with minute anchor-shaped spicula. 
 Portions of the imbricated integument of one genus (Psolns) have been 
 found in the glacial clays of Bute ; and the spicula of others occur fossil 
 so early as the Chalk and Oolite. 
 
 Homalon6tus (Gr. homalos, on the same level or plane, and notes, the 
 back. A genus of trilobites occurring in Silurian and Devonian strata, and 
 so termed because the three-lobed aspect so characteristic of the family is 
 in a great measure obliterated, and the back appears smooth and uniform. 
 
 Homo- (Gr. homos, one and the same). A term often employed in com- 
 position to denote similarity or sameness, as hetero indicates difference or 
 dissimilarity. Thus, homogeneous, consisting of similar parts or properties ; 
 homologous, having the same ratio or proportion. 
 
 Homocercal (Gr. homos, alike, and kerkos, tail). A term applied by 
 Agassiz to those fishes which have equally- bilobate tails, as the herring, 
 cod, salmon, &c., in contradistinction to those that are unequally lobed or 
 heterocercal, like the sharks and sturgeons. In geological formations, the 
 homocercal tail is not known till the Oolitic period all the palaeozoic fishes 
 being heterocerques. 
 
 Homoesolen (Gr. homoios, similar, sundsolen, a tube). A delicate branch- 
 ing coral of the Chalk formation, composed, according to Lonsdale, " of 
 large and small tubes of similar form, all inclined in the same direction, 
 partially visible on the surface, and limited to one side of the coral ; mouths 
 simple tubular extremities ; back without pores, and forming a continuous 
 lamina." 
 
 Hom6iozoic (Gr. homoios, the same, and zoe, life). Zones or belts of the 
 ocean which, being under nearly the same circumstances as to climate, 
 and consequently peopled in their different parts either by the same or 
 representative species of animals, are said to be homoiozoic, or marked by 
 the same life. 
 
 Homol6gue, Hom6logous (Gr. homos, the same, and logos ; reasoning). 
 " Analogue " has reference to similarity of function, as the wing of the bird 
 and the dermal expansion of the bat, because they each enable their re- 
 spective possessors to fly, or sustain themselves in the air. Homologue, 
 on the other hand, has reference to identity of parts, as the bone of the 
 fore-limb, or humerus, whether it occurs in the arm of man, the wing 
 
 241 Q 
 
HOM HOR 
 
 of a bird, the paddle of a whale, or the fore-leg of the horse. See ANA- 
 LOGUE and AFFINITY. 
 
 Hom6logy (Gr. homos, the same, and logos, reasoning). In general terms, 
 the idea or doctrine of the answerable relation of parts in animal structures; 
 e.g., the bones of the human arm and hand find their homologues or an- 
 swerable parts in the wing of the bird, in the fore-limb of the quadruped, 
 and in the paddle of the whale the identical parts being modified, fused 
 together, or atrophied, so as best to answer the functions or economy of 
 the animal. As with the homologies of the vertebrate skeleton or bones, so 
 also with regard to the crust or outer skeleton and its appendages in the 
 articulata ; and so also, as science advances, " the next important step," 
 remarks Professor Owen, " will be to determine the homologous parts of the 
 nervous system, of the muscular system, of the respiratory and vascular 
 system, and of the digestive, secretory, and generative organs in the same 
 primary group or province." See Owen's 'Archetype of the Skeleton,' 
 and Ogilvie's ' Master-Builder's Plan,' for the doctrine of Homology. 
 
 Hone (Sax. hoeri). Whet-slate ; whet-stone. The best hones, or oil- 
 stones, as they are generally termed by the workmen using them, are ob- 
 tained from those varieties of talc-slate which are sufficiently compact, and 
 in which the particles of quartz are extremely minute and regularly dis- 
 seminated, so as to give them a uniform consistence. Among the varieties 
 most prized are the Turkey oilstones, obtained from the interior of Asia 
 Minor ; the German razor-hone, from the slate hills in the neighbourhood of 
 Eatisbon ; the Arkansas oilstone, from North America ; the Water-of-Ayr 
 or Snakestone, chiefly used for polishing copper plates; the Welsh and 
 Devon oilstones ; the Charnley Forest oilstone, from Leicestershire ; and the 
 Norway ragstone, of a coarser and keener texture than the ordinary hones 
 or oilstones. 
 
 Honeystone. A popular synonyme of mellite or mellilite, which derives its 
 name from its honey-yellow colour. See MELLITE. 
 
 Hoo-Cannel. A miner's term in Yorkshire and Lancashire for an earthy 
 and impure variety of cannel coal, showing lines of lamination like splint 
 and other varieties of ordinary coal. 
 
 Horizon (Gr., from horizo, to bound, horos, a limit). The horizon is 
 usually defined as " the line that terminates the view, when extended on 
 the surface of the earth ; or a great circle of the sphere, dividing the 
 world into two parts or hemispheres ; the upper hemisphere which is 
 visible, and the lower which is hid. The horizon is sensible, and natural or 
 real. The sensible, apparent, or visible horizon, is a lesser circle of the 
 sphere, which divides the visible part of the sphere from the invisible. . It 
 is eastern or western ; the eastern is that wherein the sun and stars rise ; 
 the western, that wherein they set. The natural, true, or astronomical 
 horizon, is a great circle whose plane passes through the centre of the earth, 
 and whose poles are the nadir and zenith. This horizon would bound the 
 sight if the eye could take in the whole hemisphere." In familiar language, 
 the line that bounds the view, and where earth and sky seem to meet. 
 
 Hornblende. The amphiboU of Haiiy. A simple mineral of frequent 
 occurrence in granitic and trappean rocks; so called from its horn -like 
 cleavage and peculiar lustre (blenden, to dazzle). In mineralogy it is often 
 taken as the type of a family under which are arranged hornblende, augite, 
 hypersthene, bronzite, diallage, &c.; and lithologically it enters largely into 
 the composition of many of the granites, syenites, greenstones, and por- 
 
 242 
 
HOR 
 
 phyries. Of Hornblende proper there are several varieties (tremolite, 
 actynolite, asbestos, &c.), the ordinary or common variety being- of a black 
 or dark-green colour, and occurring in flat prismatic crystals in fibrous 
 and radiated aggregates, or in lamellar, granular masses. Analyses also 
 show considerable variations in composition, the chief ingredients being 
 silica (46 to 60), magnesia (14 to 28), lime (7 to 14), with minor proportions 
 of iron protoxide, alumina, and fluoric acid. It is softer than quartz or 
 felspar, but heavier than either; it is also heavier, and contains more silica, 
 but is softer and more fusible than augite ; its lamellar structure and soft- 
 ness distinguish it from schorl ; and it emits a peculiar bitter odour when 
 breathed on. It generally occurs confusedly crystalline, forming with 
 quartz "hornblende rock," which is massive, and "hornblende schist," 
 which is fissile and slaty ; with quartz and felspar it forms " syenite ; " 
 and with felspar alone, the numerous varieties of "greenstone." As a 
 mineral, hornblende is often confounded with augite, and from their simi- 
 larity it has even been proposed to unite them into one species. " The 
 former, however," as has been well remarked by Prof. Nicol, " contains 
 more silica, and Bonsdorf has found in it from to 1 per cent of fluoric 
 acid, which does not appear in the latter. Hornblende, too, is more 
 fusible than augite, and ranges lower in specific gravity. Though both 
 possess a cleavage parallel to their vertical prisms, yet these differ in an- 
 gular dimensions, and both are never observed in the same individual. 
 These minerals also occur in distinct geognostic positions : hornblende in 
 rocks containing quartz or free silica, and mostly with minerals that are 
 neutral compounds of silica, as orthoclase and albite ; augite in rocks that 
 do not contain free silica, and mostly with minerals that are not neutral 
 silicates, as labradorite, olivine, and leucite. Hence there are two distinct 
 series of massive or igneous rocks the hornblende series, including granite, 
 syenite, diorite, diorite porphyry, and red porphyry ; and the augite series 
 or hypersthene rock, gabbro, dolerite, nepheline rock, augite porphyry, 
 and leucite porphyry." See tabulations, "MINERAL SCHEME." 
 
 Hornitos or Hornos. Literally ovens ; a Spanish term for the low oven- 
 shaped mounds or hillocks so frequent in the volcanic districts of South 
 America, and from whose sides and summits columns of hot smoke and 
 other vapours are usually emitted. They are only a few feet in height 
 (five to ten), and, according to Humboldt, are not eruptive cones, but mere 
 intumescences on the fields and sides of the larger volcanoes. They occur 
 in vast numbers, sending up their dense hot vapours to the height of twenty 
 or thirty feet, and in many of them a subterranean noise is heard, which 
 appears to announce the proximity of a fluid in ebullition. 
 
 Hornstone. A mixed siliceous mineral and rock of various colours 
 (generally grey, tinged with blue, green, brown, or yellow), having a dull 
 splintery or sub-conchoidal fracture, and very much the aspect of a tough 
 massive flint or chert. Indeed it is often difficult to distinguish between 
 jasper, flint, and hornstone, though the latter term is more properly ap- 
 plied to all compact, tough, and massive varieties of siliceous rock, having 
 in general a tendency to the slaty structure, and in the small fracture less 
 translucent than the flints and jaspers. It consists chiefly of silex, with a 
 varying proportion of alumina, and differs from the felspars in containing 
 neither soda nor potash ; hence its infusibility. A common igneous rock, 
 consisting of hornstone, with imbedded crystals of quartz or felspar, is 
 known as hornstone porphyry. " Hornstone," says Mr Bristow, "is used for 
 
 243 
 
HOR HUR 
 
 snuff-boxes, seals, mortars, &c., but chiefly for the handles of knives and 
 forks. It is exported from Germany in large quantities for mounting 
 butter and dessert knives." 
 
 Horse. Remains of the existing genus Equus are not known in deposits 
 of earlier date than the Pleistocene or uppermost Tertiary epoch. Bones 
 and teeth of more than one species occur in the alluvia, osseous breccias, 
 and bone-caves of Europe, Asia, and America, although in the latter con- 
 tinent the horse was extinct at the period of its discovery by Columbus. 
 A closely allied form (Hippotherium), distinguished by the extreme length 
 and slenderness of its limbs, and about the size of a common deer, occurs, 
 however, in the Siwalik deposits associated with the gigantic pachyderms, 
 ruminants, and carnivora of that celebrated region. Horse. In mining, a 
 somewhat indefinite term, but usually applied to some obstructing mass of 
 rock-matter that lies in the way of the miner, whether situated in a metal- 
 liferous vein or in the body of a coal-seam. 
 
 Horses' Teeth. A quarryman's term for the large independent crystals 
 of felspar which occur in the granites of Devon and Cornwall, and give to 
 them their well-known porphyritic character. The term has reference to 
 the elongated shape and whitish colour of these crystals. 
 
 Huckle. A provincial mining term, used in Staffordshire and Derby- 
 shire to designate the summit or apex of an anticline or saddle-back. As 
 many of these saddles are sharply curved they are necessarily jointed and 
 fissured, and that main joint which passes through the crown downwards 
 is known as the Chuckle-joint" or "saddle-joint." 
 
 Humholdtilite (after Humboldt). A rather rare mineral, occurring in 
 thick tabular or short prismatic crystals of a pale honey colour in the 
 ejected blocks on Mount Vesuvius. Consists, according to Von Kobell, of 
 43.96 silica, 11.20 alumina, 31.96 lime, 6.10 magnesia, 2.32 iron peroxide, 
 4.28 soda, and a trace of potash. 
 
 Humholdtine. Known also as Oxalite. A native oxalate of iron occur- 
 ring in yellowish capillary crystals in the brown coal of Germany. 
 
 Humite (after Sir A. Hume). A variety of Chondrodite, A gem of a 
 transparent vitreous brown colour, found in the ejected masses of Monte 
 Somma, Vesuvius. 
 
 Hummock (Sax., a knoll or mound). Applied by sailors to blocks and 
 masses of ice which have been frozen together so as to produce a rugged 
 and uneven surface of the general ice-field. 
 
 Humus (Lat. humus, the soil). When wood or woody fibre is exposed 
 to the action of air and moisture, it suffers eremacausis or decay, and 
 crumbles down into a black or dark brown powder commonly called vege- 
 table mould, and to which chemists give the name of humus, See EREMA- 
 CAUSIS. 
 
 Huronian System. A term applied by Sir W. Logan and the Canadian 
 geologists to a vast formation of strata (in parts metamorphic) of siliceous 
 sandstones and conglomerates, chloritic and quartzose schists, and crys- 
 talline limestones, interstratified with heavy beds of greenstone the whole 
 resting unconformably upon the Laurentian formation. The system con- 
 tains important metalliferous veins, particularly of native copper; is 
 destitute of organic remains ; and is considered the equivalent of the lower 
 Cambrian rocks of Britain. It derives its name from its extensive devel- 
 opment in the neighbourhood of Lakes Superio^ and Huron, where it 
 acquires a total thickness of about 12,000 feet. 
 
 244 
 
HUH HYD 
 
 Hurricane (Sp., allied to Lat. furio, I rage). A violent storm of wind, 
 usually accompanied by thunder and lightning, and by rain or hail, and 
 further characterised by its sudden changes and fitful vehemence. Hurri- 
 canes are most frequent in tropical and sub-tropical latitudes ; appear to 
 have an electrical origin ; and are alike destructive whether on land or at 
 sea. Typhoons and Cyclones are special varieties, which see. 
 
 Hyacinth (Gr. hyakinthos, said to be from an Oriental word yacunt, sig- 
 nifying ruby). A variety of pyramidal zircon, of a brilliant hyacinth-red. 
 It is esteemed one of the gems, and is usually found in alluvial sands and 
 gravels along with rubies, sapphires, and the like. See ZIRCON. 
 
 Hyaena. Bones, teeth, and the fossil excrement (album groecum) of 
 hyaenas are common in all the ossiferous caverns and breccias of Europe 
 some of these remains indicating species larger and more powerful than 
 any of the existing species of Africa. 
 
 Hyse'nodon. A carnivorous quadruped about the size of a large hyaena 
 or leopard, found in the eocene and miocene Tertiaries of Europe, and spe- 
 cially characterised by its flesh -cutting teeth (carnassials), which, "instead 
 of being one in each ramus of the jaw, as in modern felines, were three in 
 number, and equally fitted by their trenchant shape to act like scissor- 
 blades on the teeth of the upper jaw in the act of cutting flesh." 
 
 Hyaline (Gr. hyalos, glass). Glassy; having the lustre and transpar- 
 ency of glass. 
 
 Hyalite (Gr. Jiyalos, glass, and lithos, stone). Glassy opal, or Mutter's 
 Glass. A variety of opal found transparent, coloxirless, very glassy, small 
 concretions or incrustations in vesicular basalt and basaltic greenstone. 
 
 Hyalosiderite (Gr. hyalos, glass, and sideros, iron). A brown or yellow- 
 coloured, very ferruginous and metallic-looking variety of olivine. See 
 OLIVINE and CHRYSOLITE. 
 
 Hybodus, Hybod6nts (Gr. hybos, a hump, and odous, tooth). Interme- 
 diate between the Cestracionts with obtuse crushing teeth, and the 
 Squaloids with sharp, angular, and pointed ones, are those fishes which 
 Agassiz has arranged in a sub-family or group under the title Hybodonts. 
 The teeth are the principal parts yet known, and these are transversely 
 elongate, and furnished with a series of sub-conical cusps or knobs which 
 compose the crown ; hence the name. Teeth and spines of the genus are 
 common in the Trias, Oolite and Chalk systems the former being readily 
 distinguished by their knobbed crowns the principal cusp or hump being 
 in the centre. 
 
 Hybrid (Gr. hybris, wanton excess, lascivious assault). The offspring of 
 two nearly allied species, whether animal or vegetable e.ff., the mule, which 
 is a hybrid between the horse and the ass. In the animal kingdom hybrids 
 are naturally of very rare occurrence ; and in the vegetable kingdom they 
 are for the most part produced by artificial fecundation ; that is, by cross- 
 ing two species of the same genus, or two varieties of the same species 
 the pollen or fertilising principle of the one being applied to the pistil 
 of the other. 
 
 Hydr-, Hydro- (Gr. hydor, water). A common prefix denoting the 
 presence, action, or quality of water ; also the presence of HYDROGEN in 
 certain chemical compounds ; as hydrosilicite, a mineral composed of 
 silica and water ; hydraulic press, an apparatus acting by the pressure of 
 water ; hydraulic cement, mortar that sets or hardens under water ; and 
 hydro-carbon, a compound of hydrogen and carbon. 
 
 245 
 
HYD 
 
 Hydrargillite (Gr. hydvr, and argilla, clay). A rarish mineral occur- 
 ring in small hexagonal crystals, and, as the name imports, composed of 
 alumina and water. Some specimens, however, yield a small percentage 
 of phosphoric acid, thus making it a phosphate of alumina. 
 
 Hydrates (Gr. hydor, water). A term applied to compounds containing 
 water in a state of chemical combination, and in definite proportions ; as 
 hydrate of lime (slaked lime), hydrated oxide of iron (iron rust), hydrate of 
 magnesia (Brucite), hydrate of alumina (diaspone), &c. Water thus unites 
 with several of the acids, the alkalies, and all salts that contain water of 
 crystallisation. 
 
 Hydraulic Cement. Any cement or mortar which sets or becomes hard 
 under water. Common lime does not possess this property ; but lime- 
 stones containing from 10 to 25 per cent of alumina, magnesia, and silica, 
 yield a lime on burning, which does not slake when moistened with water, 
 but forms a mortar with it, which hardens in a few days when covered 
 by water. Piizzuolana, septaria, certain argillo-siliceous limestones and 
 calcareous earths, burnt either with or without the addition of common 
 limestone, form the usual "hydraulic cements." See CEMENTS. 
 
 Hydroboracite. Hydrated borate of magnesia and lime ; a gypseous- 
 looking compound having a radiating- fibrous and foliated structure, but 
 distinguished from gypsum by its fusibility. In the mass, it is riddled 
 with small holes, like worm-eaten wood, these being filled with clay and 
 salt, and is generally freckled with spots of iron-oxide. 
 
 Hydroborocalcite or Hayesine, which see. The name has reference to the 
 composition of the mineral viz., hydor, water; boron; and calx, calcis, lime. 
 
 Hydro-Carbons. Composed of hydrogen and carbon. A term usually 
 applied to the bitumens, mineral resins, and mineral fats, which are 
 chiefly or altogether composed of hydrogen and carbon in varying propor- 
 tions ; as naphtha, petroleum, asphalt, amber, ozokerite, &c. 
 
 Hydro-Carburet. Carburetted hydrogen ; a compound of hydrogen and 
 carbon. There are several definite combinations of these elements, such 
 as light carlonetted hydrogen or fire-damp, and ote/tant gas, bi-carburet of 
 hydrogen. 
 
 Hydrogen (Gr. hydor, and gennao, I produce). Literally "water-former;" 
 one of the elementary gases which occurs most generally and abundantly 
 in combination with oxygen, in the form of water water being composed 
 of eight parts by weight of oxygen and one of hydrogen, or of one volume 
 of oxygen and two of hydrogen. As a simple substance hydrogen is 
 colourless, and has commonly a slight odour of garlic ; is not absorbable 
 by water ; is devoid of taste, and is destructive of life when breathed for 
 any time. It is the lightest of all known bodies 100 cubic inches weighing 
 only 2.25 grains, or being nearly thirteen times lighter than atmospheric 
 air (as 69 to 1000), and exactly sixteen times lighter than oxygen. It is 
 combustible, and when pure bums with a pale-blue flame ; hence the early 
 terms "inflammable air," and "phlogiston." In nature hydrogen is an 
 abundant substance, and next to oxygen enters most largely into the com- 
 position of the earth's crust. In common with other gases, it is evolved by 
 volcanic vents ; as light carburetted hydrogen or fire-damp it is discharged 
 from coal-mines and other openings in connection with coaly strata ; in 
 combination with carbon it forms the hydro-carburets, naphtha, petroleum, 
 bitumen, &c. ; and as sulphuretted hydrogen it is largely discharged by 
 volcanoes, and evolved by organic substances in the process of decay. 
 
 246 
 
HYD HYL 
 
 Hydrography (Gr. hydor, and grapho, I write). That branch of geo- 
 graphy which treats of the waters that form part of the surface of the 
 terraqueous globe as streams, rivers, lakes, seas, and the great ocean. 
 The art of describing and measuring the areas, depths, configurations, 
 currents, velocities, &c., of the oceanic and terrestrial waters. 
 
 Hydr6ida (Gr. hydra and eidos, hydra-like). The Hydroid or Hydra- 
 form polypes ; an extensive order of zoophytes, occurring singly and inde- 
 pendent, or in compound groups. In the compound species the body is 
 implanted in a horny tubular sheath, and the polypidoms form branched 
 corallines, which are fixed at the base to rocks, sea-weeds, and shells. 
 The order embraces the Hydridce, Sertularidce, and Tubularidce ; and under 
 the same head palaeontologists would also arrange the extinct Oraptolites of 
 the Silurian epoch. 
 
 Hydrology (Gr. hydor, and logos, discourse). That department of science 
 which treats of water in all its properties, manifestations, and relations in 
 the economy of nature. 
 
 Hydromagnesite. Native carbonate of magnesia, occurring in white 
 earthy, amorphous masses in serpentinous rocks, and consisting of 36.2 
 carbonic acid, 44 magnesia, and 19.8 water. 
 
 Hydrophone (Gr. hydor, smdphaino, I appear). A variety of cachalong- 
 opal, which is pearly-opaque when dry, but becomes transparent when 
 saturated with water; hence the name. 
 
 Hydrophytes (Gr. hydor, and phyton, a shoot). Literally "water-plants ; " 
 a term occasionally applied to the algae, fnci, and other strictly aquatic 
 vegetation, whether fresh- water or marine. They occur fossil in all for- 
 mations, but generally in states too imperfect to permit of being classed 
 with existing families. 
 
 Hydrothermal. Of or pertaining to hot water ; applied to the action 
 of heated Waters in dissolving, re-depositing, and otherwise producing 
 mineral changes within the crust of the globe. As these waters appear at 
 all temperatures, from gently tepid (80) to boiling-point (212), and often 
 far above it when under sufficient pressure, we can readily conceive the 
 importance of their agency in the production of metamorphosis, the forma- 
 tion of mineral veins, and other analogous phenomena. 
 
 Hyetography (Gr. hyetos, rain, and graphe). The science of rain ; the 
 study of the quantities and localities in which rain has fallen in a given 
 time. Hyetographic. Of or pertaining to the science of rain, as hyeto- 
 graphic maps showing by engraved tints, or otherwise, the comparative 
 amount of rainfall in different regions. 
 
 Hygr6meter (Gr. hygros, moist, and metron, a measure). An instrument 
 for determining the humidity of the atmosphere. There are various kinds 
 of hygrometers some depending upon the principle of absorption of mois- 
 ture, others upon the contraction of absorptive materials, and some, again, 
 upon the principle of condensation upon cold polished surfaces. 
 
 H^groscope (Gr. hygros, and scopeo, I perceive). An instrument for 
 indicating the presence of aqueous vapour in the atmosphere, without 
 measuring its exact amount. 
 
 Hylseosauros (Gr. hyla, a wood, weald, or forest, and saurus, lizard). 
 One of the Dinosaurs ; a gigantic terrestrial reptile whose remains were 
 first discovered (1832) by Dr Man tell in the Wealden strata of Tilgate 
 Forest ; hence the name. "The Hylffiosaurus," says the discoverer, "so 
 far as the size and form of its body may be inferred from the remains of 
 
 247 
 
HYL HYP 
 
 the skeleton hitherto discovered for of its head and jaws nothing is at 
 present [1851] known probably attained a length of from twenty to thirty 
 feet. The body was broader than high, and terminated in a long slender 
 flexible tail ; the limbs were relatively short ; the skin was covered with 
 scutes and tubercles ; and a row of very large, thin angular spines ex- 
 tended down the back, and formed a serrated dermal crest. The coracoids, 
 scapulae, and ribs, indicate a pectoral arch, in which were blended the 
 osteological characters of the Monitors and Crocodilians." The Hylaeo- 
 saurus, we may add, occupies a prominent place among the Palaeontological 
 restorations in the Crystal Palace Gardens. 
 
 Hylerpeton (Gr. hyle, wood, and herpeton, reptile). A provisional genus 
 of reptiles, apparently belonging to the lower and earlier order of Gano- 
 cephala, and instituted by Professor Owen to embrace some fragmentary 
 remains of jaws and teeth from the Nova-Scotian coal-field. 
 
 Hylonomus (Gr. hyle, a wood, and nomos, an abode). Literally "wood- 
 dweller ; " a small lacertian reptile, several species of which have been dis- 
 covered by Principal Dawson enclosed in the fossil trunks of sigillarise from 
 the lower Coal-measures of Nova Scotia. Other reptiles (dendrerpeton], 
 small rnyriapods (xylobius), and land-shells like pupa; have been found in 
 similar situations in the same formation. 
 
 Hymenocaris (Gr. hymen, membrane, and caris, shrimp). A small 
 phyllopod or shrimp-like crustacean . of the Silurian epoch, having its 
 anterior portion enclosed in a thin bivalvular carapace, and its abdominal 
 or terminal segments free, and capable of being turned under the body. 
 
 Hyopotamus (Gr. hys, hyos, a hog, and potamos, river). Literally 
 " river-hog ; " a non-ruminant, even-toed (artiodactyle) mammal, whose 
 remains occur in the Tertiary strata of England and France. Described 
 by Professor Owen (' Geological Journal,' vol. iv.), who regards it as allied 
 to the Anthracotherium, Cheer opotamus, and other hog-like mammals of 
 that period. 
 
 Hyp-, Hypo- (Gr. hypo, under). A common prefix in scientific ter- 
 minology signifying under or Mow, in reference o place or position, 
 and indicating deficiency or less than when applied to quality or composi- 
 tion : as hypogene, formed below ; hyponitrous acid, an acid intermediate 
 between nitric oxide and nitrous acid. Synonymous with the Latin pre- 
 fix sub. 
 
 Hypanthocrinns (Gr. hypantheo, to begin to flower). A genus of Rose- 
 encrinites, occurring in Upper Silurian strata, and so termed from the 
 flower-like contour of its ornamental receptacle and bifurcating arms. 
 The column is cylindrical, but traversed internally by a pentagonal canal. 
 
 Hyper- (Gr. hyper, above). A frequent prefix in scientific terminology, 
 signifying above or upon, in reference to places or position, and indicating 
 excess, with regard to quality or composition. Thus hyperthyrum, the 
 lintel or over-piece of a doorway ; hypercriticism, exaggerated or excessive 
 criticism ; hypertrophy, a morbid enlargement of any organ, as if from 
 excess of nutrition. Synonymous with the Latin prefix super. 
 
 Hypersthene (Gr. hyper, above or excess, and sthenos, strength). A 
 mineral of the Hornblende family, so called from its power of resisting 
 acids as compared with augite, to which it is closely related the ' ' prisma- 
 toidal schiller-spar " of Mohs, and the "Labrador hornblende" of other 
 authors. It occurs massive, in crystalline and granular aggregates, or 
 disseminated; has a vitreo-resinous lustre, but pearly-metallic on the 
 
 248 
 
HYP HYR 
 
 principal cleavage-planes ; and has usually a pinchbeck-brown or greyish- 
 green colour, passing into black. It is a ferrosilicate of magnesia, with 
 traces of alumina and lime, and differs in this respect from augite, which 
 contains from 18 to 24 per cent of lime. It is a constituent of several 
 rocks, forming, with labradorite, "hypersthene rock;" with labradorite 
 and chlorite, " diabase ; " and it occurs also in the euphotide or " gabbro." 
 Hypersthene rock is common in primary districts, and in Sweden the finer 
 varieties are polished as an ornamental stone. 
 
 Hypogene (Gr. hypo, under, and ginomai, I am formed). "As all the 
 crystalline rocks," says Lyell, "may, in some respects, be viewed as belong- 
 ing to one great family, whether they be stratified or unstratified, plutonic 
 or metamorphic, it will often be convenient to speak of them by one com- 
 mon name. For this purpose I propose the term 'hypogene' a word 
 implying the theory that granite, gneiss, and the other crystalline forma- 
 tions, are alike nether-formed rocks, or rocks which have not assumed their 
 present form and structure at the surface. They occupy the lowest place 
 in the order of superposition. Even in regions such as the Alps, where 
 some masses of granite can be shown to be of Tertiary epoch, they are still 
 underlying rocks." 
 
 Hypostilbite. By some mineralogists regarded as an altered form of 
 stilbite, and by others as a distinct mineral or hydrated lime-oligoclase. 
 Occurs with stilbite, &c., in the Faroe Islands. 
 
 Hypoz6ic (Gr. hypo, under, and zoe, life). Applied to those rocks which, 
 like gneiss and mica-schist, lie beneath the undoubtedly fossiliferous strata, 
 and which have yet yielded no organic remains. "Azoic," which is also 
 applied to these rocks, means destitute of fossils ; " hypozoic " simply 
 points out their position, without offering any opinion as to their fossili- 
 ferous or non-fossiliferous character. Since the discovery of organisms 
 in the Laurentian schists of Canada, it is very questionable whether any 
 of the stratified rocks can be considered as strictly Azoic or Hypozoic. 
 See tabulations, "GEOLOGICAL SCHEME." 
 
 Hypsiprymn6psis. A genus of small mammals whose teeth have been 
 found by Mr B. Dawkins in the Rhaetic or Infra- Liassic beds of Watchet 
 in Somersetshire, and so named from the resemblance that these bear to 
 the teeth of the existing Hypsiprymnus or Kangaroo-rat of Australia. 
 
 Hypsodon (Gr. hypsos, height, and odous, tooth). Literally "tall- 
 tooth ; " a genus of saury-pikes (scomber-esocidce) occurring in the Chalk of 
 Kent and Sussex, and so termed from their extremely upright, long, coni- 
 cal, compressed, and pointed teeth. The teeth and fragments discovered 
 indicate fishes of a very large size. 
 
 Hyracotherium (Gr. hyrax, the hare-rat or cony, and therion, beast). 
 A small pachydermatous mammal, occurring in the Tertiary strata of Eng- 
 land, and so termed by Prof essor Owen ('Foss. Mammals '), from its apparent 
 relationship to the Hyracidce or Conies of Southern Africa. The genus 
 stands intermediate between the Hog and Hyrax ; and the species range 
 from the size of a rabbit to that of a large hare. 
 
 249 
 
ICE 
 
 Ice (Sax. ; Ger. eis). The familiar as well as technical term for frozen 
 water, or water converted into the solid state under the influence of extreme 
 cold. Water is at its minimum volume when about 40 Fahr., and above 
 or under this temperature it increases in bulk passing into steam on the 
 one hand, and being converted into ice on the other. At 32 or under, it 
 exists in the condition of ice ; and this ice, being greater in volume than 
 the water of which it is composed, is lighter, and consequently floats on 
 the surface. It is owing to this expansion of water that frost becomes 
 such a powerful agent in the disintegration of soils and rock-masses the 
 water in their interstices being converted into ice, and irresistibly break- 
 ing asunder the cohesion of their parts. It is also owing to this lightness 
 and floating power that we have the phenomena of ground-ice lifting up 
 and transporting masses of shingle and sand of icebergs floating their bur- 
 dens of boulders and rock-debris, and scattering them over the bed of the 
 ocean and of avalanche and glacier wasting, smoothing, and moulding into 
 new forms the contours of all arctic and Alpine mountains. See FROST. 
 
 Iceberg (Ger. eis, ice, and berg, mountain). The name given to the 
 mountainous masses of ice often found floating in polar seas. Sometimes 
 they are formed by the accumulation of ice and snow on the surface of the 
 water ; at other times they seem to have been originally glaciers launched 
 from precipitous coasts into the ocean, and there further augmented by 
 numbers of them freezing en masse. These "fields" or "packs" are often 
 of great extent stretching across the ocean as far as the eye can reach, 
 and rising in perpendicular cliffs from 80 to 100 or 150 feet above the 
 water. Solitary or independent icebergs are also often of vast dimen- 
 sions, and instances are given, both in arctic and antarctic voyages, of 
 bergs several miles in circumference, rising from 40 to 200 feet above the 
 sea-level, and loaded with blocks of rocks and shingle. Some idea of their 
 size may be formed from the fact that little more than a tenth of their 
 bulk rises above the surface (the specific gravity of ice being only 0.9) 
 the greater portion being submerged and apt to be grounded on shoals and 
 flats. As they are floated by the polar currents to warmer latitudes they 
 melt away, dropping their burdens of boulder and rock-debris on the 
 bottom of the ocean. Could we lay bare this sea-bottom, we should find 
 appearances strictly analogous to the "drift" or "boulder-clay" of geolo- 
 gists ; and it is in this way that the boulder-clay or Northern Drift, with 
 its water-worn blocks, its gravel and shingle, its smoothed and furrowed 
 rock-surfaces, and other kindred appearances, can alone be accounted for. 
 At the present day icebergs are familiar phenomena both in arctic and 
 antarctic seas those of the north being seldom carried southward beyond 
 the 44th parallel of latitude, while those of the south are not unfrequently 
 found northward as far as the Cape of Good Hope, or on an average at 10 
 degrees lower latitude. As the glacier smooths and furrows the rocks 
 over which it passes, so the iceberg, with its immense weight and greater 
 motion, grinds, and rubs, and ploughs ; and while the one lays down its 
 
 250 
 
ICE ICH 
 
 lateral and terminal moraines in ridge-like mounds, the other carries from 
 the cliffs and shores its mud and gravel arid boulders, and strews them 
 along the bottom of the ocean. 
 
 Ice-Floe (Dan., ice-island). Applied by voyagers to the smaller masses 
 of ice that encumber the polar seas. Floes are rarely a quarter of a mile 
 in circumference, and usually much smaller. 
 
 Iceland-Spar. A variety of calcareous spar remarkable for its transpar- 
 ency and double refraction. According to Nicol, it is not found in crystals, 
 but occurs massive in a trap-rock in Iceland, and has been considered as a 
 portion of altered limestone. 
 
 Ice-Spar. A familiar term for a variety of orthoclase or common pris- 
 matic felspar; transparent or translucent; colourless and white, or but 
 slightly tinged with grey or faint yellowish-green ; and of a vitreous or 
 glassy lustre. See FELSPAR. 
 
 Ichnites (Gr. ichnos, a footprint). A term applied to all fossil footprints, 
 many of which have been discovered in palaeozoic and secondary formations 
 as ornithichnites, bird- footsteps ; sauroidichniles, saurian footsteps, &c. 
 Footprints, supposed to be those of reptiles, have been discovered in rocks 
 of Devonian age in Canada, and in Scotland, and also in the Coal-measures 
 of Europe and America ; and those of reptiles, birds, and undetermined 
 animals occur abundantly in the New Red Sandstone of Britain, Germany, 
 and North America. These creatures seem to have frequented muddy 
 shores and estuaries, and to have left the impress of their feet on the yield- 
 ing and half- dried mud, over which the next deposit of sediment spread 
 and filled up the mould. On splitting many of these sediments (now con- 
 verted into shales and sandstones) the mould and its cast are found in 
 great perfection so much so that not only the joints of the toes, but the 
 very texture of the skin is apparent. Hildburghausen in Saxony, Corn- 
 cockle Muir in Dumfriesshire, Stourton, Weston, and Taporley in Cheshire, 
 Grimsell in Shropshire, and the valley of the Connecticut in North Amer- 
 ica, are the localities most celebrated for their fossil footprints and this 
 in strata of Permian or of Triassic age. 
 
 Ichnolite (Gr. ichnos, a footprint, and litltos, stone). Any fossil foot- 
 mark, or stone retaining the impression of the feet of extinct animals. 
 
 Ichn6logy, Ichnolithology (Gr. ichnos, a footprint, lithos, and logos). 
 The science of fossil footprints; e.g., the 'Ichnologyof Annandale,' by 
 Sir William Jardine ; the ' Ichnology of New England,' by Dr Hitchcock. 
 
 Ichthyocdprus, Ichthyoc6prolite (Gr. ichthys, fish ; copros, excrement ; 
 and lithos). Literally, the fossil excrement of fishes. Coprolites of this 
 nature occur in all the Secondary formations ; but in great profusion and 
 of gigantic size in the shales of the lower Coal formation. 
 
 Iclithyod6rulite (Gr. ichthys, fish ; doru, spear ; and lithos, stone). The 
 fossil fin-spines or defences of fishes, found abundantly in all the fossilifer- 
 ous strata those of the shark-like fishes (Ceslracionts) of the lower Coal- 
 measures being often more than a foot in length, and strong in proportion. 
 These spines are generally straight and tapering, but many of them are 
 more or less recurved or falcate. The inserted portion is blunt and plain ; 
 the external defence enamelled and often highly sculptured some being 
 grooved transversely and spirally (gyr acanthus), others striated or fluted 
 longitudinally (onchus) ; some ornamented with points and tubercles (cos- 
 inacanthus), and others serrated or hooked on the posterior margin (ctena- 
 canthus). 
 
 251 
 
ICH 
 
 I'chthyoid (Gr. ickthys, fish, and eidos, likeness). Fish-like ; partaking 
 of the fish type, as the ichthyosaurus, which is partly ichthyoid and partly 
 sauroid. 
 
 Ichthyolite (Gr. ickthys, fish, and lithos, stone). A palseontological term 
 for a fossil fish, or any portion of a fish, as a scale, tooth, spine, &c. The 
 most celebrated deposits of fossil fishes in Europe are the bituminous 
 schists of the lower Old Red of Orkney, Caithness, and Forfar ; the yellow 
 sandstones (upper Old Red) of Dura Den, Fifeshire ; the lower Coal-measures 
 of Burdiehouse, &c., near Edinburgh ; the Coal formation of Saarbruck in 
 Lorraine ; the Permian bituminous slate of Mansfield in Thuringia ; the 
 calcareous lithographic slate of Solenhofen (Oolitic) ; the compact blue slaty 
 shale of Glaris (cretaceous) ; and the Tertiary limestones of Monte Bolca, 
 near Verona, the marlstones of Oeningen in Switzerland, and of Aix in 
 Provence. 
 
 Ichthy61ogy (Gr. ichthys, fish, and logos, discourse). That branch of 
 zoology which treats of the structure, classification, habits, and history of 
 fishes ; Ichthyological, relating to the science of ichthyology ; Ichthyologist, 
 one who studies, or is devoted to, the science of fishes. See PISCES, and 
 tabulations, " ANIMAL SCHEME." 
 
 Ichthyopatolites (Gr. ichthys, fish ; patos, footpath ; and lithos, stone). 
 Fish-tracks, or the imprints of the pectoral fin-rays of certain fishes, which, 
 like the gurnard and climbing perch, can move on solid surfaces by means 
 of these organs. Under this name Dr Buckland described ( ' Proceedings 
 of Geol. Soc.,' vol. iv.) certain problematical markings observed on a flag- 
 stone from the Coal-measures of Flintshire. It consists of curvilineal 
 scratches or imprints, disposed symmetrically at regular intervals on each 
 side a smooth level space, about two inches wide, which may correspond 
 to the body of a fish, the pectoral fins of which, Dr Buckland suggests, 
 were the instruments that formed the markings in question. 
 
 Idithydphagous (Gr. ichthys, fish, and phagein, to eat). Fish-eating ; 
 feeding on fish. 
 
 Ichthyophthdlmite (Gr. ichthys, and ophthalmos, the eye). Fish-eye- 
 stone ; a variety of apophyllite or pyramidal zeolite, characterised by its 
 peculiar pearly lustre. 
 
 Ichthyopter^gia (Gr. ichthys, a fish, and pier ~yx, a wing or fin). One of 
 the thirteen orders into which Professor Owen proposes to arrange the 
 Reptilia, living and extinct. The term relates to the piscine character of 
 the numerous and many- jointed rays or digits in the fore and hind paddles. 
 The ichthyosaurus may be taken as the type of the order, the genera of 
 which are exclusively marine. The bones of the head include the "post- 
 orbital" and "supra-temporal" bones that characterise the Labyrintho- 
 donts and Ganocephalans, but there are temporal and other vacuities be- 
 tween the cranial bones ; there is a single, convex, occipital condyle ; the 
 vertebral centres are ossified and biconcave ; the pleurapophyses long and 
 bent, the anterior ones with bifurcate heads ; the teeth are confined to 
 the maxillary, premaxillary, and premandibular bones, the premaxillary 
 greatly exceeding in size ; the orbits large, the eyes being defended by a 
 broad circle of sclerotic plates ; the limbs natatory, with more than five 
 many- jointed digits ; no sacrum. 
 
 Ichthyosdrcolite (Gr. ichthys, fish ; sarcos, flesh ; and lithos, stone). 
 Literally, " fish-flesh-stone ; " a term at one time applied to certain thick, 
 heavy, tapering organisms from the Chalk, in allusion to their flaky or 
 
 252 
 
ICH IDO 
 
 foliaceous structure. They are now known as Radiolites and Sphceruliles, 
 peculiar bivalve shells belonging to the family HIPPURITID^;, which see. 
 
 Ichthyosaurus (Gr. ichthys, fish, and saurus, lizard). Literally "fish- 
 lizard ; " a well-known genus of the extinct Enaliosaurs or marine saurians, 
 and so called from its combining the characters of saurian reptiles and of 
 fishes with some of the peculiarities of the whales. The ichthyosaurs were 
 in fact the "reptile whales" of their period a period extending from the 
 deposition of the middle Trias or rauschelkalk till near the close of the Chalk 
 formation. The peculiarities of their structure have been thus described : 
 Their vertebrae resemble those of fishes in being biconcave, or concave 
 at both ends ; but the superior arches remain permanently detached as in 
 reptiles. The cranium resembles that of the crocodiles, but is character- 
 ised by a peculiarly large eye-orbit furnished with a circular series of bony 
 sclerotic plates a structure not occurring in fishes, but observable in the 
 eyes of turtles, lizards, and many birds. The nostrils are situated, not, as 
 in the crocodile, near the extremity of the snout, but close to the anterior 
 part of the orbit, approaching in this respect some of the recent lizards. 
 The teeth, which are extremely numerous (amounting in some species to 
 nearly 200), resemble in structure those of the crocodiles being conical, 
 longitudinally striated, and expanded at the base ; but are implanted, as 
 in some of the lizards, in a deep continuous groove, and not in distinct 
 sockets. The locomotive extremities are similar in construction to the 
 paddles of the whale ; but they are four instead of two in number, and the 
 front paddles are connected by a broad coracoid, a complete clavicle, and a 
 supplementary coracoid bone to a strong sternum ; the flattened phalan- 
 geal bones supporting the fin are polygonal, and are relatively shorter and 
 more numerous than in the whale. The hind paddles are smaller than the 
 fore, and are attached to a pelvis similar to that of the crocodile. Small 
 supplemental bones are wedged into the lower part of the joint of the 
 atlas and occiput, and a few of the succeeding vertebral joints ; and the 
 tail often presents a fracture or abrupt bend about a third of its length 
 from the extremity, as if it had been swayed aside during decomposition 
 by the weight of a large vertical tail-fin. From the form and position of 
 masses of crushed and apparently half-digested fish-bones and scales in 
 the abdominal cavity of certain specimens, it is concluded that they preyed 
 on fish ; and from the shape of their coprolites (fossil excrements) it is 
 obvious that their intestinal canals were furnished with spiral valves as in 
 the sharks. In one or two instances, very small, and to all appearance 
 fcetal specimens, have been found within the pelvic cavities of large 
 skeletons, and from this circumstance it has been inferred that the 
 ichthyosaurs, like the whales, were viviparous. As already mentioned, 
 the great era of ichthyosaur development was from the middle Trias to 
 the Chalk inclusive the Lias formation being the chief repository of their 
 remains in England. In this deposit specimens of all ages and of all sizes 
 have been found from the foetus of a few inches to the adult more than 
 thirty feet in length ; and of these the finest are now preserved in the 
 British Museum, and the museum at York. 
 
 I'docrase (Gr. eidos, form, and krasis, mixture). Known also as Vesuvian 
 and Pyramidal Garnet, and differs from common garnet chiefly in form. 
 Idocrase (so termed from its crystalline forms being mixed figures, which 
 are apt to be mistaken for those of other minerals) was originally found in 
 the ejected calcareous blocks on Vesuvius, in druses with garnet, augite, 
 
 253 
 
IDE IMP 
 
 &c. ; but it also occurs in subordinate beds in the primitive rocks with 
 calc-spar, garnet, epidote, chlorite, and other silicates. It forms an in- 
 different ornamental stone, the brown being named hyacinth, and sold at 
 Naples under the name of " Gemmes de Vesuve ; " the green, chrysolite. 
 Several local varieties are also distinguished, as Wiluite, from Wiloui in 
 Siberia, an obscure green ; Cyprine, a blue variety containing copper, from 
 Norway ; and Egrane, a liver-brown sort from Eger in Bohemia. 
 
 I'drialine, Idrialite. One of the mineral resins, so named from its 
 being found at Idria in Carniola, in thin layers among the slates containing 
 the mercury ores. It occurs in soft, brownish-black, flaky masses, having 
 a resinous lustre and a greasy feel ; and from these masses, which consist 
 of idrialine and cinnabar, with a little silica, alumina, pyrites, and lime, 
 the pure pearly idrialine may be extracted by oil of turpentine. 
 
 I'gneous (Lat. ignis, fire). Applied to all agencies, operations, and re- 
 sults which seem connected with, or to have arisen from, subterranean heat, 
 as " igneous rocks," ' ' igneous fusion," &c. The igneous rocks, properly 
 so called, comprehend the Volcanic, Trappean, and Granitic series, all of 
 which are evidently the products of fusion either in the interior or at the 
 surface of the crust. The term igneous is thus synonymous with unstrati- 
 fied, Plutonic, pyrogenous, and others in use by geologists. 
 
 Ignigenons (Lat. ignis, and Gr. ginomai, I am formed). Fire-formed : 
 used as synonymous with igneous, though, properly speaking, igneous re- 
 fers to the operation or agency, and ignigenous to the result. 
 
 Igudnodon. One of the Dinosaurs; a colossal lizard-like reptile found 
 in the Wealden strata, and so called from the resemblance of its teeth to 
 those of the existing iguana of South America. " According to the pre- 
 sent state of our knowledge," says Dr Mantell in 1851, " it is not at all 
 improbable that the largest iguanodons may have attained a length of from 
 sixty to seventy feet. Although some important points in the osteology 
 of the iguanodon are still unknown, we may safely conclude that the 
 stupendous reptile equalled in bulk the largest herbivorous mammalia, 
 and was as massive in proportions. Its limbs must have been of propor- 
 tionate size and strength to sustain, and move, so enormous a carcass ; the 
 hinder extremities in all probability resembled the unwieldy contour of 
 the hippopotamus or rhinoceros, and were supported by strong short feet, 
 protected by broad unequal phalanges : the fore-feet appear to have been 
 less bulky, and adapted for seizing and pulling down the foliage and 
 branches of trees ; the jaws and teeth demonstrate its power of mastica- 
 tion, and the character of its food ; while the remains of the coniferous 
 trees, arborescent ferns, and cycadeous plants which are found imbedded 
 with its remains, attest the nature of the flora adapted for its sustenance." 
 The iguanodon occupies a chief place among Mr Hawkins's palseontological 
 restorations in the grounds of the Crystal Palace. 
 
 I'lmenite. Known also as tilanitic iron; an ore of iron occurring in 
 various formations, as in the miascite of the Ilmen mountains : hence the 
 name. According to H. Eose and Scheerer, it is a combination of per- 
 oxide of iron and the blue oxide of titanium in various proportions the 
 specific gravity increasing with the amount of iron. 
 
 Imbricated (Lat. imbrex, a gutter-tile). Overlapping, or laid over each 
 other like the tiles or slates of a roof ; applied to the scales of fishes, the 
 scutes of reptiles, the persistent leaflets or petioles of certain trees, &c. 
 
 Impalpable (Lat.) Not perceptible to the touch ; applied to dust, 
 254 
 
IMP IND 
 
 powdery substances, mud, and the like, in which no gritty particles can 
 be felt by the touch. Keduced to the minutest particles or ultimate stage 
 of subdivision. 
 
 Imperforate, Imperforated (Lat. im, not ; per, through; and/oro, I bore). 
 Not perforate ; having no opening or passage of communication ; pot 
 pierced. Applied in various branches of natural science. 
 
 Impermeable (Lat. im, not ; per, through ; and meo, I pass). Not ad- 
 mitting the passage of water ; applied to strata or other masses which, 
 like clay, obstruct the natural passage or percolation of subterraneous 
 waters. 
 
 Impervious (Lat. im, not ; per, through ; and via, a way). Impenetrable ; 
 impassable ; affording no way or passage. Hence we speak of certain 
 strata being ' ' impervious to water," and so on. 
 
 Imponderables (Lat. in, priv., and pondus, weight). A term applied in 
 physical science to agents which, like heat, light, and electricity, are desti- 
 tute of weight, and only known by their effects on other bodies. 
 
 Incandescence, Incandescent (Lat. candesco, to begin to grow white). 
 A glowing white heat ; having a white heat, or greater degree of heat 
 than red heat. 
 
 Incineration (Lat. in, and cinis, cineris, a cinder). The act of burning 
 or reducing to ashes ; distinct from calcination, which see. 
 
 Incisors (Lat. in, and casdo, I cut). The cutting teeth or front teeth of 
 mammals, as distinguished from the grinding or molar teeth. See TEETH. 
 
 Incombustible (Lat.) Applied to substances that will not burn, or 
 which cannot be consumed by the action of fire. 
 
 Incrustation (Lat. in, and crusta, a crust or rind). A crust or coating 
 formed on the surface of any substance. Waters containing lime, clay, 
 and other mineral impurities, leave an " incrustation" on the inside of the 
 vessels in which they are boiled ; calcareous waters " incrust " the rocky 
 surfaces over which they flow with a coating of calc-tuff. 
 
 I'ndianite. A reddish-grey variety of Anorthite (one of the felspars) 
 found in the Carnatic, where it forms the matrix of the corundum. v It 
 consists of 42 silica, 34 alumina, and 15 lime, with iron, potash, and soda. 
 
 Indian Red. A kind of ochre (protoxide of iron, silica, and alumina), of 
 a deep red with a shade of purple, imported from the Persian Gulf in 
 small lumps, and partly as a coarse, hard, and gritty powder the crude 
 material from which the pigment of this name is obtained. 
 
 Indicollite, Indigolite. A variety of tourmaline found at Utoe in 
 Sweden, and so named from its deep-blue indigo colour. 
 
 Indigenous (Lat. in, and geno, I produce). Born or produced in a par- 
 ticular country ; native to a country. Applied to plants and animals, but 
 more especially to the former, in contradistinction to exotic; that is, those 
 not native to the country in which they are cultivated. 
 
 Indurated (Lat. durus, hard). Restricted in geology to rocks that have 
 been hardened by the action of heat, and in this sense distinct from 
 " hard " or " compact." 
 
 Indiisial Limestone. "There is another remarkable form of fresh-water 
 limestone in Auvergne," says Lyell, "called 'indusial,' from the cases or 
 indusice of caddis- worms (the larvae of Phryganea), great heaps of which 
 have been incrusted, as they lay, by carbonate of lime, and formed into a 
 hard travertin. The rock is sometimes purely calcareous, but there is 
 occasionally an intermixture of siliceous matter. Several beds of it are 
 
 255 
 
IND INO 
 
 frequently seen, either in continuous masses or in concretionary nodules, 
 one upon another, with layers of marl interposed." These limestones 
 point, of course, to a time (Eocene) when certain districts of Auvergne 
 were covered by fresh- water lakes, in which the larvae of the Phryganea 
 swarmed as they do now in the stagnant pools and ditches of England. 
 It is but fair to state that Mr Waterhouse and some other entomologists 
 entertain doubts as to this limestone being really of indusial origin. 
 
 Indiisium (Lat.) Literally, a garment or covering. In natural science 
 applied variously ; e.g., the indusium or case of the caddis-worm ; the 
 brown dried epidermis which covers the fertile son or reproductive specks 
 on the fronds of ferns, &c. 
 
 Inflammable Air. An old chemical term for hydrogen gas-: so named 
 on account of its highly inflammable nature. 
 
 Infusoria. Minute animal organisms or animalcules ; so called from 
 their being readily obtained (for microscopic investigation) in infusions of 
 vegetable matter which have been freely exposed to the air. In modern 
 zoology they constitute the highest class of the Protozoa, and have been 
 arranged into numerous families which are yet far from being well denned 
 partly from the minuteness of the organisms, and partly from the liability 
 to mistake for infusoria the embryonic germs of other creatures, and, above 
 all, the active germs or spores of the lower forms of vegetation. They 
 are generally unicellular animals ; are furnished with a mouth and rudi- 
 mentary digestive apparatus ; and their bodies, for the most part, consist 
 of three distinct layers, the outer of which is usually furnished with cilia 
 or vibratory appendages. They inhabit lakes, pools, and ditches ; many 
 are found in the ocean ; and some are indifferent alike to salt or fresh 
 water. Mistaking other microscopic forms for infusoria, it has been cus- 
 tomary to speak of their calcareous and siliceous shields as entering largely 
 into the composition of many recent muds and marls, as well as into that 
 of several of the more ancient stratified deposits ; but according to the 
 latest zoological authorities, there are no fossil infusoria, the organisms 
 usually designated by this name being either Foraminifera, Polycystina, 
 or Diatomacece. See PROTOZOA. 
 
 Ink-Bags. In the Squids and Cuttle-fishes the bags or membranes 
 which contain the inky fluid with which these cephalopods discolour the 
 surrounding water when irritated or surprised. These organs have been 
 found fossil in the Lias and Oolite of England in such a state of perfection, 
 that Dr Buckland had drawings of the remains of extinct species of Sepia 
 made with their own ink. 
 
 Inlier. A term introduced by Mr Drew, of the Geological Survey, to 
 express the converse of "outlier," which see. "It means," says Mi- 
 Drew, " a space occupied by one formation which is completely surrounded 
 by another that rests upon it. It is useful to have a word that well ex- 
 presses this ; and ' inlier ' is a very appropriate one ; for the circumstance 
 to be named is the exact converse of * outlier,' which is an isolated mass 
 surrounded by a formation that underlies it." 
 
 Inoceramus (Gr. is, inos, fibre, and keramos, vessel-shell). A genus of 
 fossil bivalves belonging to the Aviculidce (wing-shells or pearl-oysters), 
 and so named from the fibrous structure of their shells. The valves are 
 unequal, ventricose radiately or concentrically furrowed, umbones promi- 
 nent ; hinge-line straight, elongated, and pitted with numerous close-set 
 cartilage grooves. The species, which range from the Silurian to the Chalk 
 
 256 
 
INO IXT 
 
 inclusive, vary in size from one inch to three or four feet in diameter. 
 The shell, in consequence of the vertical arrangement of the fibres, readily 
 breaks to pieces, and large flat fragments are found in the Chalk, often 
 perforated, as in recent oysters, by the Cliona (clionites). The French 
 restrict the name Inoceramus to the beaked and laminated species of the 
 Gault ; and arrange the Chalk Inocerami under the term Catillus. 
 
 Inorganic (Lat. in, not, and organum, a member or instrument). Not 
 produced by vital action. Applied to mineral substances which are the 
 results of chemical or mechanical aggregation, in contradistinction to 
 vegetable and animal substances, which are produced by vital action, or 
 through the instrumentality of vital organs. See ORGANIC. 
 
 Insect Limestone. A term applied by the Rev. P. B. Brodie (' History 
 of Fossil Insects') to certain bands of the Lower Lias in the central and 
 western counties of England, from their being charged with the remains 
 of beetles, grasshoppers, dragon-flies, may-flies, and other insects, belong- 
 ing, according to Mr Westwood, to not fewer than twenty-four families. 
 These insect remains are accompanied by ferns, cycads, and leaves of 
 monocotyledon ous plants, and also by some apparently brackish and fresh- 
 water shells, so that they seem to have had an estuary or lagoon origin. 
 
 Insecta (Lat. insectum, divided into segments). An extensive class 
 of articulated animals, and so called from the segmented aspect of their 
 bodies, in Cuvier's arrangement it includes the following orders : Myria- 
 poda (e.g., centipede) ; Thysauoura (springtail) ; Parasita (louse) ; Suctoria 
 (flea) ; Coleopiera (beetle) ; Orthoptera (earwig) ; Hemiptera (bug) ; Neu~ 
 roptera (ant-lion) ; Hymenoptera (wasp) ; Lepidoptera (butterfly) ; Rhipiptera 
 (stylops) ; and Diptera (fly). The insects are well known by their seg- 
 mented bodies, three pairs of feet, one pair of antennae, compound eyes, 
 generally undergo metamorphosis and acquire wings, and are oviparous, 
 with the sexes distinct. Remains of some of the orders are found as early 
 as the Carboniferous formation, and they abound in the Oolite and later 
 deposits. See the respective Orders. 
 
 Insectivora (Lat. insecta, insects, and voro, I devour). An interesting 
 group of the Carnivorous mammalia, characterised by their molar teeth 
 being studded with sharp points, which enables them to feed on insects. 
 The group comprises the mole, hedgehog, shrew, bat, &c. The teeth and 
 jaw-bones of animals apparently insectivorous (spalacotherium, microlestes, 
 &c. ) have been found as low as the Oolite and Upper Trias. 
 
 In situ (Lat.) Literally " in its natural position or place." A rock or 
 fossil is said to be "in situ" when it is found in the situation or place in 
 which it was originally formed or deposited ; but it is not in situ when 
 removed or drifted to another position or locality. 
 
 Inspissated (Lat. in, and spissatus, thickened). Thickened ; made thick 
 by evaporation, whether natural or artificial ; as opium, which is the 
 inspissated juice of the poppy. . 4 
 
 Interambulacra, Interambulacral (Lat. ambulare, to walk). The im- 
 perforate plates which lie between (inter) the perforate plates or ambulacra 
 in the shells or crusts of the sea-urchin and cidaris. 
 
 Intercalated, Intercalation (Lat.) Interposed, something placed be- 
 tween ; the act of placing between. Subordinate beds of a different nature 
 occurring between the main beds of a series are said to be intercalated; the 
 occurrence of such beds or of intervals of deposition are said to be inter- 
 calations. Of frequent use in geology. 
 
 257 R 
 
INT IOD 
 
 Intercolline (Lat. inter, between, and collis, a hill). A term proposed 
 by Sir Charles Lyell to designate those valley-like spaces or hollows that 
 occur in volcanic regions between the cols or crateriform hillocks of accum- 
 ulation, and which are not formed by aqueous erosion, nor by subsidence, 
 nor by anticlinal or synclinal flexures, but simply by the building up on 
 two or more sides of erupted materials. Such intercolline spaces abound 
 in all volcanic regions of sub-aerial origin. 
 
 Intermittent, Intermitting (Lat. inter, between, and mitto, I send). 
 Ceasing for a time and then returning; ceasing and acting by turns. 
 Intermitting Springs are those which, having flowed for a certain time, 
 stop altogether, and after a time begin to run again, and then stop ; and 
 so on alternately, the flowings and intermissions generally succeeding each 
 other at pretty regular intervals. Such phenomena are easily explicable 
 on the supposition of caverns and subterranean areas being fed by small 
 chinks, and discharged by larger fissures acting on the principle of the 
 siphon the larger outlet, acting more rapidly than the united chinks, 
 when once set a-running, flows till the cavern is emptied, and then ceases 
 till the water again accumulates to its siphon-level. 
 
 Interstratified. Occurring in the midst of, or along with, other strata. 
 In this sense coal may be said to be interstratified with sandstones, shales, 
 tire-clays, and limestones : but the term is generally restricted to those 
 bed-like masses or overflows of igneous rock (lava, basalt, and greenstone) 
 which occur imbedded with true stratified or sedimentary rocks the 
 igneous overflow having spread over the bottom of the sea of deposit, and 
 been subsequently overlaid by other strata. 
 
 Intertropical (Lat. inter, between, and tropical). Situated between the 
 tropics ; applied also to plants and animals whose habitats lie between the 
 tropics, or in the torrid zone. 
 
 Intrusive Bocks. Applied to those igneous rocks which seem to have 
 thrust themselves, when in a state of fusion, between the beds of the strat- 
 ified formations. Intrusive masses of this kind are sometimes apt to be 
 mistaken for contemporaneously interbedded overflows ; but in general 
 they are not so extensive, wedge-out or thin-out abruptly, and alter the 
 strata both above and below them. 
 
 Intnmesce (Lat. inturnesco, to begin to swell). To swell or bubble up as 
 zeolite and other kindred minerals do under the action of the blow-pipe. 
 
 Invertebrata. One of the two great divisions of the animal kingdom ; 
 animals without vertebra or back-bones, including the Mollusca, Articulata, 
 Kadiata, and Protozoa. See tabulations, "ANIMAL SCHEME." 
 
 Involutina (Lat. involvo, to wind or coil up). A genus of Foraminifera 
 chiefly from the Lias, and so named by Mr H. Brady, its investigator, from 
 the manner in which the tuberculated tube-like organism is coiled upon 
 itself. The shell- wall between the successive coils is not double as in the 
 true Rotalince, with which it is apt to be confounded ; the septa are some- 
 what irregular, but increase with the enlarging whorls ; the shell-substance 
 is partly composed of arenaceous grains, indicating a lower organisation 
 than the nummulite ; and Mr Brady places it in the family Lituolidce, and 
 near the genus Trochammina. 
 
 Iodine (Gr. ion, violet, and eidos, likeness; violet-coloured). One of 
 the chemical elements, occurring as a non-metallic, crystallised, acidifying, 
 and basifying solid substance. It is obtained from marine plants, from 
 sea-water, and from certain mineral springs, and is of considerable repute 
 
 258 
 
IOD IRO 
 
 in materia medica. It becomes volatile at a low temperature, and passes 
 off in a beautiful violet-coloured vapour ; hence the name. 
 
 lodite or lodic Silver. An ore of silver, consisting of iodine and silver, 
 and occurring in thin flexible foliae or plates of a pearl-grey or yellowish- 
 grey colour. It is found in the mining districts of Mexico and South 
 America, and recently in the south of Spain. 
 
 lolite (Gr. ion, violet, and litkos, stone). One of the Gems, known also 
 as Dichroite, Cordierite, and Prismatic quartz. It occurs in granitic and 
 primitive rocks, associated with quartz, garnet, and iron and copper 
 pyrites, and derives its name from its colour, which ranges from violet to 
 dark-blue. It has many allied and doubtful species ; and according to 
 Stronmeyer, consists of 48.35 silica, 31,71 alumina, 10.16 magnesia, 8.32 
 iron protoxide, with traces of manganese. The transparent variety (clear 
 white, with a tinsre of celestial blue) found in rolled masses in Ceylon con- 
 stitutes the Sapphire deau of the jewellers. 
 
 Iridescent (Gr. iris, the rainbow). The property of producing a play of 
 colours resembling those of the rainbow ; possessed both by animal and 
 mineral substances. Iridescence. Shining with the colours of the rainbow ; 
 a property depending generally on internal structure, or the arrangement 
 of internal surfaces which refract the light ; but sometimes also arising 
 from mere external tarnish, occasioned by partial decomposition, or the 
 action of acids. 
 
 Iridium (Gr. iris, the rainbow). The most infusible of the known metals, 
 and used chiefly in porcelain-painting to produce black and grey colours. 
 It is also used for the nibs of steel-pens, and is said to be worth 24 an 
 ounce. It occurs in nature in combination with platina, palladium, 
 osmium, and copper ; and derives its name from the variety of hues which 
 the mixture displays while dissolving in hydro-chloric acid. It was dis- 
 covered by Dr Wollaston ; is of a grey colour, brittle, very infusible, and 
 has a specific gravity of about 18.6. 
 
 Irish Deer, Irish Elk. Remains of the Irish gigantic deer (Cerviis 
 megaceros, or deer with great antlers) are found in the peat-bogs, marls, 
 gravels, and other superficial deposits of Europe ; but particularly in the 
 shell-marls and peat-bogs (the sites of ancient lakes) in Ireland : hence the 
 name. It is usually, but erroneously, termed Elk the creature being a 
 true deer, thougk far exceeding in magnitude any living species. Skeletons 
 have been found ten feet high from the ground to the point of the antlers, 
 which are palmated, and often measure from ten to fourteen feet from tip 
 to tip. Chronologically, the Irish deer seems to have been antecedent to 
 man in Europe, though some of the species appear also to have been 
 contemporary with him, and to have been extirpated by the earliest hunter 
 tribes that took possession of its plains and forests. See Denny in 'Pro- 
 ceedings of York Geolog. Soc.' for 1855. 
 
 Irish Diamond. A frequent term, like "Bristol Diamond," for fine 
 transparent varieties of crystallised quartz or Rock-crystal, which see. 
 
 Iron (Gr. sideros; Lat. f en-urn ; Fr. fer ; Ger. eisen}. One of the best- 
 known, and, economically speaking, by far the most important of the 
 metals. Though readily tarnished, rusted, or oxidised by exposure to air 
 and moisture, it has in the fresh fracture a peculiar grey colour, known 
 as "iron-grey" or "steel-grey," and, when polished, possesses much 
 lustre. It is not very malleable, but extremely ductile and very tenacious. 
 At common temperatures it is hard and unyielding, but at a red heat it is 
 
 259 
 
IRQ 
 
 soft and pliable, and at a high red heat two pieces may be inseparably 
 united by hammering or welded, as it is technically termed into one 
 mass. It is very difficult effusion, requiring for that purpose the highest 
 heat of the blast-furnace. In this state it can be run into moulds, and is 
 then known as cast-iron, which is hard, brittle, and of a granular texture. 
 Subjected to repeated heating and hammering (puddled, as it is termed), it 
 becomes less fusible, assumes a fibrous texture, gets tough and malleable, 
 and is then known as forged or wrought iron. The average specific gravity 
 of cast-iron is 7.27; that of forged, 7.78. Iron is attracted by the 
 magnet, and is itself susceptible of being rendered magnetic a property 
 possessed by no other metal except nickel. It is capable of forming alloys 
 with several of the metals, though in this state little used ; and with a 
 small proportion of combined carbon it forms steel, a substance of incal- 
 culable importance to all the industrial arts and manufactures. 
 
 Unlike many of the other metals, iron is rarely found in a native state ; 
 and this in scarcely appreciable quantities, in stones and masses of 
 meteoric origin. This meteoric iron, as it has been termed, contains nickel, 
 along with cobalt and other metals ; and what is known as telluric iron, 
 occurs in minute grains and scales in other mineral veins, and contains 
 carbon, graphite, or occasionally some other metal, but not nickel. On 
 the whole, native iron is a very rare and doubtful substance ; and all the 
 iron of commerce is derived from ores (oxides, carbonates, &c.) either pure 
 or in combination with various earthy ingredients forming ironstones. 
 These ores and ironstones occur in rocks of all ages the ores chiefly in 
 veins and abnormal masses among metamorphic schists, the ironstones in 
 bands and layers among the strata of the Carboniferous, Oolitic, and other 
 later formations. The ores are usually regarded as belonging to two 
 families 1st, the SPARRY IRON ORES, the most important member of 
 which is siderite, spathose iron, or carbonate of iron, and which includes the 
 clay ironstones, or the " clay-bands" and "black-bands" of the Coal and 
 other formations ; and 2d, the OXIDISED IRON ORES, embracing such well- 
 known species as magnetite or magnetic iron, hematite or specular iron, 
 limonite or brown iron-ore, and the like. In nature, iron enters largely 
 into the composition of many rocks and rocky compounds ; and also forms 
 many chemical combinations, as oxides, carbonates, chromates, phosphates, 
 sulphurets, and sulphates. Its presence in water is readily detected by 
 the tincture of galls, or by the ferro-cyanate of potash the former turn- 
 ing weak solutions purple or dark-blue, and forming a black precipitate 
 where the metal is more abundant the latter producing Prussian blue 
 under similar circumstances. See tabulations, "MINERAL SCHEME." 
 
 Iron-Earth. A black pulverulent compound of peroxide of iron and 
 protoxide of manganese, occurring in veins of ironstone in the crystalline 
 schists. It attaches itself closely to anything on which it is rubbed, and 
 is strongly attracted by the magnet. 
 
 Iron-Flint. A familiar mineralogical term for some varieties of ferru- 
 ginous quartz, which see. 
 
 Iron Pyrites. Bi-sulphurets of iron, of which mineralogists distinguish 
 three species, 1. Pyrite, yellow sulphuret of iron, or hexahedral iron 
 pyrites ; 2. Marcasite, white sulphuret of iron, or prismatic iron pyrites ; 
 and, 3. Pyrrhotine, magnetic iron pyrites, or rhombohedral iron pyrites. 
 
 Iron Sinter. Known also as pitchy iron ore or pittacite ; a recent pro- 
 duct, arising apparently from the decomposition of mispickel, and occur- 
 
 260 
 
IRQ ISO 
 
 ring in old mines in reniform or stalactitic brittle crusts of a dark-brown 
 colour and vitreous lustre. It consists of 35 iron protoxide, 26 arsenic 
 acid, 9 sulphuric acid, and 30 water. 
 
 Ironstone. The familiar as well as technical term for the ores of iron, 
 whether occurring in sparry veins like hematite, magnetite, and siderite, or 
 in regular stratified layers like the clay-bands and black-bands of the Coal- 
 measures. Industrially, it is usual to apply the term to any ore, rock, or 
 matrix that yields an available percentage of iron ; though in geology it 
 were advisable to restrict it to ferriferous rocks of sedimentary origin. 
 
 Ischnacanthus (Gr. ischnos, slender, and acantha, spine). A genus of 
 Acanthodian fishes occurring abundantly in the Lower Old Red Sandstone 
 of Forfarshire, and resembling in general form the smaller species of dipla- 
 canthus, but differing in having the body longer and more fusiform, the 
 scales smooth, the spines more slender, the teeth larger, the cranial bones 
 covered with granular tubercles, and the eye-orbits larger and more 
 widely apart. 
 
 Ischypterus (Gr. ischys, strength, and pteron, fin). A genus of ganoid 
 fishes, with smooth rhomboid al scales, from the Triassic strata of Virginia, 
 and so named by Sir P. Egerton from the great size and strength of the 
 fulcral rays of the dorsal fin. They differ from Palceoniscus, with which 
 they were first classed, in being less heterocercal, having stronger and 
 more conical teeth, smaller mouth, and scales less ornamented. 
 
 Islands (Lat. insula). Occur either singly, when they are said to be 
 independent ; or in groups or clusters, when they constitute archipelagoes. 
 They are also distinguished as continental and pelagic continental when 
 their proximity and geological character show them to be dependencies 
 of the continent ; and pelagic when far off in the ocean they rise up inde- 
 pendently, and are generally of volcanic or coralline formation. 
 
 Iso (Gr. isos, equal). A prefix denoting equality or similarity, as iso- 
 chronous, occurring in equal times ; isometrical, having similar dimensions. 
 
 Isocardia (Gr. isos, like ; cardia, the heart). The heart-cockle ; a genus 
 of bivalve shells belonging to the family Cyprinidce, and characterised by 
 their large, ventricose, or sub-globular shells ; the umbones of which are 
 distant and curved inwards, giving to the shell its peculiar heart-like 
 shape. The living species are few, littoral, and burrowing in sand ; the 
 fossil exceed seventy species, and are found in the Trias upwards. 
 
 Isocheimal, Isochimenal (Gr. isos, and dwima, winter). Having the 
 same winter temperature ; hence isocheimal lines are those drawn through 
 such places as have the same mean winter temperature. 
 
 Isochronous (Gr. isos, and chronos, time). Occurring in equal times, or 
 at intervals of the same duration ; as the strokes of the pulse, the swing 
 of pendulums of equal lengths, and the like. 
 
 Isocrymal (Gr. isos, and krymos, extreme cold). Lines laid down on a 
 map or chart to mark the limits of equal extreme cold are termed isocry- 
 mal, just as those of equal extreme heat are termed isothermal. 
 
 Isodynamic (Gr. isos, and dynamis, power). Having the same power or 
 force. Equal in power, and capable of producing the same results. 
 
 Isogeothermal (Gr. isos ; ge, the earth ; and therme, heat). Applied to 
 lines or divisions in the earth's crust which have the same mean annual 
 temperature ; and employed as being more definite than isothermal, inas- 
 much as it refers solely to the land, whereas isothermal applies equally to 
 air, land, and water. 
 
 261 
 
ISO IXO 
 
 Isdmerism, Isomeric (Gr. isos, and meros, part). Applied in chemistry 
 to express the relation existing between bodies which agree in composition 
 but differ in properties. Isomeric bodies generally agree in the relative 
 proportion of their constituents only, and differ either in the aggregate 
 number of their atoms, or in the manner in which these atoms are arranged. 
 
 Isomorphism (Gr. isos, and morpJie, form). A term employed in chem- 
 istry and mineralogy to designate the capability shown by two or more 
 simple or compound substances to crystallise in one and the same form ; 
 or often in forms which, though not identical, yet approximate very closely, 
 when it has been named homceomorphism. This similarity of form is gener- 
 ally combined with a similarity in other physical properties. The law of 
 isomorphism, as expressed by Mitscherlich, the discoverer of the doctrine, 
 is this : The same number of atoms combined in the same way produce 
 the same crystalline form ; and crystalline form is independent of the 
 chemical nature of the atoms, and determined only by their number and 
 relative position. 
 
 Isdpoda (Gr. isos, and pous, podos, a foot). An order of Crustaceans, 
 which, like the oniscus or woodlouse, have the trunk divided into seven 
 rings or segments, each segment sustaining a pair of similar unguiculate 
 feet ; hence the name. In the Isopods, the head or cephalic segment is 
 distinct from the trunk ; is furnished with antennae, and with sessile eyes, 
 which are either composed of clusters of ocelli or compound. Remains of 
 the order (Archceoniscus) have been found in the Purbeck beds. 
 
 Fsopyre (Gr. isos, and pyr, fire). An amorphous, brittle, greyish -black 
 mineral, of a vitreous lustre, and slightly magnetic. It occurs in the 
 granites of Cornwall, and in the trap-rocks near Edinburgh ; and consists, 
 according to Turner, of 47.09 silica, 13.91 alumina, 15.43 lime, 20.07 iron 
 peroxide, and 1.94 copper oxide. The name refers to the slight change 
 produced on its aspect by fusion. 
 
 Isotheral (Gr. isos, and theros, summer). Having the same summer 
 temperature ; Isotheral lines, lines connecting all those places on the 
 surface of the globe which have the same mean summer temperature. 
 
 Isothermal (Gr. isos, and therme, heat). Having the same temperature ; 
 of equal temperature. In physical geography, Isothermal lines are lines 
 connecting all those places on the surface of the globe which have the 
 same mean temperature ; and as temperature is governed by relative dis- 
 tribution of land and water, by altitude, and other conditions, places on 
 the same parallels of latitude are often on very different isothermal lines. 
 
 I'ttnerite (after Ittner). A rather rare mineral, occurring in granular 
 aggregates in trap and volcanic rocks, and consisting of silica, alumina, 
 and soda, with lime, sulphuric acid, and water. Allied to sodalite, nosean, 
 and haiiyne. 
 
 Ivory, Fossil. The terms "Fossil Ivory" and "Siberian Ivory" are 
 frequently given to the teeth and tusks of the mammoth, which at one 
 time were, and are still, collected in considerable abundance from the 
 plains, shores, and low islands of Siberia. In 1844, it is said that about 
 16,000 Ib. weight of this ivory was obtained from these regions, and of a 
 quality, for the most part, superior to the recent ivory of Africa. 
 
 I'xolyte (Gr. ixos, glue or birdlime, and lithos, stone). One of the min- 
 eral resins, of a hyacinth-red colour, and found in amorphous lumps in the 
 Tertiary lignites of Austria ; allied to Hartite. It becomes soft at 169, 
 and is still viscid at 212 Fahr. ; hence its name. 
 
 262 
 
JAD JAS 
 
 Jade. A hard, tough, siliceo-magnesian rock of a dark leek-green 
 colour, smooth surface, and somewhat soapy feel. It occurs in compact 
 masses, has a coarse, splintery fracture, and is found in various parts of. 
 Europe, America, Egypt, China, and New Zealand. It consists chiefly of 
 silica, magnesia, and lime, with a small percentage of iron and alumina, 
 and from its composition is supposed to be a peculiar condition of augite 
 and hornblende. Being tenacious and susceptible of a fine polish, it is 
 worked into amulets, ringstones, chains, and other ornaments. In China 
 it is valued for its supposed medicinal properties in nephritic or kidney 
 diseases, hence the synonyme nephrite; and in New Zealand a variety, 
 called by the natives "Poenamu," is fashioned into axes, hangers, idols, 
 &c. : hence also the occasional term axe-stone. 
 
 Jagged. Irregularly cut or notched; denticulated or toothed like a 
 saw. Applied to the sharp irregular edges and surfaces of minerals and 
 rock-masses. 
 
 Jamb. A miner's term for any thick mass of rock which prevents them 
 pursuing the lode or vein. 
 
 Jamesonite (after Professor Jameson). Sulphantimonite of lead ; an ore 
 consisting principally of the sulphurets of lead and antimony ; or, accord- 
 ing to analysis, of 43.44 lead, 35.47 antimony, 17.20 sulphur, with traces 
 of copper, zinc, and iron. .. 
 
 Japan Current. That branch of the equatorial current of the Pacific 
 which trends northward along the Japan coasts, and carries along with it 
 the warm waters of the equator to the North Pacific. In its origin, course, 
 and character, this current greatly resembles the Gulf Stream of the 
 Atlantic, which see. 
 
 Jargon or Jargon of Diamond. A lapidary's term for a Cingalese variety 
 of zircon, colourless specimens of which are often sold for diamonds. Col- 
 oured sorts are known as " Matura diamonds," from a district in Ceylon 
 where they occur in worn angular fragments among the river sands. See 
 ZIRCON. 
 
 Jasper (Gr. jaspis). A somewhat loosely-applied term for many siliceous 
 compounds. When quartz is combined with a small proportion of alu- 
 mina and iron, it loses its transparency and becomes jasper, which is con- 
 sequently tougher or less easily broken. "Jasper," says Nicol, "is col- 
 oured red by the peroxide, yellow or brown by the hydrate of iron, but 
 also exhibits many other colours, as green, grey, white, and black, in 
 some kinds alone, in others in spots, veins, and bands the latter the 
 ribbon or Egyptian jasper." It is found abundantly, in veins and bands, 
 in rocks of all ages ; and some varieties, as the porcelain jasper, are evi- 
 dently beds of slaty shale, altered by the action of heat. Jasper is sus- 
 ceptible of a fine polish, and is largely manufactured into brooches, brace- 
 lets, snuff-boxes, knife-handles, vases, inlaid-work, &c. 
 
 Jaspideous, Jaspidean. Resembling jasper ; of the nature of, or con- 
 taining jasper. 
 
 263 
 
JEF JUM 
 
 Jeffersonite (after Jefferson). A variety of augite from Sparta in New 
 Jersey, of a dark olive or black colour, and resinous or semi-metallic 
 lustre. 
 
 Jet (jayet, gagites, from Gaga, a river in Asia Minor). This well-known 
 substance is rather a species of amber than coal, and is usually known in 
 Prussia as " black amber." It occurs in nodules and lumps, in lignitic 
 strata ; is electric when rubbed ; is more resinous in lustre than the finest 
 cannel coal, and is also specifically lighter. Though evidently of vegetable 
 origin, it seldom reveals to the naked eye the woody texture like lignite, 
 but is uniform like asphalt its intense velvety -black well adapting it for 
 mourning ornaments, as ear-rings, brooches, bracelets, buttons, and the 
 like. It is found in great purity and abundance in the cliffs of alum-shale 
 on the Yorkshire coast; hence the "jet manufactories" of Whitby and 
 Scarborough. 
 
 Jigging. A miner's term for a method of dressing the smaller ores of 
 copper, lead, &c., by the aid of a wire sieve suspended and shaken in a vat 
 of water, so that the smallest particles pass through the sieve, and the 
 larger are " soi'ted " that is, the lighter and more earthy remain at the 
 top, and the heavier and more metallic settle below. 
 
 Johnsonite (after Professor Johnstone of Durham). A supersulphide of 
 lead, consisting of 90.38 galena and 8.71 sulphur. It occurs associated 
 with galena in many lead mines, and seems merely a finely granular variety 
 mixed with more or less free sulphur. It is known among miners by the 
 name of " burning galena." 
 
 Joints. The fissures or rents which divide rock-masses into blocks 
 more or less regular are properly so termed. They have been defined as 
 " natural fissures, traversing rocks in straight and well-determined lines, 
 and forming planes of separation which are often slightly open, and which, 
 as they do not merely pass through strata, but through various semi- 
 crystalline aggregations within the stratified mass, were evidently formed 
 since the original accumulation of the strata." This jointed structure 
 appears to have arisen in certain strata from shrinkage or contraction of 
 the deposit while in the process of solidifying ; in many instances it is the 
 result of mechanical upheaval and disturbance ; while in others the lines 
 of fissure have definite compass-bearings, are arranged in sets, and seem 
 to obey some more general but as yet undetermined law. In basalt and 
 other columnar structures the joints are usually regarded as the results of 
 crystallisation on a large scale. Referring the direction of joints in strati- 
 fied rocks to lines of upheaval, Professor Sedgwick calls those which run 
 parallel to the strike ''strike joints ;" those parallel to the dip, "dip joints;" 
 and all others he calls <f diagonal joints." It is also customary to speak of 
 " master joints," or those that are regular and run parallel for considerable 
 distances, in contradistinction to "ordinary joints," the former constitut- 
 ing the " backs " and the latter the " cutters " of the quarryman. Again, 
 in mining phraseology the jointings and fissures which accompany sudden 
 flexures (anticlines or saddles, and synclines or troughs) are known respec- 
 tively as " saddle- joints," or " huckle- joints," and " trough-joints." 
 
 Jtiloeido-Coprolites (Gr. ioulos, a catkin, and eidos, resemblance). The 
 name given to the coprolites or fossil excrement of some unknown animal, 
 in allusion to their catkin-like form. 
 
 Jumper. In mining and quarrying, a large iron borer steeled at each 
 end and worked by the hand. 
 
 264 
 
JUN KAN 
 
 Juncites (Lat. juncus, a rush). Fossil stems and leaves apparently re- 
 lated to the Juncacece or Rush family, which are chiefly inhabitants of marshy 
 tracts in the temperate and colder regions. Such striated, grooved, and 
 tapering rush-like fragments of leaves occur from the Devonian formation 
 upwards, but their true affinities are not yet determined. 
 
 Juiiiperites (Lat. juniperus, the juniper-tree). The generic term for 
 such fossil coniferse as are evidently allied to the juniper. Several species 
 occur in Tertiary lignites, and are known by their short, obtuse, broad- 
 based leaves, arranged in four opposite rows round irregularly-forking 
 branches. 
 
 Jura Limestone. A term applied by Continental geologists to the lime- 
 stones of the Jura Mountains, as equivalent with the Oolite and Lias of 
 English geologists. It is the Jura-kalk of German geologists. 
 
 Jurassic. A synonyme of the Oolitic system, from the characteristic oc- 
 currence of its strata in the Jura Mountains, between France and Switzer- 
 land. The Jura beds are composed of limestones of various qualities, 
 sands, sandstones, and thin-bedded clays, and contain the same fossils as 
 those found in the Oolite and Lias of England. Indeed, it is remarked by 
 Sir C. Lyell, " that in the Jura (distant about 400 geographical miles) the 
 analogy to the accepted English type, notwithstanding the thinness or 
 occasional absence of the clays, is more perfect than in Yorkshire or Nor- 
 mandy." There is this difference, however, to be observed, that while the 
 English beds are little altered or disturbed from their original sedimentary 
 character, those of the Jura and the outer ranges of the Alps are often 
 highly indurated and crystalline. Continental geologists are in the habit 
 of dividing the Jurassic formation into three groups viz., the " White (or 
 Upper) Jura," " Brown (or Middle) Jura," and "Black (or Lower) Jura." 
 See OOLITIC SYSTEM, and tabulations, " GEOLOGICAL SCHEME." 
 
 Kaims or Kames. The name given in Scotland to the elongated and 
 often flat-topped mounds of post-glacial gravel which occur scattered over 
 the lower ends of almost all the grent valleys of that country. Known as 
 esJcirs or escars in Ireland, and as ifsars in Sweden, which see. 
 
 Kampecaris (Gr. kampe, a grub or caterpillar, and cam, shrimp). A 
 small crustacean discovered by the Author in the grey flagstones (Lower 
 Old Red) of Forfarshire, and so named from its appearance. From its 
 imperfect preservation its true affinities cannot be well ascertained 
 that is, whether a small phyllopod, or the larval stage of some larger 
 crustacean. 
 
 Kampylite (Gr. kampylos, curved). An arseniate of lead or variety of 
 mimetite, occurring with other ores of the metal in hexagonal prisms of a 
 fine orange-yellow, and containing in addition phosphate of lime and traces 
 of chromate of lead. So called from the curved or barrel-shaped form of 
 its crystals. 
 
 Kand or Cand. A familiar term among Cornish miners for fluor-spar. 
 265 
 
KAN KEL 
 
 Kaneelstein. A variety of garnet ranging from hyacinth-red to orange- 
 yellow, and known also as Hessoniie and Cinnamon-stone. 
 
 Kangaroo. A well-known marsupial, the species of which are exclusively 
 restricted to the Australian continent. Remains of more gigantic propor- 
 tions than any existing species occur in the ossiferous caverns of Austra- 
 lia ; and in the earlier Post- Tertiary deposits remains of still larger mar- 
 supials (Diprotodon, Zygomaturus, &c.), apparently allied to the kangaroo, 
 are by no means uncommon. See MACROPUS. 
 
 Kaolin (Chin. Kan-ling, high -ridge; the name of a hill whence the 
 mineral is obtained). The name given to the finest porcelain or China 
 clays, arising for the most part from the decomposition of felspar in soft 
 earthy granites. Kaolin occurs in beds and masses, more or less pure, and 
 is generally prepared for use by repeated levigations. The best varieties 
 of this hydrous silicate of alumina are of a white or grey colour, soft and 
 meagre to the touch when dry, and plastic when wet. Their composition 
 is variable ; but 48 silica, 39 alumina, and 13 water, may be taken as an 
 available average. 
 
 Kapnite. A variety of calamine or carbonate of zinc, containing more 
 than 15 per cent of iron protoxide. The light-green varieties are generally 
 known as ferruginous zinc-spar ; and the dark-green, or those which be- 
 come brown by the oxidation of the iron, as zinc-iron spar. 
 
 Karoo. A term applied to the open clayey flats of Southern Africa, 
 which often rise, terrace-like, to considerable elevations, and are hard and 
 steppe-like in the dry season, but in the wet season are speedily trans- 
 formed into grassy, flower-besplangled plains. The term is thought to be 
 derived from the Hottentot word Karusa, signifying " hard," and to refer 
 to the quality of the red clayey soil, which, being impregnated with iron 
 and mixed with sand, becomes hard as burnt clay under the influence of 
 continued drought. 
 
 Karpholite, Carpholite (Gr. Icarphos, straw, and lithos). One of the 
 hornblende family, occurring in zeolitic, or fine radiating capillary crystals, 
 of a straw-yellow ; hence the name. 
 
 Karphosiderite, Carphosiderite (Gr. Tcarphos, straw, and sideros, iron). 
 A straw-coloured mineral occurring in kidney-shaped resinous-looking 
 concretions, resembling iron-sinter ; and consisting, according to Harkort, 
 of hydrous phosphate of iron, with a little oxide of zinc. 
 
 Karstenite (after Karsten). Hausmann's synonyme for anhydrite or 
 prismatic gypsum. 
 
 Kastor and Pollux. Two minerals of the Felspar family, so named by 
 Breithaupt from their always occurring together. They resemble quartz 
 in their hardness, transparency, and vitreous lustre; and are the most 
 siliceous of the crystalline silicates. 
 
 Keene's Cement. A calcareous cement or plaster now much used in the 
 interior of houses, from its taking a fine polish. " If," says Ansted, " in- 
 stead of being used with water, plaster-of-Paris in fine powder is thrown 
 into a vessel containing a saturated solution of alum, and after soaking for 
 some time is taken out, rebaked, once more reduced to powder, and then 
 moistened with a solution of alum instead of pure water before use, you 
 have Keene's Cement" 
 
 Keil. The same as reddle (rcethel) or red-clay. An argillaceous peroxide 
 of iron, of a fine deep red, and used for marking. 
 
 Kelloway-Rock. A calcareous or rather calcareo-arenaceous member of 
 266 
 
KEL KIE 
 
 the Middle Oolite, from three to five feet thick, abounding in fossil shells 
 (often entirely made up of them), and so called from its being well de- 
 veloped at Kelloway-bridge, Wiltshire. See OOLITIC SYSTEM. 
 
 Kelp. The common term for the crude soda, obtained from the ashes of 
 various fuci, and other sea- weeds. It was at one time extensively prepared 
 along the northern coasts of Scotland and Ireland, as well as on the coasts 
 of Holland and France, and used in the preparation of soap, alum, bottle- 
 glass, &c., but is now almost entirely superseded by the soda obtained 
 from sea-salt. See BARILLA. 
 
 Kentish Rag. A provincial term for a member of the Lower Greensand, 
 consisting of a highly fossiliferous grey cherty or arenaceous limestone, 
 much used for building in Kent and Sussex. 
 
 'Kent's Hole. A celebrated ossiferous cavern situated in the Devonian 
 limestone near Torquay, in Devonshire, and which has largely yielded to 
 its explorers remains of mammoth, tichorhine rhinoceros, cave-bear, cave- 
 hyaena, and other extinct mammals, associated with flint implements and 
 other evidences of man's comtemporaneity with this ancient and now ob- 
 literated fauna. See OSSIFEROUS CAVERNS. 
 
 Kerate, Kerargyne (Gr. keras, a horn, and argyron, silver). Chloride 
 of silver ; horn silver so called from its cutting like horn. Kerate is 
 generally a recent formation, occurring in the upper part of veins, and on 
 silver that has been buried in the earth, or long immersed in sea- water. 
 
 Keratophytes (Gr. keras, horn, and phyton, a shoot). An old zoological 
 term for those polypes which have a horny axis like the sea-fans, in con- 
 tradistinction to the lithophytes or true stony corals. 
 
 Kennes, Kermesite (kermes, the cochineal insect). One of the ores of 
 antimony (oxy-sulphide), so called from its deep cherry-red colour. It 
 consists, according to Hose, of 75.06 antimony, 4.78 oxygen, and 20.49 sul- 
 phur. 
 
 Kerolite (Gr. keros, wax, lithos, stone). Sesquihydrate of silicate of mag- 
 nesia, consisting of 46.96 silica, 31.26 magnesia, and 21.22 water, and 
 found in variously-shaped masses in connection with serplutine and other 
 magnesian rocks. It is white or greenish white, has a resinous or waxy 
 lustre, feels greasy, but does not adhere to the tongue. 
 
 Kerosene Oil (Gr. keros, wax, and elaion, oil). The name given by C. 
 Gesner to a distillation from coals, bitumen, petroleum, or other bitumi- 
 nous minerals, and largely employed for lighting purposes in the United 
 States. The same or closely related to the paraffine oils of the British pa- 
 tentees. 
 
 Keuper (Ger.) Literally "copper ;" an abbreviated term for the upper 
 member of the Trias, which consists in Germany of variegated cupriferous 
 marls and marl slates, sandstones, gypsum, and carbonaceous slate-clay 
 making in all a thickness of from 800 to 1000 feet. The keuper is the equi- 
 valent of the saliferous and gypseous shales and sandstones of Cheshire. 
 See TRIASSIC SYSTEM. 
 
 Kibble. In mining, a bucket, usually of iron, in which ore is drawn to 
 the surface. 
 
 Kidney-Iron-ore. A familiar term for those varieties of haematite which 
 occur in reniform or kidney-shaped concretions. 
 
 Kieselguhr (Ger.) Literally " flint-fermentation ;" the German term for 
 the bergmahl or mountain-meal of Lapland, which resembles a siliceous 
 paste or yeast, and consists chiefly of the siliceous shields of diatomacese. 
 
 267 
 
KIL KLE 
 
 Kilkenny Coal. A name occasionally given to anthracite, from its oc- 
 curring at Kilkenny in Ireland. See ANTHRACITE. 
 
 Killas. A Cornish name for a coarse argillaceous schist, or clay-slate, 
 in which many of the metalliferous veins in that county and Devonshire 
 occur. 
 
 Killinite. A greenish grey or yellowish mineral, belonging to the 
 Felspar family, and supposed by some to be only a decomposed spodwmene, 
 with which it occurs in the granite at Killiney, near Dublin. 
 
 Kim-Coal. A provincial term for a highly bituminous shale occurring in 
 the Oolitic beds at Kimmeridge. This shale has been locally used as an 
 inferior coal, and attempts have been made to distil from it naphtha, par- 
 affine, and other analogous products. Sir O. Lyell is inclined to believe 
 that its bitumen is partly of vegetable and partly of animal origin. 
 
 Kimmeridge Clay. A member of the Upper Oolite, consisting of thick 
 beds of bluish-grey slaty clay, and in great part of a bituminous shale, 
 which sometimes forms an impure coal (Kim-Coal). The group is well 
 developed at Kimmeridge in the isle of Purbeck, Dorsetshire ; hence the 
 name. It is also largely developed and highly fossiliferous near Hartwell, 
 in the vale of Aylesbury, Buckinghamshire. 
 
 King-Crab. Known also as the " horse-shoe crab," from the shape of 
 its carapace or shield ; the Limulus of systematic zoology, which see. 
 
 Kirkdale Cave. A celebrated cavern occurring in the Coralline Oolite 
 at Kirkdale, about twenty-five miles N.N.E. of York, and remarkable for 
 the variety as well as abundance of bones found imbedded in the calcareous 
 mud that overspreads its floor. See OSSIFEROUS CAVERNS. 
 
 Kirwanite (after Richard Kirwan of Dublin, a distinguished mineralogist 
 of the last century). A mineral nearly allied to prehnite, of a dark olive 
 green, and occurring in spheroidal masses, with a radiating fibrous texture 
 in basalt in the Mourne Mountains, Ireland. Probably a variety of Green 
 Earth. 
 
 Kitchen-Middens. The shell-mounds or Kjokken-moddings of Denmark 
 and other northern shores, which see. 
 
 Kivi-Kivi. The native name for the Apteryx, or wingless bird of New 
 Zealand, sub-fossil congeners of which have been found in the river-silts of 
 that country. See APTERYX. 
 
 Kjokken-Modding (Dan.) Literally "Kitchen-middens;" the name 
 given by the Danes to certain mounds which occur along their sea-coasts, 
 and which consist chiefly of the castaway shells of the oyster, cockle, peri- 
 winkle, and other edible kinds of shell-fish. These mounds, which have 
 also been found on the shores of Moray and the north of Scotland, are 
 from 3 to 10 feet high, and from 100 to 1000 feet in their longest diameter. 
 They greatly resemble heaps of shells formed by the Red Indians, along 
 the eastern shores of the United States, before these tribes were extirpated. 
 The "Kitchen-middens" of Europe are ascribed by archaeologists to an 
 early people unacquainted with the use of metal, as all the implements 
 found in them are of stone, horn, bone, or wood, with fragments of rude 
 pottery and traces of wood-fires. All the bones yet found are those of 
 wild animals, with the exception perhaps of the dog, which seems to have 
 been domesticated. 
 
 Klaprothine (after Klaproth the chemist). Same as Azurite, Prismatic 
 Azure-spar, or Lazulit, which see. 
 
 Kleyn Spawen or Lunburg Beds.- An important group of highly fossil - 
 268 
 
KNE RUN 
 
 iferous strata belonging to the Upper Eocene or Lower Miocene epoch. 
 They consist of sands, clays, and marls of marine or fluvio-marine origin, 
 and are the equivalents of the Hempstead beds in the Isle of Wight. 
 
 Knebellite. A mineral of a grey, green, or reddish-brown colour, 
 apparently a variety of olivine, and consisting of about equal parts of silica, 
 iron protoxide, and manganese. 
 
 Knorria (after Knorr). A genus of Coal-measure plants, embracing 
 those stems the leaves of which were densely arranged in spiral manner, 
 and left projecting instead of depressed leaf-scars. They are usually ranked 
 as Lycopods, but seem intermediate between them and the Coniferce. See 
 HALONIA. 
 
 Kobellite (after Von Kobell). Sulphobismuthate of lead; an ore occur- 
 ring in the cobalt-mines of Sweden, of a dark lead-grey like grey anti- 
 mony, but with a brighter lustre ; soft ; with a radiated structure. 
 
 Koessen Beds. Known also as the "Upper St Cassian Beds," from their 
 occurrence at St Cassian in the Austrian Alps ; a series of grey and black 
 limestone with calcareous marls, by some regarded as Upper Triassic and 
 by others as Lower Liassic. They contain abundantly Avicula contorta, 
 Cardium Rhceticum,, &c., and are supposed to represent the bone bed of 
 Swabia. See RHAETIC BEDS and AVICULA CONTORTA ZONE. 
 
 Koninckia. In honour of M. De Koninck; a genus of brachiopods 
 belonging to the Orlhidce, and characteristic of the St Cassian or Upper 
 Triassic beds of the Austrian Alps. The shell is distinguished by its 
 smooth, round, concavo-convex valves ; incurved beak destitute of hinge 
 area and foramen ; and by the four-coiled spiral furrows which mark 
 either valve and were once occupied by the arms. 
 
 Koth. A name given by the Spaniards to an earthy slimy substance 
 ejected from the volcanoes of South America. It is of a blackish- brown 
 colour ; has an earthy texture ; and is but slightly coherent. Known also 
 as Mot/a and Canagua. 
 
 Konlite, Konleinite. One of the hydro-carbons (92.43 carbon, 7.57 
 hydrogen) occurring in thin white plates and scales in the Brown Coals of 
 Germany, and resembling Scheer&*ite. 
 
 Koupholite (Gr. kouphos, light, and lithos). A term used by Lametheric 
 for Prehnite, which see. 
 
 Erantzite (after Dr Krantz of Bonn). A fossil resin of a yellowish- 
 brown or dark-brown colour, occurring in grains and roundish pieces in 
 the Brown Coals of Germany ; somewhat elastic ; sectile ; fuses at 437 
 Fahr., and at 572 distils over a brownish oil having a very disagreeable 
 and penetrating odour. 
 
 Kryolite ; more commonly Cryolite, which see. 
 
 Kulock or Kahloch, near Rabenstein in Franconia, on the bank of the 
 Esbach, celebrated for its remarkable ossiferous cave. See OSSIFEROUS 
 CAVERNS. 
 
 Kunkur. A Hindostanee term for a superficial accumulation, which in 
 point of time seems to correspond pretty well with the Drift or Boulder- 
 Clay of Europe. " It is compact,'' says Ansted, "often nodular or tufaceous, 
 and frequently small-concretionary ; of light-brown, reddish, or ash-grey 
 colour ; and rarely fossiliferous. In its composition it is chiefly calcareous, 
 containing about 72 per cent of carbonate of lime, and 15 per cent of 
 silica, with 18 per cent of alumina. It spreads over a very large propor- 
 tion of India and the adjoining countries, being more especially abundant 
 
 269 
 
KUP LAB 
 
 in the line of country running up from Guzerat to the north-east, towards 
 Delhi. It is constantly observed, not only occupying the low ground, but 
 reposing under the vegetable soil of the elevated plains and plateaux of 
 Central India, and even on the summits of hills between 2000 and 3000 feet 
 above the level of the sea." Kunkur deposits are sometimes 60 and 70 
 feet thick, and seem, according to Captain Newbold, to have arisen from 
 calcareous springs. All the lime of the Punjaub is derived from the 
 Kunkur. 
 
 Kupfer-Nickel (Ger.) Copper-nickel, prismatic nickel pyrites, or Nickel- 
 ine t which see. It consists of arsenic and nickel, with sulphur, traces of 
 cobalt, iron, lead, &c., and is used as an ore of nickel, and in the manufac- 
 ture of German silver. 
 
 Kupfer-Schiefer (Ger.) Literally copper-slate; a dark bituminous- 
 looking slaty marl-stone, associated with the Zechstein (mine-stone) of 
 Germany, and richly impregnated with copper-pyrites, for which it is 
 extensively worked. It is the equivalent of the magnesian marl-slates 
 (Lower Permian) of Durham, &c., and abounds in finely-preserved fishes 
 palseoniscus, pygopterus, platysomus, &c. peculiar to that formation. 
 
 Kyanite. Same as Cyanite, which see. 
 
 Kyson Sands. A bed of Eocene sand, occurring at Kyson or Kingston, 
 a few miles east of Woodbridge in Suffolk, and celebrated for its yielding 
 the remains of the monkey tribe Macacus eoc<xnu$ of Owen. 
 
 Labradorite. Called also opalescent felspar, or Labrador felspar, from 
 the locality where first found ; a variety of disseminated felspar having a 
 peculiar pearly and iridescent play of colours when the light falls on it in 
 certain directions. Bonsdorff ascribes this property to an excess of silica ; 
 Haidinger affirms that the play of colours proceeds from certain regularly- 
 defined points. Labradorite is a soda-lime felspar, and occurs most abun- 
 dantly as a constituent of rocks ; when found in crystals or in veins it 
 takes a fine polish, and is used as an ornamental stone. 
 
 Labyrinthodon (Gr. labyrinthos, a place full of intricate passages, and 
 odous, tooth). A name given by Professor Owen to a batrachian reptile 
 of the New Red Sandstone, in allusion to the labyrinthine structure ex- 
 hibited by sections of its teeth. No complete skeleton of the labyrinth- 
 odon has yet been discovered, but it is supposed to be one and the same 
 with the Cheirotherium, the hand-like impressions of whose feet are so 
 frequent on the slabs of the New Red Sandstone formation. The Laby- 
 rinthodont saurians, described at different times under the names Cheiro- 
 tlierium, Mastodonsaurus, Salamandroides, and Phytosaurus, are all referred 
 by Owen to the genus Labyrinthodon, and appear to range from the 
 Devonian to the Triassic inclusive. 
 
 Lafoyrintliod6ntia (Gr. labyrinthos, a labyrinth, and odous, tooth). One 
 of the thirteen orders into which Professor Owen proposes to arrange the 
 
 270 
 
LAC LAK 
 
 Reptilia, living and extinct. The name refers to the complex structure 
 characterising the teeth in the several genera of the order, the complications 
 being produced by undulations and side-branches of the converging folds 
 of cement. As in the Ganocephaia (which see), the head is defended by a 
 continuous casque of externally sculptured and usually hard and polished 
 osseous plates ; there are two occipital condyles ; the vomer is divided 
 and is dentigerous ; there are two external nostrils ; the vertebral centres, 
 as well as arches, are ossified and are biconcave ; the pleurapophyses of 
 the trunk are long and bent ; the limbs ambulatory, and the hinder large 
 in proportion. The order embraces such genera as Labyrinlhodon, Masto- 
 donsaurus, Capitosaurus, &c., all founded on minor modifications of the 
 skull, teeth, scutes, &c. 
 
 Lacertian, Lacertilian (Lat. lacerta, a lizard). Belonging to or resem- 
 bling the Lacertinidse or Lizard family, a well-known group of saurian 
 reptiles, recent and fossil. In Owen's arrangement of the Reptiles, the 
 Lacertilia constitute his tenth order ; and are specialised as having pro- 
 coelian vertebrae, with a single transverse process on each side, and with 
 single-headed ribs ; the sacral vertebrae not exceeding two. The order 
 seems to range from the Wealden to the present day, and includes such 
 fossil forms as Coniosaurus, Dolichosaurus, Mosesaurus, &c., the head of 
 the latter being fully five feet long. 
 
 Lacustrine, Lacustral (Lat. locus, a lake). Of or belonging to a lake ; 
 as " lacustrine deposits," that is, deposits which have been accumulated 
 in fresh- water areas, as lakes and marshes. They usually consist of mud, 
 sand, clay, marl (fresh-water limestone), peat-moss, and the like, and 
 contain the remains of aquatic plants and animals, mingled less or more 
 with those of land species. See LAKES. 
 
 Lsemodipoda (Gr. laimos, the throat ; dis, two ; and pom, podos, foot). 
 A family of crustaceans, thus named because they have the anterior pair 
 of feet placed under the head, as though at the throat the first segment 
 of the trunk, which carries these feet, being conjoined with that of the 
 head ; e.g., the cyamus, or whale-louse. In the Ltemodipods the eyes are 
 sessile; the posterior part of the body is little developed; they do not 
 swim, but creep on marine plants and animals in search of food ; and in 
 most (says Van der Hoeven) the feet are wanting in those rings that carry 
 gill-vesicles, and conversely the gill-vesicles are wanting on those rings 
 that have feet. 
 
 Lagomys (Gr. lagos, hare, and mus, rat). Literally, " hare-rat ; " the Pika 
 of Siberia ; a small tailless rodent forming a link between the hare and the 
 rat, and occurring only in the northern regions of Asia and America. 
 Several species have been found fossil in the ossiferous caverns and breccia, 
 as well as in the ancient lacustrine deposits of Europe. 
 
 Lagoon, Lagune (Ital. laguna). Generally applied, as in the Adriatic, 
 to shallow salt-water lakes or sheets of water cut off (or nearly so) from the 
 sea by intervening strips of beach or river-deposit ; also to the waters en- 
 closed by circular coral-reefs ; as well as to the lake-like sheets that fre- 
 quently occur in tidal and periodically inundated deltas. 
 
 Lake (Lat. locus}. The general term for any inland body of water not 
 connected with the ocean or any of its branches. Lakes occur in depres- 
 sions of the earth's surface more or less below the level of the surrounding 
 country, and, generally speaking, have a tendency to become shallower, 
 both from the silt that is carried into them by their feeding streams, and 
 
 271 
 
LAK LAM 
 
 from the gradual deepening of the river-channel which forms their natural 
 drainage. This tendency being continued, they, in process of time, become 
 silted up, drained, and converted into tracts of alluvial land ; hence it may 
 be laid down as a geological axiom that in all long-established continents 
 and islands lakes are now shallower, smaller, and fewer than in former ages. 
 In the Current as well as in the Tertiary epoch we have abundant evidence 
 of such obliterations ; the formations arising from lake-silt (lacustrine 
 deposits) being characterised by peculiarities lithological and palaeontolo- 
 gical which separate them in a marked manner from marine sediments. 
 These peculiarities are, tranquillity of deposition, absence of littoral action, 
 the remains of fresh-water plants and animals, with a greater admixture of 
 terrestrial organisms ; and with these as guides there is little difficulty in 
 determining lacustrine from estuary or oceanic deposits. Existing lakes 
 are usually divided into four kinds viz., 1. Those that have neither out- 
 let nor inlet subterranean springs and rains supplying the water, and 
 evaporation carrying off the excess. These are usually small mountain- 
 lakes or tarns, and the craters of extinct volcanoes. 2. Those which have 
 an outlet, but receive no running water, being fed by springs rising from 
 their bottoms and rocky margins. Lakes of this class are also small and 
 situated in mountainous regions. 3. Those which both receive and dis- 
 charge streams of running water, and which form alike the most numer- 
 ous and most extensive in both hemispheres. 4. Those which, like the 
 Caspian, &c., receive streams of running water, but have no visible outlet 
 the balance of level being maintained by evaporation. Such lakes are 
 more or less impregnated with saline matter ; and their saltness must be 
 on the increase. 
 
 Lake-Basin. In geography, the depressed area which contains the 
 waters of a lake ; also the entire area drained by the streams that fall into 
 a lake. In geology, the concavity or basin-shaped hollow in which the 
 waters of a lake rest, and which in some instances has arisen from an ori- 
 ginal depression of the surface, in others from a damming up of valleys by 
 cross mounds of debris, such as moraines, &c., and in some again from 
 excavations that have been scooped out by the forcible and long-continued 
 pressure of glaciers and analogous ice-masses. 
 
 Lake-Dwellings. The name given by archaeologists and geologists to 
 the remains of dwellings now found in marshes and lake-silts, and which 
 seem to have been erected on piles driven in the water, or on mounds partly 
 formed of stones, wood, and other debris. These lake-dwellings have been 
 found in Switzerland, Ireland, Scotland, and other countries of Europe, 
 and point to a time when the early inhabitants betook themselves to this 
 style of habitation for purposes of defence and protection. In some in- 
 stances, as in Switzerland, the piled area is of considerable extent (forming 
 an aquatic village as it were) and connected with the shore by a piled 
 way or causeway. Known in Ireland as Crannoges, and in Switzerland as 
 Pfahlbauten, which see. 
 
 Lamantin. The manatus, manatee, or sea-cow ; an herbivorous ceta- 
 cean, inhabiting the mouths of tropical rivers in Africa and South America. 
 Fossil species occur in the Miocene and Pliocene Tertiaries of Europe. 
 
 Lamellar, Lamellated (Lat. lamella, diminutive of lamina, a little plate). 
 Composed of very thin plates or scales ; foliated ; in paper-like leaves, as 
 talc, mica, the oyster-shell, &c. 
 
 Lamellibranchidta (lamella, a little plate, and branchiae, the gills). 
 272 
 
LAM LAN 
 
 Blainville's term for the Conchifera, a class of bivalve shell-fish which, like 
 the oysters, scallops, mussels, and cockles, respire by membraneous or 
 leaf-like gills attached to the mantle. See CONCHIFERA. 
 
 Lamina, plur. Laminae. The Latin term for any thin leaf-like plate, as 
 of metal. Many stratified rocks split up into thin layers or laminae; hence 
 the terms laminated, laminar, &c. 
 
 Laminarian Zone (laminaria, the sea-tangle). That zone or belt of ma- 
 rine life which commences at low-water mark, and extends to a depth from 
 forty to ninety feet, and in British seas is characterised, as its name im- 
 plies, by the broad waving sea-tangle and larger algse, by star-fishes, the 
 common echinus, by tubularia, modiola, and pullastra. See ZONE. 
 
 Laminarites (laminaria, the broad sea-tangle). A term applied by 
 Brongniart to the broad-leaved fossil algse of the Upper, Secondary, and 
 Tertiary formations. 
 
 Laminated (Lat lamina, a thin plate). Applied to strata splitting up 
 into thin layers, as certain flagstones and tilestones, which occasionally 
 exhibit from twenty to thirty laminae in the thickness of a single inch- 
 each lamina being the result of an independent deposit in tranquil waters. 
 
 Lamination (Lat. lamina, a plate or layer.) Arrangement in layers. 
 Lamination prevails less or more in all sedimentary deposits, and is, for 
 the most part, parallel to the lines of bedding or stratification ; oblique 
 lamination or false bedding occurs, however, in many coarse thick-bedded 
 sandstones, and seems as if the material composing the stratum had been 
 carried forward by currents into deep water, and laid mass after mass on 
 the sloping edge of the advancing deposit. 
 
 Lamna (Gr., a plate of metal). A genus of sharks whose thin, sharp, 
 plate-like teeth occur abundantly in the Chalk and Tertiary formations. 
 These teeth are rather flat, sharp-pointed, with smooth trenchant edges, 
 and a small sharp denticle (or little tooth) on either side the base. 
 
 Lanarkite. Sulphate and carbonate of lead, occurring either massive 
 or in long, slender, right-rhombic prisms, of a greenish- white or grey colour, 
 sectile, and in thin laminae flexible like gypsum. First found at LeadhilLs 
 in Lanarkshire, hence the name. 
 
 Lanceolate, Lanciform (Lat. lancea, a lance or spear). Lance-shaped ; 
 narrow and tapering like the leaves of many plants ; e.g., the common rib- 
 wort. 
 
 Landes (Fr.) Literally, heaths; but applied in particular by French 
 writers to those extensive areas of sand-drift which stretch southward from 
 the mouth of the Garonne along the Bay of Biscay, and inwards towards 
 Bourdeaux hence often spoken of as the " Landes de Bourdeaux." They 
 are extensively planted with the sea-pine (Pinus maritimus) on the seaward 
 side, but stretch away inland in heathy undulating plains, chiefly occupied 
 as sheep-runs. 
 
 Laud-Locked. Applied to seas that are isolated from the rest of the 
 ocean by peninsulas and chains of islands, as the Sea of Japan, the Sea of 
 Okhotsk, &c. Land-locked seas are thus only partially enclosed or locked 
 in by the land, while inland seas are surrounded on all sides by the land 
 in a continuous manner, as the Baltic and Mediterranean. 
 
 Landslip. Any portion of land that has slidden down in consequence of 
 some undermining or disturbing action. Landslips, as might be expected, 
 are most frequent in districts subjected to earthquake disturbance, and 
 there they sometimes take place on such a scale as materially to affect tho 
 
 273 s 
 
LAN LAR 
 
 surface configuration of the country. They also occur extensively in steep 
 mountainous regions like the Alps and Himalayas, especially on the break- 
 ing up of the winter's frosts, when large masses of the cliffs and mountain- 
 sides, losing their cohesion, are precipitated into the valleys and river- 
 courses below, with all their burden of soil, shrubs, and trees. In our own 
 country they are sometimes occasioned by the undermining action of the 
 waves, and not unfrequently, after heavy rains, by the softening of sub- 
 jacent clayey beds where the strata are considerably inclined. For ex- 
 amples see Lyell's ' Principles.' 
 
 Langite (after Prof. Victor Von Lang). A basic sulphate of copper 
 occurring as an incrustation upon the very soft Killas slate of Cornwall, 
 in masses of a rich blue colour, and accompanied by crystals belonging to 
 the prismatic system. According to Professor Maskelyne, who first de- 
 scribed it, Langite differs from common sulphate of copper in being insol- 
 uble in water. 
 
 Laniary, Laniariform (Lat. lanio, I cut or tear). Applied to the canine 
 or cutting teeth of the Carnivora, in reference to their function. 
 
 Lanthanum!, Lanthanum (Gr. lanthano, I conceal). A rare metal, dis- 
 covered by Mossander, associated with didymium in the oxide of cerium, 
 and so named from its properties being concealed, as it were, by those of 
 Cerium, which see. 
 
 Laopnis (Gr. laas, rock, and ophis, serpent). A Tertiary serpent, the 
 detached vertebrae of which, according to Owen, indicate a length of ten 
 or twelve feet, and present some affinities to those of the rattlesnake. 
 
 Lapidify, Lapidification (Lat. lapis, a stone, and fio, I become). Con- 
 version into stone ; the process by which soft, loose, or incohering sub- 
 stances, organic or inorganic, are converted into stony matter. 
 
 Lapilli (Lat. lapillus, a little stone). Applied to a peculiar variety of 
 volcanic cinders, or small slaggy concretions. 
 
 Lapis (Lat.) A general term for any kind of stone; as lapis ollaris, 
 potstone ; lapis lazuli, ultramarine ; lapis cetites, eaglestone ; lapis ampelites 
 jet or cannel-coal, &c. 
 
 Lapis Lazuli. A well-known mineral of an ultramarine or fine azure- 
 blue colour, of various intensity. It is generally found massive and dis- 
 seminated ; of a finely granular or compact texture ; and so hard as to 
 scratch glass. It varies considerably in composition, but on the whole may 
 be said to consist of about 50 silica, 11 alumina, and 16 lime, with minor 
 proportions of sulphuric acid, 'iron peroxide, magnesia, and sulphur. The 
 depth of its colour seems to depend on the amount of iron and sulphur. It 
 is found chiefly in crystalline limestone, but occurs also in the granitic and 
 crystalline rocks. The finest specimens are obtained from China and 
 Central Asia. It is used as an ornamental stone when sufficiently large 
 and pure ; but chiefly in the preparation of the fine pigment called ultra- 
 marine, which see. 
 
 Laridae (Lat. larus, the sea-gull). The Gull family, which includes the 
 gulls, terns, petrels, and other well-known marine Natatores, or swimming- 
 birds. The bones of allied species have been discovered in Post-tertiary 
 and Tertiary strata ; e.g., halcyornis, pelagornis, &c. 
 
 Larva (Lat., a mask). Properly, an insect in its grub, caterpillar, or mag- 
 got state, before it has attained its winged or perfect condition. Larval. 
 Applied to the embry otic stage of Crustacea and other animals which under- 
 go metamorphoses in their development, as well as to the grubs of insects. 
 
 274 
 
LAS LAU 
 
 Lasionite. A phosphate of alumina, better known as Devonite and 
 Wavellite, the latter of which see. 
 
 Literite (Lat. later, a brick). Literally "brick-stone; " a compound of 
 clay (silicate of alumina) and oxide of iron, often arising from the decom- 
 position of trap and volcanic rocks. The term is most frequently applied, 
 however, to a peculiar clayey deposit of Middle Tertiary age, found in India, 
 and so named from being cut into bricks and used for building. " It varies 
 much," says Ansted, " in colour and composition, but generally consists 
 of a reddish-brown or brick-coloured cellular clay, more or less indurated, 
 and used by the natives as bricks when cut square. It hardens greatly 
 and permanently on exposure, and is well adapted for buildings and fortifi- 
 cations." Portions of the deposit, however, pass into hard, compact jas- 
 pideous rock on the one hand, or into loosely-aggregated grits and soft 
 ochrey clays on the other. 
 
 Latitude (Lat. latitude, breadth). The latitude of a place on the earth's 
 surface is its distance from the equator, measured in degrees, minutes, and 
 seconds along its own meridian. If in the northern hemisphere, it is said 
 to be in North Latitude (N. Lat.) ; and if in the southern, in South Latitude 
 (S. Lat.) As the distance between the equator and either of the poles is 
 only the fourth part of the earth's circumference, or 90, the latitude of a 
 place can never exceed that amount. Parallels of latitude are small circles 
 drawn parallel to the equator ; and in each such circle every place has, of 
 course, the same latitude. The terms longitude and latitude arose from a 
 notion of the ancients that the earth was longer from east to west than 
 from south to north ; in other words, that it had length and breadth, which 
 these terms express. 
 
 Ldtrobite (after M. Latrobe). A pink or rose-red mineral, allied to fel- 
 spar, and occurring in indistinct crystals or massive, associated with fel- 
 spar, mica, and calc-spar. 
 
 Laumonite (after M. de Laumont). One of the zeolites, occurring in 
 druses in the trap- rocks, and known also as efflorescent zeolite, because, 
 when exposed to the air, it loses its lustre and transparency, and is de- 
 composed. 
 
 Laurentian, Laurentian System. The term employed by Sir W. Logan, 
 of the Canadian Geological Survey, to designate the highly crystalline 
 sedimentary strata which belong especially to the valley of the St Law- 
 rence, and constitute the Laurentide Mountains, the equivalents of the 
 " Older Metamorphic " strata of Europe. "The rocks of this system," 
 says Sir William, "are, almost without exception, ancient sedimentary 
 strata which have become highly crystalline. They have been very much 
 disturbed, and form ranges of hills having a direction nearly north-east 
 and south-west, rising to the height of 2000 or 3000 feet, and even higher. 
 The rocks of this formation are the most ancient known on the American 
 continent, and correspond, probably, to the oldest gneiss of Finland and 
 Scandinavia, and to some similar rocks in the north of Scotland. They 
 consist, in great part, of crystalline schists (chiefly gneissoid or hornblende), 
 associated with felspars, quartzites, and limestones, and are largely broken 
 up by granites, syenites, and diorites, which form important intrusive 
 masses. Among the economic minerals of the formation, the ores of iron 
 are the most important, and are generally found associated with lime- 
 stones." The total thickness of the system has been estimated at 23,000 
 feet. See tabulations, " GEOLOGICAL SCHEME." 
 
 275 
 
LAV LEA 
 
 Lava (Ital.) The general term for all rock-matter that flows in a molten 
 state from volcanoes, and which, when cooled down, forms varieties of tufa, 
 trachyte, trachytic greenstone, and basalt, according to the varying pro- 
 portions of felspar, hornblende, augite, &c., which enter into the composi- 
 tion of the mass ; and according to the slowness or rapidity with which it 
 is cooled. The more rapid the process of cooling, the more compact the 
 rock ; and thus we have among Volcanic products, just as among the older 
 igneous rocks, every variety of texture, from that of a glassy basalt to a 
 granular trachyte or greystone, and from that to a soft earthy tufa or light 
 vesicular pumice. The rocks known as obsidian, pumice, scoriae, &c., are 
 therefore mere varieties of lava or volcanic rock-matter. Respecting the 
 temperature, liquidity, rate of cooling, and other conditions of newly- 
 ejected lava, we have no very certain data, nor is it likely that any two 
 eruptions will exactly coincide in any of these particulars. This much, 
 however, we know, that while some lavas are sufficiently hot to melt frag- 
 ments of rocks thrown into their current, others are so little above the melt- 
 ing-point that they are covered with a stony crust almost immediately on 
 their exposure to the open air. Again, some are so liquid as to penetrate 
 the fibres of wood, while others are so viscid that their flow is scarcely per- 
 ceptible. The rate of cooling also depends on many correlative circum- 
 stances ; and while the lava of Mauna Loa was covered with a crust which 
 could be walked upon in a few days after eruption, that of Vesuvius has 
 been known to remain red-hot for years at a few feet beneath the surface. 
 
 Lizulite (Arabic, azul, sky-blue). A mineral of a light-blue colour, 
 known also as azurite and prismatic azure-spar. It is usually massive or 
 disseminated in granular aggregations, and consists of a hydrous combina- 
 tion of phosphate of alumina and phosphate of magnesia, with protoxide of 
 iron. Distinct from Lapis-lazuli, which it faintly resembles only in colour. 
 
 Lead. A well-known metal of a bluish-grey colour ; soft, flexible, and 
 inelastic ; and though ductile and malleable, yet possessed of very little 
 tenacity. Its specific gravity varies from 11.3 to 11.4; its hardness is 
 1.5 ; and it fuses at a temperature of about 600 Fahr. In close vessels it 
 does not appear to be volatile at a white heat, but melted in open vessels 
 it soon oxidises and passes into a grey powder, which, upon further ex- 
 posure to heat and air, becomes yellow, and is called massicot or protoxide 
 of lead. If massicot be heated, and stirred to prevent fusion, it gra- 
 dually absorbs oxygen, acquires a red colour, and is called red-lead ; and 
 this red-lead, heated in nitric acid, is partly converted into a brown in- 
 soluble powder which is a peroxide of lead. By treating these oxides with 
 acids we obtain white-lead or carbonate of lead, and sugar of lead or 
 acetate of lead preparations extensively used in the arts and in pharmacy. 
 Lead is rarely found native, and that chiefly in volcanic rocks, where it 
 appears as a product of fusion. Commercially, it is wholly obtained from 
 the ores, and these occur in rocks and formations of all ages almost 
 always in veins, as in the metamorphic schists and carboniferous limestones 
 of our own country. One of the most abundant and best known of its 
 ores is Galena sulphuret of lead or lead-glance which has been taken as 
 the representative of the LEAD-GLANCE FAMILY ; of less importance com- 
 mercially, but of great mineralogical interest, occur the LEAD-SALTS 
 FAMILY, which are usually associated with the former in crystalline forms 
 less or more distinct. See tabulations, "MINERAL SCHEME," for the 
 species included under these respective families. 
 
 276 
 
LEA * LEI 
 
 Lead, Black. Known also as Plumbago, and technically and more pro- 
 perly as Graphite, which see. 
 
 Lead-Glance. An early and familiar term for the sulphuret of lead or 
 Galena, which see. 
 
 Leadhillite. A sulphato-tri-carbonate of lead, occurring in tabular 
 crystals, or in foliated aggregates ; and so called from its being first found 
 among the usual ores of Leadhills in Scotland. 
 
 Lead-Ochre. A massive, opaque, sulphur-yellow oxide of lead, occurring 
 among volcanic products, but in other respects similar to the artificial yel- 
 low oxide. 
 
 Lead-Spar. The carbonate of lead, or Cerusite. Red-Lead Spar. The 
 chromate of lead or Crocoisite, both of which see. 
 
 Leaia (After Dr J. Lea of Philadelphia). A genus of small bivalved en- 
 tomostraca from the Carboniferous formations of Europe and America, 
 characterised by their dark-coloured, thin, horny, quadrangular valves, 
 either lying separate or with their dorsal edges approximate, and marked 
 with concentric furrows, running parallel with the three sides of the 
 valves, and by two oblique transverse ridges crossing the valve, from 
 the umbo to the ventral angles. Sometimes confounded with Estkeria 
 and Cypricardia. 
 
 Lecontite (After Dr J. Le Conte). Sulphate of soda and ammonia, with 
 much water of crystallisation ; a substance occurring in rhombic crystals, 
 clear and colourless when free from extraneous matter, and of a bitter 
 saline taste. It was first discovered by Dr John Le Conte in a cave in 
 Honduras, in a black bituminous-looking matrix, considered to be the 
 decomposed excrement of bats, which infest these caverns in vast numbers, 
 and have likely inhabited them for ages. The caves in which this sub- 
 stance occurs are worked out for nitre. 
 
 Leelite. A species, or rather a variety, of compact felspar, of a reddish 
 colour, waxy texture, and horn-like translucency ; found at Grypthy ttan in 
 Westmannia, and so named after Dr Lee of Cambridge. 
 
 Leeward. A nautical term of frequent occurrence in geographical de- 
 scriptions. In sailing, that side of a ship against which the wind blows is 
 called her weather-side, while the opposite one is known as the lee-side. All 
 objects on the weather-side are said to be to the ^oindward, and those on 
 the lee-side to be to the leeward of the vessel. 
 
 Legion (Lat.) Literally "a gathering or group." A term occasionally 
 used in natural history classification to express an assemblage of objects 
 intermediate in extent between a class and order. A class may thus em- 
 brace several legions, and a legion contain many orders. 
 
 Leguminosftes (Lat. legumen, a pod). Fossils occurring chiefly in Ter- 
 tiary strata, and apparently the seeds of pod-bearing plants. About twenty 
 species from the London Clay have been enumerated by Dr Bowerbank. 
 
 Lehm. An ancient alluvium of the Rhine, better known as Loess, which 
 see. 
 
 Leiacanthus(Gr. leios, smooth, tmdacantha, a spine). Literally "smooth 
 spine ; " a provisional genus of fossil fishes, the ichthyodorulites or fin-spines 
 of which are found in the Muschelkalk. 
 
 Leiodon (Gr. leios, smooth, and odous, odontos, tooth). A generic name 
 given to certain smooth mosasauroid teeth from the Chalk formations, in 
 order to separate them provisionaDy from Mosasaurus proper, under which 
 they were at one time included. 
 
 277 
 
LEM LEP 
 
 Lemnian Earth. A variety of clay or aluminous earth, so called from 
 the island of Lemnos in the JEgean Sea. It is of a yellowish-grey or white, 
 with ochreous spots on the surface ; has a meagre feel ; adheres slightly to 
 the tongue ; falls to powder in water ; and, according to some, seems to be 
 only a decomposed trachyte. It has been used as a medicine from the 
 time of Homer, and is sometimes termed sphragide (sphragis, a seal) or 
 terra-sigillata from its being made up in cakes and stamped for the 
 market. This earth, like the " Armenian Bole" has been the subject 
 of innumerable fables and traditions. When Vulcan was hurled from 
 heaven and fell on Lemnos, it stopped the bleeding of his wounds and 
 bruises ; subsequently it was used not only to stop bleedings, but as an 
 antidote to poisons and the plague ; and, from its reputation, has been 
 greatly valued by all the successive possessors of the island, Greeks, 
 Christians, and Mohammedans. Hence also the various stamps which it 
 has successively borne Diana, Vulcan, the Seal of the Grand Signor, and 
 that of a goat, from the practice of working up the smaller and friable 
 portions into a cake with goat's blood. If it has any medicinal properties, 
 it is merely as an aluminous astringent. 
 
 Lemnian Reddle. An ochre of a deep-red colour and firm consistence, 
 occurring in conjunction with the Lemnian Earth, and used as a pigment. 
 
 Lenticular (Lat. lens, a lentil). Resembling a lentil ; having the form 
 of a lens. Hence we speak of " lenticular concretions," " lenticular 
 pebbles," &c. 
 
 Lenzinite. One of the Clay family ; a milk-white variety of Halloysite 
 or semi-translucent silicate of alumina, consisting of 37.5 silica, 27.5 
 alumina, and 25 water, and named after Lenzins, a German mineralogist. 
 
 Leonina. A rare variety of agate, of a pale-yellow colour, variegated 
 with white, black, and green, and bearing some resemblance to a lion's 
 skin ; whence the name. 
 
 Lepadites. A term occasionally applied to fossil shells, apparently those 
 of the goose-barnacle (Upas), as balanites is sometimes applied to those of 
 the balanus or acorn-barnacle. The term has also been used to designate 
 those bivalvular shell-like organisms, better known as solanites, aptychus, 
 and trigonellites, the last of which see. 
 
 Lepidodendron (Gr. lepis, lepidos, a scale, and dendron, tree). An 
 abundant family of fossil plants, so called from the scale-like arrangement 
 of the leaf-scars that adorn their stems. They are characteristic of the 
 Upper Palaeozoic strata, and especially of the Carboniferous system, in 
 which they figure as one of the prevailing vegetable forms. They occur 
 of all sizes, from mere twigs and branchlets to stems more than fifty feet 
 in length, and often from three to five feet in breadth. A great number 
 of species have been recorded, but many of these must in the mean time 
 .be regarded as uncertain and provisional. As regards the affinities of the 
 family, botanists are by no means agreed, and it is more than likely that 
 the Lepidodendron, like many other fossil plants, has no existing analogues. 
 Thus, in the arrangement of their leaf-scars they resemble both the 
 Coniferae and Lycopods ; in their foliage they more resemble the Conifers ; 
 in their dichotomous ramification they are more like the Lycopods ; while 
 in their texture and size they seem more akin to the Coniferae. " On the 
 whole," says Professor Lindley, " we are led to conclude that the Lepido- 
 dendron genus was not exactly like either Coniferae or Lycopodiaceae, but 
 that it occupied an intermediate station between those two orders, 
 
 278 
 
LEP 
 
 approaching more nearly to the latter than to the former." On the other 
 hand, M. Brongniart, Dr Joseph Hooker, and other eminent botanists, 
 concur in regarding them as gigantic arborescent club-mosses, of which 
 Lepidophyllum was the leaf, and Lepidostrobus the fruit. From a minute 
 examination of the cones (Lepidostrobus), Professor Schimper considers the 
 genus more nearly allied to Selaginella than to Lycopodium. 
 
 Lepidoganoid, Lepidoganoidei (Gr. lepis, lepidos, a scale, and ganos, 
 splendour). A sub-order of the Ganoid fishes, and so termed in contra- 
 distinction to the Placoganoids, because their external skeleton or cover- 
 ing consists of scales, whereas that of the latter consists mainly of large 
 and often reticulated plates. The Lepidoganoids are more especially 
 characteristic of the Upper Palaeozoic strata, the Placoganoids of the 
 Lower or Devonian. See PLACOGANOID. 
 
 Lepidoidei, Lepidoids (Gr. lepis, a scale, and eidos, resemblance). A 
 family of Ganoid fishes, characterised by their strong rhomboidal bony 
 scales, and occurring in Carboniferous, Triassic, and Oolitic strata, but 
 most abundantly in the latter. The scales of lepidoids are readily dis- 
 tinguished by the hook-like process on their upper margins, this process 
 fitting, like the hook of a roofing- tile, into a corresponding depression on 
 the lower margin of the scale placed immediately above it. 
 
 Lepidolite (Gr. lepis, a scale, and lithos, stone). A term applied to the 
 fine pink-coloured varieties of lithia-mica, which differ chiefly from common 
 or potash-mica in containing a considerable percentage of fluorine, and 
 from 2 to 6 per cent of lithia. 
 
 Lepidomelane (Gr. lepis, scale, and melar, black). A variety of uniaxial 
 mica usually found in granitic veins, and occurring in small six-sided tables, 
 or an aggregation of minute, opaque scales, united in granulo-laminar 
 masses. So called from its usually raven-black colour. 
 
 Lepidophyllum (Gr. lepis, scale, and phyllon, leaf). Small lanceolate 
 leaves occurring abundantly in the shales of the Coal-measures, evidently 
 of a woody rigid texture, having a midrib, and triangular at the base or 
 point of attachment. They are regarded as the leaves of Lepidodendron ; 
 hence the name. 
 
 Lepid6ptera (Gr.) Literally " scale-wings ; " an order of insects having 
 two large wings covered with minute feathery-looking scales, as the Butter- 
 fly and Moth. The Lepidopters, like the Dipters and Hemipters, have 
 sucking mouths. They have been found in Eocene and Miocene strata. 
 See INSECTA. 
 
 Lepid6steus (Gr. lepis, scale, and osteon, bone). Bony Pikes ; a genus of 
 malacopterygian or soft-finned fishes, remarkable for the hard, bony scales 
 with which they are covered. The body is, as it were, encased in these, 
 and the two outer rays of the tail and fins are fringed with them. There 
 are only three or four species known, and these inhabit the lakes and rivers 
 of the warmer parts of America. They belong to the GANOID order of 
 Agassiz, and, along with the genus Polypterus or Bony Pike of Northern 
 Africa, are almost the only living representatives of the numerous ganoid 
 or enamelled -scale fishes of the Secondary epoch. 
 
 Lepid6strobus (Gr. lepis, scale, and strobllos, a fir-cone). Fossil cone-like 
 organisms occurring abundantly throughout the Carboniferous formation. 
 There is considerable variety in their configuration, the arrangement of 
 their scales, and the form of their bases or points of attachment ; and 
 while there is no doubt of there being reproductive bodies analogous to the 
 
 279 
 
LEP LEV 
 
 cones of recent conifers and lycopods, there is still great difficulty in 
 assigning the various forms to their proper places. In other words, while 
 some may be the seed-cones of true Coniferse, others may belong to the 
 Lepidodendron and Ulodendron, to Cycadacese, or even to Calamites, with 
 the stems of which they are so frequently associated. 
 
 Leptacantlms (Gr. leptos, slight, and acantka, a thorn or spine). Liter- 
 ally " slender-spine ; " a provisional genus of fossil fishes, so named by 
 Agassiz, from their slender fin-spines, which are found in the Carboniferous 
 Limestone, and in the Lias and Oolite. These ichthyodorulites are the 
 only parts known ; and it is more than likely that the " slender-spines" of 
 the Mountain Limestone and of the Oolite belong to very different species 
 of cestraciont fishes. 
 
 Leptolepis (Gr. leptos, slender, and lepis, scale). Literally " slight or 
 slender scale ; " a genus of small sauroid fishes occurring in the Lias and 
 Oolitic formations. 
 
 Leptopleuron (Gr. leptos, slender, and pleuron, rib). Laterally "slender- 
 rib ; " the name originally proposed by Professor Owen for the small rep- 
 tile found in the Upper Old Red of Elgin, now generally known by the 
 generic term telerpeton, which see. 
 
 Leptospond^lus (Gr. leptos, slender, and spondylos, vertebra). The gen- 
 eric term applied by Professor Owen to certain saurian vertebrae collected 
 by Dr Orpen in the Drakenberg Mountains in Southern Africa. 
 
 Leucite (Gr. leukos, white). Literally " white-spar ;" a mineral allied to 
 felspar, but by some taken as the type of a separate family. It is known 
 also as amphigene, and is frequently associated with augite in lava, tufa, 
 and other recent volcanic rocks. It consists, according to Klaproth, of 
 53.75 silica, 24.63 alumina, and 21.35 potash; and is remarkable as being 
 the first mineral in which that chemist discovered that potash was a con- 
 stituent of the mineral kingdom. From its occurring in trapezohedrons, 
 similar to those of the common garnet, it is sometimes known as " white 
 garnet" or "white garnet of Vesuvius*" 
 
 Leucopyrite (Gr. leukos, white, and pyrites). Arsenical pyrites ; arsen- 
 ite of iron, consisting of 65. 88 arsenic, 32. 35 iron, and 1 . 77 sulphur. This 
 ore is abundant in many localities, and is used for the production of 
 white arsenic, and also of artificial orpiment. 
 
 Leiicostine (Gr. leukos, white). A Continental term for a white-coloured 
 felspathic variety of lava. 
 
 Levant (Lat.) Rising from below; the fourth of the fifteen series into 
 which Professor Rogers subdivides the Palaeozoic strata of the Appalachian 
 chain the "Sunrise" of the North American palaeozoics; and the equiva- 
 lents in part of our Lower Silurians. See PALEOZOIC FORMATIONS. 
 
 Level. An English term for any flat alluvial plain of recent formation, 
 in allusion to its usually level-like surface; e.g., "Lewes Levels" and 
 " Beeding Levels" in Sussex, " Bedford Level" in Lincolnshire, &c. 
 
 Levigation (Lat. levigo, I polish, from Icevis, smooth). The process of 
 pounding or rubbing down earths and minerals to a powder or paste. It 
 is generally done with a mutter on a metallic or stone table, and some 
 fluid added to assist the operation. In this respect it differs from trilura- 
 tion, which may be called the dry method. 
 
 Levyne (after Levy the mineralogist). One of the Zeolite family ; a 
 variety of Chabasite, occurring chiefly in amygdaloid and other trap- 
 rocks, in white or yellowish hexagonal crystals. 
 
 280 
 
LEY LIE 
 
 ley or Lye. A technical term for a solution of any alkali, as soda or 
 potash, in water. See LIXIVIATION. 
 
 Lias, Lidssic. This term is said to be a corruption of lyers, or layers, 
 and was originally applied to those thin-bedded limestones occurring at 
 the base of the Oolitic system the layers of limestone being conspicuously 
 separated by thin partings of clay. It is now extended, in geological 
 classification, to that group or series of strata which in England immedi- 
 ately overlies the Trias or Upper New Red Sandstone, and is in turn over- 
 laid by the thick-bedded limestones of the Oolite proper. As developed 
 in England, the Lias occupies a belt of variable breadth, extending from 
 Lyme Regis in Dorset, northwards by Bath, Gloucester, Leicester, Newark, 
 and Gainsborough to the Humber, and thence to the east coast of York- 
 shire. Taken in Yorkshire, Northampton, and Somerset, the formation 
 (according to Professor Phillips) exhibits in descending order the following 
 members : 
 
 1. Upper lias clay or shale, full of belemnites and other fossils, inter- 
 
 calated with or graduating into the sands of the Inferior Oolite, and 
 in some cases containing nodules and bands of limestone. 
 
 2. Marlstone.A suite of calcareous, sandy, and irony beds, very rich 
 
 in fossils, and much analogous to the lowest beds of the Lower Oolite 
 formation. 
 
 3. Lower lias day or shale, full of fossil remains, interlaminated with 
 
 bands and nodules of limestone, especially in the lower part, where 
 a collection of these layers constitutes the " Lias rock." 
 
 4. I/ias rock. A suite of laminated limestones, with partings of clay, 
 
 blue, grey, and white, the former in particular containing gryphites 
 and other shells ; the latter usually devoid of organic remaips. This 
 rock is sometimes consolidated into a united mass, and sometimes 
 divided into separate portions. 
 
 For further details and foreign equivalents, see OOLITE SYSTEM, and pre- 
 liminary tabulations, " GEOLOGICAL SCHEME." 
 
 Libethenite (Libethen in Hungary). Phosphate of copper, occurring in. 
 many copper mines, in rhombic prisms or in radiated masses of an olive- 
 green colour, resinous lustre, and brittle. 
 
 Licks. An American term for swampy or boggy areas surrounding 
 saline springs, the soil of which, being impregnated with salt or covered 
 with saline incrustations, is licked by the wild cattle for the sake of the 
 salt. Several of these seem to have been licks even during the Upper 
 Tertiary period, for the surrounding soil contains the bones of the mastodon 
 and other extinct mammals in such profusion (Big-bone Lick in Kentucky) 
 as to warrant the conclusion that they were frequented by herds of those 
 animals, just as they are by the herds of the present day. 
 
 Liebigite (after Baron Liebig, chemist). Carbonate of uranium and lime, 
 found in mammillary crusts and concretions in the mines of Saxony and 
 Bohemia ; of a beautiful apple-green colour, vitreous lustre, and transparent. 
 
 Lievrite. A brownish -black mineral, occurring in long vertically-striated 
 prismatic crystals along with quartz, magnetic iron ore, and copper 
 pyrites in veins in the crystalline strata, and consisting, according to 
 Vauquelin, of 30 silica, 57.5 iron peroxide, and 12.5 lime. It is named 
 after the discoverer, Le Lievre ; and is also known as llvaite, from Elba, 
 and Yenite, in commemoration of the battle of Jena in 1806. 
 
 281 
 
LIG LIM 
 
 Ligneous (Lat. lignum, wood). Woody ; having the texture or quality 
 of wood ; as " ligneous fibre," " ligneous stems," &c. 
 
 Lignite (Lat. lignum, wood). Wood-coal or fossil wood more or less 
 mineralised and converted into coal. The lignites are usually of a dull 
 dark -brown appearance ; compact or laminated, and revealing the woody 
 texture ; and never present the crystalline structure or pitchy lustre of 
 true coal. They burn with much smoke and dull flame ; are poorer in 
 carbon or coke than common coal; give much less heat; and leave in 
 general a large residuum of earthy ashes. Lignitic beds occur in the New 
 Ked Sandstone and Oolite, but chiefly in the Upper Cretaceous and Terti- 
 ary formations, and present a great variety of aspects, some being almost 
 as hard as true coal, and known as " stone-coal;" others being distinctly 
 woody, and hence called "wood or board coal;" some again consisting 
 of thin layers like compressed leaves, "paper-coal ;" and others soft and 
 earthy, and known as " peat-coal." Lignite thus passes, it may be said, 
 through every gradation of texture, from the compacter peat-beds of the 
 present day to the stone or mineral coal of the older formations. According 
 to M. Fremy, lignites may be distinguished from mere wood and peat, on the 
 one hand, by their complete solubility in nitric acid and in hypochlorites ; 
 and from the true coals, on the other, which are insoluble in hypochlor- 
 ites, and only slowly attacked by nitric acid. The well-known lignites or 
 "Brown Coals" of Germany and the continent of Europe are chiefly Ter- 
 tiary, and from the leaves, fruits, and stems of palms (fan-palm, date- 
 palm, cocoanut-palm, &c.) which they contain, give evidence of the more 
 genial climate of these latitudes during the Tertiary epoch. See COAL, 
 and TERTIARY FORMATION. 
 
 Lignitiferous (lignite, and fero, I yield). Applied to strata or forma- 
 tions which contain suboi'dinate beds of lignite or brown-coal. 
 
 Ligulate (Lat. ligula, a strap). Strap -shaped; applied in natural 
 history to objects, organs, and processes which are long and narrow like 
 a strap. 
 
 Ligurite (from Liguria}.K variety of Sphene ; a mineral of an apple- 
 green colour, consisting of silicate of alumina, lime, and magnesia ; occur- 
 ring in mica and talc-schists ; and from its colour, hardness, and trans- 
 parency, used as a gem. 
 
 Lily-Stone, Lily-Encrinite. Familiar terms for the common Encrinite, 
 from the fanciful resemblance of its stalk and clustered tentacles to the 
 stem and flower of a lily. See ENCRINITE and CRINOIDEA. 
 
 Limbelite. A subordinate variety of olivine or chrysolite, occurring in 
 small honey-coloured masses, and so named by Saussure, from the volcanic 
 hill of Limbourg, where it occurs. 
 
 Lime. Chemically, the protoxide of calcium, one of the metallic bases 
 discovered by Davy in 1807. Mineralogically, one of the primitive earths, 
 usually occurring in nature as a limestone or carbonate of lime, from which 
 it is obtained by roasting at a red heat so as to expel the carbonic acid, 
 and thus leave the lime or quicklime behind. If the limestone employed 
 be very pure, as white chalk or Carrara marble, the residue will be the 
 earth " lime "white, very infusible, highly luminous when heated to 
 full redness, and of a specific gravity about 2. 3. It requires for solution 
 about 500 parts of water, but diluted as this may appear, it acts power- 
 fully as an alkali ; has an acrid taste ; and is thence regarded as one of 
 the alkaline earths. If quicklime be sprinkled with water, it rapidly 
 
 282 
 
LIM 
 
 crumbles down to powder with great evolution of heat, and becomes 
 slaked lime or hydrate of lime; and if this hydrate continue exposed to 
 the air it gradually absorbs moisture and carbonic acid, and is reconverted 
 into the carbonate. Combining readily with acids, the salts of lime occur 
 abundantly in nature as sulphate of lime or gypsum ; fluate of lime or 
 fluor-spar ; phosphate of lime or apatite ; and so forth. The most abundant 
 compound, however, is the carbonate of lime or ordinary limestone, which 
 occurs in all states of purity, and in all stages of mineralisation from soft 
 earthy chalk to crystalline limestones or even transparent crystallised 
 calc-spars. As an earth, lime is profusely disseminated in nature : as a 
 rock, it enters largely into the composition of the earth's crust ; it is less 
 or more diffused in all its waters ; it forms the principal ingredient (earth 
 of bone) in the skeletons of the larger animals ; and is secreted by many 
 classes of the invertebrata to form their shells, crusts, shields, corals, and 
 other means of protection. Economically it is also of vast importance, 
 being used in the manufacture of mortars and cements, in tanning, bleach- 
 ing, deodorising, and the like, and also in agriculture as a fertiliser, or 
 promoter of vegetable decay. 
 
 Limestone. The familiar as well as technical term for all rocks and 
 rock-masses that are mainly composed of carbonate of lime, and are in 
 their texture either earthy (chalk), compact (ordinary limestone), or 
 crystalline (marble) crystallised varieties of the carbonate being better 
 known as calc-spars. Limestones occur in all formations ; in all degrees 
 of purity ; and owe their origin some to corals, encrinites, and shell-fish, 
 others to accumulations of foraminiferal and kindred organisms, and 
 others again to chemical precipitation from the waters in which they were 
 deposited. The names by which their varieties are known to the geologist 
 have reference to their origin, composition, texture, or other physical pro- 
 perty, as "encrinal limestone," "shell limestone," "magnesian lime- 
 stone," " saccharoid limestone," "concretionary limestone," and the like. 
 The quality or richness of a limestone is in general perceptible to the eye ; 
 and where this fails to satisfy, the application of sulphuric or muriatic acid 
 (both of which dissolve limestone with violent effervescence), or the heating 
 of a fragment before the blowpipe so as to convert it into quicklime, will 
 without much trouble give the necessary indication. 
 
 Limnaclnse and Liinneidse (Gr. limne, a marsh). Terms applied to the 
 River-snails ; a sub-family of the HELICINJ3 or true Snails, and represented 
 by the well-known marsh-shells limncea, pht/sa, and planorbis. 
 
 Limnse'a (Gr. limnaios, marshy). The "Pond-shell;" a well-known 
 genus of fresh-water molluscs inhabiting lakes and ponds, and character- 
 ised by their pointed spire, elongated oval body, and delicate thin shell. 
 About seventy species occur in Tertiary strata ; the existing species are 
 somewhat fewer in number. 
 
 Limonite. The mineralogical term employed by Beudant and other 
 modern writers for Brown Iron Ore, which embraces the brown hsemitites, 
 ochry iron ore, ochre, bog-iron-ore, and other allied varieties of hydrated 
 peroxide of iron. See IRON. 
 
 Limpid (Lat. ) Clear, pure, transparent. Applied to fluids and crystals. 
 
 Limulus. The Molucca-crab, king-crab, or horseshoe-crab. A genus 
 of crustaceans belonging to the family Xiphosura or sword-tails, and to the 
 order Pcecilipoda, or those having feet of different forms. In the limulus 
 the dorsal plates are united in one piece or carapace ; the abdominal shield 
 
 283 
 
LIN LIT 
 
 is more complex ; of the feet some are leaf-like and fitted for swimming, 
 others are shear-shaped and perform the office of jaws, hence the term 
 "jaw-feet." The tail is long, spear-shaped, and pointed. There are few 
 species of existing limuli ; several limuloid crustaceans have been dis- 
 covered in the Coal-measures ; but of these some may likely belong to the 
 Eurypteridce, which are altogether fossil. 
 
 Line of Dip and Line of Bearing. The direction in which strata dip 
 or incline from the horizon is said to be the " line of dip ; " the direction 
 of their strike or outcrop " the line of bearing." As the dip is always at 
 right angles to the strike, if the one is known the other can readily be 
 laid down ; thus', if the dip be to the N.W., the line of bearing will run 
 from S. W. to N.E, and vice versa. 
 
 Lingula (Lat., a little tongue). A genus of brachiopodous mollusca, so 
 called from the tongue-like form of their valves. In the Lingula the two 
 valves are nearly equal, of a horny texture, rather compressed, somewhat 
 truncated in front, the hinge toothless, the beak of the valves rather 
 pointed, and united to a tendinous pedicle by which the animal is attached 
 to the sea-bottom. The existing lingulse are found only in southern seas ; 
 the fossil species, nearly forty in number, occur in all formations from the 
 Lowest Silurian upwards, being found in British strata so recent as the 
 Coralline Crag. The Lingulidoe are thus one of the oldest families of 
 mollusca several species being highly characteristic of, and peculiar to, 
 the lowest fossiliferous strata with which geology is yet acquainted. 
 
 Lingulate, Linguiform (Lat. lingua, the tongue). Applied to leaves 
 and other organisms which are shaped like the tongue ; tongue-shaped. 
 
 Linnaean. Systems of classification, nomenclature, and methods intro- 
 duced by Linnaeus the great Swedish naturalist, who was born in 1707, 
 and died in 1778, are so termed. The Linncean Systems are often spoken 
 of as Artificial, in contradistinction to the more Natural systems intro- 
 duced by Jessieu in botany, and by Cuvier in zoology. 
 
 Liquefaction (Lat. liquefacio, I make liquid). Literally, the passing of a 
 substance from the solid to the liquid state, as the melting of ice ; but also 
 often used as synonymous with fusion, sohition, and deliquescence. 
 
 Liroconite (Gr. leiros, pale, and konis, dust ; in allusion to the paleness 
 of its streak). A hydrated arseniate of copper occurring in several copper 
 mines in obtuse pyramidal crystals ; of a sky-blue or verdigris green ; 
 vitreous lustre ; translucent ; and sectile. 
 
 Lithia (Gr. lithos, a stone). An alkali or alkaline earth, discovered in 
 1818 by Arfwedson in a mineral called petalite, but since found in other 
 minerals, and in very minute quantities in some mineral springs, as those 
 of Carlsbad. As an earth it is caustic, alkaline, and sparingly soluble in 
 water. It obtains its name from being found only in the mineral or stone 
 kingdom. 
 
 Lithium. The metallic base, of which lithia is the oxide, first obtained 
 by Sir H. Davy from the hydrate of that earth by the action of the 
 galvanic battery. Like sodium, &c., it is a white-coloured metal, but so 
 exceeding oxidable that its properties cannot be fully examined. 
 
 Lithocarp (Gr. lithos, and carpos, fruit). Any fossil fruit; same as 
 Carpolite, which is the term principally used. 
 
 Lithodomi, Lithodomous (Gr. lithos, and domos, a house). Applied to 
 certain mollusca, which, like the pholas, bore into solid rocks and form 
 for themselves permanent lodgments the perforation widening as the 
 
 284 
 
LIT 
 
 animal grows larger and descends the deeper. It has been a long-dis- 
 cussed question among naturalists whether the perforation is made by 
 mere mechanical rasping, or by the secretion of some chemical solvent ; 
 but the fact seems now well ascertained that the boring is performed 
 solely by gradual and incessant friction. 
 
 Lithogenous (Gr. lilhos, stone, and ginomai, I beget). Applied to polyps 
 which secrete or build up stony structures, as the Coral-polype. 
 
 Lithographic Limestone, Lithographic Slate. A peculiar magnesian 
 limestone, slaty, compact, and fine-grained, usually obtained from the 
 Lias and Oolite, and extensively employed in lithography. The finest 
 stones are from Solenhofen and Pappenheim in northern Bavaria, but some 
 of fair quality have been procured from the Lias of England. The most 
 esteemed colour is a pale cream yellow, but excellent slabs of bluish-grey 
 are not uncommon. 
 
 Lithoidal (Gr. lithos, and eidos, appearance). Stone-like ; having the 
 texture or appearance of stone. 
 
 Lith6logy, Lithological (Gr. lithos, a stone, and logos, doctrine). Applied 
 to the physical characteristics or stratigraphical relations of rock -groups, 
 in contradistinction to their palaeontology or palseontological aspects. 
 Lithology or Petrology treats of the earth's crust as made up of mere inor- 
 ganic rock-masses, aud endeavours to discover their composition, origin, 
 and the successive changes to which they may have been subjected ; leav- 
 ing to Palaeontology all that relates to the fossils they contain, as mani- 
 festations of the life that has successively peopled the earth's surface. It 
 has been proposed to distinguish between Lithology and Petralogy, by 
 restricting the former to "the study of the internal structure, the miner- 
 alogical composition, the texture, and other characters of rocks, such as 
 could be determined in the closet by the aid of hand specimens ; " and the 
 latter to " the study of rock-masses, their planes of division, their forms, 
 their positions and mutual relations, and other characters that can only 
 be studied in the field." Such a distinction, however, is rarely or never 
 attended to the two terms being employed synonymously. 
 
 Lithomarge (Gr. lithos, and marga, marl). Literally " stone-marrow;" 
 a term applied to several varieties of clay or fine-grained silicate of 
 alumina, arising in some cases from the decomposition of felspathic rocks 
 (e. g., Kaolin or China-clay) and in others from the deposition of aluminous 
 springs. It is of various colours, striped and spotted ; is massive, soft, 
 and opaque ; adheres strongly to the tongue ; falls to powder in water, 
 but does not form a paste, and has a greasy feel when containing a little 
 magnesia, as is the case with some varieties. What is called Hard litho- 
 marge is a more complex compound of a blue mottled colour, found in the 
 Coal formation of Planitz in Saxony, and known as the Terra Miraculosa 
 Saxonice, from its supposed medicinal virtues. 
 
 Lithophagi, Lithophagidse (Gr. lithos, and phago, I eat). Applied to 
 those shell-fish and other animals which bore holes, and form for them- 
 selves a lodgment, in limestone, coral, and other stony masses. Certain 
 fish, like the Scarus, and many of the Holothurice, are said to be litJiophagous, 
 as browsing and subsisting on the living coral. 
 
 Lithophyllnjn (Gr. lithos, and phyllon, leaf. Volkmann's term for the 
 stigmaria ; and like phytolithus, which was Martin's designation for the 
 same plant, often found in the older geologists. 
 
 Lithopliyta, Lithophytes (Gr. lithos, and phyton, a shoot). Literally 
 285 
 
LIT LLA 
 
 " stone-plants ;" those polyps which secrete a stony axis, as the Corals, in 
 contradistinction to Ceratophyta, or those which secrete a horny axis, like 
 the Gorgonia or Sea-fan. 
 
 Lithomis (Gr. lithos, stone, and ornis, bird). Literally "petrified bird ; " 
 a generic term applied by Professor Owen to certain bird-remains from the 
 London or Eocene clay of the isle of Sheppey. From the close resemblance 
 
 these bones to those of the vulture tribe, they are designated specifically 
 as the Lithornis mdturinus. 
 
 Lithoxylon (Gr. lithos, stone, xylon, wood). A mineralogical term for 
 Wood-Opal, which see. 
 
 littoral (Lat. littus, the sea-shore). Belonging to, inhabiting, or taking 
 place on the shore. Applied to operations and deposits which take place 
 near the shore, in contradistinction to those of a deep-water or pelagic 
 character. 
 
 Littoral C6ncrete. " This term, which is of Bombay origin " (we quote 
 Dr Buist of that town), " indicates distinctly and intelligibly a particular 
 variety of rock, formed by the cementation of sea-sand or shells the same 
 as those now prevalent along our shores." The rains of certain regions 
 are more surcharged with carbonic acid than others, and where this is the 
 case " littoral concrete," often of great hardness and durability, is sure to 
 be formed, by the action of these carbonated waters on the shells and 
 other calcareous matter of the sands the dissolved lime acting as the 
 cement in artificial Concretes, which see. 
 
 Littoral Zone (Lat. littus, the shore). That zone of marine life which 
 lies between high and low water mark (varying in extent according to the 
 rise and fall of the tide, and the shallowness of the shore), and which in 
 British seas is characterised, as the bottom may be rocky, sandy, or 
 muddy, by such mollusca as the periwinkle, limpet, mussel, cockle, razor- 
 shell, &c., and by such plants as the bladder- wrack, dulse, and carigeen. 
 See ZONE. 
 
 Lituites (Lat. lituus, a trumpet). A genus of chambered shells peculiar 
 to Silurian strata, and so named from their form their whorls being 
 partially coiled up at the smaller end, and the last chamber being produced 
 into a straight trumpet-like tube. The lituite is ranked under the nauti- 
 lidce; has the septa outwardly concave, and the siphuncle internal. 
 
 Litiiolite (lituola, diminutive form of lituus). A genus of minute fora- 
 minifera, so called from their spiral form and straight prolonged outer 
 whorl ; occur chiefly in the Chalk formation. 
 
 Liver Ore. The Hepatic cinnabar of Phillips; a dark liver-coloured 
 variety of sulphuret of mercury intimately intermixed with idrialite (Tosia 
 in Spain), carbon, and earthy matter. 
 
 Liver Pyrites. A familiar term for a liver-coloured concretionary variety 
 of sulphuret of iron having an internal radiated texture. 
 
 Lixiviation (Lat.) The process of extracting the saline matter of bodies, 
 more especially of ashes (as kelp), by means of steeping and washing in 
 water. Such a solution is called a ley, lye, or lixivium, and the salts 
 resulting from its evaporation lixivial salts. 
 
 Llanddvery Rocks. A term applied by Sir E. Murchison to certain 
 sandstones and shales which seem to form a connecting link between the 
 Lower and Upper Silurian series of South Wales. They are specially char- 
 acterised by Pentamerus, Atrypa, and Petraia, and derive their name 
 from the locality where their relations are most clearly developed. 
 
 286 
 
LLA LOG 
 
 Llanos (Span.) In physical geography, the flat treeless plains that 
 extend along the banks of the Orinoco. They are, for the most part, 
 within the tropics, and during one half of the year are covered with grass, 
 and for the rest desolate. They are of very recent alluvial growth, and 
 are partly still in progress of formation. 
 
 Loadstone, Lodestone (Eng. lead and stone). A familiar term for the 
 magnet, which see ; an ore of iron that possesses the peculiar property of 
 attracting iron, and which, when freely suspended, invariably turns towards 
 the North Pole or "Magnetic North." 
 
 Loam (Sax.) A general, but not very definite term, applied to soils 
 that are native admixtures of clay, sand, and vegetable mould as being 
 moderately cohesive, less tenacious than clay, and more so than sand. 
 Agriculturists speak of light and heavy loams according to the proportion 
 of clay they contain ; and also of sandy, calcareous, and gravelly loams, 
 just as sand, lime, or gravel happen to be characteristic ingredients. 
 
 Lode. A Cornish term for any regular vein or course, whether metal- 
 liferous or merely composed of veinstone. In the former instance they 
 are said to be alive, in the latter they are termed dead lodes. 
 
 Loess or Lehm. A German term for an ancient alluvial deposit of the 
 Rhine replete with fresh- water shells of existing species. According to 
 Lyell, ' ' it is a finely-comminuted sand or pulverulent loam of a yellowish 
 grey colour, consisting chiefly of argillaceous matter, combined with a 
 sixth part of carbonate of lime, and a sixth of quartzose and micaceous 
 sand" thus closely agreeing in composition, as ascertained by Bischoff, 
 with the mud of the Nile. Interstratified with it are volcanic ashes thrown 
 out by the now extinct volcanoes of the Eifel and adjacent districts, and 
 the Rhine has since eaten out a passage, frequently leaving exposed cliffs 
 of considerable altitude. In general it ranges from thirty to fifty feet in 
 thickness ; is found as much as 1500 feet above the present sea-level ; and 
 where it terminates near Switzerland, it is said to repose on rolled flints 
 and pebbles of the Older Drift period. 
 
 Loganite (after Sir W. E. Logan, director of the Canadian Geological 
 Survey). A hydrated silicate of magnesia and lime ; a variety of Pyros- 
 clerite occurring in the serpentinous rocks of Canada in short, thick, 
 oblique-rhombic crystals, of a clove-brown colour, sub- transparent, and of 
 a weak sub-resinous lustre. 
 
 Logan-Stones. Properly "Logging-stones," and perhaps better known 
 as " Rocking-stones ; " weather-worn blocks so finely balanced on their 
 pivot-like bases that a very ordinary force suffices to make them "log," or 
 " rock " from side to side. The following description, by Dr Paris, of the 
 celebrated Logan -stone near the Land's End, conveys an intelligible idea 
 of the nature and origin of these curiously-poised blocks : " The founda- 
 tion of this part of the coast of Cornwall is a stupendous group of granite 
 rocks, which rise in pyramidal clusters to a great altitude and overhang 
 the sea. The celebrated Logan -stone is an immense block, weighing above 
 sixty tons. The surface in contact with the under rock is of very small 
 extent, and the whole mass is so nicely balanced, that, notwithstanding its 
 magnitude, the strength of a single man applied to its under edge is suffi- 
 cient to make it oscillate. It is the nature of granite to disintegrate into 
 rhomboidal and tabular masses, which, by the further operation of air and 
 moisture, gradually lose their solid angles and approach the spheroidal 
 form. "The fact of the upper part of the cliff being more exposed to the 
 
 287 
 
LON LOX 
 
 atmospheric agency than the parts beneath, will sufficiently explain why 
 these rounded masses so frequently rest on blocks which will preserve the 
 tabular form ; and since such spheroidal blocks must obviously rest in 
 that position in which their lesser axes are perpendicular to the horizon, it 
 is equally evident that, whenever an adequate force is applied, they must 
 vibrate on their point of support." 
 
 Lonchopteris (Gr. louche, a spear, and pteris, fern). Literally "spear- 
 leaf ; " a fossil fern-like frond occurring in the Coal - measures, Lias, 
 Oolite, and Wealden, and so called from its resemblance to the recent 
 Lonchitis. The leaves are many times pinnate ; leaflets adherent to each 
 other at their base, traversed by a midrib, and furnished with reticulated 
 veins. 
 
 London Clay. One of the members of the Lower Tertiary or Eocene 
 beds of the London basin, and so called from its being largely developed 
 under, and in the vicinity of, the metropolis. It consists of a tenacious 
 bluish-black clay, varying from 300 to 600 feet in thickness, enclosing 
 numerous bands of septaria, and (along with the accompanying strata) 
 abounding in marine shells of extinct species crabs, lobsters, and other 
 crustaceans teeth of sharks and many other genera of fishes bones of 
 crocodiles, turtles, serpents, and birds leaves, fruits, stems of plants, and 
 rolled trunks of trees perforated by boring mollusca all indicating a warm 
 and genial climate. See TERTIARY SYSTEM. 
 
 Longitude (Lat. longitudo, length). The distance of a place measured in 
 degrees, minutes, and seconds, east or west of any fixed meridian. In 
 Britain, the fixed meridian is that of the Observatory of Greenwich ; and 
 in other countries it is usually that of their capitals. If the place be east 
 of the fixed meridian, it is said to be in E. Long., and if west, in W. Long. 
 See LATITUDE. 
 
 Longmynd Rocks. In geological classification the terms " Longmynd 
 Rocks" or "Bottom Rocks" are meant to embrace all those unfossiliferous, 
 or but sparingly fossiliferous, conglomerates, grits, schists, and slates, 
 which lie at the base of the Silurian system. They are typically developed 
 in the Longmynd Hills, Shropshire (whence the name) ; are regarded by 
 the Government Geological Surveyors as constituting the " Cambrian 
 System ; " but are still retained by Professor Sedgwick as the mere basis 
 or under-group of his original " Cambrian Rocks." 
 
 Lophiodon (Gr. lophion, a small crest or ridge, and odous, tooth). An 
 extinct tapir-like pachyderm of the Tertiary epoch ; so called from certain 
 points or eminences on its teeth. Several species have been catalogued, 
 but as yet very little is known as to its true relationship. 
 
 Lorate (Lat. lorum, a thong). Applied in botany and zoology to organs 
 or members having the shape of a thong or strap. 
 
 Loricated (Lat. lorica, a coat of mail). Covered or clad with horny or 
 bony plates or scutes, like the alligator and crocodile. 
 
 Lower-Level Gravels. The term now generally applied to all the sands 
 and gravels that occur in the lower terraces of valleys, in contradistinction 
 to the " high-level gravels," which see. While the high-level deposits are 
 destitute or nearly so of organic remains, the lower are generally replete 
 with the remains of extinct minerals, such as the mammoth, Irish elk, and 
 reindeer, associated in many instances with flint implements and other 
 evidences of human contemporaneity. 
 
 Loxoclase (Gr. loxos, oblique, and klasis, cleavage). A variety of ortho- 
 288 
 
LOX LUS 
 
 clase (which see), containing a large proportion of soda (from 7 to 9 per 
 cent) ; of a yellowish-grey colour, and semi-translucent. 
 
 Loxodon (Gr. loxos, oblique, and odous, tooth). One of the sub-genera 
 into which Dr Falconer divides the Elephants. The term has reference to 
 the rhomb-shaped discs of the worn molars ; and comprises both extinct 
 and living species. . ' , 
 
 Loxomma (Gr. loxos, oblique, and omma, the eye). A genus of labyrin- 
 thodon reptiles founded by Professor Huxley on a portion of a skull in the 
 University Museum, Edinburgh, from the Midlothian Coalfield ; and so 
 named from the very oblique disposition of the long axes of the eye-orbits, 
 which in addition to this feature are also larger and more backward in 
 position than in any known genera of Labyrinthodonts. 
 
 Loxonema (Gr. loxos, and nema, thread). A fossil genus of pyramidal- 
 shaped shells, belonging to the gasteropodous family Pyramidellidce, and 
 so named in allusion to the thread-like striae which mark the surface of 
 many species. The shell is elongated and many-whorled ; aperture simple, 
 attenuated above, effused below, with a sigmoidal edge to the outer lip. 
 The species are numerous, and occur from the Silurian to the Trias 
 inclusive. 
 
 Lucullite. A variety of black marble, so called from its being first 
 brought by Lucullus to Rome, from an island in the Nile. 
 
 Ludlow Rocks. According to Murchison, the uppermost group of the 
 Silurian system ; and so termed from being characteristically developed 
 near the town and castle of Ludlow, in Shropshire. They consist, in that 
 district, of thin flaggy sandstones (tilestones) ; of shales with calcareous 
 bands ; and of limestones (Aymestry limestone) all highly fossiliferous. 
 See SILURIAN SYSTEM. 
 
 Ludus Helmontii (after Von Helmont). An old mineralogical term for 
 a variety of Septarium, (which see) in which the sparry veins were frequent 
 and anastomosing. , 
 
 Lumachello, Ltunachelli (Ital.) A variety of marble full of fossil shells, 
 exhibiting beautiful iridescent colours ; sometimes deep red or orange, when 
 it is known by the name of Fire-marble. 
 
 Lumbar (Lat. lumlus, the loins). Pertaining to the loins, as "lumbar 
 muscles," "lumbar vertebrae," &c. 
 
 Lustre (in Rocks and Minerals). Lustre, like colour, fracture, cleavage, 
 &c., is often taken as a characteristic of minerals and rock-compounds, 
 but cannot be well described without the inspection of actual specimens. 
 It refers to the intensity and quality of the light reflected from their newly- 
 fractured surfaces, and in this respect differs from colour, which is an in- 
 herent property. Several degrees of intensity have been named by miner- 
 alogists ; as Splendent, when a mineral reflects the light so as to be visible 
 at a distance, and well-defined images are formed on its surface, as in 
 galena and rock-crystal ; Shining, when it is weaker and cloudy, and 
 images only are formed, as in heavy-spar ; Glistening, when the light is 
 not observable at greater distance than an arm's length ; Glimmering, 
 when only a number of small shining points are observable near the eye, 
 as in crystalline limestone ; and Dull, when no lustre can be discerned, as 
 in chalk. The kind cr quality of lustre is also defined by such terms as 
 Metallic, seen in pyrites and glance-coal; Adamantine, as seen in the 
 diamond ; Vitreous, as in glass or rock-crystal ; Resinous, as in pitchstone 
 and garnet ; Pearly, as in some gypsums, talc, and mica ; and Silky, as 
 
 289 T 
 
LUS LYN 
 
 seen on the polished surfaces of amianthus. These degrees and qualities 
 often shade insensibly into one another, and though exceedingly useful 
 in description, often require a very practised eye to distinguish between 
 them. 
 
 Lusus Naturae. Literally "sport or freak of nature." A frequent term 
 of the older naturalists for any appearance or production that seemed to 
 lie out of the ordinary course of nature's operations. Thus fossil organ- 
 isms were regarded as " lusus naturae" by those who believed that the 
 earth's crust was the result of one simultaneous act of creation, and not 
 the result of long-continued operations, such as those that are now taking 
 place around us. 
 
 Lycopodidcese. A natural order of Cryptogamic or flowerless plants, of 
 which the lycopodium or club-moss has been taken as the type. In their 
 tissues and mode of fructification the club-mosses resemble ferns ; in their 
 foliage they approach the coniferse ; and in their general aspect they 
 are like the mosses ; hence they are said to stand intermediate between 
 the Conifers and Ferns on the one hand, and the Ferns and Mosses on 
 the other. Their stems divide by forking repeatedly, and are closely 
 covered with simple leaves, which are arranged in two rows, having their 
 edges vertical with respect to the axis of growth, and not horizontal. 
 These leaves are placed alternately, and are furnished with smaller lateral 
 leaflets of the nature of stipules. The scars left by the leaves arrange 
 themselves spirally round the stem, and in this arrangement, as well as in 
 their rhomboidal or lanceolate shape, greatly resemble the leaf-scars of 
 the Coniferae. See LEPIDODENDRA and CONIFERS. 
 
 Lycopodites. Fossil plants apparently allied to the Lycopodiums or 
 club-mosses of the present day. They occur in the Tertiary, Secondary, 
 and Upper Palaeozoic strata those of the Coal-measures being represented 
 by gigantic arborescent species. 
 
 Lydian Stone. Flinty slate; a mixed siliceous rock, usually of a grey- 
 ish-black colour, splintery or conchoidal fracture, and keen cutting grain. 
 It is common in many countries, and has long been used as a touchstone 
 for gold, whose purity is shown by the colour of the streak which it leaves 
 on the smoothened surface of the touch-slate. It often passes insensibly 
 into jasper, Jiornstone, and other allied siliceous rocks ; and hence is some- 
 times known as "black jasper." See BASANITE. 
 
 Lye or Ley. A solution of an alkaline substance, as potash or soda, in 
 water. See LIXIVIUM. 
 
 Lynx Sapphire. A lapidary's term for dark-grey or greenish -blue 
 varieties of sapphire ; also for varieties of lolite, having the same colour. 
 The paler shades are known as Saphire cFeau, or Water Sapphire. See 
 IOLITE. 
 
 290 
 
MAC 
 
 Macacus. The Bonnet-apes, or Ape-baboons. A genus of Old World 
 monkeys, belonging to the group Cercopitfiecina and family Simiidce ; 
 characterised by having a fifth tubercle on their last molars ; ischial cal- 
 losities and check-pouches ; comparatively short and thick limbs ; a pro- 
 jecting muzzle and prominent eyebrows ; and generally very short tails. 
 According to Owen, remains of a genuine ape have been found in the 
 Pliocene deposits of Essex, and still earlier in the Eocenes of Suffolk ; hence 
 the species Macacus eoccenus. 
 
 Maccagn6ne. The Grotta di Maccagnone ; an important ossiferous 
 cavern situated in the Hippurite limestone, westward of the Bay of Carini 
 (between Palermo and Trapani), and containing the usual cave-remains of 
 elephants, hippopotami, rhinoceroses, bears, hyaenas, horses, deers, &c., 
 in the main mass of stalagmite ; and in the upper layers, bits of carbon, 
 and abundance of flint and agate knives of human manufacture. 
 
 Maceration (Lat. macerare, to make soft by steeping). The steeping of 
 vegetable or animal substances in a cold liquid till their tissue or fibres 
 become softened, and part more readily with any peculiar principle (oily, 
 aromatic, &c.) which they may contain. Infusion is performed by pouring 
 the hot liquid over them ; decoction, by boiling them in it for a longer or 
 shorter period. 
 
 Machdirodus (Gr. machaira, a sabre, and odous, tooth). A genus of car- 
 nivorous mammals found in the Miocene, Pliocene, and Pleistocene Terti- 
 aries and bone-caves of Europe ; and so called from the trenchant, sharp- 
 pointed, sabre shape of its upper canines. There were several species, 
 some as large as the grizzly bear and lion, others about the size of the 
 leopard and under. Professor Owen finds its nearest affinities in the lion ; 
 hence his synonyme of Felis spelcea. 
 
 Macigno or Macigna Retra. An Italian term for a hard siliceous sand- 
 stone, apparently of Cretaceous age, imbedding calcareous grains, &c., and 
 occurring interstratified with the fine saccharoid marbles of Carrara. 
 
 Macled (Lat. macula, a spot). Literally " spotted ;" applied to surfaces 
 that are covered with spots of a hue deeper than, or different from, the 
 main ground of the substance. Some sandstones, for example, are macled 
 with reddish spots of iron peroxide ; some clay-slates macled with crystals 
 of iron-pyrites. 
 
 Macles. Applied in mineralogy to "twin-crystals," which are united 
 by simple contact of their faces by interpenetration, or by incorporation. 
 These twin forms are often repeated so as to form groups or compound 
 macles. Chiastolite (which see), from the twin form of its crystals, is not 
 unfrequently termed " Macle." 
 
 Macliirea (after Dr Maclure). A genus of flatly-spiral operculated 
 shells, often of large dimensions, and especially characteristic of Lower 
 Silurian strata. The species differ in the convexity and number of the 
 whorls. Supposed by some to be gasteropod ; but the character of the 
 spiral operculum or small upper valve inclines Mr Woodward to regard it 
 as an ancient form of the RUDISTA or HIPPURITE group, which see. 
 
 291 
 
MAC M.JK 
 
 Maclureite (after Dr Maclure). One of the gems, known also as Brucite, 
 Hemiprismatic Chrysolite, and Chondrodite, which see. 
 
 Macrauchenia (Gr. makros, long, and aucken, the neck). Literally 
 " long-neck ; " an extinct Tertiary mammal of South America, having the 
 nearest affinities to the existing llama of that continent, but of more 
 gigantic dimensions, and standing intermediate, as it were, between the 
 camels and llamas. 
 
 Macro- (Gr. macros, large). A frequent prefix in natural science, 
 signifying large ; as macrocepJialous, large-headed ; macrodactylous, long- 
 toed ; macropodal, large-footed ; macrourous, long-tailed, &c. 
 
 Macropoma (Gr. makros, large, and poma, operculum). A genus of 
 sauroid fishes peculiar to the Chalk and Wealden, and so named from its 
 large opercula the head being equal to one-fourth of the entire length of 
 the body, which in full-grown specimens was about two feet. In the 
 macropoina the scales were large, and the anterior dorsal fin armed with 
 spines. The coprolites, which often contain scales of other fishes, show 
 that it was carnivorous in its habits. 
 
 Macropus (Gr. makros, large, and pous, foot). The kangaroo, in allusion 
 to the great length of its hind feet ; a well-known* marsupial, confined ex- 
 clusively to the Australian continent, and in the ossiferous caverns of which 
 remains of much larger species than any now existing occur in considerable 
 abundance. 
 
 Macrotherium (Gr.) Literally "large beast;" a genus of edentate 
 mammals from the Miocene Tertiaries of Europe, having affinities to the 
 African pangolin or ant-eater, but six or eight times its size. 
 
 Macroura, Macnira (Gr. makros, long, and oura, tail). A family of 
 decapod crustaceans, characterised by the large size of the tail, as in the 
 common lobster ; and distinguished from the brackyoiira or short-tailed, 
 like the crab. Both families are found fossil in Secondary and Tertiary 
 strata ; but in the Palaeozoic only the macroura are as yet known. 
 
 Mactra (Gr., a kneading-trough). A well-known littoral bivalve in- 
 habiting sandy and muddy shores ranging from ten to twelve fathoms in 
 depth, and so named from a fanciful allusion to its shape. There are 
 several species, recent and fossil ; the latter occurring only in the Upper 
 Tertiaries. 
 
 Madrepore (Fr.) Literally " spotted pore ; " an extensive genus of coral- 
 building polypes, whose stony secretion is characterised by its spreading 
 or branching form, and by the numerous star-shaped cavities that dot its 
 surface, each cell being the abode of a single but united polype. The 
 term is more frequently applied to the stony-coral than to the polype 
 madrepores being amongst the most abundant corals in the reefs of exist- 
 ing seas. 
 
 Madreporite. Fossil madrepore; also a variety of limestone having a 
 small prismatic or columnar structure which looks like the pore arrange- 
 ment of coral, but which in reality is a species of crystallisation. 
 
 Maestricht Beds. "On the banks of the Meuse, at Maastricht," says 
 Lyell, "reposing on ordinary white chalk with flints, we find an upper 
 calcareous formation about 100 feet thick, the fossils of which are on the 
 whole very peculiar, and all distinct from Tertiary species. The upper 
 part of the rock, about 20 feet thick, abounds in corals and bryozoa ; these 
 beds are succeeded by a soft yellowish limestone 50 feet thick ; and the 
 stone below is white, and encloses occasional nodules of grey chert and 
 
 292 
 
MAG 
 
 chalcedony." These so-called "Maastricht beds," from containing belemnifrs, 
 hamites, baculites, &c., are regarded as the uppermost member of the Chalk 
 formation in Europe ; they are wanting in England ; and in geological 
 classification are erected into a group which embraces the calcaire puoli- 
 tique near Paris, the Mcestricht beds proper, and the coralline limestone of 
 Faxoe in Denmark. See CRETACEOUS FORMATION. 
 
 Magues. An ancient name for the Lodestone, after Magnesia, a pro- 
 vince in Lydia, where it was said to have been first formed. 
 
 Magnesia. One of the alkaline earths, a light whitish substance, occur- 
 ring abundantly in nature in various states of combination. It is found 
 native in veins of serpentine, forming a hydrate of 'magnesia (69 magnesia 
 and 31 water), but soon passes into the carbonate on exposure to the air. 
 Magnesia enters largely into the composition of many primary rocks (stea- 
 tite, serpentine, talc, &c.), giving to them a soft soapy feel : as a carbonate, 
 in combination with carbonate of lime, it constitutes magnesian limestone, 
 found extensively in the Secondary and Palaeozoic strata ; as a sulphate, it 
 is common in many waters, as those of Epsom, Seidlitz, &c. ; as a muriate, 
 it is found in the waters of the ocean ; and other combinations, as borates, 
 silicates, &c., are by no means rare. The origin of the word is conjectural ; 
 some deriving it from the city Magnesia ; others from an old term applied 
 to such substances as had the power of attracting some principle from air 
 or water. 
 
 Magnesia Alum. A substance occurring in white fibrous masses and 
 efflorescences in the salinas of South America, and consisting of 13.4 
 sulphate of magnesia, 38.3 sulphate of alumina, and 47 water, with traces 
 of lime and iron. 
 
 Magnesian Limestone. Any limestone containing upwards of 20 per 
 cent of magnesia may be so called. The term is often used by English 
 geologists as synonymous with Permian or Lower New Red Sandstone 
 magnesian limestone being largely developed in that formation in the 
 North of England. As magnesian limestones occur, however, in other for- 
 mations, the term should be regarded as descriptive of a rock merely, and 
 not as the synonyme of any stratified series. Magnesian limestone, in its 
 compacter states, forms a most durable building-stone ; and on assuming 
 the semi-crystalline and crystalline state passes into Dolomite. See PER- 
 MIAN SYSTEM. 
 
 Magnesite. A compact amorphous carbonate of magnesia, usually found 
 in serpentine rocks, white or greyish-white, somewhat meagre to the touch, 
 adheres to the tongue, and consists in its purest state of about 51 magnesia 
 and 49 carbonic acid. 
 
 Magnesium. The metallic base of magnesia, a silvery-looking metal, 
 which fuses at a red heat, and on burning passes into magnesia or oxide of 
 magnesium (61.4 magnesium, 38.6 oxygen). 
 
 Magnet (said to be from Magnesia, where the loadstone, or native 
 magnetic iron, was found in abundance). Magnets are defined as "sub- 
 stances which attract certain metals ; which display towards one another 
 a force partly attractive and partly repulsive ; and which exhibit a tend- 
 ency to arrange their mass in certain directions, or according to a law of 
 polarity" They are spoken of as natural and artificial the former being 
 the "loadstone" or native magnetic iron, and the latter certain arrange- 
 ments of steel bars to which the magnetic property has been communi- 
 cated by induction, and known as "bar magnets," "horse-shoe magnets," 
 
 293 
 
MAG 
 
 "compound magnets," &c. When the artifical magnet is left to move 
 freely on a pivot or otherwise, as in the mariner's compass, it is spoken of 
 as a needle, and invariably assumes a definite direction as regards the 
 earth, this direction being towards the magnetic north or magnetic pole. 
 
 Magnetic Fluid. The hypothetical natural agent to which the various 
 phenomena of magnetism are usually referred, and spoken of as a fluid 
 from its continuous motion or flow in certain fixed directions. 
 
 Magnetic Iron Pyrites. Known also as rhombohedral iron pyrites, and 
 pyrrhotine, a native sulphuret of iron occurring in tabular or short pris- 
 matic crystals of a bronze-yellow or copper-red colour, and more or less 
 magnetic. It is found chiefly in veins with other ores in the igneous and 
 older crystalline rocks. 
 
 Magnetic Meridian, Magnetic North. The mean direction which a freely 
 suspended horizontal needle assumes when left to itself is termed the "mag- 
 netic meridian," in contradistinction to the true meridional north and south 
 as indicated by the sun's shadow at noon. The magnetic meridians coincide 
 with the geographical meridians in some places, and in these the magnet 
 points to the true north and south that is, to the poles of the earth's 
 rotation. But if it be carried successively to different longitudes, it will 
 deviate sometimes to the east and sometimes to the west of the true north. 
 This deviation appears to be secular ; in other words, to oscillate within 
 certain limits in a given time. Thus in 1660 the needle pointed due north 
 in London ; after 1662 it began to diverge to the westward, till in 1815 it 
 pointed 24 15' west of north. Since 1815 it has been gradually returning 
 from this extreme divergence, till now, in the British Islands, the geologist 
 has to allow from 22 to 23 for his compass bearings. The dip and strike 
 of strata, lines of fault, veins and cleavage, axis of elevation, and the like, 
 are almost invariably laid down in reference to the true meridian. 
 
 Magnetic Needles. The magnetised bars of steel known as "magnetic 
 needles" are of two kinds the declination-needle and the dipping-needle. 
 The former, as seen on the common mariner's compass, revolves in a hori- 
 zontal direction, and points to the magnetic north ; the latter moves in a 
 plane perpendicular to the horizon, and dips more and more as we approach 
 the magnetic poles, where its position becomes vertical. 
 
 Magnetic Poles. In the northern hemisphere the north end of the 
 dipping-needle leads or dips to the north ; in the southern hemisphere 
 the south end dips to the south ; but between the two there is a line en- 
 circling the whole earth where the needle remains horizontal. This line 
 is termed the magnetic equator, or "line of no dip." As we proceed north- 
 wards or southwards of this line the needle dips more and more, till at last 
 it becomes vertical or perpendicular to the horizon in two points, or rather 
 linear spaces, which are known as the north and south magnetic poles. 
 These poles differ from the poles of the earth's rotation the north, as 
 determined by Sir J. Ross, being in 70 N. lat. and 97 W. long. ; and the 
 south in 75 5' S. lat. and 154 8' E. long. 
 
 Magnetism. Literally, the attractive and repulsive power of the natu- 
 ral magnet or loadstone ; generally, that peculiar property possessed by 
 many mineral bodies and by the whole mass of the earth itself, by which, 
 under certain circumstances, they mutually attract and repel one another, 
 according to determinate laws. " Very delicate experiments have shown 
 that all bodies are more or less susceptible of magnetism. Many of the 
 gems give signs of it ; titanium and nickel always possess the properties 
 
 294 
 
MAG MAL 
 
 of attraction and repulsion ; but the magnetic agency is most powerfully 
 developed in iron, and in that particular ore of iron called loadstone or 
 magnetite. A metal is often susceptible of magnetism if it contain only 
 the 130,000th part of its weight of iron a quantity too small to be detected 
 by any chemical test. One of the most distinguishing tests of magnetism 
 is polarity, or the property a magnet possesses, when freely suspended, of 
 spontaneously pointing nearly north and south, and always returning to 
 that position after being disturbed. Induction is the power which a mag- 
 net possesses of exciting temporary or permanent magnetism in such 
 bodies in its vicinity as are capable of receiving it. By this property the 
 mere approach of a magnet renders iron or steel magnetic the more 
 powerfully, the less the distance. Iron acquires magnetism more readily 
 than steel, yet it loses it as quickly on the removal of the magnet, whereas 
 the steel is impressed with a lasting polarity. There can hardly be a 
 doubt but that all the phenomena of magnetism, like those of electricity, 
 may be explained on the hypothesis of one ethereal fluid, which is con- 
 densed or redundant in the positive pole, and deficient in the negative." 
 (Mrs Somerville, as abridged by Dr Humble.) While there can be little 
 doubt of the identity of magnetism with electricity (since magnets can be 
 made to exhibit all the phenomena of electrical machines), still it must be 
 regarded in great measure as one of those unseen existences which are only 
 known by their effects. Terrestrial magnetism, which pervades the whole 
 earth, and with which geologists have most to do, is a subject of extreme 
 complicity ; and though often called in by the theorist to aid him in his 
 views respecting crystallisation, cleavage, jointing, and other phenomena, 
 it must be fairly admitted that science is not yet in a position to point out 
 either the extent of its results or its precise mode of working. 
 
 Magnetite. Known also as magnetic iron, oxidulated iron, and octahedral 
 iron-ore ; consists of about 69 iron peroxide, with 31 iron protoxide. It 
 occurs largely in the igneous and metamorphic rocks, either in distinct 
 octahedral crystals, disseminated through the mass, or more frequently in 
 compact beds, forming, as in Norway, Sweden, and Russia, a most import- 
 ant ore of iron. It rarely appears in veins ; and the largest known masses 
 are situated in the northern parts of the globe Scandinavia, Russia, Si- 
 beria, and North America. 
 
 Mailed (Fr. maille, a coat of armour). Having the body protected by a 
 coat or covering of scales, bony plates, or other hard substance; e. g., the 
 Armadillo, Glyptodon, &c. 
 
 Malachite. The green carbonate of copper, consisting of 71.8 copper 
 protoxide, 20 carbonic acid, and 8.2 water, and deriving its name, it is said, 
 from the Greek malacJw, the marsh-mallow, in allusion to its colour. As 
 an ore of copper, malachite rarely occurs crystallised, but is either foliated, 
 fibrous, compact, or earthy; and usually in reniform, concretionary, or 
 stalactitiform masses. The copper^mines'^of Siberia and the Ural furnish 
 the finest specimens, which, when cut and polished, are highly prized for 
 ornamental purposes. Malachite seems, in many instances, to be a recent 
 production, caused by the action of the water and carbonic acid of the 
 atmosphere on other copper ores ; and is in fact a copper-stalagmite. 
 
 Malacolite (Gr. malakos, soft, and lithos). Known also as Sahlite ; a 
 variety of augite of various shades of green, and of a vitreous or sub-pearly 
 lustre. 
 
 Malac6logy (Gr. malakos, soft, and logos, discourse). The science which 
 295* 
 
MAL MAM 
 
 treats of the mollusca a term occasionally substituted for that of Concko- 
 logy, as referring more immediately to the structure and functions of the 
 animals, many of which are shell-less ; while Conchology relates, on the 
 other hand, more especially to the shell or mere external covering (concM., 
 a shell) of those orders so provided. 
 
 Malacopterygii (Gr. malakos, soft, and pterygion, winglet or fin). One 
 of Cuvier's primary divisions of Osseous Fishes, in which the fins are all soft 
 or jointed. It is farther subdivided, according to the position or absence 
 of the ventral fin, into 1. M. abdominales, in which the ventral fins are 
 attached to the abdomen behind the pectorals (chiefly fresh-water species) ; 
 2. M. snb-brachiati, in which the ventral fins are brought forward under 
 the pectorals (chiefly marine fishes) ; and, 3. M. apoda, in which the ven- 
 tral fins are always wanting, and not unfrequently the pectoral also. 
 
 Malleable, Malleability (Lat. malleus, a hammer). A property of many 
 metals, by which they are capable of being beaten out into thin plates or 
 leaves by the hammer. Gold, silver, iron, copper, &c., are malleable. 
 
 Mall6tus (Gr. mallos, a lock of wool). The capelan, a small, soft-finned 
 fish (whence the name) rather larger than a sprat, which inhabits the banks 
 of Newfoundland, and other parts of the coasts of northern seas. Fossil 
 specimens occur in nodules of indurated clay-marl on the coast of Green- 
 land ; but these are of very recent date, and, it may be said, still in the 
 process of formation. 
 
 Malm-Rock. A local term for a calcareous sandstone which forms por- 
 tions of the Upper Gfreensand in the counties of Surrey and Sussex. It is 
 known also as " fire-stone." 
 
 Maltha. A term occasionally applied to slaggy mineral pitch, as distinct 
 from fluid petroleum on the one hand, and from solid asphalt on the other. 
 
 MammaUferous. A term applied to strata containing mammalian re- 
 mains, as the " Mammaliferous Crag " of Norfolk, the " Mammaliferous 
 Gravels " of Siberia, &c. 
 
 Mammals, Mammalia (Lat. mamma, a teat or pap). The general term 
 for all animals that give suck to their young. They constitute the first or 
 highest class of VERTEBRATA, and are usually divided into Placentalia and 
 Implacentalia the former being those that are nourished previous to birth 
 by a uterine network of blood-vessels called the placenta, and do not come 
 into the world until they are provided with all their organs ; the latter, 
 those that are non-placental, or have no attachment to the uterus, and are 
 brought forth in an imperfect state the young being received into an ex- 
 ternal pouch (marsupium), and there nourished till their organs are matured. 
 The non-placentals are comparatively few in number, are chiefly confined 
 to the Australasian continent, and are regarded as lower in the scale of 
 being than the placentals. Remains of Marsupial Mammals have been 
 found in the Triassic and Oolitic rocks ; the higher orders not till the 
 Chalk and Tertiaries. See tabulations, " ANIMAL SCHEME." 
 
 Mammifers (Lat. mamma, abreast, and/ero, I bear). Literally "breast- 
 bearing animals," or those which give suck to their young. Same as 
 mammals and mammalia. 
 
 Mammillary, Mammillated (Lat. mamilla, little pap). Applied to sur- 
 faces covered with pap-like excrescences or concretions, as some magnesian 
 limestones studded with rounded projections. See BOTRYOIDAL. 
 
 Mammoth (Tartar). The great fossil elephant of Siberia ; the EUph-as 
 primi'genius of scientific authors. Remains of the mammoth are found 
 
 296 
 
MAN MAR 
 
 abundantly in many of the Post-pliocene or Upper Tertiary deposits of 
 northern Asia and Europe the range of the animal being apparently be- 
 tween the 40th and 70th parallels of latitude, and its metropolis, according 
 to Professor Owen, " the northern extreme of the temperate zone." The 
 Mammoth differs from existing elephants chiefly in its greater size, its 
 dentition, which was fitted for milling coarser and less succulent vegeta- 
 tion, its immense recurved tusks, and its dense covering of shaggy hair, 
 which fitted it for a cold and rigorous climate. Whole drifts of its tusks 
 and bones are found in the northern ocean, and in the tundras and river- 
 gravels of Siberia ( Von Wrangell) ; and scattered tusks and bones are fre- 
 quent in all the ancient alluvia of northern Europe and the British Islands. 
 Owen's ' Fossil Mammals.' 
 
 Manatidse (Lat. manatus, the sea-cow). The Sirenia of some system- 
 atists ; a family of aquatic herbivorous mammals, including the manatee, 
 dugong, &c. Remains apparently of this family are occasionally found in 
 Pleistocene and ancient estuary-deposits. 
 
 Manganese (Lat.) A hard, brittle, greyish-white metal (somewhat re- 
 sembling iron), discovered by Gahn in the black oxide of manganese of 
 commerce. Its specific gravity is about 8 ; it is fused with great difficulty, 
 but is readily oxidised. In an oxidised state manganese is abundant in the 
 mineral kingdom, and traces of it have been found in the ashes of plants, 
 and in mineral waters. The ores of manganese are erected by some miner- 
 alogists into a separate family, including such genera as manganite, or the 
 grey oxide ; load, or the earthy protoxide ; cupreus manganese ; pyrolusite, 
 or the dark peroxide ; psilomelane, a compound of the peroxide and baryta ; 
 Hausmannite, Braunite, &c. all described under their separate heads. 
 The ores of manganese are largely used in the arts : as in glass-making ; 
 in pottery painting and glazing ; in painting glass and enamel ; in the 
 production of oxygen, chlorine, and chloride of lime ; and occasionally for 
 an admixture for improving the make of iron and steel. 
 
 Manganite. Grey oxide of manganese, consisting, according to Turner, 
 of 62. 72 manganese, 27.18 oxygen, and 10.10 water. It occurs in veins in 
 gneiss and other crystalline rocks, either in groups of prismatic crystals, 
 or in radiating and columnar aggregates ; and is the purest and most 
 beautifully crystallised of the ores of manganese. 
 
 Mantellia. Considering the fossil cycadeoidea of the Isle of Portland as 
 a peculiar type, M. Brongniart has referred them to a new genus under the 
 name of Mantellia, in honour of the late Dr Mantell. These stems are 
 of a sub- cylindrical shape, covered with rhomboidal leaf -scars, which are 
 widest transversely, and are from one to two feet in height, and from one 
 to three in circumference. They are termed " Crows' nests " by the quarry- 
 men, who regard them as the nests of the former inhabitants of the now 
 petrified forests of the Oolite. 
 
 Marble (Lat. marmor). Any rock susceptible of a fine polish is termed 
 " marble " by the stone-cutters ; hence we hear of Portsoy marble, which 
 is a true serpentine ; of Silician marble, which is often a brecciated lava, 
 and so forth. The term, however, should be, and is restricted by geolo- 
 gists to limestones capable of receiving a polish, and frequently exhibiting 
 a variety of colours. We have thus uni-coloured marbles, such as pure 
 blacks or whites ; and parti- coloured varieties, deriving their shades from 
 accidental minerals, from metallic oxides giving them a veined and clouded 
 appearance, or from shells, encrinites, corals, and other organisms which 
 
 297 
 
MAR 
 
 impart a variety of f ' figure " as well as of hue. Every country has its own 
 peculiar marbles, and almost every age has had its own whims and fancies 
 for certain varieties. The following are a few of the most esteemed varie- 
 ties, ancient and modern : Carrara, pure white, crystalline, and semi- 
 transparent ; highly esteemed for statuary purposes. Parian, of a waxy 
 cream-colour, also crystalline, and employed in statuary. Giallo-anlico, 
 yellow and mixed with a small proportion of hydrate of iron ; used for 
 ornamental purposes. Rosso-antico, a deep blood-red, less or more veined. 
 Mandelato, a light red, veined and clouded. Verde-antique, a cloudy green 
 mixed with serpentine. Cipoline, a mixture of talcose schist with white 
 saccharoidal marble. Lumachello or fire-marble, a dark brown variety, 
 having brilliant chatoyant reflections, which it owes to the nacreous matter 
 of enclosed shells. Black marbles, like those of Derbyshire and Kilkenny, 
 deriving then: dark colours from bitumen. Encrinal marbles, like those of 
 Derbyshire, and other Carboniferous districts, deriving their "figure" from 
 the stems and joints of encrinites. Shell marbles, like those of Purbeck 
 and Petworth in Dorset and Sussex, receiving their "figure" from the 
 enclosed shells of various mollusca. 
 
 Marcasite (said to be from an Arabic word signifying " fire-giving 
 stone "). Iron pyrites, or bisulphide of iron, occurring crystallised in 
 modified rhombic prisms, and also in reniform and botryoidal masses, and 
 in stalactitic crusts ; hence such varieties as hepatic pyrites, cockscomb 
 pyrites, radiated pyrites, &c. Marcasite is more liable to decomposition 
 than ordinary pyrites, is of a paler colour, being nearly tin-white, and is 
 more strongly metallic in lustre. Is abundant in nature ; used commer- 
 cially as ordinary pyrites, and sometimes for ornamental purposes. By 
 the older mineralogists the term Marcasite was applied to iron pyrites 
 occurring in thin veins, and Pyrites to the varieties occurring in nodular 
 masses. See PYRITES. 
 
 Maremme (Lat. mare, the sea). The Italian term for those unwholesome 
 sea-marshes that diffuse with more or less virulence their pestilential ex- 
 halations along the whole west coast of Italy. See PONTINE MARSHES. 
 
 Margarite (Gr. margarites, a pearl). One of the Mica family ; known 
 also as pearl-mica, or hemiprismatic pearl-mica. A pearly-grey mineral 
 generally occurring with chlorite in scaly irregular masses, and rarely crys- 
 tallised in six-sided tables. 
 
 Marl (Sax.) Any soft admixture of clay and lime is termed a marl 
 "clay-marl" when the clay predominates; "marl-clay" when the lime is 
 most abundant ; and " shell-marl " when it contains fresh- water shells, as 
 the lymnea, puludina, &c. In geological nomenclature we have " chalk- 
 marls," "lias marlstone," and other appropriate enough terms ; but occa- 
 sionally the word is used to designate soft friable clays with which not 
 a particle of lime is intermingled, just as agriculturists call any soil a 
 " marl " that falls readily to pieces on exposure to the air. For Varie- 
 gated Marls or Keuper, see TRIASSIC SYSTEM. 
 
 Marlstone. In geological classification, the middle member of the Lias 
 formation, ranging in the eastern counties of England (York, Lincolnshire, 
 c.) from 100 to 150 feet in thickness, and consisting of arenaceous shales, 
 laminated sandy limestones, and several bands of stratified and nodular 
 limestone, the whole series being peculiarly rich in fossils shells, corals, 
 Crustacea, and fishes. "The marlstone beds," says Phillips, "are in fact 
 the first term of the Oolitic deposits, interpolated among the last terms of 
 
MAR MAS 
 
 the Lias ; and according as the clay above them is attenuated or developed, 
 they may be ranked with the Oolite or Lias formation." 
 
 Marmolite (Gr. marmairo, to shine, and lithos). A variety of foliated 
 serpentine, of a pale-green, yellow, or light-grey colour. 
 
 Marsupialia, Marsupiata (Lat. marsupium, a pouch or purse). Literally 
 " pouched animals ;" an order of mammalia having a sack or pouch under 
 the belly, in which they carry their young, as the kangaroo, wombat, and 
 opossum. They are sometimes termed ovoviviparous mammals, as being 
 intermediate between the viviparous mammals and the oviparous birds 
 and reptiles. For the same reason they are classed as implacentalia, in 
 contradistinction to the true placental animals the pouch-like apparatus 
 for their imperfect young being a sort of extra- uterine gestation. Mar- 
 supial remains occur in the Oolite and Trias (amphitherium, phascalotherium, 
 &c.), and, according to American authority, even in the Permian (droma- 
 therium), thus making them the earliest mammiferous creatures with which 
 palaeontologists are yet acquainted. See tabulations, "ANIMAL SCHEME." 
 
 Marsupite (Lat. marsupium, a purse). A genus of free-floating crinoidea 
 found in the Chalk formation ; having a bag-like shape when closed ; and 
 often known by the quarrymen's term "cluster-stones." See CKINOIDEA. 
 
 Massicot. Yellow protoxide of lead. The dross that forms on melted 
 lead exposed to a current of air, and roasted till it acquires a uniform .yellow 
 colour. Used as a pigment. 
 
 Massospondylus (Gr. masson, longer, and spondylos, a vertebra). A 
 provisional genus of huge fossil saurians, occurring in the Triassic sand- 
 stones of South Africa ; and so named by Professor Owen from the length 
 of their vertebrae, the only remains yet discovered. 
 
 Master- Joints. A term applied to the larger planes of division which 
 pass through rock-masses, and which run regularly parallel to each other 
 for considerable distances, in contradistinction to the ordinary and smaller 
 joints which traverse the rocks in all directions. In speaking of these 
 fissures the quarryman employs the terms "backs and cutters" the 
 former being the master-joints and the latter the smaller and ordinary 
 ones. See JOINTS. 
 
 Mastodon (Gr. mastos, nipple, and odous, tooth). A genus of Tertiary and 
 Post-tertiary elephantine mammals ; so called from the nipple-like protu- 
 berances on the grinding-surfaces of their molar teeth. According to 
 Falconer, who separates the Mastodons from the true Jttephants, the genus 
 includes " all the elephantoid species which have the crowns of the molars 
 comparatively simple, and uniformly divided into two sub-equal divisions 
 by a longitudinal line or cleft ; the ridges limited in number, each with 
 fewer mammillary eminences, and invariably more or less concave across ; 
 the enamel thick, and in conical or compressed points ; and the valleys 
 between the ridges deep and empty, or with but a sparing quantity of 
 cement." The same authority divides the genus into two sub-genera 
 (Trilophodon and Tetralophodon), -and enumerates upwards of a dozen 
 species, which seem to have had a truly cosmopolitan range during the 
 Pliocene and Post-pliocene periods. See ' Geological Journal,' vol. xiii. 
 
 Mastodonsaurns (Gr. mastos, a nipple; odous, tooth; and sauros, lizard). 
 A provisional genus of saurian reptiles occurring in Triassic strata, and 
 so called from the peculiar form of their teeth the only portion of their 
 remains yet discovered. Regarded by Owen as the s^me with LABYRLNTH- 
 ODON, which see. 
 
 299 
 
MAT MEG 
 
 Matinal (Lat.) Appertaining to the morning; the third of the fifteen 
 series into which Professor Rogers subdivides the Palaeozoic strata of the 
 Appalachian chain the "Morning" of the North American Palaeozoics, 
 and the equivalents apparently of our Upper Cambrians. See PALAEOZOIC 
 FORMATIONS. 
 
 Matrix (Lat., the womb). The rock or main substance in which any 
 accidental crystal, mineral, or fossil is imbedded, is said to be the matrix 
 of that mineral or fossil. 
 
 Meadow-Ore. A term occasionally used for bog-iron ore, from its occur- 
 rence in marshy or low-lying meadow-lands. 
 
 Meandrina (Lat.) Brain-coral; madrepores in which the laminae 
 assume a meandering direction. The Meandrinae are large hemispherical 
 corals having their surfaces covered with serpentine ridges and depres- 
 sions, resembling the convolutions of the human brain. They occur 
 abundantly in modern coral-reefs, but seem not to be represented in 
 earlier formations. 
 
 Medina Sandstones. An important group of North American Silurians 
 which, taken in conjunction with the Oneida Conglomerates, are believed to 
 be the representatives, in time, of the Lower Llandovery rocks of England 
 that is, the upper portion of the " Lower Silurian" division of Murchison. 
 
 Meerschaum (Ger., sea-scum; sea- foam). A white, light, earthy or 
 compact hydrated silicate of magnesia the purer sorts consisting of 50 
 silica, 25 magnesia, and 25 water. It occurs among the serpentine rocks 
 of several countries, but that used for the bowls of tobacco-pipes comes 
 chiefly from Greece and Asia Minor, and is found in stratified earthy or 
 alluvial deposits. It has a soapy feel, adheres to the tongue, and is usually 
 dull and opaque. Being capable of forming a paste with water, it is some- 
 times spoken of as "plastic magnesia" the commoner sorts being used in 
 the manufacture of porcelain, and the finer (after undergoing various pro- 
 cesses, such as boiling in milk, &c.) in the making of meerschaum pipes. 
 
 Megaceros Hibernicus (Gr. mega, great, and keras, horn). Literally, 
 the "great antlered deer of Ireland." The fossil or sub-fossil gigantic 
 deer of our Pleistocene marls and peat'-bogs, often, but erroneously, termed 
 the " Irish Elk." See IRISH DEER. 
 
 Megaldnea. The name given by Professor Owen to a gigantic sub-fossil 
 land-lizard whose remains have been discovered in the Pleistocene deposits 
 of Australia. These remains indicate an affinity to the existing lace-lizards 
 of that continent, but must have belonged to an animal at least twenty 
 feet in length, and equalling in size the largest crocodiles. 
 
 Megalfchthys (Gr. megale, great, and ickthys, fish). A large sauroid fish 
 of the Carboniferous period, occurring most abundantly in the lower beds, 
 and characterised by its smooth but minutely punctured, enamelled, 
 lozenge-shaped scales. The scales, jaws, and imperfect specimens which 
 have been found in the Coal-measures of Scotland, indicate a fish of great 
 size ; but the teeth (which are numerous, sharp, and conical) are small in 
 comparison with those of holoptychius and rkizodus, with which the remains 
 of megalickthys are often confounded. 
 
 Megal6nyx (Gr. megale, great, and onyx, claw). A huge edentate mam- 
 mal, found chiefly in the Upper Tertiaries of America, and so called from 
 the great size of its claw or unguical bones, the largest of which was about 
 seven inches long. From the admirable inductions of Cuvier and others, 
 it would appear that the Megalonyx somewhat resembled the Megatherium 
 
 300 
 
MEG MEL 
 
 in its general character, configuration, and habits, but was a third smaller 
 than that colossal animal. 
 
 Megalosaurus (Gr. megale, great, and sauros, lizard). One of the Dino- 
 saurs, or gigantic land-saurian s, whose teeth, vertebrae, femora] and other 
 bones occur in the Oolite and Wealden strata. In these remains the 
 character of the monitors seems blended with that of the crocodiles ; and 
 judging from its decidedly trenchant teeth, the Megalosaur was highly 
 carnivorous, preying in all likelihood on smaller reptiles, and on the young 
 of its gigantic contemporaries, the iguanodon and hylreosaurus. 
 
 Megaphytum (Gr. mega, great, and phyton, a shoot). A genus of Coal- 
 measure stems, so called from the large size of their leaf-scars. In mega- 
 phytum the stem is not furrowed, but irregularly dotted or rugose ; the 
 leaf-scars large, horseshoe-shaped, and arranged on each side the stem in 
 vertical rows. Allied to Bothrodendron and Ulodendron, and apparently 
 coniferous. 
 
 Megatherium (Gr. mega, great, and therion, beast). A huge edentate 
 mammal whose remains occur abundantly in the Upper Tertiary or Pam- 
 pean deposits of South America. In anatomical structure the Mega- 
 therium exhibits features intermediate between the Sloths, Armadilloes, 
 and Ant-eaters ; for while in its skull and shoulders it resembles the 
 former, its legs and feet present an admixture of the characters of the 
 latter. Larger than the largest rhinoceros, its length was about nine or 
 ten feet ; but its bones were proportionally much more colossal than those 
 either of the rhinoceros or elephant. The structure of its teeth indicates 
 herbivorous habits, and its powerfully- clawed fore-feet (about a yard in 
 length) seem admirably formed for digging up the succulent roots and 
 luxuriant herbage which would then adorn the fertile surface of the 
 virgin Pampas. 
 
 Meionite (Gr. meion, less). Prismatic-pyramidal felspar, occurring in 
 Monte Somma near Vesuvius, and so called from its terminating pyramids 
 being lower or less acute than in Idocrase. Known also as Wernerite and 
 Scapolite, which see. 
 
 Melaconite, Melaconise (Gr. melas, black, and Jconis, powder). An earthy 
 and impure black oxide of copper, occurring in veins in pulverulent masses 
 (whence the name), and arising in all likelihood from the decomposition 
 of other ores. 
 
 Melanasphalt. Literally " black asphalt," the name given by some 
 American mineralogists to the Albert Coal or Albertite of Nova Scotia, 
 which see. 
 
 Melanite (Gr. melas, black). A variety of iron garnet, so called from 
 its black colour ; and, according to Klaproth, consisting of 35.5 silica, 
 6 alumina, 26 iron peroxide, and 32.5 lime. See GARNET. 
 
 Melanochroite (Gr. melas, black ; ckroa, colour). Chromate of lead, oc- 
 curring in rhombic prisms or massive ; of a deep hyacinth-red ; resinous 
 lustre ; and consists of 76.7 protoxide of lead, and 23.3 chromic acid. 
 
 Melanterite (Gr. melas, black). The mineralogical term for the native 
 sulphate of iron, which is a recent production from the decomposition of 
 iron pyrites. 
 
 Mellite (Lat. mel, honey). Honey-stone; mellitate of alumina; a rare 
 mineral, of a honey-yellow colour, resinous lustre, and more or less trans- 
 parent, occurring in connection with Tertiary and Cretaceous lignites. 
 According to Klaproth, it consists of 46 mejlic acid, 16 alumina, and 38 water. 
 
 301 
 
MEN MET 
 
 Menilite. A variety or sub-species of opaline quartz, occurring in com- 
 pact kidney-shaped nodules, in a bed of adhesive slate at Mont Menil near 
 Paris ; hence the name. It is sometimes known as " liver opal," from its 
 brown colour, though varying shades of bluish-grey are not uncommon. 
 
 Mephitic (Lat. mephitis, an offensive odour). Offensive to the smell, 
 foul, noxious. Thus mephitic air, azote or nitrogen ; mephitic acid, car- 
 bonic acid. 
 
 Mercury. A well-known metal, which is always fluid at a temperature 
 higher than 39 ; and hence, from its mobility and silvery lustre, usually 
 called " quicksilver." At temperatures less than 40 it becomes solid, and 
 has a specific gravity of 15.6 ; when fluid, its gravity is only 13.5 ; under the 
 blowpipe it is altogether volatile, or leaves a slight residuum of silver. It 
 occurs in rocks of all ages, but is rarely found in a state of native purity 
 its more abundant ores being cinnabar or bisulphuret of mercury ; native 
 amalgam, an ore consisting of silver and mercury ; and calomel, or chloride 
 of mercury. The best-known mercury mines in Europe are those of Idria 
 in Carniola, and Almaden in Spain. At Almaden the mercury is said not 
 to form veins, but to have impregnated the vertical strata of quartzose 
 sandstone associated with carbonaceous slates; and in the Asturias the 
 mines are worked in coal strata. 
 
 Meridian (Lat.) Mid-day ; the eighth of the fifteen series into which 
 Professor Eogers subdivides the Palaeozoic strata of the Appalachian chain 
 the "Mid-day" of the North American Palaeozoics, and the equivalents 
 perhaps of our lowermost Devonians. See PALAEOZOIC FORMATIONS. 
 
 Merycotherium (Gr. meryko, I ruminate, and therion, beast). A huge 
 ruminant found along with the mammoth and rhinoceros in the " Drift " 
 or Upper Tertiary beds of Siberia, and having affinity to the existing 
 Bactrian camel. 
 
 Meso- (Gr. mesos, the middle). A frequent prefix of scientific com- 
 pounds, signifying intermediate, or that which holds a middle place 
 between others. 
 
 Mesopithecus (Gr. mesos, intermediate, and pitfwcos, ape). A generic 
 term applied by Professor Wagner to the remains of a quadrumane dis- 
 covered in the Tertiary formations of Greece, and regarded by him as 
 intermediate between the long-armed apes (hylobates) and the tailed 
 monkeys (semnopithecus). 
 
 Mesostylus. The generic term for a small crustacean, whose cheliferous 
 claws or pincers occur abundantly in the Chalk formation, and that with- 
 out any vestige of carapace or body-crust. From this circumstance, as 
 well as from the fact of the right claw always being the largest, it is pre- 
 sumed that the Mesostylus had the structure and habit of the living Hermit- 
 crab (Pagurus) viz., an abdomen unprotected by a calcareous crust, 
 which it thrust for shelter into the shells of those molluscs with which 
 its claws are now found associated. 
 
 Mesotype (Gr. mesos, intermediate, and typos, form). Prismatic Zeolite ; 
 a silicate of soda and alumina occurring abundantly in trap-rocks, and 
 known also as Natrolite, which see. 
 
 Mesozoic (Gr. mesos, middle, and zoe, life). The great division of 
 stratified formations holding the middle forms of Life, as differing from 
 the Palaeozoic and Cainozoic. The Mesozoic period thus embraces the 
 Triassic, the Oolitic, and Cretaceous systems. 
 
 Metallic. Of, or pertaining to, a metal ; partaking of the nature of a 
 302 
 
MET 
 
 metal. We thus speak of metallic ores, metallic veins, metallic lustre, and so 
 forth all implying the nature, quality, and characteristics of metals. 
 
 Metalliferous. Literally "metal-yielding;" applied to rocks, veins, 
 and deposits productive of metals or metallic ores. 
 
 Metallography. Literally a description of the metals : that branch of 
 science which treats of the nature and properties of the metals. 
 
 Metalloid (Gr. eidos, likeness). A term sometimes applied to the metal- 
 lic bases of the alkalies and earths, as calcium, potassium, sodium, &c. ; and 
 also to the inflammable non-metallic bodies, as sulphur, phosphorus, &c. 
 
 Metallurgy. Literally metal-working ; the art of separating the metals 
 from their ores, and comprising the operations of smelting, refining, 
 assaying, and so forth. 
 
 Metals (Gr. metallon, a mine, metal, or mineral). A well-known class of 
 elementary bodies, most of which are characterised by their peculiar lustre 
 (metallic lustre), and generally speaking by their great specific gravities, 
 some of them being the heaviest substances known. Geologically, few of 
 them occur in a state of purity, or as native metals, the most of them being 
 found in the state of ores that is, in combination with other elements, and 
 mixed with various mineral matters. Some occur in beds or strata, most 
 of them in veins ; and these veins generally abound in the older rocks, 
 and in districts which have been most subjected to igneous disturbance. 
 Some metals also occur more abundantly in one rock-formation than 
 another, but the causes which have led to this peculiar arrangement are 
 yet unknown. Chemically, it is usual to arrange the metals into different 
 classes, according to their affinity for oxygen, and the peculiar properties 
 of their various oxides. Thus they are distinguished : 1. Perfect Metals, or 
 those which combine, with difficulty, with oxygen, and consequently are not 
 easily oxidised ; and as such they readily part with oxygen by the simple 
 application of heat, and are converted into pure metals. The best known 
 of this class are platinum, gold, and silver. Mercury holds an intermediate 
 place between these and the next class. 2. Base Metals, or those which 
 readily combine with oxygen, partly by mere contact with the atmosphere, 
 or when heated and fused they are not reducible by the action of heat only, 
 but require the admixture of some substance, as coal, to attract the oxygen 
 from the oxide. The best known of this class are iron, copper, lead, tin, 
 and zinc. The metals composing this and the preceding class are usually 
 termed, from their great specific gravity, the heavy metals. 3. Acidifying 
 Metals, or those which, entering into combination with oxygen, possess the 
 property of acids, which are hence called metallic acids. The metals of 
 this class are tellurium, arsenic, chromium, molybdenum, tungsten, col- 
 umbium, and selenium. 4. Terrigenous Metals, or those whose oxides con- 
 stitute the Earths proper. They resist the action of heat, and are insol- 
 uble in water. These are aluminium, yttrium, cerium, lantanum, thorium, 
 glucinum, and zirconium. And, 5. Kaligenoiis Metals, or those which 
 oxidise most readily, their oxides constituting the alkalies. These are 
 magnesium, calcium, strontium, barium, lithium, sodium, and potassium. 
 As the metals of this and the preceding class are some lighter and some 
 little heavier than water, they are usually called the light metals. See 
 tabulations, " CHEMICAL SCHEME," ORES, EARTHS, and ALKALIES. 
 
 Metameric (Gr. meta, implying change, and meros, part). A term ap- 
 plied to compounds in which the ultimate elements are the same as in 
 other well-known combinations, but are considered to be arranged in a 
 
 303 
 
MET 
 
 different way ; thus, oxygen, hydrogen, sulphur, and a metal may be con- 
 sidered as combined in the form of sulphuretted hydrogen and metallic 
 oxide, or of water and metallic sulphuret. 
 
 Metam6rpliic (Gr. meta, change, and morphe, form). Literally "changed 
 in form ; " applied to rocks and rock-formations which seefai changed from 
 their original condition by some external or internal agency. In geological 
 nomenclature the crystalline stratified rocks Gneiss, Mica-schist, Clay- 
 slate, &c. are termed Metamorphic, and erected into a separate system. 
 Strictly speaking, " metamorphic " applies to the power or force causing 
 the change; " metamorphism," the process ; and "metamorphosis," the 
 result. Hence we ought to speak of metamorphic agency, and metamor- 
 phosed rocks. See METAMORPHISM. 
 
 Metamorphic System. Althoxigh the rocks of every formation may be, 
 and to a great extent often are, subjected to mineral metamorphisms, still 
 in geological classification it is usual to restrict the term " Metamorphic 
 System" to those crystalline schists Gneiss, Quartz-rock, Mica-schist, and 
 Clay-slate which underlie all the fossiliferous strata, and in which no 
 trace of organic remains has yet been detected. In grouping these schists 
 it is often difficult to draw lines of distinction between them, and to say 
 where the one ends or the other begins ; still, on the whole, it may be re- 
 ceived as a truth that Gneiss, or rocks of a gneissic character, occupy the 
 lowest position in the metamorphic system ; that these (at least in such 
 typical districts as the Scottish Highlands) are succeeded by a zone of 
 quartzitic compounds ; and these again by mica-schists, which graduate 
 imperceptibly into the chloritic and argillaceous slates that cap the series, 
 thus : 
 
 4. CLAY-SLATE Chloritic and argillaceous slates. 
 
 3. MICA-SCHIST micaceous, talcose, and chloritic schists. 
 
 2. QUARTZ-ROCK quartzitic compounds, generally thick-bedded. 
 
 1. GNEISS gneiss-rock and granitoid schists. 
 
 The rocks composing these groups are less or more indurated and crystal- 
 line ; exhibit, for the most part, cleavage, crumpling, foliation, and other 
 kindred structure; have their lines of stratification indistinct, or often 
 altogether obliterated ; and, as sedimentary strata, have evidently under- 
 gone some peculiar change in their internal structure. This change, or 
 metamorphism, whether produced by heat, pressure, or chemical agency, 
 has conferred upon them the term of Metamorphic rocks ; and by this 
 designation they are now generally known among geologists. As strata, 
 they are the deepest or lowest in the crust of the earth, and are therefore 
 regarded as Primary or first-formed. They are also known as Non-fossil- 
 iferous, Azoic, or Hypozoic strata, from the fact that, with the exception 
 of the Laurentian eozoon, no distinct traces of plants or animals have yet 
 been discovered in any part of the system. Azoic and Hypozoic are, 
 however, mere provisional terms, the likelihood being that all stratified 
 rocks, no matter how ancient, were originally fossiliferous. See tabula- 
 tions, " GEOLOGICAL SCHEME." 
 
 Metam6rphism (Gr. meta, change, and nnorphe, form). Literally change 
 of form, or transformation. That change of structure or of texture which 
 has been effected on many rocks by the agency of heat, chemical action, 
 or otherwise ; as, for example, when chalk is converted into crystalline 
 marble, or sandstone into jaspery quartz-rock. " The problem of meta- 
 morphism," we have elsewhere observed ('Advanced Text-Book'), "isalto- 
 
 304 
 
MET 
 
 gether a difficult one, and one involving so many questions in the obscurer 
 departments of chemistry, electricity, and crystallography, that geology 
 must rest satisfied, in the mean time, with Indicating rather than defining 
 the nature of the operative causes. The most obvious and general of 
 these may be briefly enumerated : 1. Heat by contact, as when any igneous 
 mass, like lava, indurates, crystallises, or otherwise changes the strata 
 over or through which it passes ; 2. Heat by transmission, conduction, or 
 absorption, which may also produce metamorphism, according to the tem- 
 perature of the heated mass, the continuance of the heat, and the con- 
 ducting powers of the strata affected ; 3. Heat by permeation of hot water, 
 steam, and other vapours, all of which, at great depths, may produce vast 
 changes among the strata, when we recollect that steam, _uuder sufficient 
 pressure, may acquire the temperature of molten lava ; 4. Electric and 
 galvanic currents in the stratified crust, which may, as the experiments of 
 Mr Fox and Mr Hunt suggest (passing galvanic currents through masses 
 of moistened pottery-clay), produce cleavage and semi-crystalline arrange- 
 ment of particles ; 5. Chemical action and reaction, which, both in the 
 dry and moist way, are incessantly producing atomic change, and all the 
 more readily when aided by an increasing temperature among the deeper- 
 seated strata ; 6. Molecular arrangement by pressure and motion a silent 
 but efficient agent of change, as yet little understood, but capable of pro- 
 ducing curious alterations in internal structure, especially when accom- 
 panied by heat, as we daily see in the manufacture of the metals, glass, 
 and earthenware. Such are the more general and likely causes of rock- 
 metamorphism, and as it is possible that several of them may be operating 
 at the same time, the student will perceive that no hypothesis that limits 
 itself to any one agent can be accepted as sufficient and satisfactory. 
 Heat and chemical action and pressure are, no doubt, the chief causes of 
 change, and by them we can readily account for new crystalline arrange- 
 ments in semi-fused masses, for fissures, joints, and cleavage, and in a great 
 measure for that flexuring and folding of the stratified laminae known as 
 foliation. And if to these we add electricity, and new crystallographic 
 and molecular arrangement under further chemical reaction, we call in a 
 sufficiency of agency, though we may not always perceive the precise 
 modes of action." 
 
 Meteoric (Gr. meteoros, raised above the earth). Of or belonging to the 
 atmosphere, and used as synonymous with atmospheric. Thus " meteoric 
 erosion," erosion produced by rain, wind, and other wasting and weathering 
 powers of the atmosphere; "meteoric iron," the iron found native in 
 aerolites or meteoric stones. 
 
 Meteorite (Gr. meteoros, raised above the earth). A general term for any 
 stone or mineral mass which has fallen through the atmosphere, and 
 which, judging from its composition and other properties, does not seem 
 to be of terrestrial origin. Such meteoric masses are of geological inter- 
 est as having been found in the auriferous drifts of the Ural and Altai 
 ranges. Meteorites or meteoric stones are perhaps better known by the term 
 aerolites, which see. 
 
 Metropolis. A term very frequently employed by naturalists when 
 treating of the geographical distribution of plants and animals. " Generic 
 assemblages of plants and animals," says Edward Forbes, "whether ter- 
 restrial or aquatic, whether fresh-water or marine, have their regions, or 
 definite geographical areas : these are what are known as 'generic areas.' 
 
 305 U 
 
MEY MIC 
 
 Each of these has its ' metropolis ' or district of greatest number, either 
 of typical or specific forms ; geographical unity seems to be one of the 
 essentials of every generic grdup." 
 
 Meyeria (after Von Meyer). A small lobster-like crustacean, having its 
 crust highly ornamented with minute bead-like tubercles, and occurring 
 for the most part in the clays and marly beds of the Chalk formation. 
 
 Miaskite, Miascite (Miask in Siberia). A granitic rock consisting of 
 cleavable white felspar (orthoclase), black mica, and greyish or yellowish- 
 white elseolite, with some hornblende and occasionally albite or quartz. 
 It is usually associated with syenite. 
 
 Mica (Lat. mico, I glisten). A mineral well known from its metallic 
 lustre, and divisibility into thin glistening plates or scales these ultimate 
 laminae, according to Haiiy, being only ^onus of an inch thick ! It enters 
 as a. primary constituent into granite, gneiss, mica-schist, and other crystal- 
 line rocks ; occurs also in several trappean and volcanic products ; and is 
 sometimes artificially produced on the walls of iron and copper furnaces. 
 As a secondary product derived from the disentegration of the granitic 
 and crystalline rocks it occurs in many sedimentary strata, as shales and 
 sandstones, giving to them their flaky and laminated texture. In miner- 
 alogy it is made the type of a family, which includes the micas proper, 
 talc, chlorite, serpentine, &c. minerals of ten differing more in aspect than 
 in chemical constitution. The typical potash-mica consists of silica, alu- 
 mina, iron-peroxide, and potash ; lithia-mica has less alumina, with lithia 
 and fluoric acid in addition ; in magnesia-mica the alumina becomes still 
 less, and is replaced by magnesia ; while in pearl-mica the main constitu- 
 ents are silica, alumina, iron-peroxide, and lime. In the chloriles the 
 silica becomes less, and is replaced by a greater percentage of magnesia 
 and iron ; while in the softer and soapier talcs the alumina all but disap- 
 pears, and is replaced by magnesia. Mineralogically the varieties of mica 
 are known as Biotite, Lepidolite, Muscovite, Lepidomelane, &c., which see. 
 In some countries, like Kussia and India, the large-plated variety of mica 
 (muscovite) is regularly mined as an article of commerce, being used in 
 the arts and for decorative purposes. 
 
 Micaceous. Applied to rocks and compounds which are mainly com- 
 posed of mica, or which contain mica in notable proportion ; as " mica- 
 ceous schistus," " micaceous sandstone," &c. 
 
 Mica-Schist (Gr. schisma, a splitting). A metamorphic foliated rock 
 composed of mica and quartz the two ingredients occurring in alternate 
 folia with greater or less regularity. It is also, but improperly, known as 
 " mica-slate" the schistose structure of a foliated rock being very differ- 
 ent from the platy cleavage of atrue slate. As a ROCK, it passes through 
 every stage of metamorphosis from that of a flaggy schist to a highly- 
 crystalline compound almost undistinguishable from gneiss. As a GEOLO- 
 GICAL GROUP, the mica-schists hold an intermediate place in the Meta- 
 morphic System between Gneiss and Clay-slate, often passing into chlo- 
 ritic slate, and being associated with beds of quartzite, serpentine, and 
 crystalline limestone. 
 
 Micr aster (Gr. mikron, small, and astron, star). A genus of Spatangidce 
 abounding in the Chalk, and so termed from the star-like arrangement of 
 its small or incomplete ambulaci al furrows. In Micraster the case is some- 
 what elongated, heart-shaped, and wider before than behind, with a 
 sulcus or furrow in front. " The shell is fragile, and composed of large 
 
 306 
 
MIC MIL 
 
 polygonal plates ; the tubercles small and irregularly distributed ; the 
 spines short. The mouth is transverse, situated anteriorly, and protected 
 by a strong projection of the odd interambulacrum, which is named the 
 lip. The vent is terminal, and placed above the margin. There are but 
 four ambulacra, and these are incomplete, comparatively of small extent, 
 and situated in deep furrows." 
 
 Microlestes (Gr. micros, small, and lestes, beast of prey). The generic 
 term applied to a small insectivorous quadruped whose molar teeth and 
 other remains were discovered in 1847 by Dr Plieninger in the bone-breccia 
 of Wurtemberg a stratum which occurs among the upper beds of the 
 Keuper, and occupying nearly the same place in the Triassic system as the 
 celebrated ''bone-bed" of Aust and Axmouth. 
 
 Microphyta, Microphytes (Gr. micron, small, andphyton, plant). Liter- 
 ally " minute vegetables ; " a term applied to those microscopic forms 
 usually known as DIATOMACE^E, and which at one time were confounded 
 with the INFUSORIA, or minute forms of animal life. It has been pro- 
 posed by Dr Mantell to substitute the term microphytal for that of infu- 
 sorial, where deposits are chiefly of vegetable origin, and not of animal, as 
 was originally supposed by Ehrenberg, who regarded the "polishing- 
 slate" of Bilin, the "berg-mahl" of Tuscany, and the "Richmond-earth" 
 of Virginia, as of infusorial origin. 
 
 Microzoa (Gr. mikron, small, and toon, animal). A convenient term to 
 denote minute animal organisms whose forms can only be defined by the 
 aid of the microscope, and this without reference to their exact place in 
 zoological classification. The contradistinguishing term to Microphyta, 
 which refers to minute vegetable organisms. 
 
 Middletonite. A mineral resin found in the older Coal formations, and 
 occurring in layers or in rounded pea-like masses of a reddish-brown colour, 
 resinous lustre, brittle, but easily sectile. So called from Middleton Col- 
 lieries, near Leeds, where it was first discovered between the layers of the 
 coal. Consists of 86 carbon, 8 hydrogen, and 5.5 oxygen. 
 
 Mile. A well-known unit of measure, of which there are two kinds 
 1, the Geographical or Nautical Mile, 60 of which are equal to one degree 
 of latitude ; and 2, the Common or Statute Mile, 69 of which are equal to 
 one degree. The geographical mile is about -6079 English feet ; the 
 statute mile, 5280 feet. 
 
 Miliola. A genus of minute foraminiferous shells, so called from their 
 occurring in myriads in certain tertiary strata. The Miliolite Limestone, . 
 which belongs to the "calcaire grossier" group of the Paris basin, is 
 almost entirely made up of these many-chambered microscopic shells, and 
 is the principal building-stone employed in the French capital. 
 
 Milk-Quartz. A compact vitreous variety of quartz, occurring in veins 
 of the older rocks, of a milk-white colour, and somewhat greasy lustre 
 whence known also as Greasy Quartz. 
 
 Millep6ra, Milleporidse (Lat. mille, a thousand, and pora, a pore or pas- 
 sage). Literally "thousand-pore;" a genus and family of branching 
 corals, whose cells or pores are minute, distinct, and perpendicular to the 
 surface, giving to the interior a finely striated fracture, disposed somewhat 
 irregularly. Species of Millepores occur fossil from the Silurian upwards. 
 
 Millerite (after Prof. Miller of Cambridge). Sulphide of nickel, occur- 
 ring in delicate, six-sided prisms, or in diverging filaments, of a bronze- 
 yellow, with a grey or iridescent tarnish, metallic lustre, and brittle. 
 
 307 
 
MIL MIN 
 
 Millstone Grit. A group of the English Carboniferous system, so called 
 from its hard gritty sandstones being extensively used for millstones. In 
 the eastern and northern counties the Millstone Grit immediately under- 
 lies the true Coal-measures, and passes downwards through a series of 
 thick-bedded sandstones, shales, thin coals, and calcareous bands, into the 
 Carboniferous Limestone below. Known as the " Farewell Rock " in the 
 Welsh coal-fields, from the fact that the miner striking it bids farewell to 
 profitable seams of coal. 
 
 Mimetic (Gr. mimetikos, imitative). Applied in natural history to 
 organs, &c., which in one plant or animal bear a close resemblance to those 
 possessed by some other belonging to a distinct group. Organs " imitat- 
 ing," as it were, those that are regarded as special to, or characteristic of, 
 another group or family. The term seems more applicable to habits and 
 actions than to mere structural forms. 
 
 Mimetite, Mimetesite (Gr. mimetes, imitator). Arseniate of lead, usually 
 containing a small percentage of chloride and phosphate of lead ; occurs 
 in regular six-sided prisms, also fibrous and mammillary ; of a yellowish- 
 brown colour, resinous lustre, sectile, but brittle. So called from its resem- 
 blance to pyromorphite, with which it is isomorphous. 
 
 Mimosites. The term applied to fossil seed-pods apparently belonging 
 to plants of the Mimosa family. They occur in the London Clay, and in 
 other Tertiary strata. 
 
 Mine. The familiar as well as technical term for any system of subter- 
 ranean work or excavation which has for its object the discovery and ex- 
 traction of the metallic ores or other mineral produce, as coal, rock-salt, 
 &c. Mining. The art or systematic management of a mine in all that 
 relates to winning, draining, ventilating, and the like. 
 
 Mineral. Literally, any substance obtained from the earth's crust by 
 mining or digging. The term, however, is used adjectively as well as sub- 
 stantively; hence we speak of the "mineral kingdom" in contradistinc- 
 tion to the animal and vegetable kingdoms, and in this sense it is equiva- 
 lent to inorganic as contrasted with organic. We also speak of " mineral 
 oil" in contradistinction to animal or vegetable oil; and of "mineral 
 green " as distinguished from vegetable green. Substantively a MINERAL 
 is regarded as an inorganic substance, the product of chemical or physical 
 forces, in contradistinction to substances resulting from the operations of 
 vitality ; and yet coral-reefs and shell-beds, peat-mosses and coal-seams, 
 become ' ' minerals " when entering into the composition of the earth's 
 crust. In the stricter language of mineralogy, a "mineral species" is a 
 substance whose form, chemical composition, and physical properties, 
 are sufficiently uniform and persistent as to permit of identification, as 
 diamond, rock-crystal, garnet, and so forth. In this sense also geologists 
 speak of ' ' simple minerals " meaning thereby the primary constituents of 
 rock-masses. Thus ordinary granite, as a compound rock, consists of the 
 simple minerals, quartz, felspar, and mica, though, chemically speaking, 
 each of these is composed of several elementary ingredients. 
 
 Mineralisation. The process ' of converting any substance into a 
 mineral ; as vegetable matter into coal, animal fibre into adipocere, or a 
 metal into an oxide, sulphuret, or other ore. Mineralisation is strictly 
 dependent on chemical changes, brought about by the natural action and 
 reaction of substances one upon another, when placed in conditions favour- 
 able to such reactions. 
 
 308 
 
MIN MIS 
 
 Mineralogy. Literally |" the science of minerals;" that branch of 
 knowledge which investigates the qualities of, describes, and classifies the 
 various mineral substances which enter into the composition of the crust 
 of the globe. In describing and classifying minerals we may be guided 
 either by their chemical composition, by their crystallographic forms, or 
 simply by their physical properties of colour, lustre, hardness, fracture, 
 and so forth; hence we hear of the "system," of this author, and the 
 11 system" of that, according as they may have adopted one or other of 
 these methods of discrimination. As yet the science of mineralogy, not- 
 withstanding the sound progress which has been made of recent years, is 
 in a very unsatisfactory state cumbered by synonymes, overloaded with 
 subdivisions into so-called " species," and devoid of that unity of nomen- 
 clature which makes the terms employed express a portion of the informa- 
 tion attempted to be conveyed. See CRYSTALLOGRAPHY. 
 
 Mineral Blue. The name usually given to azurite when reduced to an 
 impalpable powder for colour purposes. 
 
 Mineral Caoutchouc. Known also as elaterite, or elastic mineral pitch ; 
 a variety of bitumen resembling caoutchouc in elasticity and softness. 
 See ELATERITE. 
 
 Mineral Charcoal. This term is usually applied to those silky fibrous 
 layers of charcoal which are interlaminated in beds of ordinary bitumin- 
 ous coal, and which give to it its staining or blackening properties. These 
 layers seem to have arisen from some process of spontaneous combustion 
 during the mineralisation of the vegetable mass, whereby their volatile pro- 
 ducts have been expelled, and the carbon of the ligneous fibre left behind. 
 Known to the miners as " mother of coal." 
 
 Mineral Oil. A familiar term for petroleum or rock-oil, which is found 
 oozing out from strata of all ages from the Silurian and Devonian upwards, 
 and appears to be the result of the decomposition of marine and land 
 plants (mainly the latter), and perhaps also of some non-nitrogenous animal 
 tissues. See PETROLEUM. 
 
 Mineral Tallow. A familiar term for Hatchetine, in allusion to its fatty 
 or spermaceti-like appearance. See HATCHETINE. 
 
 Miocene (Gr. melon, less, and kainos, recent). Sir Charles Lyell's term 
 for the Middle Tertiaries, as holding a less percentage of recent shells than 
 the Pliocene or Upper Tertiaries. In 1830, when the terms were intro- 
 duced, the percentages were Pliocene, 35 to 50 ; Miocene, 17 ; and Eocene, 3. 
 See TERTIARY SYSTEM. 
 
 Mirage (Fr.) A meteorological phenomenon occurring most frequently 
 on level tracts and during hot weather, and occasioned partly by the un- 
 equal rarefication of the vapour of the atmosphere, and partly by the in- 
 termixture of strata of air having different temperatures and densities. It 
 assumes the appearance of a lake-like sheet of water, often exhibiting the 
 reflected or inverted images of distant objects. See FATA MORGANA. 
 
 Mispickel (Gr. mysy, a kind of pyrites). Arsenical pyrites ; an arsenide 
 with sulphide of iron, consisting of 36 iron, 43 arsenic, and 21 sulphur, 
 and occurring either crystallised in rhombic prisms, or more frequently 
 massive, acicular, and columnar, in connection with iron or copper pyr- 
 ites, with ores of zinc, tin, lead, and silver. It is of a tin-white colour, 
 strong metallic lustre, brittle, and very hard ; and is worked as an ore of 
 arsenic. 
 
 Mist. The term applied to atmospheric vapour when it becomes visible 
 
MIT MOL 
 
 in consequence of a reduction of the temperature of the air. Mists, fogs, 
 haurs, and the like, are common phenomena in insular and estuary-inter- 
 sected countries like Great Britain and Ireland. 
 
 Mithracites. A provisional genus of brachyurous crustaceans found in 
 the Lower Greensand of England, and so termed from their general resem- 
 blance to the mithracia of the London Clay. The genus is characterised 
 by its well-defined carapace, pointed rostrum, and shallow orbits, having 
 the under edge anterior to the upper. 
 
 Moa. The Maori or native name for the Deinornis or gigantic extinct 
 cursorial bird of New Zealand, which see. According to native accounts 
 the moa was recently alive, if not still existing in the remote interior ; but 
 of its comparatively recent extirpation we have evidence in the fact that 
 its bones have been found along with charred wood, showing that it had 
 been killed and eaten by the inhabitants. 
 
 Mocha Stone. A variety of dendritic or moss agate, so called from its 
 being found in abundance near Mocha in Arabia. The dendritic lines and 
 patches, being of a dark colour, are finely shown off in the glassy translu- 
 cent matrix of the agate. See AGATE. 
 
 Modiola (Lat modiolus, a small measure). A genus of bivalves belong- 
 ing to the family Mytilidae, but distinguished from the mussels by their 
 habit of burrowing or spinning a nest. The living species are chiefly tropi- 
 cal ; the fossil occur in all formations from the Silurian (?) upwards. The 
 name has reference to the shape of the shell, which is oblong and inflated 
 in front. 
 
 Modiol6psis (Gr.) Literally " modiola-looking ; " a genus of fossil 
 conchifera occurring in Silurian strata and sometimes known as mytiloides. 
 Shell like modiola, thin and smooth, front end somewhat lobed ; anterior 
 adductor scar large and oval. 
 
 Molar (Lat. mold, a mill). The molar or grinding teeth of mammals ; 
 so termed from their function of milling or grinding the food before it is 
 fit to be swallowed. The shape of the molars differs in the different tribes 
 of animals according to the nature of the food they consume, and the kind 
 of work they have accordingly to perform. Thus in the carnivorous or 
 flesh-feeding tribes they are raised into sharp prongs, and often serrated 
 edges, for cutting ; in the insectivora they are furnished with rounded 
 tubercles for bruising and pounding ; and in the graminivorous and herbi- 
 vorous races they have flattened surfaces more or less rough for the pur- 
 pose of simply grinding or milling. These distinctions afford important 
 aid to the discriminations of the palaeontologist. See ODONTOLOGY. 
 
 Molasse (Lat. mollis, Fr. mol, soft). A provincial term for' those soft 
 arenaceous beds which constitute the Middle Tertiaries of Switzerland. 
 This deposit, occasionally alternating with lignite, but generally composed 
 of incoherent greenish sandstone, is thickly developed in the great Swiss 
 valley, and spreads also over large tracts in France, overlying the other 
 and better -known Tertiaries. The Molasse comprises three divisions, an 
 upper fresh-water, a middle marine, and lower fresh-water, which is of 
 older Miocene age. 
 
 Molecular Attraction. In natural philosophy, that force or attraction 
 by which the particles or molecules of bodies are kept together en masse, 
 as distinguished from the attraction or force of gravitation. " According 
 to the molecular theory," says Hoblyn, " all bodies are viewed as aggre- 
 gates of minute particles or molecules, and are formed by the attractive 
 
 310 
 
MOL MON 
 
 and repulsive forces acting on these molecules, at immeasurably small 
 distances." 
 
 Molecule (diminutive of moles, a mass). Any minute particle of matter; 
 the ultimate visible particles of which any body or mass is composed, are 
 usually termed molecules. 
 
 Mollusca (Lat. mollis, soft). One of Cuvier's grand divisions of the Ani- 
 mal Kingdom, including all the " shell-fish " proper, and having reference 
 to the circumstance that these creatures have soft bodies, unsupported by 
 any internal or tegumentary framework of sufficient density to merit the 
 name of skeleton. The term has been much objected to, but the words 
 mollusc, mollusca, and molluscous, are now too thoroughly incorporated 
 with the language of zoology and palaeontology to be readily abandoned. 
 Since Cuvier's time the meaning of the term has undergone some modifica- 
 tion, and it is now common to speak of the MOLLUSCA and the MOLLUS- 
 COIDA the former embracing the "shell-fish" proper; the latter, those 
 which have only coriaceous or horny integuments ; thus 
 
 ( Cephalopoda cuttle-fish, calamary, nautilus. 
 ! Pteropoda hyalfea, xslio. 
 MOLLUSCA. / Gasteropoda snails, slugs, whelks, cowries. 
 
 (Acephala oysters, mussels, shipworms. 
 Branchiopoda terebratula, lingula. 
 
 ,. ( Tunicata biphora, simple and compound ascideans. 
 
 A ' \ Polyzoa or Bryozoa plumatella, flustra, eschara. 
 
 The shells and frameworks of most of the mollusca being calcareous and 
 readily preserved, and each family having its own habitat as to depth, 
 nature of sea-bottom, and the like, their remains become important aids 
 to the geologist in the solution of his problems. See tabulations, " ANI- 
 MAL SCHEME." 
 
 Molluskite. A dark-brown carbonaceous substance occurring in shelly 
 marbles, and originating from the mineral transmutation of the soft bodies 
 of the mollusca. Speaking of the Sussex marble, which is chiefly composed 
 of paludinse (river-snails), Dr Mantell observes " Those shells which were 
 empty at the period of their becoming imbedded had their cavities filled 
 with mud, silt, or other detritus, which has subsequently hardened into 
 clay, marl, limestone, &c., but those which contained the gelatinous 
 bodies of the snails are occupied by a mass consisting of carbon and a 
 large proportion of phosphate of lime. In the polished sections of the 
 marble, this carbonaceous animal matter often appears in black or dark- 
 brown spots and veins ; and the most beautiful slabs owe their varie- 
 gated appearance to the contrast produced by the molluskite with the white 
 calcareous spar." 
 
 Molybdenite. Sulphuret of molybdenum ; molybdena-glance ; an ore 
 found in various rocks, as granite, gneiss, and chlorite slate, and in veins 
 with tin and other ores. It much resembles graphite, but is readily dis- 
 tinguished by its streak, lustre, and action before the blowpipe. It is 
 used for preparing a blue pigment for pottery ware. 
 
 Molybdenum (Gr. molyldos, lead). A very rare metal, discovered by 
 Hielm in 1782, of a whitish colour, brittle, very infusible, and having a 
 specific gravity of 8.625. It derives its name from the resemblance of the 
 native sulphuret (molybdenite] to that of lead. 
 
 Mon-, Mono- (Gr. mows, single) A common prefix derived from the 
 311 
 
MON MOO 
 
 Greek, and signifying singleness or unity ; as monolith, a monument com- 
 posed of a single stone ; monoceras, having one horn ; monocotyledonous, 
 possessed of a single cotyledon or seed-lobe. 
 
 Monad (Gr. monas, an atom). The smallest of all visible animalcules, 
 and sometimes spoken of as constituting " the ultimate term of animality." 
 According to Ehrenberg, monads have an average diameter of not more 
 than 24,000th of an inch, so that 500,000,000 of them might be contained 
 in a single drop of water. 
 
 Monoclinal (Gr. monos, single, and Uino, I bend). Applied to strata 
 that dip for an indefinite or unknown length in one direction, and which 
 do not apparently form sides of ascertained anticlines or synclines. Mono- 
 clinal strata often form series of hills the abrupt outcrops constituting 
 ridges which follow each other like the teeth of a saw. 
 
 Monocotyledonous (Gr. monos, one, and cotyledon, seed-lobe). A grand 
 division of the vegetable kingdom, comprising all those plants whose seeds 
 have only one lobe or seed-leaf. They are endogenous in growth, or increase 
 from within like the palms, lilies, grasses, &c., and are characterised by a 
 parallel venation of the leaves. See tabulations, " VEGETABLE SCHEME." 
 
 Monograph (Gr. monos, sole, and graphe, description). An account or 
 description of a single object or class of objects ; as a monograph of the mas- 
 todon; a monograph of the mollusca; the monographs of the Palceontological 
 Society. 
 
 Monograpsus (Gr. monos, single, and grapho, I write). A term proposed 
 by Geiuitz to embrace all those graptolites with a single row of teeth-like 
 cells, as rastrites, graptolithus, &c., which see. 
 
 Monolith (Gr. monos, single, alone, and lithos). A pillar, obelisk, or 
 other monument, consisting of a single stone. Many of the Egyptian 
 monuments were of this monolithic character. 
 
 Monomyaria (Gr. monos, single, and mus, a muscle). A term employed 
 by Lamarck to distinguish those bivalves whose shell is closed by a single 
 adductor muscle, in contradistinction to the dimyaria, or those having a 
 second adductor. The monomyaries are the oysters, aviculidae, and clam- 
 
 Monoprion (Gr. monos, alone, single, and prion, a saw). Barrande's 
 term for the common graptolite, its toothleted cells being arranged, like 
 the teeth of a saw, all on one side. 
 
 Monsoons (Arabic, moussin, season). The periodical or seasonal winds of 
 the Indian Ocean the south-west monsoon blowing, in general terms, from 
 April to October ; and the north-east, from October to April. The alter- 
 nate heating and cooling of the African and Asiatic continents during the 
 southern and northern summers are the prime producers of these periodi- 
 cal air-currents. 
 
 Monte Bolca, near Verona, in Italy ; a locality celebrated for its fossil 
 fishes, which are found in a fissile, cream-coloured limestone of Upper Ter- 
 tiary age the deep-brown, semi-bituminous colour of the organisms con- 
 trasting finely with the lighter hue of the matrix. According to Agassiz, 
 the species, though related to those still existing, are all extinct ; and from 
 the immense numbers imbedded in so limited an area, it is conjectured that 
 the limestone had been erupted as a calcareous mud by volcanic agency, 
 and thus suddenly suffocated the fishes within its influence. 
 
 Moonstone. A fine variety of adularia felspar, so called from the pale- 
 bluish opalescence it exhibits when cut en cabochon. The rough mineral is 
 
 312 
 
MOR MOS 
 
 said to constitute the famous petuntse or vitrifying ingredient of the Chinese 
 porcelain. 
 
 Moraines. The name given in Switzerland to the longitudinal mounds 
 of stony detritus which occur at the bases and along the edges of all the 
 great glaciers. The formation of these accumulations is thus explained by 
 Professor Agassiz : The glaciers, it is well known, are continually moving 
 downwards, in consequence, probably, of the introduction of water into 
 their fissures, which, in freezing, expands the ice ; and the ice being thus 
 loosened or detached from the rocks on which it rests, is gradually pressed 
 forward by its own weight. In consequence of this motion, the gravel and 
 fragments of rocks, which fall upon the glaciers from the sides of the ad- 
 jacent mountains, are accumulated in longitudinal ridges or moraines as the 
 glacier melts away. There are thus two sets of moraines viz., " lateral" 
 and "terminal," the former flanking the margins of the glacier in its down- 
 ward course in long narrow spits, the latter occurring in mounds at the free 
 edge or terminus that projects into the valley below. As the terminus ad- 
 vances and retreats according to the nature of the seasons, there will often 
 be several terminal moraines arranged in concentric form ; and this dispo- 
 sition of gravel-mounds is very observable in all mountainous regions, either 
 now or during former epochs, the theatres of glacial phenomena. Where 
 the lateral moraines exhibit a terraced appearance, it proves a gradual 
 diminution of the glacier each shelf or terrace marking a former surface- 
 level. See GLACIER. 
 
 Morass (Sax.) A marsh, swamp, fen, or tract of low wet ground whose 
 drainage is insufficient, either from its depressed area or from its uniform 
 flatness. Marshes of this kind are often partially silted-up lakes, and con- 
 tain in their accumulations the usual remains of lacustrine areas. Occa- 
 sionally they occupy estuarine areas, in which case they are " salt-marshes," 
 and contain the remains both of marine and terrestrial plants and animals. 
 See SWAMP. 
 
 Morphology (Gr. morpJie, form, and logos, discourse or reasoning). Liter- 
 ally "the science of form ; " that department of biology which treats of liv- 
 ing beings as possessing definite forms, which, in most instances, are found 
 to be made up of a number of dissimilar parts or organs. Physiology, in 
 contradistinction to Morphology, takes cognisance of the vital actions or 
 functions which those organs perform. 
 
 Mortar. The term applied by builders to the well-known admixture of 
 slaked lime and siliceous sand, with which they cement or bind together 
 the stones and bricks of their buildings. Like other hydrates of lime, 
 mortar, if well prepared, " sets " readily, and acquires great hardness and 
 durability. 
 
 Mossesaiirus. A gigantic marine reptile of the Upper Chalk, apparently 
 intermediate between the monitors and iguanas ; and so called from its 
 being first found in the Maestricht beds. The jaw of the Maestricht ani- 
 mal is 3 feet 9 inches long, and the entire length of the skeleton is estimated 
 at 24 feet the head being thus about one-sixth of the whole length. In 
 this respect it resembles the crocodiles more than the monitors ; but in the 
 shortness of the tail it is altogether unlike the crocodiles and alligators. 
 Its extremities are imperfectly known, but those attributed to the mosce- 
 saurus would indicate swimming rather than progression on land ; hence 
 the inference of its marine nature. 
 
 Moss Agate. A variety of agate which, on being cut and polished, ex- 
 313 
 
MOT MOU 
 
 hibits numerous minute dendritic branchings of various shades like the 
 filaments of moss ; hence the name. See AGATE. 
 
 Mother of Coal. The name given by the miners to the fine silky-fibrous 
 laminae of carbon or mineral charcoal, which occur imbedded in the seams 
 of ordinary coal. See MINERAL CHARCOAL. 
 
 Mountain. In physical geography, any portion of the earth's crust 
 rising considerably above the surrounding surface. The term is usually 
 applied to heights of more than 2000 feet, all beneath that amount being 
 regarded as hills, and when of inconsiderable height, as hillocks. A Moun- 
 tain-Chain or mountain-range is a series of elevations having their bases in 
 contact, and their axis continuous over a considerable extent of country, as 
 the Grampians, Urals, Himalayas, &c. Their summits are distinguished 
 by such terms as cones, when gradually tapering to a point ; domes, when 
 more massive and rounded ; peaks, when abrupt and insulated ; and needles 
 or aiguilles, when still more pointed and detached. As mountain-ranges 
 exercise very decided influences on the natural history of the globe, and as 
 they extend in directions more or less definite, various theories have been 
 advanced to account for their upheaval, their parallelism, and geographical 
 connection, and also to determine their age or relative antiquity. Thus, as 
 their central masses generally consist of igneous rocks which have been 
 protruded from below, and as this protruding force must have acted along 
 the line of least resistance, the question arises, What is the determining 
 cause of these directions ? According to Elie de Beaumont, every system 
 of mountains occupies a portion of a great circle of the globe the cleft 
 being more easily made in that than in any other direction ; and he shows 
 that the mountain-chains of the same age are parallel to one another, 
 even when in opposite hemispheres. Mr Hopkins, treating the subject 
 from a purely mathematical point of view, has also shown that when the 
 upheaving force acts on a single point, the lines of upheaval must radiate 
 from that point ; hence lofty central mountains with diverging spurs. He 
 also shows that when the expansive force acts uniformly over a wide area, 
 the lines of greatest tension or upheaval must be in the direction either of 
 the length or breadth of the area, and that if the crust yields in inore 
 places than one, the fissures would necessarily be parallel. Proceeding 
 upon these views, the various mountains of the world have been so far 
 arranged into " Systems ;" and their relative antiquities determined partly 
 by these means, and partly by the stratified rocks which had been broken 
 through, and which now flank their declivities. Of course this uniformity 
 of system has been considerably obscured, if not modified, by subsequent 
 geological changes ; and we can only accept such generalisations as initia- 
 tory steps towards the elucidation of one of the most important problems 
 connected with the history of our globe. 
 
 Mountain-Blue and Mountain-Green. Familiar terms for the blue and 
 green carbonates of copper; the epithet "mountain" being at onetime 
 very much used as synonymous with " mineral." 
 
 Mountain-Cork, Mountain-Leather, &c. Asbestos, as it occurs in veins 
 and crevices, often assumes very curious appearances ; hence the light 
 elastic variety is known as mountain-cork ; the tough variety as mountain- 
 leather ; the woody-fibrous looking variety as mountain-wood ; and when 
 it occurs in thin papery pieces, it is known as mountain-paper. See 
 ASBESTOS. 
 
 Mountain Limestone. An early, and still used, term for the Carloni- 
 314 
 
MOU MUR 
 
 ferous Limestone, from its being frequently thrown up in thick bluffs or 
 scars on the flanks of such hills as those of Yorkshire and Derbyshire, 
 and in contradistinction to the comparatively low-lying strata of the Lias 
 and Oolite Limestones. See CARBONIFEROUS SYSTEM. 
 
 Mountain-Meal. An infusorial earth, usually and better known perhaps 
 as Bergmahl, which see. 
 
 Mountain-Soap. A variety of soapstone or silicate of magnesia found 
 in the Isle of Skye, and used in crayon drawing. 
 
 Mountain -Tallow. Another name for mineral tallow, or ffatchetine 
 (which see) ; terms which include several waxy or tallow-like mineral sub- 
 stances, concerning whose nature and origin very little is yet known. 
 
 Moya (Span.) A term applied in South America to the fetid sulphurous 
 mud discharged by certain volcanoes ; the Koth of the natives. 
 
 Muck (Sax.) A familiar term for manure ; but applied also (especially 
 by American geologists) to those impure earthy varieties of peat, bog- 
 earths, and swamp-earths, which are employed as manures, and consist 
 largely of decomposed vegetable matter. 
 
 Mud (Gr. mudos, moistness). The familiar as well as scientific term for 
 all wet slimy debris, whether produced by rains on the earthy surface, by 
 sediment from turbid waters, or by ejections from springs and volcanoes. 
 Mud may thus be argillaceous, calcareous, sulphurous, or otherwise, accord- 
 ing to every notable ingredient which enters into its composition. Con- 
 solidated mud becomes shale, and this assumes a less or more laminated 
 structure according to composition, age, pressure, and other conditions to 
 which it has been subjected. 
 
 Mudstone. A term originally applied by Sir R. Murchison to certain 
 dark-grey, fine-grained, shivery shales of the Silurian system in Wales, 
 which, on being exposed to the atmosphere, are rapidly decomposed and 
 converted into their primitive state of mud ; but now extended to all 
 similar shales in whatever formation they may occur. 
 
 Mud, Volcanic. See MOYA and CANGAUA. 
 
 Midler's Glass. Another name for glassy opal, or hyalite, which see. 
 
 Multivalve (Lat. multus, many ; valvce, valves or folding doors). Shells 
 composed of more valves or pieces than two (as the Clinton) are said to be 
 multivalve, in contradistinction to univalves, which consist of one piece, 
 and bivalves, which have two. Linnaeus arranged the Testacea into these 
 three great sections, univalve, bivalve, and multivalve embracing under 
 the last the barnacles, &c., which are not Mollusca, but belong to the 
 Articulata. 
 
 Murchis6nia (after Sir R. Murchison). An elongated spiral shell, having 
 the outer lip deeply notched, as in the Pleurotomaria. Of Murchisonia 
 (family Haliotidce) about fifty species have been enumerated, and these 
 occur in the Silurian, Devonian, Carboniferous, and Permian formations. 
 
 Miirchisonite (after Sir R. Murchison). A golden or greyish-yellow 
 variety of felspar from the granite of Arran, and from the New Red Sand- 
 stone conglomerate of Dawlish in Devonshire. 
 
 Muriacite, Muriazit. A term usually applied to the crystalline varieties 
 of anhydrous sulphate of lime, or anhydrite, which also occurs in granular, 
 fibrous, compact, and fibro-compact masses. See ANHYDRITE. 
 
 Muriate (Lat. muria, brine). Muriates are salts formed by the combin- 
 ation of muriatic or hydrochloric acid with a base, as muriate of soda, 
 muriate of iron, &c. 
 
 315 
 
MUR MYL 
 
 Muriatic Acid (muria, brine). Known also as hydrochloric acid; an 
 acid consisting of chlorine and hydrogen, and occurring abundantly in 
 sea-water, in combination with soda and magnesia common salt being a 
 " muriate of soda." 
 
 Muricalcite (muria, brine, bitterness ; and calx, lime). Another name 
 for rhomb-spar, or bitter-spar (which see) ; a mineral consisting of the car- 
 bonates of lime and magnesia. 
 
 MiiridsB (Lat. mus, muris, a mouse). The Rat family ; a well-known 
 tribe of Rodents, including the mice, rats, water-voles, &c. Their re- 
 mains are found in the bone-caves and deposits of the Pleistocene epoch. 
 
 Muriform (Lat. murus, a wall, and/orwia, likeness). Wall-like ; a term 
 applied to tissues and organic structures presenting the appearance of 
 bricks in a wall ; e.g.) the muriform tissue which constitutes the medullary 
 rays in plants. 
 
 Miischelkalk (Ger.) Literally " shell-limestone ;" the middle member 
 of the Triassic system as it occurs in Germany the Trias consisting of the 
 Keuper, MuschelkalJc, and Bunter-sandstein. The muschelkalk is wanting 
 in England, but constitutes the calcaire coguillier, the calcaire a ceratites, or 
 the terrain conchylien of French geologists. In Germany it consists chiefly 
 of a compact greyish limestone, but includes beds of dolomite in many 
 places, together with gypsum and rock-salt. It is rich in fossil shells, as 
 the name implies the ceratite, posidonia, and amcula being the prevailing 
 forms. See TRIASSIC SYSTEM. 
 
 Muscites (Lat. musctis, moss). A general term for fossil plants of the 
 Moss family, which as yet have been found only in amber, and in certain 
 fresh-water Tertiary strata. 
 
 Muscovy Glass. A familiar term for a variety of mica (muscomte), most 
 of the large plates used in the arts being brought from Eastern Russia, 
 where they are employed as a substitute for glass. See MICA. 
 
 Mask-Ox. Properly the " musk-buffalo " (Bubalus Moschatus) ; a living 
 Arctic form whose remains occur in the " Drift" of middle and southern 
 Europe. See BUBALUS. 
 
 Mussel-Bind, Mussel-Band. A miner's term for thin shelly bands, 
 calcareous and ferruginous, that occur in the Coal-measures. They are 
 almost entirely composed of shells resembling the existing fresh-water 
 mussels, the anodon and unio. 
 
 Myadae, Myacidse (Gr. myax, the gaping mussel). A family of conchi- 
 ferous molluscs, generally known as the Gaping Bivalves, named from the 
 genus mya, and having the valves less or more gaping at one or both 
 extremities. It includes the mya, corbula, necera, thetis, panopcea, saxi- 
 cava, &c., many species of which are fossil as well as recent. 
 
 Myliobitis (Gr. mylias, a millstone, and batis, the thorn-back, a species 
 of skate or ray, from batia, a bramble). A genus of rays (the Eagle-rays) 
 characterised by the extraordinary development of the median teeth in 
 both jaws. Instead of pointed teeth, they have wide, flat, tesselated 
 dentary plates in each jaw, composed of distinct pieces, juxtaposed and 
 connected by their margins, and united by fine sutures. These " milling " 
 or "grinding" teeth occur abundantly in Tertiary strata about twenty 
 species having been found in the Isle of Sheppey, &c., while only five 
 species of existing Myliobates are known. 
 
 Mylodon (Gr. mylos, a mill, and odous, tooth). A gigantic edentate 
 animal from the Upper Tertiaries of America, and so called in allusion 
 
 316 
 
MYO MYT 
 
 to the flat grinding surfaces of its molar teeth. There is a skeleton of the 
 Mylodon in the Hunterian Museum, London, almost as perfect as if the 
 animal had been but recently buried, and its bones dug up entire. It is 
 eleven feet long from the muzzle to the extremity of the tail ; thus indi- 
 cating a size as large as that of the hippopotamus, with the bones more 
 than proportionately massive. The Mylodon, like the Megatherium, was 
 a vegetable feeder ; and from the conformation of its fore feet and arms, 
 which are fitted for grasping and wrenching, as well as that of its hinder 
 extremities and strong thick tail, which seem adapted for supporting the 
 body in an upright position, it is supposed that it sat in this position 
 stripping the trees of their leaves and succulent branches. See Owen's 
 ' Memoir on the Hunterian Skeleton,' published in 1842. 
 
 My6caris (Gr. mys, myos, a bivalved- shell, and tarts, shrimp). A pro- 
 visional genus of Silurian bivalved crustaceans, somewhat resembling Cer- 
 atiocaris (which see), but more obtusely truncate in front, and furnished 
 with two strongly projecting ridges which terminate in pointed processes 
 behind. The valves (the only portions yet known) are marked with 
 concentric striae somewhat sparsely and indistinctly displayed. Salter in 
 'Geol. Magazine,' vol. i. page 11. 
 
 Myriacanthus!(Gr. myria, innumerable, and akantha, a thorn or spine). 
 Literally " many-spined ; " a genus of fossil rays whose ichthyodorulites, 
 or serrated spines, occur abundantly in the Lias formation of England. 
 
 Myriapoda (Gr. myria, innumerable, and poiis, podos, foot). An 
 order of articulate or annulose animals, including the centipedes and 
 millepedes, and represented by the scolopendra and julus. They are so 
 called from the numerous segments of the body being each provided with 
 one or more pairs of jointed ambulatory feet. 
 
 Myriophyllites (Gr. myria, innumerable, and phyllon, leaf). Coal- 
 measure stems, or rather roots, surrounded, as the name implies, with 
 numerous fibres. Regarded by Lindley as "aquatic plant roots," though 
 by others ranked as having affinity with Haloragece. 
 
 Myripristis (Gr. myrioi, many, and prisiis, sawing). A genus of fossil 
 fishes of the Perch family occurring in the London Clay, and so called 
 from their peculiar dentition. 
 
 Mytilacea (Lat. mytilus, the sea-mussel). The Mussel tribe ; also known 
 as the MYTILID^B or mussel-family an extensive group of conchiferous 
 molluscs, including the genera mytilus, myalina, modiola, lithodomus, 
 crenella, &c., many species of which are fossil as well as recent. Their 
 shells are equivalve, oval or elongated, closed, umbones anterior, furnished 
 with a thick epidermis, more or less pearly within, and have the hinge 
 edentulous. Shells undetermined, but, approaching in form to that of the 
 mytilus or common mussel, are said to be mytiloid. 
 
 317 
 
NAG NAP 
 
 N 
 
 Nacreous (Fr. nacre, mother-of-pearl). Applied to shells and minerals 
 which have a pearly or iridescent lustre like mother-of-pearl. The nacre- 
 ous portion of some shells (the ammonite, for example) is still preserved in 
 a fossil state. 
 
 Nacrite (Fr. nacre, mother-of-pearl). A mineral of the Mica family, 
 having a pearly lustre, massive, and of a fine scaly texture. When rubbed 
 between the fingers it leaves a pearly gloss. Talcite, earthy-talc, and phol- 
 lerite, are occasional synonymes. Consists of 41.78 silica, 43.10 alumina, 
 and 15.12 water. 
 
 Nadir (Arabic, down). As the zenith is that point of the heavens direct- 
 ly above the head of a spectator, so the nadir is that point diametrically 
 opposite, or vertically beneath his feet. In other words, they are the op- 
 posite poles of the visible horizon. 
 
 Nagelflue or Nagelfluhe (Ger.) A provincial Swiss term for a soft 
 arenaceo- calcareous conglomerate, occurring among the Middle or Miocene 
 Tertiaries of the Alps, and said to derive its name from the enclosed 
 pebbles appearing like swarms (fluge) of nail-heads (nagel] in the mass. It 
 is termed gompholite or nail-stone by Brongniart, and sometimes attains the 
 truly wonderful thickness of 6000 or 8000 feet, as in the Rigi near Lucerne, 
 and in the Speer near Woren. 
 
 Nagyagite. Foliated tellurium ; a mineral consisting of tellurium and 
 lead, with traces of gold, silver, copper, and sulphur. So called by 
 Haidinger from its occurring in veins with gold and other ores at Nagyag 
 in the Siebenberg. 
 
 Naiades (Nalas, a water-nymph). The fresh-water mussels or UNION- 
 IDM, which see. 
 
 Naker Feldspar. Pearly felspar ; a mineralogical term somewhat loosely 
 applied to varieties of adularia, moonstone, avanturine, and other pearly 
 felspars. 
 
 Naphtha. A variety of bitumen (which see), thin, volatile, fluid, and 
 highly inflammable. Springs of it exist in many volcanic countries, and 
 in most districts where coal strata seem undergoing a slow natural process 
 of distillation. One of the finest and purest varieties is that obtained 
 from Baku and Scamachia on the western shores of the Caspian, where 
 it rises from calcareous rocks in the state of an odorous inflammable 
 vapour, or is collected in shallow wells. Naturally it is of a yellowish 
 colour, but may be rendered colourless by distillation. Its specific gra- 
 vity is about .75 ; it boils at 160 ; and appears to be a pure hydro-carbon 
 100 parts consisting of about 83 carbon and 15 hydrogen. Most of the 
 naphtha of commerce is obtained by distillation from coal-tar, or directly 
 from coal. Used largely as a solvent for caoutchouc. 
 
 Naphthaline. A soft, greyish- white, flaky crystalline substance found 
 incmsting the pipes during the rectification of coal-tar. It also occurs in 
 a native state associated with certain coals and lignites. It is a hydro- 
 carbon, consisting of 60 carbon and 40 hydrogen ; has a peculiar aromatic 
 
 318 
 
NAT NAU 
 
 odour ; is extremely volatile, fusing at 180 ; burns with much smoke ; and 
 dissolves in alcohol and ether. 
 
 Natat6res, Natatorial (Lat. nato, I swim). In ornithology, the 
 swimming or natatorial order of birds, readily distinguished by their oar- 
 like, webbed, or partially-webbed feet. The order includes the ducks, 
 gulls, pelicans, divers, and penguins. 
 
 Naticidse. Sea-snails ; a family of carnivorous gasteropods, named 
 from the genus natica, which has been taken as the type of the family. 
 The Naticidce occur fossil in all formations from the Silurian up- 
 wards ; the existing genera are also widely distributed. The naticae 
 frequent sandy and gravelly bottoms, ranging from low- water to 90 
 fathoms. 
 
 Native. A term largely employed in mineralogy to designate any min- 
 eral or metallic substance which occurs in nature in a state of absolute 
 purity, or all but absolute purity. We have thus native alum and native 
 sulphur, in contradistinction to those prepared artificially ; and native gold 
 and native copper occurring in the pure metallic slate and not in that of ores. 
 Most of the substances termed " native " are generally more or less con- 
 taminated with extraneous impurities. 
 
 Natrolite. Prismatic zeolite or mesotype, occurring in many varieties 
 of trap-rock, either in veins, drusy cavities, or disseminated. Derives its 
 name from the amount of soda it contains. According to Thomson, a 
 specimen from Antrim consisted of 48 silica, 25 alumina, 16 soda, 10 water, 
 and traces of potash, lime, and iron peroxide. 
 
 Natron (natrium, an early chemical term for sodium). Natron is a 
 native carbonate of soda, occurring in solution in the waters of many springs 
 and salt lakes (Egypt) ; as a crystalline crust on the beds of dried-up lakes, 
 in deserted river- courses, and on numerous salinas or upheaved sea- reaches 
 (South America) ; as a pulverulent efflorescence on the ground, as in the 
 plain of Debreczin in Hungary ; and as a product of decomposition in 
 many lavas, traps, and other volcanic rocks. Natron is extensively em- 
 ployed in the arts and in agriculture, and large quantities are annually im- 
 ported from various regions. 
 
 Naumannite (after Dr Naumann, the Saxon mineralogist). Selenide of 
 silver, occurring in cubical crystals, and also massive, in thin plates and 
 granular; of an iron-black colour, and metallic lustre. Consists of 26.8 
 selenium, and 73.2 silver. 
 
 Nautilidse. A well-known family of tetrabranch cephalopods, of which 
 the nautilus has been taken as the type. It includes the genera nautilus, 
 lituites, trochoceras, and clymenia, which see. Of the existing nautilus 
 there are only three or four species found in Indian seas, while the fossil 
 species exceed 100. " In the recent nautilus," remarks Dr Buckland, "the 
 shell is smooth, but in many fossil species it is arranged like the patent 
 iron-roofing, so remarkable for its strength and lightness." See CEPHA- 
 LOPODA, and tabulations, "ANIMAL SCHEME." 
 
 Nautilites. A general term for fossil shells apparently allied to the 
 existing nautilus. They are found in all formations from the Silurian 
 upwards, but are now represented by three or four species only. They 
 are distinguished from the ammonites by their central siphuncle, simple 
 sutures, and fewer whorls. 
 
 Nautiloid (nautilus, and eidos, likeness). Literally "nautilus-like;" a 
 term usually applied to the many-chambered shells, or rather cell-cases, 
 
 319 
 
NAV NEM 
 
 of those foraminifera whose coils present externally a remarkable resem- 
 blance to those of the pearly nautilus. 
 
 Navicula (Lat., a little boat). A genus of Diatoms or microscopic 
 plant-growths, so called from their siliceous boat-like cases, which are 
 perforated by six transverse slits, and in many species exquisitely orna- 
 mented. They are free floaters, and seem to move by ciliary action ; 
 abound in existing waters, as well as in many Post-tertiary and Tertiary 
 strata. 
 
 Neanderthal. A portion of the valley of the Diissel near Dusseldorf, 
 and celebrated since 1857 for its cssiferous cavern, and the peculiarly 
 shaped human cranium discovered therein by Dr Fuhlrott. The cave 
 occurs in the precipitous southern or left side of the winding ravine, about 
 sixty feet above the stream, and a hundred feet below the top of the cliff. 
 The cranium whose conformation has given rise to much speculation is of 
 unusual size and thickness, with a very low and narrow forehead, and 
 enormously developed supra-orbital ridges so much so that in this latter 
 respect it somewhat resembles the skull of the gorilla. Anatomists are 
 now agreed that the skull is either abnormal, or belongs to an early and 
 extinct European race. The cranium, along with other bones of the same 
 skeleton, were found in the cave-mud, which is five feet thick, but uncovered 
 by any crust of stalagmite. 
 
 Nebular Theory (Lat. nebulae, thin filmy clouds). A theory or hypo- 
 thesis often referred to in speculative geology. In the primal condition 
 of the solar system, it is supposed that the sun was the centre or nucleus 
 of a nebulosity or luminous mass, which revolved on its axis, and extended 
 far beyond the orbit of the most distant of the planets these bodies then 
 having no existence. The temperature gradually diminishing, and the 
 nebula contracting by refrigeration, the rotation increased in rapidity, and 
 zones of nebulosity were successively thrown off in consequence of the cen- 
 trifugal force overpowering the central attraction. These zones, being 
 condensed, and partaking of the primary rotation, constituted the planets, 
 some of which in turn threw off zones which now form their satellites. In 
 this way the formation of the Solar group is accounted for a view which 
 the nebulists attempt to support by certain appearances in space (nebulce 
 and nebulous clusters) which present themselves to the telescope of the 
 astronomer. 
 
 Necrolite (Gr. nekros. dead, and lithos, stone). A term applied to cer- 
 tain nodules in limestone strata, such as those of Baltimore, U.S., which 
 when struck exhale a fetid odour, like that of putrid flesh. Concentrated 
 nodules of fetid limestone or stinJcstein, which see. 
 
 Necronite. A variety of orthoclase, which when struck gives off a fetid 
 odour. 
 
 Needles. A familiar term in geography and geology for pointed, de- 
 tached masses of rock standing out from the cliffs or shores to which they 
 geologically belong, and from which they have been severed by the erosive 
 action of the tides and waves, as the "Needles" off the Isle of Wight. 
 Applied also to the pointed summits of mountains, the aiguille or needle- 
 top of the French, which see. 
 
 Needle-Stone. A name given by the older mineralogists to acicular 
 varieties of natrolite, scolecite, &c. Needle-spar, arragonite; Needle-ore, 
 aikenite; &c. 
 
 Nemacanthus (Gr. nemo, I scatter, and akantha, spine). A genus of 
 320 
 
NEO NER 
 
 Oolitic ichthyodorulites or ray-spines, so called from their being covered 
 with minute denticles or prickles, and supposed to belong to the cestraciont 
 fish CERATODUS, which see. 
 
 Neocdmian. A term of D'Orbigny's for the Greensand or Lower Cretace- 
 ous formation, which is specially developed in the vicinity of Neufchatel 
 (Neocomum). The term is now very generally used by English and 
 American geologists, some of whom (considering the intimate relation 
 of the Lower Greensand and Wealden fossils) arrange the Wealden as 
 11 Lower Neocomian." See tabulations, "GEOLOGICAL SCHEME." 
 
 Neogene (Gr. neos, new, and ginomai, I am formed). The Pliocene and 
 Miocene Tertiaries are grouped together by some Continental geologists 
 under the term Neogene (new-born), in contradistinction to the decidedly 
 older strata of the Eocene. 
 
 Neolite (Gr. neos, new, lilhos, stone). A massive or rather laminar-mas- 
 sive variety of talc, in which portion of the silica is replaced by alumina, 
 and to which a blackish-green colour is imparted by the presence of pro- 
 toxide of iron, so named by Scheeres from the belief of its being newly 
 formed by the infiltration of waters which have passed over rocks con- 
 taining magnesia. 
 
 Neozoic (Gr. neos, new, and zoe, life). Arranging the fossiliferous strata 
 into two great categories the Palaeozoic and Neozoic the former includes 
 all up to the close of the Permian, the latter all from the commencement 
 of the Trias up to the existing order of things. It thus embraces the 
 Mesozoic and Cainozoic of some palaeontologists. The term was proposed 
 by the late Edward Forbes on the ground that, while there was a wide dif- 
 ference between Palaeozoic and Mesozoic fossils, there wasj-eally no essen- 
 tial difference between Mesozoic and Cainozoic, and that therefore it would 
 be more philosophical to divide the whole lapse of geological time into two 
 great epochs only viz., the Palaeozoic and Neozoic. See tabulations, 
 " GEOLOGICAL SCHEME." 
 
 Nepheline (Gr. nephele, a cloud). A double silicate of alumina and 
 soda, occurring in small crystals in the igneous rocks (imbedded or in 
 druses), and so termed from its transparent fragments becoming cloudy in 
 nitric acid. Closely related to or identical with elceolite the nephelines 
 being more or less transparent, of vitreous lustre, and colourless or white, 
 whereas the elaeolites are more opaque, of resinous lustre, and generally of 
 reddish-brown hues. Nepheline is also less fusible than elaeolite. Being 
 found in ejected blocks on Monte Somma, Vesuvius, it is sometimes known 
 as Sommite. 
 
 Nephrite (Gr. nephros, a kidney). A technical term for the tough 
 siliceo-magnesian mineral better known as Jade, which see. Formerly 
 little plates of it were suspended from the neck as a charm in the case of 
 nephritic or kidney complaints ; hence the name. 
 
 Neptunian (Neptunus, god of the sea). Applied to stratified rocks, or 
 to those deposited in and by the agency of water (aqueous), in contradis- 
 tinction to Plutonic or igneous. 
 
 Nereites. Long, sinuous, annulated tracks and impressions occurring 
 on Silurian and other strata, and from their numerous segments and cir- 
 rhated or tentacled feet, apparently allied to the existing Nereidce or Sea- 
 centipedes. The living family includes some elongated and distinctly 
 annulated worms, which possess- a well-developed head, furnished with 
 tentacles and eyes, and a mouth with a proboscis which is sometimes 
 
 321 X 
 
NER NEW 
 
 unarmed, and sometimes furnished with three or four feet. The cirri or 
 tentacles attached to the feet are often of considerable length, and in 
 some species are even annulated. Many of the fossil impressions present 
 analogous characters, hence their presumed affinities to annelids of the 
 Dorsibranchiate order (Errantia) ; but in others the characters are not so 
 obvious, and it has been suggested by M. Geinitz that not a few of the 
 so-called Nereites may be soft and fleshy forms of Graptolithina. 
 
 Nereograpsus. A term applied by M. Geinitz to many of the Silurian 
 organisms known as Nereites, from the belief that they were soft-stemmed 
 creatures like the graptolites, and not annelids resembling the existing 
 nereis. 
 
 Ness, Naes, or Naze (literally nose}. In geography, any promontory or 
 sudden projection of the land into the sea ; as Dungeness, Fifeness, the 
 "Naze," &c. 
 
 Neuroptera (Gr. neuron, nerve, and pteron, wing). Literally "nerve- 
 wings ; " an order of insects characterised by the finely reticulated 
 nervures of their membraneous wings, of which there are two pairs ; as 
 the Dragonfly, the Phryganea, &c. Several fossil species have been 
 found in the Oolitic strata of England and Germany, and these seem 
 referable to the family Libellulidce or Dragonflies. See INSECTA. 
 
 Neur6pteris (Gr. neuron, nerve, and pteris, fern). An extensive, but 
 indifferently defined, genus of fossil ferns occurring abundantly in the 
 Coal-measures, and also, but in less profusion, in the Permian, Trias, and 
 Oolite. In neuropteris the leaves are usually bi-pinnate ; leaflets more or 
 less pointed at the apex, somewhat cordate at the base, and attached by 
 the middle portion only, have no midrib but what is produced by the 
 union of the nervures or veins, that proceed from the axis of the leaflet 
 in branching well-marked lines to the margin, which is entire in the Coal- 
 measure and Permian species, but occasionally slightly serrated in those of 
 the Oolite. The genus takes its name from the curved dichotomous veins 
 of its leaflets ; many of the species were of gigantic habits ; and in several 
 the pinnated divisions were furnished with a small circular leaflet, which, 
 when detached, is apt to be mistaken for a cyclopteris. 
 
 New Red. A brief expression for the New Red Sandstones (Permian and 
 Triassic) which occur above the Coal-measures, in contradistinction to the 
 Old Red, which lies below. 
 
 New Bed Sandstone. Immediately above the Coal-measures in some 
 instances lying unconformably on and in others insensibly graduating from 
 them occurs a set of red sandstones and pebbly conglomerates, yellowish 
 magnesian limestones, and variegated shales and marls, enclosing irregular 
 masses of rock-salt and gypsum. To this series of strata, as more especially 
 developed in England, the earlier geologists applied the term New Red 
 Sandstone, in contradistinction to the Old Red Sandstone system which 
 lies beneath the Carboniferous formation. More recently it has been pro- 
 posed to divide these new red sandstones, magnesian limestones, and 
 saliferous marls into two distinct systems, the Permian and the Triassic 
 the former embracing the lower members, which are largely and typically 
 developed in the government of Perm, in Russia ; and the latter com- 
 prising the \ipper members, known as the "Trias," or triple group, in 
 Germany. The reasons for this new arrangement are, that the fossils of 
 the magnesian limestone and lower red sandstones seem more closely 
 allied to those of the Coal-measures beneath, than to those of the varie- 
 
 322 
 
NIC 
 
 gated sandstones and saliferous marls above, in other words, present a 
 Palaeozoic aspect ; while those of the upper sandstones and marls are de- 
 cidedly Mesozok. To render this new arrangement more intelligible, let 
 us suppose all the red sandstones, marls, and magnesian limestones 
 hitherto known in England as " The New Red Sandstone," to be present 
 in one section. We should then have, reposing unconformably on the Coal- 
 measures, the following series of strata : 
 
 j Purple-coloured marls below the Lias. 
 I Alternations of red and bluish- white marls, 
 4. Series of col- \ with layers and nodules of gypsum, 
 cured marls. j Thin layers of argillo-calcareous stone. 
 
 \ Red and bluish marls, with gypsum and beds 
 
 
 
 
 of rock-salt. 
 
 (Red and white sandstone, mostly fine-grained, 
 , J and often impregnated with salt. 
 " j Red conglomerate, full of pebbles of older 
 
 v. rocks. 
 ' -Red and white marls. 
 
 Thin-bedded compact limestone, with very 
 
 little magnesia, and few organic remains. 
 Red and white marls and gypsum. 
 
 2. Magnesian lime- White, yellow, or reddish magnesian lime- 
 stone, stone in thick beds, crystallised, compact, 
 or earthy, often full of sparry cavities, and 
 containing marine organic remains. 
 Marl slate in thin layers, occasionally enclos- 
 ing fishes. 
 
 fAn extremely variable series of sandstones, 
 1. Yellow or purple I sands, and clays of various colours, irregu- 
 sand and sandstone, ( lar thickness, and much local diversity of 
 \aud marl. j character. Plants like those of the Coal- 
 
 \ measures. 
 
 From the preceding tabulation, the reader will perceive at a glance the 
 nature of the strata formerly designated the New Red Sandstone, as well 
 as the limits of the Permian and Triassic systems into which it is now 
 divided, and which are still occasionally spoken of as the Lower and Upper 
 New Red Sandstones. 
 
 Nickel (Ger.) One of the metals ; white, ductile, malleable, attracted 
 by the magnet, and, like iron, capable of being rendered magnetic. Its 
 specific gravity, when hammered, is about 9. It is rather more fusible 
 than pure iron ; is not altered by exposure to the air and moisture at ordi- 
 nary temperatures, but is slowly oxidised at a red heat. It is found in 
 all meteoric iron ; but its principal ore is a copper- coloured mineral found 
 in Germany, and called nickeline or kupfer-nickel "nickel" being a term 
 of detraction used by the miners, who expected from the colour of the ore 
 that it would contain copper. Since the manufacture of German silver or 
 argentane, nickel has, however, become an object of considerable import- 
 ance, and is extracted from severel ores, as from Gersdovffite or nickel- 
 glance, Nickeline or copper-nickel, and the like. These are usually com- 
 pounds (speise) of nickel, cobalt, antimony, arsenic, sulphur, or iron, and 
 belong to the family Pi RITES. The salts of nickel are mostly of a grass- 
 green colour, and the ammoniacal solution of its oxide is deep blue, like 
 that of copper. 
 
 323 
 
NIC NIT 
 
 Nick el- Glance. Known also as Gersdorffite, a greyish-white, massive 
 and granular ore of nickel, occurring in the transition rocks of upper 
 Germany, Sweden, Spain, Brazil, and other countries, and consisting, on 
 the average, of 35.5 nickel, 45.2 arsenic, and 19.3 sulphur part of the 
 nickel being replaced by iron or cobalt. 
 
 Nickeline. The kupfer-nickel or copper - nickel of Werner, and the 
 arsenical nickel of other authors. One of the chief ores of nickel, occurring 
 in strings and nodules, but generally massive and disseminated in veins 
 (rarely in beds), in the granitic and crystalline rocks, and also in Secondary 
 strata associated with cobalt, silver, and copper. It is found abundantly in 
 Germany, and to some amount in America, Cornwall, and other countries. 
 It consists of 44 nickel and 54 arsenic (part of the latter being often 
 replaced by antimony), with traces of sulphur, iron, cobalt, and lead. 
 Family PYRITES. 
 
 Nickel-Ochre, Nickel-Green. An arsenate of nickel occurring massive, 
 earthy, friable, and in short capillary crystals of an apple-green colour, 
 whence the familiar name. Consists of nickel, 37.6 ; arsenic acid, 38.4 ; and 
 water, 24. 
 
 Nidulites (Lat. nidus, a nest). Undetermined organisms occurring in 
 Silurian strata, and so named because at first supposed to be the nidi or 
 egg-masses of a gasteropod, similar to those of the modern natica. *'This 
 explanation," says Mr Salter, " fails, however, when the organism is more 
 closely examined ; since the cells are equal and regular on both sides of a 
 central lamina, and are set back to back like the cells of a honeycomb." 
 They seem more akin to the Bryozoa (retepora and flustra) ; but differ in 
 their great size and in the absence of any plate or cover to the cells. 
 
 Nilsonia (after Nilson). One of Brongniart's genera of Cycadaceous 
 leaves, occurring in the Lias and Oolite ; but now ranked as a species of 
 PUrophylltim, which see. 
 
 Nipadites. A genus of fossil palm-nuts found by Mr Bowerbank in the 
 Tertiary clays of the island of Sheppey, near London ; and so called from 
 their resemblance to the fruit of the existing Nipa fruticans of Bengal 
 and the East India Islands. The Nipa is allied to the cocoa-nut tribe on 
 the one side, and on the other to the Pandanus or screw-pine. It is a 
 low-growing plant, luxuriating in marshy tracts at the mouths of great 
 rivers, particularly where the waters are brackish. And Mr Bowerbank 
 remarks, that " if the habits of the plants to which the fossil fruits be- 
 longed were similar to those of the recent Nipa, it will account for their 
 abundance in the London Clay in the Isle of Sheppey; which formation, 
 from the great variety of stems and branches, mixed up with star-fishes, 
 shells of molluscs, and bones of fishes, crustaceans, and reptiles of numer- 
 ous marine and fresh-water genera, is strikingly characteristic of the delta 
 of a river, which probably flowed from near the equator towards the 
 spot where these interesting relics are deposited." 
 
 Nitre (Gr. nitron). The familiar as well as technical term for the 
 nitrate of potash 46.6 potash and 53.4 nitric acid. Known also as salt- 
 petre and prismatic nitre-salt. " It is," says Brande, ' Diet, of Science,' 
 " spontaneously generated in the soil, and crystallises upon its surface in 
 several parts of the world, especially in India, whence nearly the whole of 
 the nitre used in Britain is derived. It has occasionally been produced 
 artificially in nitre beds, formed of a mixture of calcareous soil and animal 
 matter. In these nitrate of lime is slowly formed, which is extracted by 
 
 324 
 
NIT NOD 
 
 lixiviation, and carbonate of potash added to the solution, which by double 
 decomposition gives rise to the formation of nitrate of potash and carbo- 
 nate of lime : the latter is precipitated ; the former remains in solution, 
 and is obtained in crystals by evaporation. Nitre crystallises in six-sided 
 prisms ; is soluble in seven parts of cold water, and in less than its weight 
 of boiling water. It has a cooling taste, and is anhydrous. At 616 it 
 fuses, and at a red heat is decomposed." It is used in glass-making, in 
 medicine, as an antiseptic, for producing nitric acid, but especially, and 
 most extensively, in the manufacture of gunpowder. 
 
 Nitratine. The mineralogical term for the nitrate of soda 36.6 soda 
 and 63.4 nitric acid. Known also as cubic nitre or rhombohedral nitre-salt) 
 from its crystallising in rhombic crystals. " This salt," says Nicol ('Man 
 of Mineral.'), " occurs in the district of Tarapaca on the northern frontier 
 of Chili, where it forms beds averaging four feet thick, and extending 
 forty leagues in length. It rests on marl containing fragments of shells 
 in a basin-like pampa, and is mixed with various salts. It is supposed to 
 have been left by the sea, but the chemical nature of the salt is against 
 this opinion." It is largely used as a manure, and is employed in the arts 
 as a substitute for nitre, but is unfitted for manufacturing gunpowder from 
 its deliquescing in the air. See SALINAS. 
 
 Nitrocalcite (nitron, and calx, lime). Nitrate of lime, occurring in pul- 
 verulent efflorescences on old walls and in limestone caves, especially near 
 decaying animal matter. Has a greyish-white colour ; sharp bitter taste ; 
 readily soluble in water ; and consists of 32.00 lime, 57.54 nitric acid, and 
 10.56 water. 
 
 Nitrogen (Gr. nitron, and ginomai, I produce). One of the elementary 
 gases ; so called from its being a constituent or generator of nitre. It 
 is a colourless, inodorous, and tasteless gas, not absorbed by water, and 
 has no action on vegetable colours. It extinguishes all burning bodies, is 
 itself uninflammable, and, being unrespirable, is destructive of life ; hence 
 the earlier term azote (a priv., and zoe, life). It is somewhat lighter than at- 
 'mospheric air, and combines with oxygen in Jive proportions, forming nitrous 
 oxide (NO), nitric oxide (NO 2 ), hyponitrous acid (NO 3 ), nitrous acid 
 (NO 4 ), and nitric acid (NO 5 ). Nitrogen is an important element in 
 nature. It constitutes four-fifths, or 79 per cent, of the volume of atmos- 
 pheric air ; it enters largely into the composition of many plants and ani- 
 mals, and forms their chief nutritive principle ; is present in the native 
 nitrates of soda and potass ; occurs in coal and a few other minerals, evi- 
 dently of organic origin ; and is given off by certain springs and volcanic 
 vents. 
 
 Nitromagnesite. Nitrate of magnesia; a saline efflorescence occurring 
 in the same places with nitrocalcite or nitrate of lime, which it closely 
 resembles in character, but consists of 24 magnesia, 65 nitric acid, and 11 
 water. 
 
 Noble. A term frequently employed in mineralogy to express excellence 
 or the highest degree of purity, as noble opal, the precious opal ; noble horn- 
 blende, pargasite ; noble tourmaline, the finest transparent varieties of that 
 mineral. 
 
 Noble Metals. The name given to those metals which can be separated 
 from oxygen by heat alone. They are gold, silver, platinum, rhodium, 
 iridium, osmium, and mercury. * . 
 
 Nodes (Lat. nodus, a knot). In astronomy, the points where the 
 325 
 
NOD NOT 
 
 orbit of a planet cuts the plane of the ecliptic ; or generally the points 
 where the orbit of one planet cuts or crosses the orbit of another. In 
 botany, the thickened part of a stem or branch from which a leaf is 
 developed. 
 
 Nodosaria (Lat. nodosus, knotted, full of knots). A genus of foramini- 
 feral organisms occurring in Chalk, Tertiary, and Eecent formations ; 
 and so termed from the arrangement of their cells, which are somewhat 
 elongated and placed end to end, forming a minute, knotty, or bead-like 
 frustule the last cell having a round central opening. 
 
 Nodule (Lat. nodus, a knot). Any irregular concretion of rock-matter 
 collected by attraction or aggregation round some central nucleus, as 
 nodules of ironstone, flint, &c. Nodular concretions may be aggregated 
 around either organic or inorganic nuclei. 
 
 Noeggerathia. A genus of palm-like leaves found in the Carboniferous 
 and Permian systems ; so named after Dr Noeggerath, who has done much 
 for the elucidation of our fossil floras. In Noeggerathia the leaves are 
 petiolated, pinnated ; the leaflets nearly cuneiform, applied against the 
 edges of the petiole, toothed towards the apex, and furnished with fine 
 diverging veins. 
 
 Nomadic (Gr. nomadikos}. Pastoral ; wandering; applied in geography 
 and ethnography to those tribes that subsist by the tending of herds and 
 flocks, and consequently wander hither and thither in search of new pas- 
 tures, like the Tartars of Central and Northern Asia. Used in contradis- 
 tinction to settl ed and civilised as subsisting by agriculture and dwell- 
 ing in towns and villages. 
 
 Nonionina. A genus of nautiloid foraminiferous organisms occurring 
 in the Chalk, in Tertiary strata, and in the existing seas. Their simple 
 cells are arranged like the chambers of the nautilus, the last having a 
 single narrow aperture. 
 
 Normal (Lat. norma, a rule). According to rule or law ; obeying what 
 is believed to be the natural law; occurring in the ordinary course of 
 nature. 
 
 Northern Drift. A synonyme of the "Glacial Drift" or "Erratic 
 Boulder Group," because in the northern parts of Europe and America 
 the materials seem to have been brought by polar currents from the north- 
 ern to the southern regions. See GLACIAL DRIFT. 
 
 Notidanus (Gr. notos, ridge, and idanos, beautiful). A genus of fossil 
 shark-teeth, each tooth having the crown or ridge composed of a series of 
 sharp angular enamelled points, the first of which is the largest, and is 
 notched on the anterior edge. The base of the tooth is bony, flat, and 
 furnished with a longitudinal groove beneath the edge of the enamel. 
 They are found in the Oolite and Chalk, but are specifically most abun- 
 dant in the Lower Tertiaries. 
 
 Notite. A variety of Palagonite (which see) from the Val di Noto in 
 Sicily, whence the name. 
 
 Notopocorystes (Gr. notos, the back, carapace). A genus of cretaceous 
 crabs, whose carapaces (the only portions yet definitely known) appear to 
 have some relations with the existing genus Corystes. The corystes have 
 elongated oval carapaces ; have the tail folded under the body when at 
 rest ; have the first pair of their ten limbs chelate, the others terminating 
 in a slender claw ; and are furnished with two pairs of antennae the outer 
 being long and setaceous. 
 
 326 
 
NOT ^ NUM 
 
 Notornis (Gr. notos, the south, and ornis, bird). Literally "southern 
 bird ; " a short-winged rail or coot first known by its sub-fossil bones 
 found in the sands and volcanic debris of New Zealand, and believed to be 
 extinct ; but subsequently one or two living specimens have been ob- 
 tained. 
 
 Nototherium (Gr. notos, the south, and therion, beast). An extinct genus 
 of gigantic quadrupeds found in the alluvial or Upper Tertiary deposits of 
 Australia. As far as the teeth, jaws, and other scattered bones enable 
 the comparative anatomist to decide, the Nototherium manifests pachyder- 
 mal modifications of the marsupial type ; hence the inference that Austra- 
 lia (whose largest native quadruped is now the kangaroo) was, immediately 
 preceding the current era, inhabited by a marsupial vegetable-feeder as 
 large as the rhinoceros. 
 
 Novaculite (Lat. novacula, a razor). A mineralogical term for wketslate, 
 in allusion to the principal purpose to which it is applied. Whetslates of 
 sufficiently fine texture, and keen siliceous grain, are found among the clay- 
 slates and mica-schists of most metamorphic districts. 
 
 Nucleolites (nucleus, a little nut or kernel, and lithos). A genus of sea- 
 urchins belonging to the family Clypeidece, and characterised by their ob- 
 long inflated shell, which is rounded in front and flat behind. The pores 
 are united by grooves ; the mouth is sub-central ; and the vent in a deep 
 furrow on the superior face. Several species occur in the Oolite, Chalk, 
 and Greensand ; one is known in Tertiary strata ; and a recent species in- 
 habits the seas of Australia. 
 
 Nucleus (Lat. nux, a nut nuckus, a little nut or kernel). The solid 
 centre of any nodule or rounded mass is said to be its nucleus ; the central 
 matter round which any mass is collected or aggregated. 
 
 Nucula (Lat., a little nut). An extensive genus of bivalves belonging to 
 the family Arcades, and characterised by their trigonal inflated shells, 
 with their umbones turned towards the short posterior side ; the valves 
 smooth or sculptured ; margins crenulated ; hinge with prominent internal 
 cartilage pit, and a series of sharp teeth on each side. Living in many 
 seas on coarse bottoms from 5 to 100 fathoms ; and fossil from the Lower 
 Silurian upwards. The species having the shell oblong and rounded in 
 front, with the posterior side produced into a long beak, have been erected 
 into the separate genus Leda. 
 
 Nugget (Sax. ) The usual name among gold-diggers for those irregular 
 pellets of the metal which occur in auriferous drifts, and which are found 
 of all sizes, from that of a pea to lumps many pounds in weight. 
 
 Nullah. A Hindostanee term for those streams, or rather stream- 
 courses, which are mountain torrents during the rainy season, and during 
 the rest of the year are dry gravelly channels, with here and there a trick- 
 ling of water. See WADI. 
 
 Nummulina, Nummmulites, Nummulite (Lat. nummus, a coin, and lithos, 
 stone). An extensive class of fossil foraminiferous organisms, so called 
 from their general resemblance to a coin or piece of money. They occur 
 in inconceivable numbers in certain rocks (the nummulitic limestone), and 
 are of all sizes, from a mere point to discs an inch and half in diameter 
 being thus the largest organisms of their class. Perfect specimens appear 
 as a calcareous solid circular body of a lenticular shape ; smooth and 
 slightly convex on both sides, and without any visible structure. On 
 splitting the fossil transversely, or rubbing down one of the convex planes, 
 
 327 
 
NUM OAZ 
 
 a series of minute cells, arranged in discoidal spire, is brought into view ; 
 and these cells, in the living organism, were all connected internally, as 
 well as communicated externally, by minute pores or foramina for the free 
 passage of the sarcode or fleshy substance of the protozoan. The numrnu- 
 lite would appear to be a strictly Tertiary form, being unknown alike in 
 Secondary or in recent deposits. It seems also to be an Old World form, 
 its representative in time and in geological function in the New World 
 being the genus ORBITOIDES, which see. 
 
 Nunmralitic Limestone. An important member of the Lower Tertiaries 
 (Middle Eocene) of the Old World, and so termed from the number and 
 variety of nummulites with which it is charged. " The nummulitic forma- 
 tion," says Lyell, " with its characteristic fossils, plays a far more con- 
 spicuous part than any other Tertiary group in the solid framework of the 
 earth's crust, whether in Europe, Asia, or Africa. It often attains a thick- 
 ness of many thousand feet, aud extends from the Alps to the Carpathians, 
 and is in full force in the north of Africa as, for example, in Algeria and 
 Morocco. It has also been traced from Egypt, where it was largely 
 quarried of old for the building of the pyramids, into Asia Minor, and 
 across Persia by Bagdad to the mouth of the Indus. It occurs not only in 
 Cutch, but in the mountain-ranges which separate Scinde from Persia, and 
 which form the passes leading to Caboul ; and it has been followed still 
 further eastward into India, as far as Eastern Bengal and the frontiers 
 of China." More recently it has been traced onward even to the Philippine 
 Islands, thus forming a zone that girdles nearly one half the globe. As 
 the Nummulitic Limestone seems characteristic of the Old World, so the 
 Orbitoidal Limestone seems characteristic of the New mountain-masses 
 full 300 feet in thickness, and almost wholly made up of Orbitoides, occur- 
 ring near Suggsville in North America, and apparently on the same, or 
 nearly the same, geological horizon. 
 
 Nuthetes. Abbreviated from the Greek Noutheietes, monitor, in refer- 
 ence to the affinities of the fossil to the northern lizards so called. A car- 
 nivorous or insectivorous lizard from the Purbeck beds of the Upper 
 Oolite, of the size of the great land-monitor of India, and furnished with 
 serrated teeth for piercing, cutting, and lacerating its prey. 
 
 O'asis (Gr.) In physical geography, a green and fertile spot in a desert ; 
 originally applied by Herodotus to the inhabited patches of fertile ground 
 which occur around springs in the Libyan desert. The word is said to be 
 of Coptic origin, signifying "inhabited." 
 
 Oaze, Ooze. The name usually given to the soft slimy mud that covers 
 extensive areas of the deeper sea-bed. Speaking of this mud, Captain 
 Dayman, in his ' Deep-Sea Soundings,' says, " Between the 15th and 45th 
 degree of west longitude, lies the deepest part of the ocean, between Ire- 
 land and Newfoundland, varying from about 1500 to 2400 fathoms, the 
 
 328 
 
OBL OCE 
 
 bottom of which is almost wholly composed of the same kind of soft mealy 
 substance, which for want of a better name I have called Oaze. This sub- 
 stance is remarkably sticky, having been found to adhere to the sounding- 
 rod and line through its passage from the bottom to the surface, in some 
 instances from a depth of more than 2000 fathoms." On microscopic ex- 
 amination this oaze was found to consist for the most part of foraminiferal 
 organisms, there being about 90 per cent of calcareous, and only 10 per 
 cent of siliceous matter ; the mass when 'dried greatly resembling chalk 
 in colour and consistency. 
 
 Oblate (Lat. oblatus). Generally applied to spherical bodies more or 
 less flattened at opposite sides or poles ; shaped like an orange. The 
 earth is an oblate spheroid, being flattened at either pole to the extent of 
 about thirteen miles, and thus deviating from the true spherical or globular 
 figure. 
 
 O'bolus (a small Greek coin). A genus of bivalves belonging to the 
 Lingula family, and characterised by their orbicular, smooth, calcareo- 
 corneous, sub-equivalve shells, which have the hinge margin somewhat 
 thickened inside, and the lower valve with a notch for the pedicle. There 
 are several species occurring in the Silurians of Northern Europe ; hence 
 the " obolite grit " of Sweden and Russia. 
 
 Obsidian (Gr. opsianos, so called, it is said, from being used by the 
 ancients for looking-glasses; others derive it from Obsidius, a Roman, who 
 first brought it from Ethiopia). A glassy lava almost undistinguishable 
 from artificial glass-slag, and placed by mineralogists under the Felspar 
 family. Its composition is variable, but it consists in general of about 80 
 silica, 10 alumina, with varying minor percentages of potash, soda, lime, 
 and oxide of iron. It is a true volcanic glass, of various colours, but 
 usually black or blackish-grey ; occasionally porph^ritic from enclosed 
 crystals of glassy felspar ; has a specific gravity of about 2.37 ; is hard 
 enough to scratch glass ; and nearly opaque. It occurs in streams or in 
 detached masses near many volcanoes ; and has been used by rude nations 
 for the fabrication of mirrors, axes, knives, arrow-heads, and the like. 
 As might be anticipated from its origin, obsidian frequently graduates 
 into pumice and pearlstone, which see. 
 
 Occidental Diamond. An occasional lapidary's term for limpid and 
 colourless varieties of rock-crystal when cut and polished. Used in con- 
 tradistinction to the Oriental or true diamond. 
 
 Occipital (Lat. occiput, the hinder part of the head). Belonging to the 
 back part of the head; hence we speak of "occipital bones," "occipital 
 parietes," &c. 
 
 Ocean (Gr. and Lat.) In geography, the vast body of water which covers 
 about three-fourths of the surface of the globe, and which, in connection, 
 composition, and other characteristics, forms one continuous "world of 
 waters." For convenience of description, and relatively to the land, it is 
 usual to subdivide it into the Atlantic, Pacific, Indian, Arctic, and Ant- 
 arctic Oceans, each of which from its position and configuration is charac- 
 terised by different kinds of waves, tides, and currents ; by differences in 
 composition, temperature, and depth ; and as a consequence by different 
 facies of animal and vegetable life. The minor ramifications of the ocean 
 into land are known as seas, bays, gulfs, creeks, inlets, and the like, ac- 
 cording to their forms and dimensions. 
 
 Oceanic. Belonging to, occurring in, or produced by, the ocean ; hence 
 329 
 
OCE ODO 
 
 we speak of " oceanic life," "oceanic currents," "oceanic deltas," and 
 the like. 
 
 Ocellaria (Lat. ocellus, a little eye). A conical- shaped zoophyte occur- 
 ring in chalk-flints, and so named by Koenig from the numerous eye-like 
 polyp-cells which stud its surface. 
 
 O'chre (Gr. and Lat. ochra). A term familiarly applied to a well-known 
 pigment, varying in colour from a pale yellow to a deep orange or brown, 
 and consisting of iron peroxide and water, with varying proportions of 
 clay in a state of impalpable subdivision. Strictly speaking, ochre is a 
 hydrated peroxide of iron, consisting of about 80 of the peroxide and 20 
 water ; but is very rarely found absolutely pure, and appears to be a pro- 
 duct of decomposition. It occurs in all formations, much of that used in 
 Britain being obtained from beds in the Coal formation. In mineralogy, 
 the term ochre is also applied to other products of decomposition result- 
 ing from the oxidised ores, as cobalt-ochre, bismuth-ochre, antimony-ochre, 
 uran-ochre, chrom-ochre, &c., most of them occurring as earthy masses or 
 pulverulent incrustations. See REDDLE. 
 
 Octaedrite, Octahedrite. A mineralogical term for the pure oxide of 
 titanium, which occurs in elongated eight-sided crystals, in veins in the 
 primary and crystalline rocks. Known also as Anatase and Pyramidal 
 Titanium ore. 
 
 Octahedral, Octaedral (octo, eight, and hedra, side). Having eight equal 
 sides, as octahedral oxide of titanium, octahedral iron ore, &c., these 
 ores occurring in eight-sided crystals. 
 
 Oculina (Lat. oculus, the eye). A genus of stony branching corals, be- 
 longing to the family of Madrepores, and so called from the eye-like or 
 star-like polyp-cells which stud its smooth, thick, short branches. The 
 common Oculina virginea is often known as " white coral," in contradis- 
 tinction to the Corallium rubrum, or "red coral" of commerce. 
 
 O'culus. A not unfrequent term of the older mineralogists for minerals 
 having an opalescent or eye-like lustre ; as oculus mundi, hydrophane ; 
 oculus piscis, icthyophthalmite or fisheye-stone, &c. 
 
 Odontaspis (Gr. odous, tooth, and aspis, buckler). Literally "buckler- 
 tooth ; " a genus of shark-like fishes occurring in the Chalk formation, and 
 so termed from the buckler-like aspect of their teeth the only portions 
 yet known. 
 
 Odontolite (Gr. odous and lithos}. Literally "tooth-stone" or bone tur- 
 quois, which consists of teeth or bone impregnated and coloured by oxide 
 of copper. See TDRQUOIS. 
 
 Odont61ogy (Gr. odous, tooth, and logos, discourse). That branch of 
 anatomical science which treats of the teeth. "The term 'tooth/" says 
 Professor Owen, "has been applied in zoology and zoonomy to various 
 organs and parts; usually to such as are so solid, so shaped, and so 
 situated, as to serve for seizing and operating on the food ; but it has been 
 also applied to parts, such as the prominences on the hinge of bivalve 
 shells, which have no relation to the digestive functions. The siliceous 
 spines of infusorial animalcules, the calcareous jaws of sea-urchins, the 
 chitinous hooks and booklets of sea-worms, and many corresponding parts 
 of invertebrate animals, are described as ' teeth ; ' but odontology proper 
 exclusively relates to those bodies, hardened chiefly by the phosphate of 
 lime, which are attached to parts of the mouth or beginning of the alimen- 
 tary canal, and which are peculiar to the vertebrated classes of animals. 
 
ODO OGY 
 
 . . . True calcified teeth vary in their tissue and composition, and 
 still more in regard to number, size, form, structure, position, and mode 
 of attachment, in different animals. They are principally adapted for 
 seizing, tearing, dividing, pounding, or grinding the food ; in some they 
 are modified, to serve as weapons of offence and defence ; in others, as 
 aids to locomotion, means of anchorage, instruments for uprooting or 
 cutting down trees, or for transport and working of building materials. 
 They are characteristic of age and sex ; and in man they have secondary 
 relations to beauty and to speech. Teeth are always most intimately 
 related to the food and habits of the animal, and are therefore highly 
 interesting to the physiologist. They form, for the same reason, most 
 important guides to the naturalist in the classification of animals ; and 
 their value as zoological characters is enhanced by the facility with which, 
 from their position, they can be examined in living or recent animals ; 
 whilst the durability of their tissues renders them not less available to the 
 palaeontologist, in the determination of the nature and affinities of extinct 
 species, of whose organisation they are often the sole remains discoverable 
 in the deposits of former periods of the earth's history." See Owen's 
 ' Odontography,' and article ' Odontology ' in ' Encyclopaedia Britannica.' 
 
 Odontopteris (Gr. odous, odontos, tooth, and pteris, fern). A somewhat 
 obscure genus of fossil ferns occurring in the Coal-measures, and so called 
 from the blunt tooth-like lobes of their leaflets. In Odontopteris the leaves 
 are bi-pinnated ; leaflets lobed, membranous, adhering by all their base to 
 the rachis, and furnished with a very indistinct midrib, from which a few 
 ill-defined branching or simple veins pass into the lobes, which have no 
 midrib. 
 
 Odour, as a characteristic of minerals, is not possessed by any of them 
 in a dry unchanged state ; but it may be obtained from several by moist- 
 ening with the breath, by friction, by heat, or by the action of an acid. 
 Hence we have the argillaceous odour, or the odour of moistened clay, 
 when certain rocks, as chlorite and serpentine, are breathed upon ; the 
 fetid, or the odour of sulphuretted hydrogen, obtained from certain lime- 
 stones when rubbed or struck with the hammer ; the sulphurous, obtained 
 by friction from pyrites, or by heat from most of the sulphurets ; and the 
 garlic odour, obtained by friction from some, and by heat from most, of 
 the arsenical salts and ores. 
 
 (E'ningen Beds. A remarkable lacustrine deposit of highly fossiliferous 
 marls and limestones, occupying a hollow in the molasse near CEningen, 
 where the Rhine issues from the Lake of Constance. They are of Upper 
 Tertiary age, and are replete with remains of dicotyledonous plants, fresh- 
 water shells, crustaceans, insects, fishes, and turtles, and have also yielded 
 remains of quadrupeds. 
 
 Offing. In maritime phraseology and geography, that part of the sea 
 which lies outward or off at some distance from a shore or harbour ; hence 
 vessels are said to ride or lie at anchor in the offing, that is, beyond the 
 shoals and other influences of the shallower shore. 
 
 Og^gia (from Ogyges}. A genus of Silurian trilobites, so named in allu- 
 sion to the obscure and remote character of these Crustaceans, or from 
 their being found in the lowest or earliest fossiliferous formations. 
 
 Og^gian. From Ogyges, one of the earliest of the Grecian monarchs. 
 His origin, the age in which he lived, and the duration of his reign, are so 
 obscure, that the term Ogygian is often applied to everything of dark or 
 
 331 
 
OIL OLD 
 
 doubtful origin or antiquity. Chronologers date his reign at some two 
 thousand years (1761) before the Christian era. Ogygian Deluge. The 
 name given to a great inundation mentioned in fabulous history, and sup- 
 posed to have taken place during the reign of Ogyges of Attica. 
 
 Oil-Coals. A commercial designation gradually coming into use for 
 those varieties of coal (chiefly cannels) which yield a large proportion of 
 oil on distillation. Many of these slaty cannels pass insensibly into shales 
 "oil-shales" and it is not always easy to draw the line of demarcation 
 between an oil-shale and oil-coal. The poorer varieties yield from 25 to 
 40 gallons of crude oil per ton, the richer from 50 to 80, and even some 
 picked samples so much as 100 gallons per ton. 
 
 Oil- Wells, Oil-Springs. The common designation, especially in America, 
 for discharges, whether natural or artificial, of petroleum or rock-oil. Since 
 the introduction of paraffin and paraffin-oil, the oil-wells of the United 
 States and Western Canada have assumed a vast commercial importance, 
 hundreds of thousands of barrels being raised annually and rectified either 
 for home use or for exportation, to Europe. See PETROLEUM. 
 
 Oldhamia. A peculiar sertularian-like zoophyte, or perhaps polyzoon, 
 occurring in the lowest Silurian or Cambrian rocks, and so termed because 
 first detected by Professor Oldham in the purplish hard schists of Bray 
 Head, near Dublin. In Oldhamia the cells occur in radiating tufts or 
 bundles alternately arranged on a common axis or stem. 
 
 Old Men's Workings." In mining," says Ansted, "this term is used in 
 reference to mines that have been formerly worked, and where under- 
 ground excavations are found on reopening the mine. By the old men, 
 miners mean any former workers of mines they are engaged in." 
 
 Old Red. A brief expression for Old Red Sandstone, in contradistinction 
 to New Red the former lying beneath, and the latter above the true 
 Coal-measures. As a system of fossiliferous strata, the Old Red Sand- 
 stone is now generally treated under the term DEVONIAN. 
 
 Old Red Sandstone, or Devonian System. Taking the Coal-measures as 
 a sort of middle formation, there is generally found in the British Islands 
 one set of reddish sandstones lying beneath, and another set lying immedi- 
 ately above them. By the earlier geologists the lower set was designated 
 the Old Red Sandstone, and the upper the New Red Sandstone ; and though 
 the progress of the science has rendered it necessary to impose certain limi- 
 tations on these terms, they are still sufficiently distinctive and easily re- 
 membered. The Old Red Sandstone may therefore be held as embracing 
 the whole series of strata which lies between the Silurian system on the one 
 hand, and the Carboniferous system on the other. Certain portions of the 
 system are peculiarly developed in Devonshire, and contain a copious and 
 varied fossil -fauna ; hence the introduction by Murchison and Sedgwick 
 of the term Devonian a term now generally employed as synonymous with 
 the earlier and more descriptive one of ' ' Old Red Sandstone. " Characterised 
 on its lower margin by strata containing the remains of fishes, and which 
 form a line of separation, as it were, between it and the underlying Silurian, 
 and defined, on its upper margin, by the rarity of that vegetation which 
 enters so profusely into the composition of the Carboniferous rocks, there 
 can, in general, be no difficulty in determining the limits of the Old Red 
 formation. On the whole, its composition is manifestly arenaceous, the 
 great bulk of the system consisting, as the name implies, of a succession of 
 sandstones, alternating with subordinate layers of sandy shale and beds of 
 
 332 
 
OLI 
 
 concretionary limestone. The sandstones pass in fineness from close-grained 
 fissile flags to thick beds of coarse conglomerate, and the shales from sandy 
 laminated clay to soft flaky sandstone. The whole system is less or more 
 coloured by the peroxide of iron the shades varying from a dull rusty grey 
 to a bright red, and from red to a fawn or cream-coloured yellow. The 
 "Devonian" proper, on the other hand, exhibits in its middle and upper 
 portions an abundant development of fossilif erous limestones and calcareous 
 shales, of slaty shales or dark bituminous-looking schists. Indeed, north 
 of the Bristol Channel, the fossiliferous limestones, schists, and grits of 
 Devonshire are altogether wanting, and the term "Old Red Sandstone" 
 then becomes the more appropriate designation for the system. In the 
 north of Europe a similar preponderance of arenaceous members prevails ; 
 while, on the Rhine and in Belgium, the fossiliferous limestones of Devon 
 have their parallels in equally fossiliferous calcareous strata. Throwing 
 the system into three great groups, as is usually done, we are presented 
 with the subjoined co-ordinations : 
 
 /'Baggy Point sandstone and Morte Bay schists, N. Devon ; goni- 
 I atite limestone, Belgium ; yellow sandstones of Dura Den, 
 UPPER / FifQ) with holoptychii and pterichthys ; Telerpeton beds, 
 j Lossiemouth (Triassic?); Cyclopteris beds of Kilkenny; red 
 V and white sandstones of Dunse. 
 
 flfracombe and Plymouth limestones, Devon, and Eifel lime- 
 stone, Belgium, both abounding in corals, crinoids, shells, 
 trilobites, and occasional fishes. Red sandstones of Berwick 
 and Roxburgh ; red sandstones, marls, conglomerates, and 
 cornstones of Hereford, Cumberland, Fife, Perth, and Forfar, 
 the characteristic fossils being holoptychii, bothriolepis, &c. 
 
 f Caithness flags and shales, abounding in fishes diptems, osteo- 
 
 I lepis, coccosteus, cheiracanthus, &c. ; N. Foreland, Porlock, 
 
 | and Torquay beds, Devon ; Spirifer sandstones and shale, 
 
 LOWER ' Rhine. Great pebbly conglomerates and flagstones of Forfar, 
 
 1 with cephalaspis, acanthodes, and pterygotus; Ludlow and 
 
 Lanark tilestones, with pterygotus, eurypterus, and other 
 
 *! kindred crustaceans. 
 
 Palaeontologically, though yielding numerous plant-impressions and re- 
 mains of corals, crinoids, shell-fish, trilobites, and eurypterites, the most 
 marked and characteristic fossils of the system are, perhaps, its numerous 
 and varied FISHES often of peculiar forms, and covered with bony plates 
 (coccosteus, pterichthys, cephalaspis, &c.), clad with hard enamelled, and 
 variously ornamented scales (holoptychins, dipterus, asterolepis, &c.), and not 
 unfrequently armed with sharp, defensive fin-spines (cheiracanthus, dipla- 
 canthus, &c.) See tabulations, "GEOLOGICAL SCHEME." 
 
 Oligiste, Oligistic (Gr. oligistos, least, signifying that it is less rich in 
 metal than magnetite). A name frequently given to specular iron ore, or 
 those varieties of haematite which have a crystalline structure. 
 
 Oligocene (Gr. oligos, small, and kainos, recent). A term employed by 
 M. Beyrich to designate certain Tertiary beds of Germany (Mayence, &c.), 
 which appear to be neither exactly of Eocene nor of Miocene age, but to 
 occupy an intermediate position. Oligocene, a little more recent than 
 Eocene slightly recent. 
 
 Oligoclase (Gr. oligos, small, and Hasis, fracture). A mineralogical 
 term for soda-felspar, in allusion to its peculiar fracture, as distinguished 
 
 333 
 
OLI OOL 
 
 from orlhoclase or potash felspar. According to Berzelius, it consists of 
 63.70 silica, 23.95 alumina, 8.11 soda, 1.20 potash, and 2.05 lime, with 
 traces of magnesia and iron. It occurs in granites and porphyries ; is of 
 a white or whitish-grey colour, and melts easier than orthoclase or albite 
 to a clear glass. See FELSPAR. 
 
 Olivenite. Hydrated arseniate of copper, occurring in prismatic crys- 
 tals, and also in reniform, granular, and fibrous crusts, and generally of a 
 deep olive green, whence the name. 
 
 O'livine. An olive-coloured semi-transparent mineral, occurring in 
 rounded grains and crystals in many basalts and lavas. It is common in 
 the basaltic greenstones of Scotland, and consists of about 40 silica, 48 mag- 
 nesia, 11 iron protoxide, with traces of manganese and alumina. Fine 
 green -coloured transparent crystallised varieties are known as Crysolile, 
 and occasionally used as gems, though not much valued, on account of 
 their softness and frequent flaws. 
 
 O'mbria (Gr. ombrios, rain). An early, but now disused, term for fossil 
 sea-urchins (echinites, cidarites, galerites, &c.), which were supposed to have 
 fallen from heaven in showers. 
 
 O'nclms (Gr. onchos, bent or hooked like a talon or arrow-barb). Ac- 
 cording to Agassiz, a genus of Cestracionts found in the Silurian, Devonian, 
 and Carboniferous formations. Their fin-spines or dorsal rays only are 
 known, and of these seven or eight species are enumerated. They are 
 wide at the base, and bent backwards, with their posterior margin desti- 
 tute of teeth. 
 
 Onyx. The general term for those varieties of agate which consist of 
 alternate layers of white, brown, or black, and which were greatly valued 
 by the ancients for cameos. The word is Greek, and signifies nail, in 
 allusion to the parallel bands of the mineral resembling those frequently 
 seen on the human nail. High prices are often given for genuine antique 
 onyx cameos. 
 
 O'olite (Gr. oon, an egg, and lithos, stone). A variety of limestone, so 
 termed from its being composed of small rounded grains, resembling the 
 eggs or roe of a fish each grain having usually some minute fragment of 
 sand as a nucleus, around which concentric layers of calcareous matter 
 have accumulated. When the grains are very distinct and well-rounded, 
 the term roestone is sometimes used as a synonyme ; and when they are 
 large and pea-like, the rock is known as pisolite or pea-stone (pisum, a pea). 
 The marked occurrence of these oolites or roestones in certain of the 
 Secondary strata of England, has given the name not only to the OOLITE 
 FORMATION, properly so called, but also to the OOLITIC SYSTEM as now 
 extended by modern geologists, which see. 
 
 Oolith.es (Gr. oon, egg, and lithos, stone). A general term for the fossil 
 eggs of birds, reptiles, and oviparous animals those of birds having been 
 found in recent and Upper Tertiary formations (jEpiornis), and those of 
 reptiles in Tertiary, and even, as recently supposed, in Oolitic strata 
 (Oolithes Bathonicce). The supposed egg-packets, or spawn of crustaceans, 
 Parka decipiens, occur abundantly at the very base of the Old Red 
 Sandstone ; and that of mollusca (Nidulites) so early as the Silurian 
 system. 
 
 Oolitic or Jurassic System. Deriving its name from the prevalence of 
 limestones of an oolitic texture as developed in England, or from the Jura 
 range, as typically exhibited on the continent of Europe. This system 
 
 334 
 
OOL 
 
 may be said to comprehend the whole of those peculiar limestones, cal- 
 careous sandstones, marls, shales, and clays which lie between the New 
 Eed Sandstone beneath and the Chalk formation above. And however 
 similar these strata may be in some features, there is no truth in geology 
 more fully established than this, that where the system is complete, the 
 argillaceous laminated limestone and shales termed the Lias constitute the 
 lowest group ; the yellowish granular limestones, calcareous sandstones, 
 sands and clays, called Oolite, the middle group ; and the greyish lami- 
 nated clays, with subordinate layers of limestone and flaggy ferruginous 
 sandstones, the Wealden or upper group. Taking these groups in descend- 
 ing order, the following synopsis exhibits their subdivisions as typically 
 developed over extensive areas in England : 
 
 f WEALD CLAY. Greyish or bluish laminated clays imbedding 
 concretions of ironstone, thin layers of argillaceous lime- 
 
 j stone, and sandy ferruginous flags. 
 
 WEALDEN / HASTINGS SANDS. Sands and sandstones frequently ferru- 
 ginous, with partings of clay ; beds of clay and sandy 
 shale more or less calcareous, with subordinate beds of 
 limestone. 
 
 PURBECK BEDS. Estuary limestones alternating with sands 
 and clays (formerly grouped with the Wealden). 
 
 UPPER OOLITE. Coarse and fine grained oolitic limestones, 
 with layers of calcareous sand and concretions (Portland 
 stone and Shotover sand) ; dark laminated clays, with 
 gypsum and bituminous shale (Kimmeridge clay}. 
 
 MIDDLE OOLITE. Coarse-grained, shelly, and coralline oolite, 
 with calcareous sands and grit (Coral rag} ; dark-blue 
 clays, with subordinate clayey limestones and bituminous 
 OOLITE / shale (Oxford day} ; shelly calcareous grit (Kelloway rock}, 
 with subjacent blue clays. 
 
 LOWER OOLITE. Coarse, rubbly, and shelly limestones 
 (Combrask) ; laminated shelly limestones and grits (Forest 
 marble) ; sandy layers and thick-bedded blue clay (Brad- 
 ford clay) ; thick-bedded oolite, more or less compact and 
 sandy (Bath or great oolite) ; flaggy grits and oolites (Stones- 
 field slate) ; marls and clays with soft marly limestone 
 (Fuller's earth) ; calcareous freestone, irregularly oolitic, 
 and yellow sand (inferior oolite). 
 
 I UPPER LIAS. Thick beds of dark bituminous shale ; beds 
 of pyritous clay and alum shale ; indurated marls or marl- 
 stone. 
 LOWER LIAS. Dark laminated limestones and clays ; bands 
 of ironstone ; layers of jet and lignite ; beds of calcareous 
 sandstone. 
 
 All the members are well developed in England ; it is chiefly the Lias and 
 Oolite that are found in France, Switzerland, and Germany ; patches of 
 the Lias and Oolite occur in Scotland ; the Oolite alone in Hindustan and 
 North America ; and beds of Wealden epoch have been detected in 
 Hanover and Westphalia. As deposits, the Lias and Oolite are eminently 
 marine, though occasionally exhibiting evidence of alternate elevation and 
 depression ; while the Wealden and Purbeck beds display frequent alter- 
 nations of marine with fresh-water or estuary conditions. 
 "With the exception of the higher mammalia, almost every existing order 
 
 335 
 
 LIAS 
 
OPA OPE 
 
 is represented in the fauna of the Oolite, but the forms are all Mesozoic, 
 and died out at the close of the Chalk era. The vegetation of the system 
 is also extremely varied, but the highest orders appear to be coniferous, 
 and as yet no example of a true exogenous timber tree has been detected. 
 Of its numerous fossils the most characteristic are the cycadacece, of which 
 the stems, fruits, and leaves are found in abundance ; the shells of the 
 gryphcea, so peculiarly plentiful in the Lias ; the ammonites and belemnites 
 of innumerable species ; the -insects of the Lias and Weald ; the pterodactyle 
 or flying-lizard ; the fresh- water and marine turtles ; and, above all, the 
 ichthyosaurus, plesiosaurus, and other sauroid reptiles, whose marvellous 
 forms and variety have suggested for the Oolite the not inappropriate title 
 of " the age of reptiles." Still higher in the scale of being than these are 
 the warm-blooded marsupial mammals, amphitherium, phascolotherium, spa- 
 lacotherium, stereognathus, triconodon, and plagiaulax the earliest of their 
 kind yet detected in the crust of the earth. For further details see LIAS 
 and WEALDEN ; and for foreign and contemporary equivalents see tabula- 
 tions, " GEOLOGICAL SCHEME." 
 
 Opal (origin unknown, but supposed to be connected with the Greek 
 words ops, opos, signifying vision). The quarx resinite of Haiiy ; the un- 
 cleavable quartz of Mohs ; and in its pure state a hydrate of silica, consist- 
 ing of from 90 to 95 of silica, and from 5 to 10 of water. In most of its 
 varieties there is some admixture of alumina, lime, and iron ; hence, as a 
 mixed siliceous mineral, it is allied to agate and chalcedony, but distin- 
 guished by its peculiar vitreous or rather resinous lustre. It occurs 
 colourless or of all colours ; is amorphous ; in the compact varieties has a 
 conchoidal fracture, but in others is splintery, or even earthy. The better- 
 known varieties are, 1. Precious or nolle opal, which owes its beautiful 
 play of colours to a multiplicity of minute pores in the mass ; 2. Hydro- 
 phane, or those sub-varieties of noble opal which, when immersed in water, 
 become transparent by the filling up of the pores ; 3. Sun or fire opal, or 
 qirasol, transparent, of a brilliant vitreous lustre, and generally of a bright 
 hyacinth red or yellow when held between the eye and the light ; 4. 
 Hyalite, glassy opal, or Muller's glass, occurring in transparent, very glassy, 
 small mammillary incrustations ; 5. Common opal, semi-transparent, vitre- 
 ous, and of various colours ; 6. Semi-opal, duller and less pellucid than 
 common opal, and often of variegated colour ; 7. Cacholong, or mother-of- 
 pearl opal, having a pearly resinous lustre, and so called from its being 
 found near the river Cach in Bucharia ; 8. Wood opal, or wood converted 
 into opal by siliceous infiltration, but still retaining its woody texture ; 
 9. Jasper opal, or such ferruginous varieties as pass imperceptibly into com- 
 mon variegated jasper ; and, 10. Menilite or liver opal, a compact semi-resin- 
 ous variety found at Mont Menil, near Paris, and usually of a dark brown 
 or liver colour. Besides the above there are other kinds enumerated by 
 lapidaries, but these are for the most part founded upon very minute and 
 unimportant distinctions. See each variety under its own designation. 
 
 Opalescent. Resembling opal in lustre ; exhibiting a play of colours like 
 some varieties of opal ; displaying iridescence. 
 
 Opalised. Converted into a substance resembling opal ; converted into 
 opal by the infiltration of silica in a state of solution (natural gelatine of 
 silica). Hence " opalised wood," or wood petrified by silica, and acquir- 
 ing a structure resembling opal. 
 
 Open Cast. In mining, the method of working a vein when the ore 
 
OPE ORE 
 
 appears at the outcrop, and can be obtained by workings open to the day, 
 and without sinking a shaft. 
 
 Operculum (Lat., a lid). In conchology, the calcareous or horny lid with 
 which gasteropodous molluscs (like the periwinkle) close the aperture of 
 their shells when they withdraw within them for shelter. By some concho- 
 logists (Adanson, Gray, &c.), the operculum is considered as the equiva- 
 lent of the right valve of the Conchifera or bivalves ; but however similar 
 in appearance, its anatomical relations are held by others to be altogether 
 different. Opercular-like organisms are frequently found fossil. In ich- 
 thyology, the gill-cover or bony flap which covers and protects the gills in 
 fishes. Opercular bones are frequently found detached in "bone beds" 
 
 and other fossiliferous strata. In botany, the membranous lid which 
 
 covers the tJieca or spore-case in mosses. 
 
 Ophidian (Gr. ophis, a serpent). -A serpent ; belonging to the serpent 
 order the Ophidia constituting one of the main orders of .Reptiles in 
 Cuvier's arrangement. The ophidia are characterised by their numerous 
 procoalian vertebrae, with a single transverse process on each side ; have 
 no sacrum, and no visible limbs. Remains of the order do not occur in 
 strata of older date than the Tertiary. 
 
 O'phite, Ophiolite (Gr. ophis, a serpent, and lithos). Mineralogical 
 terms for serpentine, but seldom used by British geologists. See SER- 
 PENTINE. 
 
 Oracanthus (Gr. oraios, beautiful, and akantha, spine). A genus of ces- 
 traciont fin-spines, or ichthyodorulites, occurring in the Carboniferous for- 
 mation, and so termed from the varied ornamentation of the species. 
 
 Orhiculina (Lat. orbicula, a little orb). A genus of minute foraminiferous 
 chambered shells, so called from their flattened globular form. Species of 
 the genus are still living in tropical seas, and others are found fossil in the 
 oldest Tertiaries. 
 
 Orbit (Lat. orbita, a track or path). The course or path of a planet 
 round the sun ; generally, the course or path described by any of the 
 heavenly bodies. The term is derived from the Latin word orbis, a globe 
 or circle ; hence the heavenly bodies are spoken of as orbs, and their courses 
 as orbits, though, strictly speaking, their form is merely spheroidal, and 
 their courses elliptical. 
 
 Ores (Ger. erz). Metals occurring in nature in a state of purity are said 
 to be native ; when combined with other substances, so as to require vari- 
 ous processes for their separation, they are termed ores ; e.g., the sulphur- 
 ets and carbonates of copper, in contradistinction from the pure ductile 
 metal. Geologically, these ores may be found in veins, in indeterminate 
 masses, or in regular strata ; and the associated mineral matter is known 
 as the matrix, gangue, vein-stone, or ore-stone of the metal. Ores of one or 
 other of the metals occur in all formations, but most abundantly and avail- 
 ably in districts that have been subjected to subterranean disturbance and 
 metamorphic agency. The idea that certain metals are peculiar to certain 
 geological epochs, or rather that they occur in certain rock-formations more 
 abundantly than in others, is one that derives support more from the dis- 
 turbing and metamorphic agencies to which these formations have been sub- 
 jected, than from any chronological succession or development of the metals 
 themselves. The metals are the same in all times : their ores only appear 
 in different states in different formations, and segregated or collected more 
 abundantly in some localities than in others. It is usual to describe the 
 
 337 T 
 
ORG ORN 
 
 metallic ores as occurring in the four following conditions : 1. In a metallic 
 state, and either solitary or combined with each other in the latter case 
 forming " alloys." 2. Combined with sulphur, forming sulphides or sul- 
 phurets. 3. Combined with oxygen, forming oxides. 4. Combined with 
 acids, forming carbonates, phosphates, &c., which generally go by the name 
 of "metallic salts." 
 
 Organic (Gr. organon, a member or instrument). Applied to plants and 
 animals, as being supplied with certain organs or instruments for the pur- 
 poses of growth and nutrition. Their structure is said to be organic, and 
 they are termed organised bodies, in contradistinction to minerals, which are 
 inorganic, and whose increase takes place by external additions, and not 
 through the instrumentality of any peculiar organs. The term Organic 
 Remains is used as synonymous with fossils, and applies to all remains of 
 plants or animals found imbedded in the crust of the earth. 
 
 Oriental. A term in very frequent use by lapidaries and jewellers, and 
 applied to gems as a mark of excellence, because^originally the finest and 
 purest varieties were brought from the East. Thus they speak of " Oriental 
 opal," "Oriental ruby," " Oriental sapphire," and the like, whether these 
 stones come from the East or not. 
 
 Ornithichnites (Gr. ornis, ornithos, a bird, and ichnon, a footprint). 
 Footsteps, supposed to be those of birds, and found abundantly on the 
 sandstone slabs of the Trias, especially on the sandstones of the Connecti- 
 cut valley in North America. Many of these are of gigantic size, and would 
 seem to indicate the existence of cursorial and grallatorial birds three or 
 four times the size of the existing ostrich. Professor Hitchcock has been 
 the great elabora tor of the Connecticut footprints, and considers many of 
 them as undoubtedly those of birds ; but Professor Owen, while admitting 
 the close resemblance, administers the following necessary caution : 
 "Footprints alone, like those termed 'Ornithichnites,' are insufficient to 
 support the inference of the possession of the highly developed organisation 
 of a bird of flight by the creatures which left them. The Rhynchosaur and 
 biped Pterodactyles already warn us how closely the ornithic type may be 
 approached without the essential characters of the saurian being lost. By 
 the Chirotherian ichnolites we learn how closely an animal, in all proba- 
 bility a Batrachian, may resemble a pedimanous mammal in the form of 
 its footprints." On the other hand, the marked tridactylous form of the 
 footprints, the texture of the epidermal impressions, and the amount of 
 uric acid contained in the coprolites usually associated with them, afford 
 pretty strong presumptive evidence of their really being the footsteps of 
 birds. 
 
 Ornithocopros (Gr. ornis, ornithos, a bird, and Jcopros, dung). Literally 
 " bird-excrement ; " a term occasionally applied to guano, which is, in the 
 main, composed of the droppings of countless seafowl, and some accumu- 
 lations of which are semi-mineralised, and evidently of vast antiquity. 
 
 Ornithodelphia (Gr. ornis, ornithos, bird, and adelphos, brother). Liter- 
 ally " allied to the birds ; " an ordinal term occasionally applied to the 
 Ornithorhynchus and Echidna, which, in their toothless jaws, in the con- 
 formation of their sternum and scapula, and especially in the structure of 
 their reproductive organs, exhibit unmistakable signs of divergence towards 
 the class of Birds. 
 
 Ornithoidichnites (Gr. ornis, ornithos, a bird ; eidos, resemblance ; and 
 ichnon, a footstep). Literally "bird-like footprints;" a term denoting 
 
 338 
 
ORN GET 
 
 resemblance merely, without affirming, as g< ornithichnites " does, that they 
 are really the footmarks of birds. 
 
 Ornitholites (Gr. ornis, a bird, and lithos, stone). The general term for 
 the remains of birds occurring in a fossil state. From the absence of teeth 
 in birds, and the close approximation of the form in many genera, it is often 
 all but impossible to determine the relations of the ornitholites that occa- 
 sionally turn up to the palaeontologist. As yet they have been found only 
 in the newer formations the Oolite, Chalk, and Tertiaries. 
 
 O'rodus (Gr. oraios, beautiful, and odous, tooth). A genus of cestraciont 
 or palatal fish-teeth occurring in the Carboniferous system, and so termed 
 from the beauty of their varied specific forms. 
 
 Orography, Orology (Gr. oros, a mountain). The science which describes 
 or treats of the mountains and mountain-systems of the globe that is, of 
 the profiles or elevations of the earth's surface. 
 
 O'rpiment (an abbreviated corruption of the Latin word auripigmentum, 
 or golden pigment). Yellow sulphuret of arsenic, consisting, according to 
 Klaproth, of 62 arsenic and 38 sulphur. It is found in metalliferous veins, 
 and imbedded in various formations, and occurs in foliated masses, in con- 
 cretions, or in minute crystals. The foliated structure of orpiment, and its 
 arsenical odour when exposed to heat, distinguish it from native sulphur. 
 Red orpiment is the name frequently given to the bisulphuret of arsenic or 
 REALGAR, which see. 
 
 Orthis (Gr. orthos, straight). A genus of fossil bivalves, known only in 
 Palaeozoic strata, and taken as the type of the family Orthidce. They are 
 characterised shell transversely oblong, radiately striated, valves slightly 
 convex, beak inconspicuous, hinge-line narrower than the shell, rarely for- 
 aminated. In the Silurian sub-genus Orthisina the shell is impunctate, 
 widest at the hinge-line, and generally perforated by a small round foramen. 
 
 O'rthite (Gr. ortfos, straight). A silico-aluminate of cerium, so called by 
 Berzelius from its occurring in straight needle-shaped or columnar masses 
 in the granites of Scandinavia. It is closely related to, if not identical 
 with, the A llanite and Cerin of other mineralogists. 
 
 Orthocanthus (Gr. orthos, straight, and akantlui, spine). A genus of 
 straight cylindrical fin-spines occurring in the Carboniferous formation, 
 and belonging to some unknown cestraciont. They have hitherto been 
 found detached, and unassociated with any teeth or scales that could lead 
 to their true systematic character. 
 
 Orth6ceras, Orthoceratite (Gr. orthos, straight, and&rew, horn). A genus 
 of straight tapering chambered shells, so called from their tapering to a 
 point like a horn. They occur from the Silurian to the Trias inclusive 
 many of their fragments indicating a length of more than six feet. 
 
 Orthocerdtidse (Gr. orthos, straight, and keras, a horn). A family of fossil 
 cephalopodous chambered shells, so called from their tapering horn-like 
 shape some being straight, others curved, and some disco idal. The family 
 includes such generic forms as orthoceras, gomphoceras, oncoceras, pkragmo- 
 ceras, cyrtoceras, gyroceras, &c., all of which are peculiar to the older forma- 
 tions. In all, the shell was essentially external ; had a small body-cham- 
 ber, into which the animal partly withdrew ; had a complicated and large 
 siphuncle ; and was less calcified than in the nautilus and ammonite. 
 
 O'rthoclase (Gr. orthos, straight, and klasis, fracture). A mineralogical 
 term for potash-felspar, because of its straight flat fracture. Orthoclase is 
 often known simply &s felspar or prismatic felspar; and whether in its trans- 
 
 339 
 
ORT OSM 
 
 parent or translucent varieties termed adularia, in the less splendent vat'ie- 
 ties known as common felspar, or in the glassy potash-soda variety known as 
 sanadine or " glassy felspar," is one of the most important constituents 
 of the globe occurring not only in granite, gneiss, and porphyry, but in 
 many secondary formations composed of their debris, as in greywacke, and 
 some sandstones and conglomerates. Orthoclase is very readily weathered 
 and decomposed, and in this state falls down to the whitish earth or clay 
 known as kaolin, and extensively used in the manufacture of porcelain and 
 stoneware. Compact felspar, or felstone as it is sometimes termed, seems 
 generally an admixture of ortkoclase and quartz, and in this state, or in its 
 softer and earthier condition of claystone, constitutes an important member 
 of the Trap series. See FELSPAR. 
 
 Orthonota, Orthonotus (Gr. orthos, straight, and notos, the back). A pro- 
 visional sub-genus of Modiola-looking bivalves occurring in Palaeozoic strata, 
 and so termed from their long straight plaited backs. The subdivisions of 
 these elongated modiola-like shells are by no means well established. 
 
 Orthdptera (Gr.) Literally " straightwings ; " an order of insects hav- 
 ing the outer pair of wings straight and a little coriaceous, as the locust, 
 grasshopper, and cockroach. The Orthopters are known from the Oolite 
 upwards. See INSECTA. 
 
 Oryctology (Gr. oryktos, dug up, and logos). Literally the " science of 
 things dug up," that is, of all bodies, whether organic or inorganic, found 
 buried in the earth. It was generally employed, however, as synonymous 
 with Palaeontology, and referred alone to fossils. It is now entirely disused. 
 
 Os, Osar. A Swedish term for those elongated hillocks or mounds of 
 gravel belonging to the Drift or Glacial period, and which are abundantly 
 and characteristically scattered over Sweden and the islands of the Baltic. 
 The greater part of the gravel of these hills, which occasionally rise to 100 
 or 200 feet, is of small dimensions, and mixed with much sand, and they 
 almost always exhibit a slope and a scarped side ; the former being towards 
 the north, which is the source of the detritus. Same as the kaims of Scot- 
 land, and the eskirs of Ireland, which see. 
 
 0'scula(Lat.) Literally "little mouths ; " the name given to the larger 
 pores that occur on the surface of a sponge these orifices being few com- 
 pared with the ordinary pores, and frequently elevated in. slight promi- 
 nences. While the pores form the openings of the incurrent, the oscular 
 form the openings of the excurrent canals, or circulatory system of the 
 living mass. 
 
 Osite (Lat. 05, a bone). A technical term proposed by Dr Leidy of 
 Philadelphia for the so-called Sombrero Guano, which see. The term has 
 reference to the composition of the substance, which appears to be a com- 
 pacted mass of altered bones the remains of turtles and other marine 
 vertebrata that had accumulated for ages on some sub-marine shoal that 
 had subsequently been elevated above the sea-level into the position of the 
 present little island of Sombrero, West Indies. Many reefs and shores of 
 vast extent are known to have had their origin in the testaceous coverings 
 of the lower animals, but Sombrero appears to be the first instance of 
 an island formed of the remains of the higher animals. 
 
 Osmeroides (Lat. osmerus, the smelt). A genus of fossil fishes found in 
 the Chalk of England by Dr Mantell, and so named by Agassiz from their 
 resemblance to the smelt. There are two or three species known to palae- 
 ontologists. 
 
 340 
 
OSM OSS 
 
 O'smium (Gr. osme, odour). A metal discovered by Tennant in crude 
 platinum, and so named from the strong disagreeable odour given out by 
 its oxide. Two native alloys of osmium and iridium are known to miner- 
 alogists under the name osmiridium and iridosmium, both of which are 
 found in flattish grains or scales in the gold and platina sands of the Ural. 
 Their composition is variable. 
 
 Osseous (Lat. os, a bone). Bony ; containing bone ; resembling bone 
 in texture or structure. 
 
 Osseous Breccia (Lat. os, a bone). Bones and fragments of bones 
 cemented together by calcareous or other matter, and found in caverns 
 and fissures, are so termed. The " Bone breccias " of Gibraltar and other 
 parts of the Mediterranean shores are well known to geologists ; and 
 accumulations of a similar nature, though containing the remains of very 
 different animals, have been discovered in Australia. The Mediterranean 
 breccias consist wholly of the bones of land animals, and of these compara- 
 tively few belonging to Carnivora ; while the absence of marine remains and 
 of the usual abrading effects of water, shows that the breccia was formed 
 on dry land, and not beneath the sea. " The only rational explanation 
 of these facts," says Dr Mantell, speaking of the Mediterranean bone 
 breccias, " is that which assumes the original union of these distant rocks 
 and islands into a continent or large island, which, like Calabria, was 
 subject to repeated visitations of earthquakes ; and that the animals 
 which inhabited the country fell into the fissures thus produced, and were 
 preserved by the calcareous infiltrations that were constantly in progress. 
 Subsequent convulsions and denuding agencies severed the country into 
 rocks and insular masses, of which catastrophes the osseous conglomerates 
 are the physical and only records." 
 
 O'ssicle (Lat. ossicuhim, a little bone). A small bone ; applied in anatomy 
 to various small bones of the skeleton ; also to the calcareous or bony-like 
 joints and segments of encrinites, star-fishes, and similar animals. 
 
 Ossiferous (Lat. os, a bone, and fero, I yield). Containing or yielding 
 bones or fragments of bones, as many of the Post-tertiary sands and 
 gravels. Thus we have ossiferous gravels, ossiferous marls, ossiferous 
 caverns, &c. 
 
 Ossiferous Caverns, Breccias, and Gravels. Of more recent date than 
 the newest Pliocene lignites, clays, and marls, there occur in many regions 
 (the northern hemisphere especially) gravels replete with bones of terres- 
 trial and marine mammals (ossiferous gravels) ; cemented and stagalmitic 
 bone-breccias in caves and fissures (osseous breccias) ; and caverns in lime- 
 stone ridges filled with bones imbedded in ochraceous mud or stalagmite 
 (ossiferous caverns), some of these the skeletons of animals that^had laired 
 and died there, and others that had been dragged thither and devoured 
 by carnivora, or had been drifted by waves and currents, while the sea 
 and land stood at varying and variable levels. Though generally of more 
 recent date than the true Tertiaries, many of these cave-deposits are of 
 vast antiquity their lower floors containing the remains of Pliocene or 
 Post-pliocene genera ; the middle deposits the remains of true Pleistocene 
 species ; while the upper layers of mud and stalagmite imbed the bones, 
 charred wood, and rude stone- implements of the human race. Their 
 epoch, therefore, as regards their organic remains, is partly Pleistocene 
 and partly recent ; and though the caves themselves were originally exca- 
 vated by the waves of Pliocene seas, most of them have undergone exten- 
 
 341 
 
OST 
 
 sive changes alike during the Pleistocene and current eras. The most 
 remarkable ossiferous caverns in England are Kirkdale Cave near Kirkby 
 Moorside in Yorkshire, the Dream Cavern near Worksworth in Derby- 
 shire, Banwell Cave in the Mendip Hills, Kent's Hole and Brixham Cave 
 near Torquay, Oreston near Plymouth, Cefn near Denbigh, and Paviland 
 near Swansea. In Germany the slopes of the Harz Mountains give us the 
 caves of Baumann, Biel, and Schwazfeld ; between the Harz and Franco- 
 nia is the Bear Cavern of Glucksbrunn ; the Jura formation near Baireuth 
 is celebrated for the rich associated caverns of Gailenreuth, Wunderhole, 
 Rabenstein, Kahloch, Zahnloch, Schneiderloch, &c. In Westphalia the 
 same Oolitic formation has the caves of Kluterhole and Sandwich. The 
 caves of Adelsberg in Carniola, and the Dragons' caves in Hungary, have 
 also yielded bones. In France, instructed by Dr Buckland's researches, 
 two caverns, rich in bones, have been described by M. Thirria, near Vesoul, 
 and several others near Narbonne by Marcel de Serres, Tournal, Christol, 
 
 &c., and one near Miremont by M. de la None. Osseoits breccia appears 
 
 singularly connected with the coasts of the Mediterranean. It occurs at 
 Gibraltar, in Languedoc, and at several other points in the south of France, 
 at Antibes, Nice, Pisa, Cape Palinurus, north of Bastea in Corsica, Cagliari 
 in Sardinia, Meridolce and Maccagnone in Sicily, in Dalmatia, &c. Ferru- 
 ginous breccia, in which bones are associated with pisolitic iron -ore, 
 occurs in Wiirtemberg, and in Carniola in Jura limestone. Such are a 
 few of the best known of these curious repositories in Europe, whose char- 
 acteristic Mammalian remains may be briefly tabulated as follows : 
 
 Pachyderms. Elephas, Mastodon, Hippopotamus, Chseropotamus, Rhino- 
 ceros, Tapir, Sus, &c. 
 
 Solipeds. Equus. 
 
 Ruminants. Cervus, Antelope, Urus, Bos, Merycotherium, &c. 
 
 Carnivors. Felis, Hysena, and the peculiar hardened excrement, album 
 grcecum, of the hyaena, Machairodus, Ursus, Gulo, Wolf, Fox, Polecat, 
 Weasel, Otter, &c. 
 
 Rodents. Porcupine, Beaver, Arvicola, Rat, Lagomys, Hare, Rabbit, 
 &c. 
 
 Edentates. Megalonyx, Megatherium, Macrauchenia, Manis, &c. 
 
 Osteolepis (Gr. osteon, a bone, and lepis, scale). Literally "bony scale ; " 
 a genus of ganoid fishes peculiar to the Old Red Sandstone, and so named 
 from the enamelled bony character of its scales. There are three or four 
 species catalogued by palaeontologists ; but in all the rhomboidal bony 
 scales, the enamelled osseous plates of the head, and the thickly-set bony 
 rays of the fins, are the distinguishing characteristics. 
 
 Oste6logy (Gr. osteon, a bone, and logos, discourse). Literally " the 
 science of bones ; " a knowledge of the skeleton or bony fabric of the dif- 
 ferent tribes of animals ; comparative anatomy. " The organs of every 
 animal," observes Cuvier, "must be regarded as forming a machine, the 
 parts of which are mutually dependent on each other, and exquisitely 
 adapted for the functions they have to perform ; and such is the intimate 
 relation of the several organs, that any variation in one part is constantly 
 accompanied by a corresponding modification in another." It is by a 
 knowledge of this law that the palaeontologist is enabled to reassemble, as 
 it were, the scattered remains of the beings of a former state of the globe 
 to determine their place in the scale of animated nature, and to reason 
 on their organisation, habits, and economy, with as much clearness and 
 
 342 
 
OST OUT 
 
 certainty as if they were still living before him. Hence the ready deter- 
 mination of a Carnivorous cutting - tooth from an Herbivorous grinding 
 one, and that again from the chisel-like tooth of a Rodent ; so also of the 
 articulation of the jaw that has to cut, the jaw that has to grind, and that 
 which has to gnaw ; the foot that has to seize, the foot that has to run, 
 and the foot that has to burrow. 
 
 O'stracite. A term occasionally applied to any fossil oyster or oyster- 
 like shell whose species is undetermined. 
 
 Ostreidse (Lat. ostrcea, an oyster- shell). The Oyster family, of which the 
 common oyster is taken as the representative. The family is characterised 
 by the shell being inequivalve, slightly inequilateral, free or adherent, 
 resting on one valve ; beak central, straight ; ligament internal ; epidermis 
 thin ; muscular impression single, behind the centre ; and hinge usually 
 toothless. The family is strictly marine, and includes the oyster, anomia, 
 placuna or window-shell, the pecten or scallop, lima, the spondylus or 
 thorny-oyster, and the plicatula. Of the living oyster there are about 
 sixty species inhabiting tropical and temperate seas ; while palaeontologists 
 enumerate about 200 fossil species occurring in strata from the Carbonifer- 
 ous Limestone upwards. 
 
 Otopteris (Gr. ous, otos, an ear, and pteris, fern). A doubtful genns of 
 fossil ferns occurring in the Coal-measures, New Red Sandstone, and Oolite, 
 and so called in allusion to the auricle (or ear -shaped projection) with 
 which the bases of their leaflets were furnished. According to Lindley, 
 who erected the genus, Otopteris was probably a simply pinnated plant 
 with a thickish petiole ; had oblong obtuse leaflets attached to the petiole 
 by the lower half of the base, the upper being free and auricled ; the leaf- 
 lets were without midrib, and furnished with veins which originated in the 
 base, and curved right and left to the margins, only forking as they pro- 
 ceeded towards the extremity. 
 
 Otoz6um (Gr. otus, a fabled pre-adamite giant, and zoon, an animal). A 
 provisional name given by Professor Hitchcock to certain unknown gi- 
 gantic footmarks found in the New Red Sandstone of Connecticut. 
 From their shape and other peculiarities they are supposed to be Batra- 
 chian (sauroidichnites). 
 
 Oudenodon (Gr. oudeis, none, and odous, tooth). A sub-genus of Dicyno- 
 dont reptiles from the sandstone rocks of Rhenostorberg, South Africa ; 
 and so termed by Mr Bain, their discoverer, from their toothless jaws, 
 which may possibly (after the analogy of the Narwals) be those of the 
 females of tusk-bearing male dicynodonts. 
 
 Outcrop. The edge of any inclined stratum when it comes to the sur- 
 face of the ground is called its outcrop, crop, basset, or basset-edge. In 
 mining language a stratum, when it comes to the surface, is said to " crop 
 out ; " and we also hear such phrases as its " coming to the day," "rising 
 to the grass," and so forth all expressive of its position as regards the 
 surface. 
 
 Outliers. In geology, portions of any stratified group which lie detach- 
 ed, or out from the main body, the intervening or connecting portion hav- 
 ing been removed by denudation. Outliers may be identified with the 
 main formations by the composition and alternations of their strata, and 
 partly also by their fossils. In zoology and botany, groups or assemblages 
 of species which " lie out from" or are separated from the main masses to 
 which they are allied, and thus give evidence of changes of conditions over 
 
 343 
 
OVE OXI 
 
 the areas in which they occur. For example, a group of northern forms 
 may now occur in a southern area showing that this southern area has 
 become warmer in the progress of geological change, and that the outlier 
 of northern forms is good evidence of such a mutation. 
 
 Overlap. A term frequently made use of by field-geologists, and em- 
 ployed to express that greater extension or spread of any set of superior 
 strata by which they overlap or conceal the edges of those on which they 
 rest. " While unconformability," says Mr Jukes, " proves an elevation and 
 denudation, and an absence of continuous deposition, overlap may take 
 place in a perfectly continuous series, merely proving the fact of a depres- 
 sion of the area contemporaneously with that of the deposition of the 
 overlapping strata." 
 
 Oviferous, Ovigerous (Lat. ovum, an egg, fero and gero, I bear). 
 Egg-carrying; applied to certain animals (e.g., some spiders and crus- 
 taceans) that carry about with them their eggs after exclusion being pro- 
 vided for that purpose with ovisacs, egg-packets, or other apparatus. 
 
 Oviparous (Lat. ovum, egg, and pario, I produce). Literally ''egg-pro- 
 ducing,'' as distinguished from viviparous or " young-producing." Ap- 
 plied to birds, reptiles, fishes, &c., whose mode of generation is by the 
 exclusion of a germ in the form and condition of an egg, the development 
 of which takes place out of the body, either with or without incubation. 
 
 Ovisac (Lat. ovum, egg, and saccus, bag). The egg-bag or membrane 
 which invests or connects in one mass the eggs, spawn, or roe of crusta- 
 cea, spiders, insects, shell-fish, and other allied creatures. Such ovisacs 
 or egg-packets occur in a fossil state in ancient as well as in recent forma- 
 tions; e.g., Parka decipiens in the Lower Old Red, which is regarded by 
 many as the ovisacs of Pterygoti. 
 
 Ovoviviparous (Lat. ovum, egg; vivo, I live; and pario, I produce). 
 Applied to animals whose mode of generation is by the exclusion of a 
 living foetus, more or less extricated from the egg-coverings, and which 
 has been developed or hatched within the body of the parent as an egg 
 that is, without any placental attachment to the womb. The marsupials 
 (kangaroo, &c.) among Mammals, the viper and salamander among 
 Reptiles, the blenny and dog-fish among Fishes, the paludina vivipara 
 and many bivalves among Molluscs, the scorpion and flesh-fly among 
 Insects, the earth-worm and many of the intestinal worms, are examples 
 of Ovoviviparous animals. 
 
 Ovulftes (Lat. ovum, and lithos). A general term for all fossil eggs, 
 whether those of birds or of reptiles. Ovulites have been found in the 
 stratified rocks from the Oolite upwards. Same as OOLITHES, which see. 
 
 O'xalite. Known also as Humboldtine ; a native oxalate of iron occur- 
 ring in yellowish capillary crystals, and occasionally in botryoidal and 
 granular crusts, in the brown coal of Germany. 
 
 Oxford Clay. The lower member of the Middle Oolite, so called from its 
 being well developed in Oxfordshire and the midland counties of England. 
 It consists of a bed of stiff, pale-blue, more or less calcareous clay (locally 
 known as " clunch "), attaining in some places a thickness of from 200 to 
 500 feet, and abounding in ammonites and belemnites. It is capped by 
 the " coral-rag," and graduates below into the shelly concretionary lime- 
 stone known as " Kelloway rock." See OOLITE. 
 
 Oxide. Any substance combined with oxygen, without being in the 
 state of an acid. Oxidised. Converted into an acid by combination with 
 
 344 
 
OXY PAG 
 
 oxygen. Oxidation. That process by which metals and other substances 
 are converted into oxides. 
 
 O'xygen (Gr.'oxys, acid, and gennao, I produce). Literally "the acid- 
 former ; " so called from its property of forming acids when in combination 
 with other elementary substances. It is one of the simple or elementary 
 bodies, and one of the five that exist in a gaseous state. It was dis- 
 covered by Priestly in 1774. As a permanent gas it is colourless ; has 
 neither taste nor smell ; and is slightly heavier than common air, the pro- 
 portion being as 11 to 10. It is sparingly absorbed by water, and is neither 
 acid nor alkaline. It has a po.werful attraction for most of the simple sub- 
 stances, forming with them acids and oxides this oxidation being often 
 rapid and attended with the evolution of heat and light (as in burning), 
 and at other times slow, unattended with such phenomena (as in rusting 
 of the metals). It is a most powerful supporter of combustion the pro- 
 ducts of such combustion being sometimes gaseous, as carbonic acid, from 
 the burning of charcoal ; liquid, as water, from the burning of hydrogen ; 
 or solid, as oxide of iron, from the burning of that metal. As an element 
 it is one of the most important and generally diffused in nature forming 
 one-fifth of the atmospheric air ; one-third, by measure, of the gases that 
 constitute water ; and so generally does it combine with all metallic and 
 non-metallic bodies, that it has been computed that about one-half of the 
 ponderable matter of the crust of the earth is composed of oxygen gas. It 
 plays also a most important part in the vital economy of the globe, being 
 inspired by animals, who give out carbonic acid gas, while carbonic acid 
 gas is absorbed by plants, which assimilate the carbon and set free the 
 oxygen, again to be breathed by animals, and thus maintain the grand 
 harmonies of nature. 
 
 Ozokerite, Ozdcerite (Gr. ozos, odour, and Jceros, wax). One of the mine- 
 ral resins or rather fats ; a soft semi-translucent waxy substance of a yel- 
 lowish brown colour and pleasant aromatic odour, occurring in bituminous 
 sandstones of the Coal formation. It melts at about 144 into a clear oily 
 fluid ; and is a pure hydro-carbon, consisting of 86 carbon and 14 hydrogen. 
 
 Pachyc6rmns (Gr. pachys, thick, and kormos, body). Literally "thick 
 body ; " a genus of sauroid fishes occurring in many specific forms in the 
 Lias of England, and so named by Agassiz in allusion to their relatively 
 robust bodies. 
 
 Pachydermata (Gr. pachys, thick, and derma, skin). Thick-skinned 
 mammalia ; an order which includes the elephants, rhinoceroses, tapirs, &c., 
 among living species, and the mastodon, palaeotherium, &c., among .ex- 
 tinct Tertiary races. The Pachyderms are perhaps the most prevalent 
 forms in European Tertiaries, a region in which the pig is now their sole 
 representative. See tabulations, " ANIMAL SCHEME." 
 
 Pachypteris (Gr. pachys, thick, and pteris, fern). A genus of fossil ferns 
 345 
 
PAC PAL 
 
 chiefly from the Lower Oolite, and so named from their thick rigid leaflets. 
 In Pachypteris the fronds are pinnate or bipinnate, the leaflets entire, 
 without visible veins, having but a single midrib, and contracted at the 
 base. 
 
 Pachyrhizodus (Gr. pachys, thick; rhiza, root; odous, tooth). Literally 
 "thick-root-tooth ;" a genus of cycloid fishes founded by Agassiz on some 
 remains from the Upper Chalk of England. The name has reference to 
 the thickness of the base of the anchylosed teeth, which are bluntly 
 conical ; the scales are large, circular, and covered with minute asperities 
 visible by the aid of a pocket lens. 
 
 Pachyspondylus (Gr. pachys, thick, and spondylus, vertebrae). The 
 generic term applied by Professor Owen to certain large sauroid vertebrae 
 collected by Dr Orpen in the Drakenberg Mountains of Southern Africa, 
 and supposed to be of Triassic age. 
 
 Paco. The Peruvian name for an earthy brown oxide of iron containing 
 minute particles of native silver, or chloride of silver, disseminated through 
 it. This argentiferous gossan, as it would be termed in Cornwall, is said to 
 be the main source of the silver obtained by mining in Peru. 
 
 Pagoda-Stone. The name given in China to a limestone containing 
 orthoceralites, whose septa when cut and polished exhibit, in section, 
 something. like the tapering structure of a pagoda. Large and entire 
 specimens of these orthoceralites are highly prized as ornaments ; the 
 belief being that they are engendered in the rock by the shadows of the 
 pagodas that stand above. 
 
 Pagodite. Same as agalmatolite or figure-stone ; a species of steatite 
 which the Chinese carve into ornamental figures and pagodas, whence the 
 name. (Poutgkad, house of a god or idol.) 
 
 Pagurus. The hermit-crab ; whose well-known habit of appropriating 
 the deserted shells of whelks and other univalves for the protection of its 
 defenceless abdomen has conferred on it the name. The remains of crabs 
 of apparently similar characters and habits (Mesostylv^, &c.) are found in 
 the Chalk and Tertiary formations. 
 
 Palsechinus, Palachinidae (Gr. palaios, ancient, and echinos, sea-urchin). 
 A genus and family of Palaeozoic sea-urchins or cidarites whose detached 
 plates and long smooth spines occur abundantly in the shales of the Car- 
 boniferous Limestone. They differ from Archceocidaris, with which they 
 are often associated, in their smooth spines and imperforate spiniferous 
 tubercles there being, as in the Echinus, no perforation for the ligament 
 of the spine. 
 
 Palseeudyptes. Literally "ancient penguin;" a provisional term ap- 
 plied by Professor Huxley to some bird -remains from the "Upper Tertiary 
 (Pliocene ?) beds of New Zealand, in consequence of their near approach, 
 in configuration, to the bones of the crested penguin (Eudyptes chryso- 
 lophus). These remains indicate a bird fully double the size of any known 
 penguin. 
 
 Palseocarabus (Gr. palaios, ancient, Jcarabos, lobster). A provisional 
 genus of macrurous or long-tailed crustaceans from the Lanarkshire Coal- 
 field, and founded by Mr Salter on the cephalo-thorax, the only portion as 
 yet discovered. This carapace is characterised by its oblong, quadrate, 
 and convex form, inconspicuous mesial furrow, and punctate surface. 
 Rostrum broad and deeply serrate ; antennae small ; and antennules spiny 
 and broadly expanded at the base. 
 
 346 
 
PAL 
 
 Palseocetus (Gr. palaios, ancient ; ketos, whale). A provisional genus of 
 fossil cetaceans founded by Mr Seelby of the Cambridge Museum on some 
 vertebral remains from the Oxford or the Kimmeridge Clay. This Oolitic 
 genus seems to stand as a connecting-link between the existing genera 
 Balcenoptera and Physalus. 
 
 False' ocrangon. Literally "ancient shrimp ;" a Permian crustacean of 
 the Zechstein or Magnesian limestone. See PROSOPONISCUS. 
 
 Palseogean (Gr. palaios, ancient ; ge,ihe earth). Belonging to the former 
 conditions of the earth's surface as revealed by geology, as distinct from 
 the existing terraqueous aspects as described by geography. 
 
 Palaeolithic (Gr. palaios, and lithos, stone). A term occasionally applied 
 to the ancient or prehistoric Stone Period, which see. 
 
 Palseoniscus. A well-known genus of ganoid fishes occurring in the 
 Carboniferous and Permian formations. The species, which are numerous, 
 are characterised by their moderate size, elegant heterocercal forms, 
 highly enamelled rhomboidal scales, which in some species are crenulated 
 or serrated on the posterior margins, rather small numerously-rayed fins 
 supported by strong triangular fulcral scales, and jaws furnished with 
 thickly-implanted brush-teeth. Amblypterus and Eurynotns, at one time 
 associated with Palceoniscus, are now erected into separate genera. 
 
 Palseontology (Gr. palaios, ancient; onta, beings ; and logos, reasoning). 
 Literally, reasoning about ancient beings ; that science or subdivision of 
 geology which devotes itself exclusively to a consideration of the plants 
 and animals found fossil in the crust of the earth. 
 
 Palse'ophis (Gr. palaios, ancient, and ophis, serpent). Literally " ancient 
 serpent ; " a provisional genus of serpents whose vertebrae (in several 
 specific forms) have been discovered in the Eocene Tertiaries of England. 
 The remains of one specimen, from the Bracklesham beds, would indicate 
 a length of about twenty feet, and from the compressed character of its 
 caudal vertebrae, it is supposed to have been of aquatic habits probably a 
 sea-serpent. 
 
 Palseophytology (Gr. palaios, ancient, and phyton, a plant). The science 
 of fossil plants ; one of the branches into which it has been proposed to 
 divide the broader science of palaeontology. 
 
 Palseosaurus (Gr. palaios, ancient, and saurus, lizard). A generic term 
 applied by Dr Riley and Mr Stutchbury to certain reptilian remains (of 
 Thecodont type) discovered by them in the Permian strata, near Bristol. 
 The term has reference to their great antiquity, compared with the reptiles 
 of the Oolite and Weald. See THECODONTOSAURUS. 
 
 Palseosiren (Gr. palaios, ancient). A fossil reptile from the Lower Per- 
 mian of Oelberg near Braunau, and so named by Dr Geinitz from its 
 apparent affinities to the existing salamander Siren lacertina of Linnaeus. 
 
 Palseospalax (Gr. palaios, ancient, and spalax, mole). Remains of the 
 existing genus Talpa (mole) occur in the upper layers of bone-caves 
 and the like ; but the generic term Palceospalax has been applied to the 
 remains of a closely- allied, if not identical animal, whose jaws and teeth 
 have been found in a lacustrine deposit on the coast of Norfolk, associated 
 with bones of elephant, deer, and beaver, and which must have been as 
 large as a hedgehog. 
 
 Palseotherium (Gr. palaios, ancient, and therion, animal). A pachy- 
 dermatous mammal of the Eocene Tertiaries which seems to stand inter- 
 mediate between the rhinoceros, horse, and tapir. About a dozen species 
 
 347 
 
PAL 
 
 have been discovered, varying from the size of a horse to that of a hog ; 
 and the bones of the nose show that, like the tapir, they had a short 
 fleshy semi-prehensile proboscis. 
 
 Palseoxylou (Gr. palaios, ancient, and xylon, wood). Literally "ancient 
 wood;" a provisional genus erected by Brongniart for the reception of 
 those coniferous-like steins found in the Coal-measures, and which are 
 characterised by the presence of thick compound medullary rays a char- 
 acter unknown in any living conifers. Several of the so-called Pinites and 
 Arai(carites belong to this genus. 
 
 Palaeozoic, Palaeozoic Formations (Gr. palaios, ancient, and zoe, life). 
 Applied to the lowest division of stratified groups, as holding the earliest 
 known forms of life, in contradistinction to the Mesozoic and Cainozoic. 
 It. includes the Cambrian, Silurian, Devonian, Carboniferous, and Permian 
 
 systems of British geologists. In treating of these formations, as 
 
 developed in the Appalachian chain of North America, Professor H. 
 Rogers has employed a nomenclature which requires explanation and 
 that explanation will be best given in his own words. " It was found," he 
 says, "that these Appalachian Rocks were far from being sufficiently co- 
 ordinate with the European Palaeozoic strata, under their British types, to 
 bear their names ; while, on the other hand, the special titles assigned to 
 them in New York were deemed too local and inexpressive, either of their 
 position in the scale of formations, or of their ruling characters, to be 
 usefully applicable. The fifteen formations, or series of deposits, defined 
 by their prevalent organic remains, and by the physical horizons which 
 separate them as sediments, extending from the lowest deposited in the 
 dawn of animal life to those formed at the end of the Coal period, are 
 called by names significant of their relative ages, the words employed 
 suggesting metaphorically the different natural periods of the day. These 
 names are Primal, Auroral, Matinal, Levant, Surgent, Scalent, Pre- 
 meridian, Meridian, Post-meridian, CadSnt, Vergent, Ponent, Vespertine, 
 Umbral, and Serai ; meaning respectively the formations of the Dawn, 
 Daybreak, Morning, Sunrise, Mounting Day, Climbing Day, Forenoon, 
 Noon, Afternoon, Declining Day, Descending Day, Sunset, Evening, Dusk, 
 and Nightfall. Some such nomenclature, based on time, is, for many 
 reasons, preferable to the inexpressive ones which rest for the most part 
 on geographical terms only locally correct, or on narrow and inconsistent 
 palseontological characters." See "PRELIMINARY TABULATIONS." 
 
 Palseozoology (Gr. palaios, ancient, and zoon, an animal). The science 
 of fossil animals ; one of the branches into which it has been proposed to 
 divide the more general science of paleontology. 
 
 Palagonite (from Palagonia in Sicily). A peculiar rock-product occur- 
 ring in connection with modern volcanoes, and considered by Bunsen to 
 have resulted from a chemical alteration of pyroxene rock. It is amor- 
 phous, of a yellowish-brown colour, glassy resinous lustre, easily broken, 
 and about the hardness of calcareous spar. The palagonile-tufa of Iceland 
 consists of 37-42 silica, 11.16 alumina, 14.7 iron peroxide, and 17.15 water, 
 with minor proportions of lime, magnesia, and soda ; and is partially 
 soluble by the hot waters of the Geysers. 
 
 Palapteryx (Gr. palaios, ancient, and apteryx, wingless). An extinct 
 gigantic bird found fossil, or rather sub-fossil, in the ancient river-silts of 
 New Zealand ; and so termed from its close relationship to the existing 
 apteryx, or wingless bird of these islands. 
 
 348 
 
PAL PAM 
 
 Pdleryx. A provisional genus of serpents from the Lower Tertiary 
 strata of England, and so named from the apparent affinities of their de- 
 tached vertebrae (the only relics yet found) to the living Eryx one of the 
 Boa and Python group of ophidians. 
 
 Palichthy6logy (Gr. palaios, ancient ; ichikys, fish ; and logos, reasoning). 
 That department of palaeontology which treats of extinct or fossil fishes ; 
 e.g., the ' Palichthyologic Notes ' of Sir Philip Egerton in various volumes 
 of the 'Quarterly Journal of the Geological Society,' the 'Poissons 
 Fossiles ' of Professor Agassiz, &c. 
 
 Palladium (Gr., from Pallas the goddess). One of the metals, discovered 
 in 1803 by Wollaston, and found in very small grains, of a steel-grey colour 
 and fibrous structure, in auriferous and platiniferous sand. Its specific 
 gravity varies from 11.3 to 11.8; and in fusibility it stands intermediate 
 between gold and platinum. When native it is alloyed with a little plat- 
 inum and iridium ; is ductile as well as malleable ; and is considerably 
 harder than platinum. It is oxidised and dissolved by nitric acid, but its 
 proper solvent is nitrohydrochloric acid. It forms alloys, most of which 
 are brittle,, with arsenic, iron, bismuth, lead, tin, copper, silver, platinum, 
 and gold ; the alloy with nickel is ductile. 
 
 Palmacites (Lat. palma, the palm-tree). The general term for any 
 fossil stem, leaf, fruit, or other organism which presents some analogy or 
 resemblance to one or other of the existing palms. Restricted, however, 
 for the most part to simple, cylindrical stems, covered by the bases of 
 fallen petiolated leaves. Remains of palms occur in the Coal-measures and 
 upwards ; but more abundantly and unmistakably in the newer strata. 
 
 Paludina (Lat. palus, paludis, a marsh). The 'marsh or river snail ;' 
 a common, turbinated, whorled, univalve, deriving its name from its pre- 
 valent habitat being marshes, ditches, or slow-running waters. About 
 sixty species are distributed over the northern hemisphere, and nearly an 
 equal number have been discovered from the Wealden upwards the well- 
 known Sussex or Petworth marble being almost wholly composed of the 
 shells of P. fluviorum. 
 
 Pampas. In physical geography, the vast treeless plains of the Para- 
 guay and La Plata in South America, stretching from the eastern ridge of 
 the Andes to the shores of Buenos Ayres, and thence southwards into the 
 deserts of Patagonia. Though treeless, they are covered with luxuriant 
 herbage tall grasses and thistles and are pastured by vast herds of wild 
 cattle and horses. See PAMPEAN FORMATION. 
 
 Pdmpean Formation. The alluvial and comparatively recent deposits 
 that overspread the Pampas of South America. " The Pampean forma- 
 tion," says Darwin, " is highly interesting from its vast extent (an area 
 larger than that of France), its disputed origin (some ascribing its accu- 
 mulation to debacles, others. to the rivers of the country, and others re- 
 garding it as an estuary or marine formation), and from the number of ex- 
 tinct gigantic mammifers imbedded in it. It has, upon the whole, a very 
 uniform character ; consisting of a more or less dull reddish, slightly in- 
 durated argillaceous earth or sand, often, but not always, including in 
 horizontal lines concretions of marl, and frequently passing into a compact 
 marly rock. These concretions often unite into irregular strata, and cover 
 very large tracts of country. The entire mass consists of a hard, but gene- 
 rally cavernous marly rock (Toska or Tosca-rock) ; some of the varieties 
 might be called calcareous tuffs." The formation thus described is ex- 
 
 349 
 
PAM PAR 
 
 tremely uniform in mineral character over the vast area of the Pampas ; is 
 regarded by Mr Darwin as having been slowly accumulated at the mouth 
 of the former estuary of the Plata, and in the sea adjoining it ; and as 
 having been gradually elevated, like most of the southern latitudes of 
 South America, above the waters of the ocean. It contains shells identical 
 with those still inhabiting the adjacent seas, and is hence considered of 
 recent or Pleistocene epoch, though imbedding the remains of numerous 
 mammalia (megatherium, mylodon, glyptodon, toxodon, macrauchenia, 
 &c. &c.) long since extinct, and bearing only a distant affinity to the 
 sloths, armadilloes, ant-eaters, and llamas of the present continent of 
 South America. See Darwin's 'Geological Observations on South Amer- 
 ica ; ' the ' Zoology of the Voyage of the Beagle ; ' D'Orbigny's ' Voyage 
 dans 1'Amerique du Sud,' &c. 
 
 Pampero. The name given in Buenos Ayres to a violent west wind, 
 which, traversing the arid plains of the Pampas, raises whirl-clouds of dust 
 and carries them forward to the coast of the Atlantic. The pamperos 
 seem to be portions of the return, or north-western trade-winds. 
 
 Paper-Coal (Ger. papier-kohle}.A. name given to certain layers of the 
 Tertiary lignites, from their papery or leaf-like composition. They are 
 evidently masses of compressed leaves ; and when taken fresh from the 
 beds, the venation and reticulations of many of the leaves are quite appar- 
 ent. Beds of a similar composition, but more obscure in their structure, 
 occur also in the older Coal formations. 
 
 Parabatrachns (Gr. para, along with, allied to, and batrachos, a frog). 
 A small batrachoid or frog-like reptile whose remains bones of the head 
 and teeth have been discovered in the Coal-measures near Glasgow, and 
 described in the ' Geological Journal,' vol. ix., by Professor Owen. 
 
 Paraffine, Paraffin (Lat. parum, little, and affinis, akin). A well-known 
 hydro-carbon obtained by distillation from petroleum, peat, pit-coal, and 
 other bituminous minerals, and so termed from its remarkable chemical 
 indifference to other substances. When pure it occurs as a tasteless, in- 
 odorous, fatty solid of a yellowish-white colour, fusible at 112, and re- 
 sisting the action of acids and alkalies. In its pure state it is now largely 
 used for making candles; in a liquid form (paraffin oil) for lighting; 
 and in a crude state, under the name of mineral grease, for lubricating 
 machinery. 
 
 Paragenesis of Minerals (Gr. para, side by side with, and genesis, genera- 
 tion). Applied in mineralogy to crystalline compounds whose mass is made 
 up of crystals interblended in imperfect and sometimes even irregular 
 forms. This innate structure arises either from the crystals of one mineral 
 having been first formed and thus prevented the regular formation of the 
 crystals of the other minerals ; or from the whole mass having crystallised 
 together, the individual crystals were prevented from attaining their full 
 development by the growth of their neighbours, and thus all become locked 
 and interlaced together in a congeries of mutually imbedded crystalline 
 particles. The innate structures of granite, marble, loaf-sugar, and the 
 like, are instances of pargenetic crystallisation. 
 
 Paramos (Span.) The name given by the Spanish settlers to the high 
 desert tracts of the Andes in South America. 
 
 Paramoiidra. A vernacular Irish term introduced by Dr Buckland in 
 his account of some gigantic flints, thus popularly named, which occur in 
 the Chalk near Belfast. They are found in other localities, and seem to 
 
 350 
 
PAR 
 
 be gigantic pear-shaped or goblet-shaped zoophytes allied to the Sponges, 
 but of so perishable a nature as to have left but few traces of their organ- 
 isation. They are furnished with a cavity in their broad or upper end 
 which extends downwards into the mass, and the narrow end shows indica- 
 tions of a pedicle by which they were attached to the sea-bottom. They 
 have been found from one to three feet in length, and from half a foot to 
 a foot in diameter. 
 
 Parexus (Gr., a ladder or gangway). -A genus of Acanthodian fishes from 
 the Lower Old Red Sandstone of Forfarshire, and so called from the notched 
 or crenated striae of their fin-spines, which were the organs first examined 
 by Agassiz. In Parexus, which varies from a few inches to more than a foot 
 in length, the head is of medium size, compressed ; body short, deep, com- 
 pressed, tapering ; tail heterocerque, very large and deep ; anterior dorsal 
 spine long, slightly falcate, toothed on the posterior edge, ridged longitudi- 
 nally, and crenate in the ridges ; other spines with crenate ridges ; four pairs 
 of intermediate dermal scutes ; scales medium-sized, smooth externally, 
 interior surface sculptured. The deep compressed body, large broad tail, 
 and high-toothed anterior dorsal spine, which is nearly half the length of 
 the entire fish, are strongly distinguishing characteristics of Parexus. 
 
 Pargasite (Pargas near Abo in Finland). Noble hornblende, or those 
 varieties of hornblende possessed of high lustre and of a paler tint of green 
 (olive or bottle-green) than common hornblende. 
 
 Paris Basin. The great area of Tertiary strata on which Paris is situ- 
 atedoften alluded to in geology, and rendered classic by the palaeontolo- 
 gical discoveries and inductions of Cuvier. The basin extends about 100 
 miles from east to west, about 180 miles from north-east to south-west, 
 and has a thickness of several hundred feet of marls, limestones, sand- 
 stones, sands, and clays. In descending section these strata present the 
 following characters : 
 
 1. Upper fresh-water marls, with interstratified layers of chert, aquatic 
 
 and terrestrial remains. 
 
 2. Upper marine formation, consisting of marls, sands, and sandstones, 
 
 and abounding in marine remains. 
 
 3. Gypseous marls and limestones ; with fluviatile shells and bones of 
 
 terrestrial animals. 
 
 4. Calcaire Orossier ; alternations of marls, liniestones, and calcareous 
 
 sandstones the various alternations containing terrestrial, fresh- 
 water, estuarine, or truly marine remains, according to the prevail- 
 ing agency and conditions of deposit. 
 
 5. Plastic clay and sand, containing fresh-water shells, drifted wood, 
 
 lignite, leaves, and fruit ; with bands of limestone enclosing marine 
 shells. 
 
 6. Basis of chalk-flints, broken and partially rolled, and sometimes con- 
 
 glomerated into ferruginous breccia. 
 
 Paroxysm, Paroxysmal (Gr. paroxysmos, excitement, exasperation). 
 Applied in geology to any sudden and violent effort of natural agency, 
 such as the explosive eruptions of a volcano, or the convulsive throes of an 
 earthquake. Fissures, fractures, and uptiltings of the solid strata are the 
 main indications of paroxysmal movements in former ages. 
 
 Parrot Coal. The common Scotch name for cannel coal, from its spirt- 
 ing or flying in pieces with a crackling or " chattering" noise when sud- 
 denly placed in the fire. The miners usually distinguish the varieties 
 
 351 
 
PAR PEA 
 
 from their structure, as " slaty" or laminated parrots, "curly" or those 
 breaking with short conchoidal fracture ; from their colours, as "brown," 
 "black," &c.; or from their qualities, as "dry" or gas parrots, " soft" 
 or oil parrots, &c. See CANNEL. 
 
 Particles (Lat. particula, a little part). Strictly speaking, the minutest 
 parts or atoms into which matter can be mechanically divided ; but gener- 
 ally and loosely applied to the component parts or granules of all solid 
 substances, as "particles of sandstone," "particles of chalk," and the 
 like. 
 
 Parting. Any thin subordinate layer occurring between two main beds, 
 and forming, as it were, a parting or line of separation between them. 
 11 Partings" of shale are frequent between strata of limestone. 
 
 Pavonine (Lat. pavo, a peacock). Having the changing iridescent lus- 
 tre of the peacock's tail ; applied to ores and metallic products which ex- 
 hibit these brilliant hues. 
 
 Peach. The name given by Cornish miners to chlorite and chloritic 
 rocks, generally of a bluish-green colour and soft. A lode composed of 
 this mineral is said to be a peachy lode. 
 
 Peacock (same as pavonine). Applied to ores and minerals which ex- 
 hibit an iridescent lustre like the changing hues of the peacock's tail, as 
 "peacock copper," or copper pyrites when covered with an iridescent 
 tarnish ; " peacock coal," &c. 
 
 Pea-Grit. A coarse pisolitic limestone forming 1 part of the Inferior 
 Oolite as developed in the south of England ; and so called from its being 
 composed of concretionary bodies, which are round, oval, or flattened, like 
 crushed peas. 
 
 Pearl-Sinter. A variety of siliceous sinter occurring in smooth and 
 shining, globular or botryoidal masses, with a pearly lustre. Known also 
 as Fiorite, from Santa Fiora in Tuscany, where it occurs incrusting vol- 
 canic tufa. 
 
 Pearlstone. A variety of felspathic lava composed of a number of 
 globules from the size of a grain of sand to that of a hazel nut, of a glassy 
 or enamelled aspect and pearly lustre ; whence the name. Pearlstone 
 passes by insensible gradations into varieties of pumice. See PITCHSTONE. 
 Peastone. Technically known as Pisolite, which see. The ' ' pea-stones " 
 and "peastone grits" are common rocks in the Oolitic formation. 
 
 Peat (Sax. ) Peat, which is a product of cold or temperate regions, 
 arises chiefly from the annual growth and decay of marsh-plants reeds, 
 rushes, equisetums, grasses, mosses, confervse, and the like, being the 
 main contributors to the mass, which in process of time becomes crowned 
 and augmented by the presence of heath and other shrubby vegetation. 
 Peat, or Peat-moss as it is often termed, has a tendency to accumulate 
 in all swamps and hollows ; and wherever stagnant water prevails there 
 it increases, filling up lakes, choking up river-courses, entombing fallen 
 forests, and spreading over every surface having sufficient moisture to 
 cherish its growth. It occurs in all stages of consolidation, from the 
 loose fibrous " turf " of the previous summer to the compact lignite-look- 
 ing "peat" formed thousands of years ago. It is sometimes attempted 
 to classify peat as turf, hill-peat, bog-peat, &c., according to the situations 
 in which it occurs, or according to its texture and composition, as fibrous, 
 papyraceous, earthy, woody, and piciform ; but seeing that the whole is so 
 irregularly and intimately blended, such distinctions are of little practical 
 
 352 
 
PEC PEL 
 
 value. Geologically, it may be considered as the youngest member of a 
 series of which lignite, coal, and anthracite are earlier and more intensified 
 mineralisations. Mineralogically, it constitutes the latest and least meta- 
 morphosed of the COAL FAMILY, which see ; and, palseontologicaliy, its 
 organic contents are all of recent, though occasionally of locally extinct, 
 species. Speaking of the peat of Denmark, Sir Charles Lyell remarks : 
 "In the lower beds weapons of stone accompany trunks of the Scotch fir, 
 while in the higher portions of the same bogs bronze implements are asso- 
 ciated with trunks and acorns of the common oak. It appears that the 
 pine has never been a native of Denmark in historical times, and it seems 
 to have given place to the oak about the time when articles and imple- 
 ments of bronze superseded those of stone. It also appears that, at a still 
 later period, the oak itself became scarce, and was nearly supplanted by 
 the beech, a tree which now flourishes luxuriantly in Denmark. Again, 
 at the still later epoch, when the beech -tree abounded, tools of iron were 
 introduced, and were gradually substituted for those of bronze." 
 
 Pech-Urane. Known also as Pitchblende, and ^t,ncleavable uranium-ore ; 
 a proto-peroxide of uranium, occurring massive and disseminated, also reni- 
 form, with a curved lamellar structure ; colour greyish or brownish-black ; 
 easily fractured ; lustre imperfect metallic ; specific gravity about 7. It 
 is found in the lead and silver mines of Bohemia, and in Saxony, in Corn- 
 wall, and in North America. It is the principal ore of uranium ; and is 
 used in porcelain-painting, glass-colouring, and the like. 
 
 Pec6pteris (Gr. peko, I comb, and pteris, fern). Comb-fern. An exten- 
 sive genus of fossil ferns occurring abundantly in the Coal-measures, less 
 numerously in the New Red Sandstone and Oolite, and sparingly in Cre- 
 taceous and Lower Tertiary strata. It derives its name from the regular 
 comb-like arrangement of its leaflets ; and is characterised by the leaves 
 being once, twice, or thrice pinnate, and by the leaflets having a perfect mid- 
 rib, from which forked veins proceed more or less at right angles with it. 
 
 Pectolite (Gr. pektos, put together, and lithos). A silicate of lime and 
 soda, occurring in trap-rocks in spheroidal masses composed of an aggrega- 
 gation of acicular crystals, of a white or greyish-white colour and some- 
 what silky lustre. Known also as soda table-spar, stellite, from the star- 
 like arrangement of its crystals, and Ratholite, from Ratho quarries near 
 Edinburgh. 
 
 Pegmatite (Gr. pegma, compacted or congealed). A binary granite 
 composed of quartz and felspar the felspar crystals lying impacted in the 
 quartz as in a matrix. It occasionally contains flakes of silvery- white mica, 
 and often passes into graphic granite. 
 
 Pelagic, Pelagian (Gr. pelagos, the deep sea). Formed or deposited 
 in deep water ; belonging to the deep sea. Used in contradistinction to 
 littoral or estuary, and characterised by a distinct flora and fauna. 
 
 Pele's Hair. The name given in the Sandwich Islands to fine glassy 
 threads of pumice carried off by the winds from the liquid lava-jets of the 
 volcano of Kilauea Pele being the goddess of this volcanic mountain. To 
 the leeward the ground is often thickly strewn with this fine hair-like 
 substance, many of the filaments having little knobs of volcanic glass at 
 the one end, precisely like those drawn off from the molten mass of a 
 glass furnace. 
 
 Pellicle (Lat. pellicula, a very thin membrane or skin). Applied to any 
 thin covering or coating of extraneous matter ; as the nacreous "pellicle " 
 
 353 z 
 
 . . 
 
PEL PEN 
 
 of some shells ; the coaly "pellicle " which covers the stems of many fossil 
 plants ; and so on. 
 
 Pelorosaurus (Gr. pelor, monstrous or unusually gigantic, and sauros, 
 lizard). A term applied by Dr Man tell to one of the huge reptiles of the 
 Wealden certain vertebrae and other bones indicating a generic difference 
 from the Iguanodon, and other dinosaurs of that formation. 
 
 Peltocaris (Gr. pelte, a half -moon shield, and karis, shrimp). A genus of 
 small phyllopod crustaceans occurring in the Lower Silurian rocks of 
 Britain, the carapace, on which the genus is founded, having the following 
 characters : round and shield-shaped ; bivalved, the valves open and im- 
 perfectly joined along the dorsal line ; deeply emarginate in front, the ex- 
 cavation so formed being filled up completely by a parabolic plate, which 
 is the analogue of the rostrum and completes the broad oval shield. 
 
 Fenarth Beds. The term employed by the English Geological Survey to 
 designate the "passage-beds" that lie between the Trias and Lias, from 
 their typical development at Penarth in Somersetshire. Known also as 
 Rhaetic Beds, Kossen Beds, Zone of Avicula contorta, &c., which see. 
 
 Penguin. The Penguins, of which there are several genera, are, perhaps, 
 the most natatorial or strictly aquatic of all birds, and occur in vast num- 
 bers in the seas of the southern hemisphere, ranging from New Guinea to 
 within the antarctic circle. Remains of extinct species have been found 
 in the Tertiary beds of New Zealand, and of existing species in old guano 
 accumulations. The fossil, like the living genera, seem to be confined to 
 the southern hemisphere. See PAL^BEUDYPTES. 
 
 Pentacrinus, Pentacrinite (Gr. pente, five, and encrinus). A genus of 
 encrinites abounding in the Lias, Oolite, and Chalk of England, and so 
 termed from the pentangular or five-sided shape of its supporting column. 
 In this genus, which is still represented by a solitary species in the West 
 India seas, the pieces composing the receptacle are firmly articulated 
 together, and the rays of the disc are fixed immediately to the summit of 
 the column by special ossicles. The receptacle is small, and situated deep 
 between the bases of the arms ; it is closed by an integument covered by 
 minute plates or flat ossicles. In many of the plumose pentacrinites the 
 arms are very long and thickly fringed with side-arms and minute pinnae 
 all of which are composed of separate articulated ossicles, so that the num- 
 ber of bones in a single endo-skeleton of these crinoids is said to amount to 
 from 50,000 to 150,000 distinct pieces. See CRINOIDEA and ENCRINITE. 
 
 Pentamerus (Gr. pente, five, and meros, part). Literally "five-parted," 
 or " five- celled ; " a palaeozoic brachiopod belonging to the family Rhyncon- 
 ellidce, and occurring characteristically in Upper Silurian and Devonian 
 strata. The shell is ovate, ventricose, with a large incurved beak ; valves 
 usually plaited ; foramen angular; no area or deltidium ; and differs spe- 
 cially from Terebratula, Rhynconella, and the like, in having an internal 
 septum or plate by which the cavity is divided into four chambers ; and 
 in one valve the septum itself contains a cell thus making in all five 
 chambers, whence the name Pentamerus (five-parted). 
 
 Pentremite Limestone. A term occasionally applied by American geo- 
 logists to the Carboniferous Limestone of the United States, on account 
 of the vast number of Pentremites which it contains. 
 
 Pentremites (Gr. pente, five, and remos, a board or plate). A remarkable 
 genus of Carboniferous crinoids, so termed from the five polygonal plates 
 which compose their pear-shaped receptacle. In the Pentremite the column 
 
 354 
 
PEP PEE 
 
 is short, cylindrical, and furnished with irregular side-arms ; the recep- 
 tacle is composed of five polygonal plates, divided by five perforated 
 grooves, which are of a petal-like form, and converge in a rosette on the 
 summit ; and from these perforations spring rows of articulated tentacles 
 which are directed upwards over the vertex of the receptacle, apparently 
 for the capture and retention of the animal's food. 
 
 Peperino. An Italian term for a light porous species of volcanic rock, 
 formed, like tufa, by the cementing together of sand, scoriae, cinders, &c. ; 
 and so called in allusion to the small peppercorn-like fragments of which 
 it is composed. According to Mr Scrope, the Italian geologists restrict 
 the term tufa to felspathic and pumiceous admixtures, which are grey or 
 white, and apply the word peperino to the basaltic tuffs, which are usually 
 brown. See ALBANI STONE. 
 
 Perched Blocks. The name given to detached blocks of rock which have 
 been left by glaciers on the brows and ridges of lofty mountains. These 
 blocks are often of large dimensions, and occur as relics of the glacial period 
 on all the highlands of the northern hemisphere, as well as on the spurs 
 and peaks of existing glacier-mountains. 
 
 Percolate, Percoldtion (Lat. per, through, and colo, I strain). Water 
 passing through sand or porous sandstone is said to percolate such a medium ; 
 and in such a passage it is filtered or deprived of all mechanically-suspended 
 impurities, as mud and clay ; but it is not chemically affected, unless it 
 may have taken up some new ingredient from the strata through which it 
 has percolated. 
 
 Periclinal (Gr. peri, all around, and klino, I bend). Dipping on all 
 sides from a central point or apex ; applied to strata which often dip in 
 this manner from some common centre of elevation. 
 
 Perigee (Gr. peri, around, about, and ge, the earth). That point of a 
 planet's orbit at which it is nearest to the earth ; its apogee being the point 
 at which it is farthest off. 
 
 Peristerite (Gr. peristera, a pigeon). A variety of Albite, or perhaps of 
 Labrador! te, occasionally containing disseminated grains of quartz, and 
 exhibiting when cut in a proper direction a fine delicate opalescence, like 
 the changing hues of a pigeon's neck, whence the name. 
 
 Permeable (Lat. per, through, and meo, 1 pass). Admitting the passage 
 of water ; applied to rocks and rock-materials sufficiently porous to permit 
 the passage of water through their pores and interstices. 
 
 Permian System. The lower or palaeozoic division of what was formerly 
 regarded as the New Red Sandstone the term Permian having been 
 introduced by Murchison in 1841 (to harmonise with his Silurian and 
 Devonian), from the fact that these strata were typically and extensively 
 developed in the government of Perm in Central Russia. Some German 
 geologists have attempted to introduce the term Dyas, to harmonise with 
 that of Trias, but as yet with no success among British geologists. In the 
 vast and undisturbed region of Perm the system consists (according to 
 Murchison) of three main members, which may be arranged in descending 
 order, thus : 
 
 3. Conglomerate and sandstone, with plants and fossil reptiles. 
 
 2. Red sands, with copper ore and many plants. 
 
 1. Sandstones and grits ; limestones in various courses, with character- 
 istic fossils, associated with marls and gypsum, the marls occasion- 
 ally containing plants, and also seams of impure coal. 
 355 
 
PET 
 
 In the north of England (more especially in Durham and Yorkshire) it is 
 composed chiefly of red sandstone and grits, of magnesian limestones and 
 gypseous marls, and of laminated calcareous flagstones. This succession 
 is usually tabulated as follows : 
 
 LAMINATED LIMESTONE, with layers of coloured marls, as 
 at Knottingley, Doncaster, &c. 
 
 GYPSEOUS MARLS Red, bluish, and mottled. 
 
 MAGNESIAN 
 LIMESTONE. 
 
 MAGNESIAN LIMESTONE Yellow and white ; of various 
 texture and structure ; some parts, as at Tynemouth, 
 
 brecciated, or made up of fragmentary masses. 
 MARL SLATES Laminated, impure calcareous flagstones of 
 soft argillaceous or sandy nature. 
 
 {RED SANDSTONE, with red and purple marls, and a few 
 micaceous beds. The grits are sometimes white or 
 yellow, and pebbly. When conformable, this sandstone 
 occasionally passes into the Coal-measures on which it 
 rests. 
 
 In France, Germany, North America, and other tracts where the system 
 has been investigated, some of these members are wanting, while others 
 are more fully and typically developed. It has been attempted to co-ordi- 
 nate, as in the subjoined synopsis, the English and German strata, taking 
 the north of England and Thuringia as the points of comparison. 
 
 England. 
 
 Laminated limestones. 
 Brecciated limestones. 
 Fossiliferous limestones. 
 Compact limestone. 
 Marl slate. 
 Red sandstones and grits. 
 
 Stinkstein. 
 
 Germany. 
 
 Rauchwacke". 
 
 Dolomit ; upper zechstein. 
 
 Zechstein (mine-stone). 
 
 Mergel-schiefer and kupfer-schief'er. 
 
 Rothe-tode-liegende. 
 
 Palseontologically, the fossils of the Permian system present a decidedly 
 palaeozoic aspect the plants being akin to those of the Coal-measures, 
 together with Carboniferous genera of corals, polyzoa, crinoids, shell-fish, 
 fishes with heterocercal tails, and labyrinthodont reptiles. See NEW RED 
 SANDSTONE. 
 
 Petrology, sometimes Petrology (Gr. petra or petros, a rock, and logos, 
 discourse). Literally, "the science of rocks," and often used synony- 
 mously with Lithology or Physical Geology, which restrict themselves 
 solely to the consideration of rocks and rock- formations, without reference 
 to the organic remains they contain. See LITHOLOGY. 
 
 Petrified Figs. The name given by collectors to compressed specimens 
 of the Tertiary fruit known as NIPADITES, which see. ' 
 
 Petrify, Petrifaction (Lat. petra, a stone, and^o, I become). Literally, 
 to convert or change into stone. When a shell, bone, or fragment of wood, 
 by being enclosed in calcareous mud or other sedimentary matter, becomes 
 hard and stony, it is said to be petrified. Petrifaction is thus caused by the 
 particles of stony matter entering, while in solution, into the pores of the 
 vegetable or animal tissue, and as the organic matter disappears, gradually 
 taking its place, particle after particle, till the whole is converted into 
 stone. The term "petrifactions" is thus often used as synonymous with 
 "fossils" and "organic remains." 
 
 Petrography (Gr. petron and graphe). Frequently used in the same 
 sense as Petralogy ; hence we speak of the "petrographic" character of a 
 formation in contradistinction to its "palaBontological." 
 
 356 
 
PET PFA 
 
 Petr6leum (Lat. petra, rock, and oleum, oil). Literally "rock-oil;" a 
 liquid mineral pitch or bitumen, so called from its oozing out from certain 
 strata like oil. It is usually of a dark yellowish-brown colour, more or less 
 liquid according to external temperature, and consists of 88 carbon and 12 
 hydrogen. It occurs in various formations, chiefly in connection with fields 
 of coal and lignite, and appears to arise from the decomposition or distil- 
 lation of these strata by subterranean heat. Known also as Mineral Oil ; 
 hence the "oil-wells" of America, Canada, Burmah, and other regions, 
 which are now largely worked for distillation into paraffine oil, paraffine, 
 and other similar products. See BITUMEN. 
 
 Petrophiloides. Fossil cones, chiefly from the London Clay, and so 
 named from their resemblance to those of the existing Petrophila of New 
 Holland, which belongs to the natural order Proteaceae an order of ever- 
 green shrubs or small trees, with hard dry leaves, and now almost exclu- 
 sively confined to the southern hemisphere. 
 
 Petrosilex (Lat. petra, rock, and silex, flint). Literally "rock-flint," in 
 contradistinction to the detached nodular flints of the Chalk formation. A 
 synonyme of hornstone, though sometimes applied to the harder kinds of 
 compact felspar, which pass insensibly into hornstone. 
 
 Petuntze (Chin.) A quartzo-felspathic rock used in China in the manu- 
 facture of porcelain. 
 
 Petworth Marble. A limestone of the Wealden formation, so called 
 from its being worked at Petworth in Sussex; known also as "Sussex 
 marble." It is chiefly composed of shells of the Paludina or river- snail, 
 together with cases of Cypris, and occasional shells of Unio, Cyclas, and 
 other fresh-water genera. It is described by Dr Man tell "as an aggrega- 
 tion of Paludinse, held together by crystallised carbonate of lime, the 
 cavities of the shells and their interstices being often filled with white cal- 
 careous spar." 
 
 Peuce, Peucites (Gr. peuTce, the fir-tree). The generic term for all fossil 
 wood that appears absolutely coniferous,, in contradistinction to Pinites, 
 which only exhibits approximations to the true coniferse. Both have a 
 central pith, wood in concentric layers, bark, and medullary rays, but with 
 no vessels. In Pinites, the cells of the woody fibre are reticulated ; in 
 Peucites, they are marked with oblong deciduous areolae, having a circle 
 in the middle. (Brongniart.) 
 
 Pfahlbaiiten (Ger.) Literally "pile-dwellings;" the term applied by 
 Swiss archaeologists to the prehistoric lake-habitations of that country. 
 Since 1854 much attention has been directed to these ancient dwellings, 
 as may be gathered from the works of MM. Troyon, Keller, Morlot, and 
 others all of them agreeing that this mode of habitation seems to have 
 been common during the stone and bronze periods, and even during the 
 earlier part of the iron period. Herodotus relates that in the time of 
 Darius (about 520 B.C.) there existed a similar settlement in the middle 
 of Lake Prasias, in Poeonia (now probably Lake Takinos, in the modern 
 Turkish province of Roumelia). "The houses," he says, "were built on 
 a platform of wood, supported by wooden stakes, and a narrow bridge, 
 which could be withdrawn at pleasure, communicated with the shore." 
 " When man," says M. Morlot, " thus stationed his dwellings on piles, 
 all the refuse of his industry and of his food were naturally thrown into 
 the lake, and were often well preserved in the mud at the bottom. If 
 occasionally such establishments were burnt, whether intentionally by the 
 
 357 
 
PHA PHO 
 
 enemy or by accident, a vast quantity and variety of articles, including 
 some of great value, would sink to the bottom of the waters. Such aqua- 
 tic sites were probably selected as places of safety, since, when the bridge 
 was removed, they could only be approached by boats, and the water would 
 serve for protection alike against wild animals and human foes." In the 
 older Pfahlbauten of Switzerland the implements are chiefly of stone, and 
 associated with the castaway bones of the deer, boar, and wild-ox; in 
 those of intermediate age bronze implements prevail, associated with the 
 bones of the domestic ox, pig, and goat ; while in the more recent, iron 
 swords and spears have been found, accompanied by carbonised grains of 
 wheat and barley, and with fragments of rude textures woven of flax and 
 straw. The more recent seem to have been anterior to the great Koman 
 invasion of northern Europe ; the more ancient may be many thousands of 
 years older than that event. For full details of these " Lake-Dwellings," 
 as also of the prehistoric "Shell-Mounds," " Earth- Mounds," "Cave- 
 Dwellings," and the like, the reader may refer to Lubbock's 'Prehistoric 
 Times,' as yet the most compendious English work devoted to these archae- 
 ologico-geological subjects. 
 
 Phacops (Gr. phaJce, a pea or lentil, and ops, the eye). A widely distri- 
 buted genus of trilobites, remarkable for the large facets of the eyes, hence 
 the name. In Phacops, the trilobation is boldly distinct ; the thorax con- 
 sists of eleven segments ; and in some species (P. caudatus) the tail is 
 greatly prolonged and pointed. 
 
 Ph&nerite Series (Gr. phaneros, evident). A term employed by Dr Flem- 
 ing in his ' Lithology of Edinburgh' to designate the uppermost stage of 
 the modern epoch, as consisting of deposits produced by causes in ordinary 
 operation, and whose origin is evident, as compared with the brick-clays 
 and boulder-clays (the Akumite and Taragmite series) which lie beneath. 
 See MODERN EPOCH. 
 
 Phanerogamic, Phanerogamia (Gr. phaneros, evident, and gamos, mar- 
 riage). Applied to those plants whose organs of reproduction (flowers and 
 .seed) are apparent, in opposition to the Cryptogamic, which have no visible 
 flowers or organs of reproduction. See BOTANY. 
 
 Phascdlomys (Gr. phaskolos, a pouch, and mus, mouse). Literally 
 "pouched or marsupial mouse;" the wombat of Australia, fossil species 
 of which (P. gigas] have been found in the uppermost Tertiaries of that 
 country, rivalling the tapir in magnitude. 
 
 Phascolotherium (Gr. phaskolos, a pouch, and therion, animal). A small 
 marsupial (or pouched) mammal from the Oolitic calcareous flagstones of 
 Stonesfield. The jaws and teeth are the only remains yet found, and these 
 seem to indicate an affinity with marsupial genera now restricted to New 
 South Wales and Vau Diemen's Land, hence the name. 
 
 Phaseolites (phaseohis, the kidney-bean). A genus of leguminous plants 
 found in the Tertiary fresh-water formation of Aix, having unequally pin- 
 nate compound leaves ; leaflets entire, disarticulating, with nearly equal 
 reticulating veins. 
 
 Phlebdpteris (Gr. phleps, pUebos, a vein, and pteris, fern). A genus of 
 Oolitic ferns, characterised by their pinnae being in contact with each other 
 at the base, and by their veins (which are simple or forking) being separ- 
 ated from the midrib by a row on each side of hemi-hexagonal areolce, or 
 space destitute of veins. 
 
 Phocsenopsis. A provisional genus of cetaceans from the Pliocene, or 
 358 
 
PHCE PHY 
 
 perhaps Pleistocene, clays of New Zealand ; and so named by Professor 
 Huxley, from the resemblance of the remains to those of the common por- 
 poise (Phoccena) of our own seas. 
 
 Phcenicites. From Phoenix dactylifera, the date-palm ; a generic term 
 employed to embrace fossil palm -leaves of the pinnated form, in contradis- 
 tinction to Flabellaria, or those having broad fan-like leaves. Phcenicites 
 have been found only in Tertiary strata. 
 
 Pholadidse (Gr. pholeo, I bore). The family of boring bivalves, of which 
 the common pkolas or piddock is the type. In these borers the shell 
 is gaping at both ends, thin, white, brittle, and exceedingly hard ; 
 armed in front with rasp-like imbrications ; without hinge or ligament, 
 but often strengthened externally by accessory valves. They perforate 
 all substances softer than their own valves, and are found from the Lias 
 upwards. 
 
 Pholadomya (Gr. pholeo, I bore, and mya, the gaper). A genus of fossil 
 equivalved shells, with the posterior end short and rounded, and the an- 
 terior elongated and gaping. The surface is generally marked with rib- 
 like elevations, diverging obliquely from the beak to the margin. They 
 occur in the Lias, Oolite, and Chalk formations. 
 
 Pholidogaster (Gr. pholis, pholidos, scale or scute, and gaster, belly). A 
 genus of labyrinthodont reptiles founded by Professor Huxley on a speci- 
 men from the Gilmerton coal-field near Edinburgh, and differing from 
 Archegosaurus in the form of the head, the extent to which the ossification 
 of the vertebral column has proceeded, and in the character of its dermal 
 armour. It shares with that genus, however, the peculiarity of having its 
 overlapping scales arranged in double oblique series between the pectoral 
 and pelvic arches only ; hence the name. 
 
 Ph6nolite (Gr. phone, sound, and lithos, stone). A mineralogical term 
 occasionally employed for CLINKSTONE, which see. 
 
 Phosphatic Nodules. A familiar term for those concretions and nodules 
 of phosphate of lime which occur in layers and bands in the gault and upper 
 greensand of the Chalk formation, and which have recently come into use 
 for manurial purposes. They are found abundantly at Farnham in Surrey, 
 at Folkestone in Kent, near Cambridge, and other places ; and are evi- 
 dently of animal origin, being partly coprolitic, and probably the excre- 
 ment of fishes. Similar nodules and concretions are also obtained from the 
 Crag formation near Felixstow, apparently derived from the waste of the 
 London Clay ; and these, it is said, often contain so much as 50 per cent 
 of available phosphate of lime. They are prepared by being ground into 
 powder, and converted into the manurial superphosphate by the action of 
 sulphuric acid. 
 
 Ph6sphorite. A massive variety of apatite or native phosphate of lime, 
 occurring in veins in the crystalline or metamorphic rocks. It contains 
 more fluorine than the crystallised varieties. 
 
 Phyllites (Gr. phyllon, a leaf). A general term for all fossil monocoty- 
 ledonous leaves in which the principal veins converge at both the base 
 and apex, and are connected by transverse or secondary veins. Dictyo- 
 phyllites are those having a reticulated venation, and, of course, dicotyle- 
 donous. 
 
 Phyllograpsus (Gr. phyllon, leaf, and grapsus). Literally "leaf-grap- 
 tolite;" a Lower Silurian organism, known also as Graptopora. '"It 
 combines," says Mr Salter, "with the shape and general character of the 
 
 359 
 
PHY PIN 
 
 net-like Bryozoa, the texture and the form of the cells of the graptolite, 
 and may be regarded as a bundle of these animals united by processes into 
 a reticulated cup." Some curiously complex branched forms of graptolites, 
 discovered by Sir W. Logan in Canada, complete the chain of affinities 
 between the Graptolites and the Fenestellidae. 
 
 Physalite (Gr. physio, to blow or swell up). A coarse variety of topaz 
 occurring in large crystals (some amounting to 80 Ib. in weight) ; and so 
 named from its intumescing when heated. Known also as pyrophysalite, 
 for the same reason of its swelling up under heat. 
 
 Physiography (Gr. physis and graphe).A term occasionally used, and es- 
 pecially by American writers, as synonymous with Physical Geography ; a 
 description of existing nature as displayed in the surface-arrangement of 
 the globe its features, atmospheric and oceanic currents, climates, mag- 
 netism, life, &c., as well as the changes or variations to which these are 
 subjected. 
 
 Physiology (Gr. physis, nature, natural capacity or constitution, and 
 logos, discourse). Literally "the science of natural function or capacity." 
 Usually applied to that department of Biology which treats of the vital 
 actions or functions performed by the organs of plants and animals. 
 Morphology, on the other hand, merely takes cognisance of the form, 
 order, and arrangement of these organs. 
 
 Phytdgraphy (Gr. phyton, plant, and grapho, I write). Descriptive 
 Botany ; the science which describes the characters, habits, distribution, 
 functions, and properties of the vegetable kingdom. 
 
 Phytollthus (Gr. pkyton, a shoot, and lithos). An old generic term for 
 such stems as stigmaria, favularia, and the like ; used by Martin, Parkinson, 
 Steinhauer, and others. 
 
 Phyt61ogy (Gr. phyton, a plant, and logos, discourse). The science of the 
 vegetable kingdom ; used as synonymous with Botany : hence the term 
 PAL^OPHYTOLOGT, or the science which treats of extinct or fossil vege- 
 table forms. 
 
 Phyt6phagous (Gr. phyton, a shoot or plant, and phago, I eat). Plant- 
 feeding, plant-eating ; a term applied to animals which live on vegetables, 
 in contradistinction to those that are zoophagous, or prey on the flesh of 
 others. 
 
 Phytopsis (Gr. phyton, a shoot; opsis, resemblance). A provisional genus 
 of the so-called fucoid of the Lower Silurian strata of North America, 
 but regarded by Mr Salter as the vertical tubes, or rather the filled-up 
 burrows, of marine worms. See BIKDS-EYE LIMESTONE. 
 
 Pigotite (after Rev. M. Pigot). A mineral compound of alumina and 
 mudeseous acid of a brownish-yellow colour found in crusts and layers in 
 certain caverns the organic matter from the vegetation above being 
 carried in through rents and fissures by rain-water, where, meeting with 
 the alumina of the decomposing rocks, it forms the compound in question. 
 In some of the granitic caverns on the coast of Cornwall it forms crusts 
 from two to three inches in thickness. 
 
 Pinite. A variety or sub-species of iolite, deriving its name from the 
 Pini mines near Schneeberg, and known also as Gieseckile. It is essentiallv 
 a silicate of alumina (55 silica, 25 alumina), with iron protoxide, magnesia, 
 and water, and occurs chiefly in granite and felspar porphyry more rarely 
 in gneiss and mica-schist. 
 
 Pinites (Lat. pinus, the pine-tree). The generic term for all fossil 
 360 
 
PIN PLA 
 
 wood which exhibits structural approximations to the Coniferous order ; 
 undoubted coniferous remains being ranked under the term Peucites. 
 Remains of both occur in the Coal-measures and upwards ; but the existing 
 genus pinus has not been found earlier than in Pleistocene or uppermost 
 Tertiary deposits. See PEUCITES. 
 
 Pinnularia (Lat. pinna, a feather). One of Lindley's provisional genera 
 of Coal-measure plants, "occurring in small fragments, consisting of a 
 slender stem (or root), from which, at regular distances on opposite sides, 
 spring capillary appendages divided in a pinnated manner." Numerous 
 root-like fragments like myriophyllites, pinnularia, &c., occur in the 
 Coal-measures, but we know little or nothing of their connection or 
 affinities. 
 
 Pinus (the Pine-tree). The existing genus Pinus has not been found 
 earlier than in Pleistocene deposits ; it is readily distinguished by its 
 leaves growing in twos, threes, or fives in the same sheath ; and by its 
 cones, which are composed of scales that enlarge at the apex into a rhom- 
 boidal disc. 
 
 Pisiform (Lat. pisum, a pea). Occurring in small concretions like pease; 
 e.g., Pisiform iron-ore. 
 
 Pisolite (Lat. pisum, a pea, and lithos, stone). Literally "pea-stone;" a 
 concretionary limestone, so called from its resemblance to an agglutination 
 of pease. In "roestone" or "oolite" the component rounded grains or 
 globules are small ; in "pisolite," as the name implies, they are consider- 
 ably larger. These calcareous spherules are composed of concentric 
 laminae, which commonly have a particle of sand, a fragment of shell, or 
 other organic substance, as a nucleus. They owe their formation to the 
 deposition of successive concfetions around the included body while sub- 
 jected to the action of water in which a rotatory motion is induced ; and 
 the spheroids continue to increase until they become too heavy for further 
 transport, and then subside, and are consolidated by subsequent infiltra- 
 tion. The springs near Carlsbad deposit a beautiful pearly -looking 
 pisolite, some portions of which are sufficiently compact to admit of being 
 polished and manufactured into boxes and other ornaments. 
 
 Pistacite. Iron and lime epidote, in which a large quantity of the lime . 
 is replaced by protoxide of iron, and a large proportion of the alumina by 
 the peroxide occurs in prismatic crystals, and also granular, earthy, 
 or in crusts ; and so called from its pistachio-green colour. 
 
 Pitchstone. A glassy rock of the trappean division, usually occurring 
 in dykes and disrupting masses ; and so called from the pitch-like aspect 
 of its fresh conchoidal and splintery fracture. It is generally black, grey- 
 ish or greenish black; and is occasionally porphyritic (pitchstone por- 
 phyry), from the presence of small spherical concretions, termed spJicerulite. 
 It is classed by mineralogists along with obsidian, pumice, and pearl- 
 stone, under the head of amorphous felspar the glassy amorphous nature 
 of these rocks being apparently owing to their rapid cooling from a state 
 of fusion. 
 
 Placodennata, Placoderms (Gr. plax, a plate, and derma, skin or cov- 
 ering). Dr Pander's term for the bony-plated or bone-encased fishes of 
 the Old Red Sandstone Coccosteus, Plerickthys, Cephalaspis, and the like. 
 Placogauoid, Placoganoidei (Gr.plax, a plate, and ganos, splendour). 
 A sub- order of the Ganoid fishes, and so termed because the head and 
 more or less of the body is protected by large ganoid, often reticulated 
 
 361 
 
PLA 
 
 plates. The Placoganoids are richly represented in the Devonian epoch and 
 disappear in the Carboniferous ; whereas the other sub-order, the Lepido- 
 ganoids or scale-covei-ed ganoids, begin at that period to increase in numbers. 
 Placoid, Placoidean (Gr. plax, a plate, and eidos, form). The first order 
 of fishes in the arrangement of Professor Agassiz. They are characterised 
 by having their skin covered irregularly with plates of enamel, often of 
 considerable dimensions, and sometimes reduced to small points like the 
 shagreen on the skin of many sharks, and the prickly tooth-like tuber- 
 cles on the skin of rays. All the cartilaginous fishes, with the exception 
 of the sturgeon, belong to this order, which includes the skates, rays, dog- 
 fish, and sharks. 
 
 Plagiaiilax, an abbreviation for Plagiaulacodon (Gr. plagios, oblique ; 
 aulax, groove ; and odous, tooth). A small herbivorous marsupial, whose 
 teeth and jaws have been found in the Purbeck beds of the Oolite ; and so 
 named in reference to the diagonal grooving of the premolars. (Falconer 
 in 'Geological Journal/ vol. xiii.) 
 
 Plagiostoma (Gr. plagios, oblique, and stoma, the mouth). A generic 
 term applied to certain compressed, obliquely-oval bivalves of the Oyster 
 family, which are found fossil from the Trias upwards. They are now 
 ranked under the synonyme Lima, and partly under Spondylus, both of 
 which see. 
 
 Planerkalk, Planerkalkstein. Literally "plain-limestone ;" the German 
 name for the upper member of the Chalk formation in Saxony ; in contra- 
 distinction to the Eergkalk or Mountain-limestone. The equivalent in part 
 of our White Chalk. 
 
 Plan6rbis (Lat. planus, flat, and orUs}. A genus of fresh- water shells 
 distinguished by their discoidal form, the whorls of the shell being coiled 
 up in a nearly vertical plane. There are about sixty living species, and 
 about the same number are enumerated from Wealden and Tertiary 
 strata. 
 
 Plaster of Paris. The familiar designation for the cement or plaster 
 obtained from gypsum or sulphate of lime, and so called from its being 
 first prepared in the neighbourhood of Paris. Gypsum or sulphate of 
 lime, when calcined, is not decomposed (as common limestone is, by part- 
 ing with its carbonic acid), but simply loses its water of solidification. 
 It is then reduced to a white powder ; and when this is again mixed with 
 water, it absorbs a certain portion, and the mass becomes a solid plaster 
 or cement. The white powder is usually solid under the name of " Plaster 
 of Paris," and is largely used in the arts. 
 
 Plastic (Gr. plastikos, suitable for being wrought or fashioned). Applied 
 to substances which, like clay, are capable of being fashioned or moulded 
 into any desired form ; also to the skill or power of so fashioning ; hence 
 we speak of the "plastic art," the "plastic power of nature," and so 
 forth. 
 
 Plastic Clay. "The clays called Plastic," says Lyell, "which lie imme- 
 diately below the London Clay, received their name originally in France, 
 from being often used in pottery. Beds of the same age (the Woolwich 
 and Reading series of Prestwich) are used for the like purpose in England." 
 Asa series, the Plastic Clay of England constitutes the middle portion of 
 the Eocene group, and consists of plastic or mottled clays and sands, and 
 well-rolled flint pebbles. It is partly of marine and partly of fresh-water 
 formation, and is characterised by two species of oyster (0. bellovacina 
 
 362 
 
PLA PLE 
 
 and edulina), and some fresh-water shells, as Melania, Cyrena, Unio, 
 Paludina, &c. It is the equivalent of the French Argile Plastique et 
 Lignite. 
 
 Plate. A north of England mining term for compact beds of shale, 
 which, when exposed to the weather, break up into thin plates or laminae. 
 
 Plateau (Fr.) Literally "a platform;" introduced by the French geo- 
 grapher Buache, and applied to any elevated and comparatively flat surface 
 of land ; a table-land, or high level region. See TABLE-LAND. 
 
 Pldtina, Pldtinnm (Span, platina, from plata, silver, in allusion to its 
 colour). A metal, discovered in 1741, in the mines of Cliveo in Peru. It 
 occurs only in the metallic state, associated or combined with various other 
 metals, such as copper, iron, lead, titanium, chromium, gold, silver, pal- 
 ladium, rhodium, osmium, and iridium. It is usually in rounded grains, 
 or flattened pellets, of a metallic lustre and white colour, mixed with sand 
 and other impurities. When pure it has very much the colour of silver, 
 but of inferior lustre. It is the heaviest of known metals, its specific 
 gravity, after hammering, being about 21.5. It is exceedingly ductile, 
 malleable, tenacious, and difficult of fusion, but capable of being welded 
 at a high temperature. It undergoes no change under the combined 
 agency of air and moisture ; resists the strongest heat of a smith's forge ; 
 but can be melted by voltaic electricity, or by the oxyhydrogen blow- 
 pipe. It is not acted upon by any of the pure acids, but is dissolved by 
 chlorine and nitro-muriatic acid, and is oxidised at high temperatures by 
 pure potassa and lithia. It is much used by chemists and in chemical 
 operations for crucibles, evaporating dishes, alembics, and the like ; and 
 forms alloys with most of the other metals. 
 
 Platinoids. Platina being invariably found associated with several other 
 metals, forming a family apart of very singular chemical habitudes, the 
 term Platinoids has been applied to the group, which embraces palladium, 
 rhodium, iridium, osmium, ruthenium, and one or two others still doubt- 
 fully ascertained, to which the names astrseum and hebeum have been 
 proposed by Sir J. Herschel. 
 
 Platycephalic (Gr. platys, broad, and hphale, the head). Broad-headed ; 
 flat-handed ; e.g., the flat-skulled tribes of the human family. 
 
 Platycrinus, Platycrinite (Gr. platys, broad). A genus of encrinites 
 peculiar to the Carboniferous limestone, and so termed from the flatness 
 and breadth of the basal and radial plates of the receptacle. 
 
 Platysomus (Gr. platys, broad, and omos, the shoulder). One of the 
 pycnodonts ; a ganoid fish of the Carboniferous and Permian epochs, and 
 so called from its deep bream-like body, which is covered with strong rect- 
 angular scales arranged in bold transverse rows. Head rather small ; 
 eye-orbits large ; tail sharply heterocerque. 
 
 Pleistocene (Gr. pleistos, most, and kainos, recent). Literally, "most 
 recent ;" that is, the most recent or uppermost of the Tertiaries, a term 
 implying that the organic remains in such accumulations belong almost 
 wholly to existing species. Sir Charles Lyell makes use of the word Post- 
 pliocene, and others employ the term Pleistocene as equivalent to Post- 
 tertiary ; but, properly speaking, the organic remains of the Post-terti- 
 aries belong exclusively to species still existing, while those of the Pleisto- 
 cene embrace a few extinct forms. As it is impossible to draw sharp lines 
 of demarcation between different formations, the Pleistocenes may be re- 
 garded as the passage-beds between Tertiary and Post-tertiary formations. 
 
 363 
 
PLE PLI 
 
 Plesiosaurns (Gr. plesios, near to, and saurus, a lizard). A genus of 
 marine reptiles (of which there are known about twenty species), occurring 
 from the Lias to the Chalk inclusive ; and so named from its being much 
 more lacertilian in structure than the ichthyosaurus, from which it differs 
 in the smallness of the head, the enormous length of neck, which consists 
 of from twenty to forty vertebrae, and in other osteological peculiarities. 
 "This reptile," says Mantell, "combines in its structure the head of a 
 lizard, with teeth implanted in sockets like the crocodile a neck resem- 
 bling the body of a serpent a trunk and tail of the proportions of those 
 of a quadruped with paddles like the turtle. The vertebrae are longer and 
 less concave than in the ichthyosaurus ; and the ribs, being connected by 
 transverse abdominal processes, present a close analogy to those of the 
 chameleon." Specimens have been found, and some of them almost entire, 
 ranging from ten to twenty feet in length. See ICHTHYOSAURUS. 
 
 Pleurac&nthus (Gr. pleuron, the side, and acantha, a thorn or spine). 
 A genus of ichthyodorulites or fin-spines occurring in the Carboniferous 
 formation, and characterised by their having a row of sharp hooks or 
 denticles on either side ; whence the name. According to Agassiz, they 
 belong to the fossil family TRYGONID^E. 
 
 Pleurodont (Gr. pleuron, the side, and odous, tooth). A term applied by 
 Professor Owen to those inferior or squamate saurians which have the teeth 
 anchylosed to the bottom of an alveolar groove, and supported by its side. 
 See THECODONT. 
 
 Pleurotomdria (Gr. pleuron, a side, and tome, a notch). An extensive 
 genus of fossil shells belonging to the gasteropod family Haliotidce, and 
 comprising about 400 species, which range from the Lower Silurian to the 
 Chalk inclusive. The shell resembles that of the Trochus, is solid, few- 
 whorled, and has its surface variously ornamented the colour being still 
 preserved in some specimens ; the aperture is somewhat square, and has a 
 deep slit in its outer margin ; hence the name. The part of the slit which 
 has been progressively filled up forms a prominent band round the whorls. 
 "In this extensive group," says Woodward, "there are some species which 
 rival the living turbines in magnitude and solidity, whilst others are as 
 frail as ianthina." 
 
 Plinthopli6nis (Gr., literally bearing tiles, in allusion to the bony scutes 
 on its sides). A genus of fishes from the Lower Chalk, distinguish- 
 ed by the following characters, as described by Dr Giinther : "Body 
 oblong, apparently scaleless, but with a dorsal and ventral series of im- 
 bricate, arrow-shaped osseous scutes on each side. Dorsal fin rather 
 short, placed in the middle of the total length, above the ventrals ; anal 
 short, at some distance behind the dorsal ; caudal fin forked. Pectorals 
 and ventrals well developed, without osseous spine, the latter nine or ten- 
 rayed." Related to Rhinellus ; but whether Ganoidean or Teleostean 
 cannot be decided from the imperfect state of the specimens. 
 
 Pliocene (Gr. pleion, more, and kainos, recent). Sir Charles Lyell's term 
 for the Upper Tertiaries, as containing more, or a greater percentage, of 
 recent testacea than the Miocene or Eocene. In 1830, according to the 
 enumeration of M. Deshayes, the percentages were, Pliocene, 35 to 50 ; 
 Miocene* 17 ; and Eocene, only 3. In the " Newer Pliocene" or uppermost 
 Tertiaries of Lyell (the Pleistocene of many authors) the percentage in- 
 creases to 90 or 95. 
 
 Pliolophus (Gr. pleion, more, and lophion, a small crest). A small lophi- 
 364 
 
PLI POI 
 
 odont mammal, whose remains have been found in Eocene and Miocene Ter- 
 tiaries, and so named by Professor Owen because it seems to be more near 
 to the lophiodont type than its close ally the hyracotherium. See LOPHI- 
 ODON (Jour. Geol. Soc., vol. xiii.) 
 
 Pliopithecus (Gr. pleion, more, and pithecos, ape). An extinct ape from 
 the Miocene deposits of the south of France, and so named by Gervais from 
 its resemblance to the tailed monkeys (semnopithecus) of Southern Asia. 
 
 Pliosaurus (Gr. pleion, more, and sauros, lizard). A marine reptile of 
 the Upper Oolites, intermediate in structure between the Plesiosaur and 
 Ichthyosaur ; literally " more lacertilian " than the common ichthyosaurus. 
 With the exception of the teeth, which are thicker and stronger, the verte- 
 brae of the neck, which are short and compressed, and the more massive 
 proportions of the jaws and paddle-bones, the framework of pliosaurus 
 closel}' accords with that of plesiosaurus. 
 
 Plumbago (Lat. plumbum, lead). One of the names given to Graphite 
 or Blacklead, from its resemblance to an ore of lead. See GRAPHITE. 
 
 Plumbiferous, Plombiferous (Lat. plumbum, lead, and fero, I yield or 
 bear). Applied to veins, strata, or other matrices yielding or containing 
 any of the ores of lead. 
 
 Plampudding-Stone. Originally applied to a very pretty conglomerate 
 of flint pebbles cemented together by a siliceo-calcareous matrix, polished 
 sections of which had a fanciful resemblance to the fruit in a slice of plum- 
 pudding, now loosely applied to all conglomerates. See PUDDING-STONE. 
 
 Plutonic (Pluto, the god of the inferior regions). Applied to igneous 
 rocks found at some depth beneath the surface of the land or sea, as 
 distinct from Volcanic, or those thrown up to, and consolidated on the 
 surface. As a class, the Plutonic are more crystalline, and exhibit more 
 structure than the Volcanic characteristics apparently induced by the 
 greater pressure under which they were cooled and consolidated. 
 
 Pluvial (Lat. pluvius, rainy). Of or belonging to rain ; applied to opera- 
 tions and results that arise from or depend on the action of rain. Thus 
 we speak of the denuding or degrading effects of " pluvial agency," just 
 as we speak of " atmospheric," " fluviatile," or other similar agency. 
 
 Pluviometer (Lat. pluvius, rain ; metron, a measure). An instrument 
 for catching falling rain, so as to determine the amount that falls at any 
 given locality within a given period ; a rain-gauge, of which there are 
 several varieties in use by meteorologists. 
 
 Poacites (Lat. poa, the meadow-grass). The generic term for all fossil 
 monocotyledonous leaves, the veins of which are parallel, simple, of equal 
 thickness, and not connected by ti-ansverse bars. In the mean time Poa- 
 cites takes rank under the Graminece or grasses, though, from the great 
 length and breadth of many of the Coal-measure species, it is more than 
 probable that some of them may be the leaves of pinnated palms. See 
 PHYLLITES. 
 
 Podosphenia (Gr. pous, podos, the foot, and sphen, a wedge). A genus 
 of Diatoms or microscopic plant-growths, deriving their name from their 
 wedge-shaped frustules, which in youth are attached by the small end, but 
 afterwards become free. They are said to be chiefly marine, and abound 
 in the polishing-slate of Bilin. 
 
 Poikilitic, Poecilitic (Gr. poikilos, variegated). A term applied by the 
 earlier English geologists to the Upper New Red Sandstone, in allusion to 
 the variegated colours red, green, purplish, &c.of its marls and sandy 
 
 365 
 
POL 
 
 shales. The Bunter Sandstein of the Germans ; the Terrain Poecilien of 
 the French. 
 
 Polders (Dutch). The name given in Holland to the low fertile lands, 
 reclaimed by vast systems of dykes and embankments from the sea. The 
 soil of the ''polders" consists of muddy deposits, mixed with comminuted 
 shells and fine sea-sand ; in other words, it is a fine marine silt rendered 
 fertile by the abundance of its organic debris. 
 
 Poles (Gr. poleo, I turn). The extremities of the axis or imaginary line 
 round which the earth turns in her daily rotation. They are respecti vely 
 the North and South, or the Arctic and Antarctic Poles ; and the districts 
 therewith connected are known as the Polar Regions. By prolonging the 
 earth's axis towards the apparent celestial concavity in which the earth 
 rotates, we form, in like manner, the Poles of the Heavens, north and south ; 
 and hence the Pole or Polar Star, from its proximity to the pole of the 
 heavenly vault. 
 
 PolierscMefer (Ger.) Polishing-slate ; a slaty infusioral or rather micro- 
 phytal rock, the same as the tripoli of Bilin, &c., and so termed from its 
 being used as a polishing powder. 
 
 Pollux. Castor and Pollux, two closely allied minerals of the Felspar 
 family : hence their names by Breithaupt. They resemble quartz in their 
 hardness, transparency, and vitreous lustre, and are the most siliceous of 
 the crystalline silicates. 
 
 Polypdrium (Lat.) The common framework or endoskeleton of any 
 group of polypes ; the secreted matter by which they are united into one 
 colony, whether fleshy, horny, calcareous, or siliceous. Same as Poly- 
 pidom, which see. 
 
 P61ypes, Polypi (Gr. polys, many, and pous, foot). The zoological term 
 applied to those radiated animals which are furnished with many tentacula 
 or foot-like organs of prehension surrounding the mouth or free orifice ; 
 as the "fresh-water polype" or hydra, the "coral polype," &c. See 
 ZOOPHYTA. 
 
 Pol^pidom (polype, and domus, a house). A name given to the stems 
 and permanent fabrics of zoophytes, around or in which are placed the 
 little cells containing the polypes or animals which construct the mass. 
 In some the polypidom is horny and flexible like the gorgonia or sea- fan ; 
 in others, as the common madrepore coral, it is strong and calcareous ; and 
 in others it is membrano-calcareous. In the stony or lime-secreting genera 
 this endoskeleton, polypidom, polyparium, or common support, becomes 
 the well-known Coral, the aggregation of which constitutes those vast 
 Reefs that rival in magnitude the limestones of the earlier formations. 
 
 Polyporites. Literally " many pores ; " the name given by Dr Lindley to 
 a fungus- like organism from the Coal-measures of Wales, from its resem- 
 blance to the existing Polyporus versicolor. 
 
 Polyptychodon (Gr. polys, many; ptyche, a fold ; and odous. tooth). A 
 Cretaceous genus of Enaliosaurs or sea-lizards, so called by Professor 
 Owen from the many-ridged or folded character of the enamel of their 
 teeth, which were the parts first known and described. Portions of the 
 cranium, ribs, vertebra?, &c., have since been discovered, all proving the 
 existence of a huge carnivorous saurian having affinities to the Plesio- 
 sauroid type. 
 
 Polythalamia (Gr. polys, many, and tkalamos, a chamber). An order of 
 compound Protozoa, so called from their being enclosed in calcareous shells 
 
 366 
 
POL PON 
 
 consisting of a series of distinct chambers. These chambers in some 
 species communicate with each other ; in others they are completely closed 
 up, and appear to be the abode of a separate and probably independent 
 animal. The general belief, however, is, that the several cells or portions 
 of the vitalised mass communicate in some way or other with each other, 
 so as to maintain the simultaneous vitality of the whole. In some in- 
 stances each chamber of the common shell presents only a single external 
 opening ; but as a general rule the substance of the shell is pierced like a 
 sieve, with numerous minute pores or foramina for the protrusion of deli- 
 cate filaments ; hence the term FOBAMINIFERA. All the Polythalamia are 
 marine, and frequently occur in such numbers that the fine calcareous 
 sand of the sea-shore and sea-bottom is entirely made up of their micro- 
 scopic shells. In former ages they appear to have been even more abun- 
 dant ; and thus the Chalk, as well as many of the marls and limestones of 
 the Tertiary epoch, are in a great measure composed of their remains 
 partly entire, and partly worn and broken by the action of the waves. As 
 an order, the Polythalamia have been divided into several families, charac- 
 terised by the arrangement of the chambers constituting the compound 
 shell ; and nearly two thousand species have been enumerated a number 
 that, in all likelihood, will be greatly reduced, as more minute investiga- 
 tion shows that many of these so-called species are only forms of the same 
 animal in various stages of development. Polythalamous. Having many 
 chambers or cells. 
 
 Polyz6a (Gr. polys, many ; zoa, animals). This term embraces alt the 
 minute mollusca which inhabit compound phytoidal structures like the 
 flustra and retepora, and which were till lately confounded with the polypes 
 or corallines. The term was introduced by Mr J. V. Thompson in 1830, 
 and is now generally adopted in preference to Bryozoa, the name subse- 
 quently employed by Ehrenberg. "The Polyzoa," says Professor Allman 
 in his monograph on the fresh-water genera, " are chiefly inhabitants of 
 the sea, where they may be witnessed under numerous plant-like guises ; 
 now spreading like a lichen over submerged stones or old shells, or broad 
 fronds of laminaria and other sea- weeds ; now forming soft, irregular, 
 fungus-like masses, or hard calcareous branchy growths, like diminutive 
 trees ; and now again presenting the appearance of the most delicate and 
 exquisitely-formed sea-weed or moss, offering even to the unassisted eye, 
 in the endless repetition of the same element of form, objects of surpass- 
 ing symmetry and beauty. The Polyzoa, however, are not by any means 
 exclusively confined to the ocean ; and though by far the greater number 
 are marine, yet in the still and running waters of the land in the broad 
 river and rushing stream in the pure cold mountain lake, and the stag- 
 nant waters of the mossy fen species are to be found, which in interest 
 yield not one jot to their' brethren of the sea, and offer to the naturalist 
 an inexhaustible source of gratification, in the beauty of their forms and 
 the wonders of their organisation." They are found fossil as well as recent, 
 and occur in all formations from the Cambrian and Silurian upwards 
 e.g., Oldhainia, fenestella, retepora, eschara, flustra, &c. To distinguish the 
 inhabitant of the polyzoan cell from the true polype, the term polypide 
 has been proposed ; and the entire structure is known as the Ccencecium or 
 " common dwelling," in contradistinction to the polypary or polypidom of 
 the polype. 
 
 Ponent (Lat.) Laying aside ; the twelfth of the fifteen series into which 
 
PON POR 
 
 Professor Rogers subdivides the Palaeozoic strata of the Appalachian chain 
 
 the " Sunset " of the North American Palaeozoics, and the equivalents of 
 
 our Upper or true Old Red Sandstone. See PALEOZOIC FORMATIONS. 
 
 Pontine Marshes. These sea- fens, so well known arid dreaded by the in- 
 habitants of Rome and the delta of the Tiber, are occasioned, according 
 to Admiral Smyth, by the quantity of water carried into the plain by in- 
 numerable streams that rise at the foot of thennountains to the east of 
 Rome, which, for want of sufficient declivity, creep sluggishly over the 
 level space, and sometimes stagnate in pools, or lose themselves in the 
 sands. Here, fermenting with decayed vegetable matter, and acted on by 
 a fervid climate, malaria is produced that invisible enemy that poisons 
 the fairest portions of Italy, otherwise so salubrious, and renders man a 
 sufferer from his cradle to his early grave. There is every appearance that 
 the basin of these marshes was once a gulf of the sea, which has been 
 gradually filled up by alluvium from the mountains. See MAREMME. 
 
 Porcelainised. Baked like potter's clay ; applied to clays, shales, and 
 other stratified rocks that have been hardened and altered by igneous con- 
 tact so as to resemble in texture porcelain or kiln-baked clay. 
 
 Porcellanite. Known also as "porcelain jasper" and "burnt earth." 
 The term applied to clays and shales that have been converted by subter- 
 ranean heat into jaspery or porcelain-like masses of various colours and 
 hardness, according to their original composition, and the degree of heat 
 to which they have been subjected. Frequent in the vicinity of dykes and 
 erupted traps. 
 
 Porifera. In modern systems of zoology, the second class of Protozoa, 
 including the sponges ; and so called from the masses formed by these 
 creatures being perforated in every part with minute orifices. Literally 
 " pore-bearing." Sponge, as we usually see it, consists of a congeries of 
 horny filaments, interlacing in every direction, so as to form an intricate 
 network of intercommunicating cells ; and imbedded in these filaments, 
 in the most of sponges, are needle-shaped particles of siliceous or calcare- 
 ous matter termed spicula. The animated portion is a mere mucilaginous 
 investment composed of an aggregation of cells. Fossil sponges occur in 
 several formations, and especially in the Chalk of England. 
 
 Porphyritic. Having the aspect or texture of porphyry ; as the " por- 
 phyritic granite " of Devon and Cornwall, which contains large prismatic 
 crystals of felspar ; the "porphyritic gneiss " of Portsoy, which imbeds in 
 its folia large irregular crystals of felspar ; or "porphyritic greenstone," 
 which has often large crystals of hornblende scattered confusedly through 
 its mass. 
 
 Porphyry (Gr. porphyreos, purple). This term was originally applied 
 to a reddish igneous rock found in Upper Egypt, and used for sculptural 
 purposes ; a red syenitic porphyry. It is now employed by geologists to 
 denote any rock (whatever its colour) which contains imbedded crystals 
 distinct from the main mass or matrix, though, strictly speaking, it ought 
 to be restricted to those having a felspathic basis. We have thus fel- 
 spar porphyry, clay stone porphyry, porphyritic granite, and porphyritic 
 greenstone. 
 
 Portage (Fr.) Applied by voyageurs to the space or watershed that lies 
 between the navigable branches of rivers belonging to the same or differ- 
 ent hydrographic basins, and so called from the circumstance that boats 
 and goods have to be carried from the one branch to the other. The name 
 
 368 
 
POR PCS 
 
 is also given to those parts where, in order to avoid cataracts or danger- 
 ous rapids, the boats are unloaded, taken out of the water, carried above 
 the obstruction, and again launched and loaded. 
 
 Portland Cement. A well-known cement, largely used for facing-up 
 brick buildings, &c., in imitation of stone. It is made from carbonate of 
 lime (common limestone) mixed with great care, in definite proportions, 
 with the muddy deposits of rivers running over clay and chalk. The 
 whole of the materials are carefully pounded together under water, and 
 are afterwards dried and calcined. See CEMENTS. 
 
 Portland Stone and Portland Sand. A well-known group of the Upper 
 Oolite as developed in the south of England. It consists of shelly free- 
 stones of variable texture underlaid by thick beds of sand, and derives its 
 name from the Isle of Portland in Dorsetshire, where certain of the free- 
 stones have for centuries been largely quarried for architectural purposes. 
 The Portland beds abound in fossil shells, bones of saurians, and drift 
 coniferous wood. See OOLITIC FORMATION. 
 
 Post- (Lat.) A frequent prefix in scientific compounds signifying after, 
 either in regard to time or position ; as post-meridian, after mid-day ; post- 
 tertiary, later or younger than the Tertiary formation ; post-abdominal, 
 placed immediately behind the abdomen ; after-abdominal. Also a quar- 
 ryman's and miner's term for any thick compact stratum of sandstone or 
 limestone ; hence such phraseology as " 16 feet of sandstone-post," &c. 
 
 Post-Meridian (Lat.) After mid-day; afternoon; the ninth of the 
 fifteen series into which Professor Rogers subdivides the Palaeozoic strata 
 of the Appalachian chain the " Afternoon " of the North American 
 Palaeozoics, and the equivalent, in part, of our Lower Devonians. See 
 PALEOZOIC FORMATIONS. 
 
 Post-Tertiary System. Under the term Post-Tertiary or Quaternary, it 
 is usual to arrange all accumulations and deposits that have been formed 
 since the close of the Boulder- Drift or Glacial period regarding that epoch 
 as the true termination of the Tertiary system. However difficult it may 
 be to account for the conditions that give rise to the " Drift," there can be 
 no doubt regarding the agencies which have been at work ever since in silt- 
 ing up lakes and estuaries, forming peat-mosses and coral-reefs, and laying 
 down beaches of sand and gravel. At the close of the Pleistocene period, 
 the present distribution of sea and land seems to have been established 
 at least in the northern hemisphere the land presenting the same surface 
 configuration, and the sea the same coast-line, with the exception of such 
 modifications as have since been produced by atmospheric, aqueous, and 
 other obvious causes. At the close of that period the earth also appears 
 to have been peopled by its present flora and fauna, with the exception of 
 some local removals of certain animals, and the general extinction of a few 
 species, whose remains are found imbedded in a partially petrified or sub- 
 fossil state in Post-tertiary accumulations. We are thus introduced to the 
 existing order of things ; and though our observations may extend over a 
 period of many thousand years, yet every phenomenon is fresh and recent 
 compared with those of the preceding epochs. With the exception of vol- 
 canic lavas, deposits from calcareous and siliceous springs, some consoli- 
 dated sands and old coral-reefs, we have now no solid strata the general- 
 ity of Post-tertiary accumulations being clays, silts, sands, gravels, and 
 peat-mosses. Arranging these in chronological order, it is usual to speak 
 of them as Post-Glacial, Pre- Historical, and Historical the full imports of 
 
 369 2 A 
 
, POT PRE 
 
 which will be readily understood by referring to the preliminary tabula- 
 tion of " CONTEMPORARY OR EQUIVALENT DEPOSITS." 
 
 Potamophyllites. Literally "river-leaves" (Gr. potamos, river, smdphyl- 
 lon, leaf) ; a genus of monocotyledonous leaves occurring in fresh-water 
 Tertiaries ; now ranked under the more general term PHYLLITES. 
 
 Potato-Stones. A quarryman's term for the geodes of the mineralogist ; 
 rounded irregular concretions of various composition, often hollow and 
 lined with crystals, or containing earthy detached nuclei. 
 
 Poteridcrinus, Poteriocrinites (Gr. poterion, a goblet, and encrinus). 
 An extensive genus of encrinite occurring in the Carboniferous Limestones 
 of Britain and Ireland ; and so called from the vase or goblet shape of its 
 body or receptacle, which is composed of three series of angular plates 
 five in each series. 
 
 Potstone. A soft magnesian or talcose rock, of a greenish-grey or leek- 
 green colour, sectile, and capable of being fashioned into pots and vases ; 
 the lapis ollaris of the ancients. Mineralogically, it is an uncertain mixture 
 of talc, chlorite, mica, asbestus, and the like, occurring in beds among the 
 crystalline rocks of various countries ; in other words, coarse granular 
 varieties of steatite or soapstone. 
 
 Pozzuolaua, Pozzolana (From Pozzuoli in the Bay of Naples). A vol- 
 canic ash or sand largely used in the manufacture of Roman cement. The 
 artificial mixture consists of fine volcanic powder, charged with about 20 
 per cent of oxide of iron, and the addition of a little lime. It forms one 
 of the best of our hydraulic cements, setting and solidifying rapidly under 
 water. 
 
 Prairies. The open, slightly undulating, and grassy plains of North 
 America. Situated in the Great Central Plain, the prairies are of vast 
 extent ; some are rolling, others are flat, and level in surface ; many of 
 them are treeless, and covered only with luxuriant grass and flowers ; to- 
 wards the south some tracts verge into a shrubby woodland ; while in the 
 extreme north the soil is largely swampy and desert. 
 
 Precession of the Equinoxes." The earth's axis," says Mr Hopkins, 
 in treating of this subject, " is at present directed to a point in the heavens 
 near to the star Polaris. This point is the exact north pole of the hea- 
 vens ; and in considering it with reference to periods of time not exceeding 
 many years, we usually speak of it as & fixed point. This, however, is not 
 strictly correct. The pole moves very slowly, so as to describe very nearly 
 what is called a small circle in the heavens. This small circle, and the 
 motion of the pole along it, are such, that in 12,000 or 13,000 years the 
 pole will be distant from the present pole by more than 40 ; but, in some 
 25,000 years, it will have returned to the point in the heavens which it now 
 occupies. Thus we see that the present distinction enjoyed by Polaris is 
 but a transitory one, which in a few centuries will pass away, with the 
 certainty, however, of returning after the period just mentioned. A fur- 
 ther reference to the celestial globe will immediately show that this motion 
 of the earth's axis or pole will necessarily superinduce a corresponding 
 motion of the equinoxes along the ecliptic. This motion is about 60" 
 a-year, and is in a direction opposite to that in which the signs of the 
 zodiac are reckoned; and consequently the sun, after leaving either 
 equinox, returns to it again in less time (by about twenty minutes) than 
 if the equinox had remained stationary. This is the precession of the 
 equinoxes." 
 
 370 
 
PEE PHI 
 
 Precious. A term in frequent use among: jewellers and lapidaries to ex- 
 press the finer varieties of minerals and gems, as " precious beryl," ' ' pre- 
 cious garnet," " precious opal," and the like. Employed much in the 
 same way as the term Oriental, which see. 
 
 Precipitate (Lat. prcecipito, I cast headlong). When substances held in 
 solution are made to combine chemically, or are otherwise changed, so as 
 to fall to the bottom in a solid state, they are said to be precipitated, or to 
 form precipitates. Substances in mechanical suspension merely, and falling 
 to the bottom by their own gravity, are, on the contrary, said to form 
 sediments. 
 
 Prehnite (after Colonel Prehn, by whom it was first brought to Europe 
 from the Cape of Good Hope). A silicate of alumina and lime occurring 
 largely in trap rocks, in closely aggregated prismatic crystals, and also 
 massive, of a greenish-white or yellowish-green colour, translucent, with 
 a vitreous lustre, brittle, and pyro-electric. Composition 44.41 silica, 
 24.55 alumina, 26.74 lime, 4.30 water, and traces of protoxides of iron 
 and manganese. 
 
 Pre-Meridian (Lat.) Immediately before mid-day; the seventh of the 
 fifteen series into which Prqfessor Rogers subdivides the Palaeozoic strata 
 of the Appalachian chain ; the "Forenoon" of the North American Palaeo- 
 zoics, and the equivalent apparently of our Upper Silurians. See PALEO- 
 ZOIC FORMATIONS. 
 
 Preternatural (Lat. prceter, beyond). Beyond what is natural ; different 
 from what we regard as natural ; irregular ; extraordinary. In the physi- 
 cal world, preternatural events are those deemed beyond or without the 
 ordinary course of things, and yet not regarded as miraculous ; while 
 supemattiral, on the other hand, are regarded as altogether beyond phy- 
 sical laws, and miraculous or ascribable to the direct intervention of 
 creative power. 
 
 Primal (Lat.) The first or earliest ; the lowest of the fifteen series into 
 which Professor Rogers subdivides the Palaeozoic rocks of the Appalachian 
 chain; the "Dawn" of the North American Palaeozoics, and the equiva- 
 lent, perhaps, of our lowest Cambrians. See PALEOZOIC FORMATIONS. 
 
 Primitive or Primary Rocks (Lat. primus, first). Under this term the 
 earlier geologists included all the crystalline deep-seated rocks (granite, 
 gneiss, mica-schist, clay-slate, &c.), as having been formed in the "prim- 
 eval" ocean, or contemporaneously with the globe itself, and before the 
 creation of Life, as none of them enclose the remains of plants or animals. 
 As general designations for the older rocks, the words primary and primi- 
 tive are still retained, though it is now well known that granite and crys- 
 talline strata are found of all ages and in all formations. The term may 
 be regarded as synonymous with the Azoic, Hypozoic, Metamorpkic, or 
 Non-fossiliferous systems of modern geologists. 
 
 Primordial (Lat. primus, first ; ordo, an order). A term used by M. 
 Barrande for the lowest or earliest zone of fossiliferous strata, more espe- 
 cially as developed in Bohemia, the field of his principal labours. May be 
 regarded as the equivalent of the Cambrian system of Professor Sedgwick. 
 
 Pristacanthus (Gr. pristis, a saw, and akantha, spine). Literally " saw- 
 spine ; " a genus of ichthyodorulites or fin-spines found in the Oolite, and 
 supposed to belong to fishes of the Cestraciont family. 
 
 Pristis (Gr.) The saw-fish; a well-known predatory fish allied to the 
 Rays and Sharks, and remarksfble for its long, flat, bony beak, which is 
 
 371 
 
PRO 
 
 armed on either side (like a saw) with sharp compressed teeth, the whole 
 constituting a most formidable weapon, offensive or defensive. The 
 beaks or " saws " of extinct species occur in the Tertiary beds of England 
 and the Continent. 
 
 Producta, Productus (Lat., produced, drawn out). A well-known genus 
 of brachiopodous molluscs, occurring abundantly in Devonian, Carboni- 
 ferous, and Permian strata, and so termed from one valve of the shell 
 being in most of the species prolonged beyond the other, and often to a 
 great extent. The Producta has been taken as the type of the family Pro- 
 ductidce, in which the shell is concavo-convex, with a straight hinge-line, 
 valves rarely articulated by teeth, closely appressed, furnished with tubu- 
 lar spines ; ventral valve boldly convex ; dorsal concave ; internal surface 
 dotted with conspicuous punctures : dorsal valve with a prominent car- 
 dinal process ; brachial processes sub-central ; vascular markings lateral, 
 broad, and simple ; adductor impressions dendritic, separated by a narrow 
 central ridge : ventral valve with a slightly notched hinge-line ; adductor 
 scar central, near the umbo ; cardinal impressions lateral, striated. The 
 Productidse are highly characteristic of the Carboniferous Limestone, occur- 
 ring in many species, and in all stages of growth and aggregation ; hence 
 the frequent term " Productus Limestone." 
 
 Prognathous (Gr. pro, forward, and gnathos, the jaw-bone). Prominent 
 or projec ting-jawed ; e.g., the prognathous skull of the negro, in which the 
 jaws project considerably beyond the vertical facial line. 
 
 Prosoponiscus (Gr. prosopon, a face or mask, and oniskos, wood-louse). 
 A Permian crustacean, apparently belonging to the family of Isopods, and 
 found in the Zechsteins of Germany and magnesian limestones of Durham. 
 So named by J. W. Kirkby, who objects to Schauroth's term " Palceo- 
 crangon" as not expressing the true affinities of the species. 
 
 Protoctista (Gr. protos, first, and ktista, created beings). A term pro- 
 posed to embrace the protophytes and protozoans, or those minute organ- 
 isms which seem to stand on the confines of the vegetable and animal 
 kingdoms, and in some instances are but doubtfully referable to either. 
 
 Prdtogine (Gr. protos, first, and ginomai, I am formed). The French 
 term for a granite composed of felspar, quartz, and talc ; lalcose granite. 
 It abounds in the Alps, in Cornwall, and other countries, and derives its 
 name from the erroneous idea that it is the oldest or first-formed of the 
 granites. The Kaolin or China-clay of Cornwall is chiefly derived from 
 its decomposition. 
 
 Protophyta (Gr. protos, first, and phyton, a plant). Literally " first or 
 earliest plants ; " a term applied to the diatoms and other microscopic or- 
 ganisms which apparently belong to the vegetable kingdom, in contradis- 
 tinction to Protozoa, which embraces those appertaining to the animal. 
 See PROTOZOA. 
 
 Protornis (Gr. protos, first, and omis, bird). Literally " first bird ; " 
 the most ancient example as yet known of a passerine fossil bird. It 
 occurs in the Eocene Tertiaiies of Glaris, is about the size of a lark, and in 
 some respects similar to that bird. 
 
 Prototaxites (Gr. protos, first, aud taxus, yew-tree). A genus of woody 
 trunks with concentric rings of growth and medullary rays, occurring in 
 the Devonian strata of Canada, and so named by Dr Dawson from their 
 having the spirally-marked cells characteristic of the genera taxiles and 
 spiropitys, but differing from any known conifer in the cylindrical form 
 
 372 
 
PRO PSA 
 
 and loose aggregation of the wood-cells. Many of the trunks show varie- 
 ties in the growth rings, which "indicate a decided difference of tempera- 
 ture in the seasons of the Devonian year." 
 
 Protorosaiirus, Protosaurus (Gr. proteros, earlier, the first, and saurus, 
 lizard). " The fossil monitor of Thuringia ; " so called from its occurring 
 in the bituminous copper - slate of Thuringia, and for a long time the 
 earliest reptile known to geologists ; hence the term Protosaurus. 
 
 Prdtotype (Gr. protos, first, and typos, a type or mould). The original 
 form after which others are fashioned or moulded ; the original from 
 which others are copied ; the primary form to which others, in their prin- 
 cipal features or characteristics, bear resemblance. Often loosely and 
 variously applied. 
 
 Protovirgularia (Gr. protos, first, the most ancient, and virgularia). A 
 genus or group of graptolites occurring in the Lower Silurian strata, and 
 so named by M'Coy from the resemblance of their opposite and distant 
 cells to those of the existing virgularia. 
 
 Protozoa (Gr. protos, first, and-joe, life). In modern systems of classifi- 
 cation, the first or lowest division of the animal kingdom. It includes a 
 number of creatures of a very lowly type of organisation, which appeal* 
 almost to occupy a sort of neutral ground betweeen animals and vegetables 
 the function of reproduction being principally performed by a plant- 
 like budding or division of the parental substance. The bodies of the 
 Protozoa consist either of a simple elementary cell, or of an aggregation 
 of cells, each cell being capable of a separate and independent existence. 
 Some are simply gelatinous ; others secrete a horny, calcareous, or siliceous 
 investment ; and most of them are of microscopic size. The Division em- 
 braces three classes : 1. The Rhizopoda, whose organs of locomotion con- 
 sist of mere root-like expansions of the body itself; 2. The Porifera, or 
 sponges ; and, 3. The Infusoria, or infusory animalcules : or, more mi- 
 nutely, according to other systematists, 1. Rhizopoda; 2. Polycystina; 
 3. Spongidce ; 4. TlvalassicoUidce ; 5. Gregarinidce ; and, 6. Infusoria. See 
 the respective classes. 
 
 Protozoic (Gr. protos, first, and zoe, life). First-life ; belonging to, or 
 containing, the first traces of life. Applied to the earlier fossiliferous 
 epoch and strata ; equivalent to Primordial ; hence such phrases as " pro- 
 tozoic zone," " protozoic world," &c. 
 
 Psammite (Gr. psammos, sand). A term in common use among Conti- 
 nental geologists for fine-grained, fissile, clayey sandstones, in contra- 
 distinction to those which are more siliceous and gritty (gres). 
 
 Psammodus (Gr. psammos, sand, and odous, tooth). Literally "sand- 
 tooth ; " a provisional genus of cestraciont teeth from the Carboniferous 
 Limestone, and so called from their granular or rough upper surface, used 
 for crushing and grinding. They are generally of a quadrangular form, 
 and of large dimensions. 
 
 Psarolites, Psaronites (Gr. psaros^ speckled, and lithos). The name 
 given to the silicified stems of Tree-ferns found so abundantly in the New 
 Red Sandstone (Permian) near Hillersdorf in Saxony, in allusion to the 
 stellated markings produced by sections of the vessels that compose the 
 tissues. From this speckled appearance, which is visible to the naked eye, 
 these fossils have also obtained the popular name of Staarein-slein or Star- 
 stone. Psaronites also occur in the Upper Coal-measures of France, United 
 States, &c.; and, like the existing tree-ferns of New Zealand, their trunks 
 
 373 
 
PSE PTE 
 
 are surrounded by a dense mass of air-roots which adds greatly to their 
 dimensions. 
 
 Pseudo- (Gr. pseudes, false). A prefix of frequent occurrence in scien- 
 tific compounds, and implying something deceptive in appearance, function, 
 or relation ; as Pseudopods, those protozoans which have the power of 
 thrusting out the fleshy substance of their bodies into feet-like organs 
 or processes (literally "false-feet"); Pseudocarps, Pseudobulbs, and the 
 like. 
 
 Pseudom6rplious (Gr. pseudes, false, and morphe, form). Applied to sub- 
 stances which, not possessing a crystalline structure, are yet found in the 
 form of regular crystals. Such pseudomorphic crystals, as they are termed, 
 are evidently moulded in cavities from which original regular crystals have 
 been dissolved the new substances, particle by particle, taking their 
 place. Blum divides pseudomorphs into two classes, which embraces 
 respectively two and three snb-classes, viz. : 
 
 1. Alteration pseudomorphs, produced either 
 
 a, by removal of constituents ; 
 
 6, by addition of constituents ; or, 
 
 c, by exchange of constituents. 
 
 2. Displacement pseudomorphs, produced either 
 
 a, by incrustation ; or, 
 
 b, by replacement. 
 
 According to Bischoff, the whole phenomena of pseudomorphism can be 
 explained by chemical agency in the wet way without calling in (as some 
 have done) the presence of igneous agency. 
 
 Pseudopodia (Gr. pseudes, false, andpous, podos, foot). Literally "false 
 feet ; " the term applied to those filiform processes by which protozoans, 
 like the Amoeba, effect their progression, and which are merely prolonga- 
 tions of the sarcode or gelatinous substance of the body thi-ust out and 
 retracted at will by the animalcule. 
 
 Psil6melane (Gr. psilon, smooth, and melan, black). Uncleavable man- 
 ganese ore ; a mixture of the protoxide and hyperoxide of manganese, with 
 impurities of baryta, silica, potash, and water. It usually occurs in botry- 
 oidal, kidney-shaped, or stalactitic masses, having a smooth surface, foli- 
 ated texture, and dark glistening colour ; whence the name. It is gene- 
 rally found along with other ores of manganese in veins in the older or 
 crystalline rocks. 
 
 Psilophyton (Gr. psilon, smooth, and phylon, stem). A genus of Lyco- 
 podiaceous plants described by Dr Dawson as occurring abundantly in all 
 the members of the Devonian series in Canada and the state of New York. 
 Psilophyton branches dichotomously, is covered with closely appressed 
 minute leaves ; the stems springing from a rhizome having circular are- 
 oles, sending forth cylindrical rootlets. Some of the under-clays in Gasp6 
 are filled with these vertical rootlets, just as the fire-clays of the Coal- 
 measures are with those of stigmaria. 
 
 Pterichthys (Gr. pteron, wing, and ichthys, fish). Literally "winged 
 fish ; " a characteristic bone-encased fish of the Old Eed Sandstone, 
 deriving its name from two wing-like lateral appendages, which seem to 
 have been used both as organs of motion and defence. Like the living 
 Osiracion or trunk-fish, the Pterichthys was encased in a framework of 
 bony plates, leaving only the caudal portion free, and this seems to have 
 
 374 
 
PTE 
 
 been covered with rounded enamelled scales, and furnished with a vertical 
 sailing-fin. The osteology and organs of the Pterichthys are yet but im- 
 perfectly known. 
 
 Pterinea (Gr. pteron, a wing). A sub-generic form of the Avicula or 
 wing-shell, occurring in Palaeozoic strata, and characterised by their thick, 
 rather inequivalve, very oblique, and broad- winged shells, which have 
 the beaks anterior, sinus shallow, and hinge-area long, straight, narrow, 
 and striated lengthwise. 
 
 Pterodactyls (Gr. pteron, wing, and daktylos, finger). Literally "winged 
 finger ; " a genus of flying reptiles, several species of which have been dis- 
 covered in the Lias, Oolite, Wealden, and Chalk formations of Europe. 
 " With a long-snouted head and long neck," says Mantell, "much resem- 
 bling that of a bird, bat-like wings, and a small trunk and tail, with 
 lacertian affinities in its skull, teeth, and skeleton, and with a bird-like 
 structure of sternum and scapular arch, these creatures present an anomaly 
 of structure as unlike their fossil contemporaries as the duck-billed ornith- 
 orhynchus of Australia to existing mammals. The cranium is small ; the 
 jaws are long, and either armed with numerous sharp-pointed teeth, or 
 toothless like those of a bird. The eye-orbit is very large ; the sclerotica 
 consists of a ring of bony plates, and the nostrils are placed near the orbits. 
 The cervical vertebrae are large and strong, and capable of great flexibility 
 backwards and forwards, probably to allow the head to fall back to the 
 centre of gravity during flight. The dorsal vertebras are from seventeen 
 to twenty in number. The sacrum is formed by the coalescence of two 
 vertebrae only, as in existing reptiles, and not of many, as in birds and 
 certain extinct saurians. The tail is generally short, an unusual character 
 with saurians ; but a species with a long tail occurs at Solenhofen. There 
 are five toes or digits on each foot ; the outer finger of the fore-arm is 
 immensely elongated for the support of a membraneous expansion (the im- 
 pression of which is preserved in some instances) ; and the other digits of 
 fore and hind feet terminated in long curved claws. The size and form of 
 the extremities show that the Pterodactylus was capable of perching on 
 trees, of hanging against perpendicular surfaces, and of standing firmly on 
 the ground,. when, with its wings folded, it might crawl on all fours, or 
 hop like a bird." Restorations of the pterodactyle have been attempted 
 by Mr Hawkins at the Crystal Palace ; and ample details are given by Dr 
 Buckland ( ' Bridgewater Treatise') ; by Owen ('Monograph Palseontogr. 
 Soc.') ; by Von Meyer (' Palseontographica ') ; and by other authorities. 
 
 Pterophylrom (Gr. pteron, awing, emdphyllon, leaf). Literally "wing- 
 leaf ; " a genus of cycadaceous leaves, chiefly from the Lias and Oolite. 
 Like ferns, they are pinnated, but are readily distinguished by their greater 
 substance, thicker midrib, and especially by their veins being in all cases 
 undivided ; that is, never forking or dichotomising as in ferns. See 
 CYCADITES. 
 
 Pter6poda (Gr. pteron, a wing or fin, and pous,podos, a foot). Literally 
 " wing or fin-footed ; " a class of encephalous molluscs, consisting of small 
 floating marine animals like the clio and hyalcea, that swim by the alter- 
 nate expansion and contraction of two lateral appendages, whence the 
 name. Their inversely - pyramidal, transversely - striated, fragile shells, 
 occur in all formations e.g., theca, ptei-otheca, conularia, &c. 
 
 Pterosaiiria (Gr. pteron, wing, and sauros, lizard). Literally "winged 
 lizards ; " a group or order of extinct saurians, organised, as the name im- 
 
 375 
 
PTE 
 
 plies, for an aerial existence, and embracing such forms as Pterodactylus, 
 Ramphorhynchus, &c. In the Pterosaurs, the whole osseous system, accord- 
 ing to Owen, is modified in accordance with the possession of wings the 
 bones being light and hollow, and most of them permeated by air-cells, 
 with thin, compact, outer walls. The modification of the pectoral limbs 
 for flight is due to an elongation of the fore-finger ; the other fingers being 
 of the ordinary length, and terminated by claws. On this elongated finger 
 the membraneous skin was expanded as in the bats ; and, as in the bats, a 
 small pelvis and weak hind limbs bespeak a creature unable to stand and 
 walk like a bird, but merely capable of dragging its body along. The 
 scapula and coracoid are long and narrow, but strong ; the vertebrae of 
 the neck are few, but large for the support of a large head with long jaws, 
 armed with sharp-pointed teeth ; the skull was lightened by large vacuities 
 between the nostrils and the orbit. The Pterosaurs range from the Lias 
 to the Chalk inclusive ; and specimens have been found ranging from one 
 to twenty feet in expanse of wing. See tabulations, " ANIMAL SCHEME." 
 Pteryg6tus (Gr. pteron, wing, and cms, otos, ear). A gigantic crustacean, 
 belonging to the fossil family Eurypteridcp., and occurring chiefly in the 
 "passage beds" between the Silurian and Devonian systems. It receives 
 its name from the peculiar shape of its detached mandibular or jaw-feet, 
 which from their scale-like sculpture were at first mistaken by Agassiz 
 for the remains of some fish. As yet the species of Pterygotus have been 
 found only in the lower flagstones or tilestones of the Old Red in Forfar 
 and Hereford shires, and in the Upper Silurians of Lesmabagow and Ludlow 
 strata which, for this marked characteristic, may not unappropriately 
 be termed the " Pterygotus beds " of Great Britain. In general aspect the 
 Pterygotus may be described as a gigantic " lobster-like crustacean," inas- 
 much as it has an elongated form, composed in the main of a cephalo- 
 thorax, an abdominal portion consisting of several segments, and a telson 
 or tail-plate. This, however, is the utmost of the similitude, the genus, 
 like the family, partaking of characters which appertain to several existing 
 orders Copepods, Poecilipods, and others. Thus, taking Ptorygotus in its 
 dorsal aspect, we are presented with a somewhat oblong cephalo-thorax or 
 carapace having two large compound eyes placed on the anterior margin ; 
 an abdominal region or main portion consisting of eleven segments, which 
 gradually swell out in width till the fifth or sixth, and then gradually 
 narrow and elongate towards the tail ; and a telson or tail-plate somewhat 
 oval, and tapering to a point like a Roman spear-head. In the abdominal 
 aspect the tail and all the segments (twelve in number) are void of 
 limbs or other appendages ; and the organs of motion are all attached to 
 the under-side of the carapace, as in the Limulus or King-crab. There are 
 three or four pairs of such limbs the first five-jointed, long, chelate, and 
 pincered like those of the lobster ; the second pair also five or six jointed, 
 and simply pointed ; and the third pair broad, and terminating in a pa- 
 lette-like paddle for oaring or swimming. The oral apparatus consists, 
 as in the King-crab, of the serrated basal-joints of these limbs, the whole 
 being protected by a heart-shaped breast-piece or metastome. The vent 
 and genital apparatus are placed forward on the first and second under- 
 segments, which separate into several pieces the separation being pro- 
 tected by a duck-biU-like plate, which differs in shape in the different 
 sexes. The whole exterior surface of the crust, which seems to have been 
 calcareo-coriaceous rather than hard-calcareous, is ornamented by a 
 
 376 
 
PTI PUM 
 
 peculiar scale-like sculpture, which becomes beaded and serrated on the 
 free margins, whether in the carapace, abdomen, or telson. See EURYP- 
 
 TERID^!. 
 
 Ptilodictyon (Gr. ptilon, a plume or feather, and dictyon, a net). Liter- 
 ally " feather-net ; " a genus of Silurian polyzoans apparently allied to 
 the living Escliara of our coasts, and so termed from its flat, branching, 
 feather-like aspect. 
 
 Ptilopora (Gr. ptilon, a plume, and pora). Literally "feather-pore;" 
 a genus of Carboniferous polyzoans, whose pores or cells are arranged in 
 feather-like form on a common axis the whole having the appearance of 
 a plume or feather of network. 
 
 Ptych6ceras, Ptychoceratite (Gr. ptyche, a fold). A genus of chambered 
 shells of the Ammonite family, peculiar to the Cretaceous formation, and 
 so named from the shell, which is bent or folded upon itself, the two 
 straight portions being in contact. 
 
 Ptychodus (Gr. ptyche, a fold or wrinkle, and odous, tooth). Literally 
 " wrinkle-tooth ; " a genus of Cestraciont fish-teeth, found in almost 
 every chalk-pit, and occasionally in conjunction with fin-spines, which are 
 striated, recurved, serrated on the posterior margin, and evidently the 
 defensive armature of the same fish. 
 
 Ptychognathus (Gr. ptyche, a ridge, and gnathos, jaw). Literally "ridge- 
 jaw ; " a sub-genus of dicynodont reptiles from the supposed Triassic sand- 
 stones of Rhenosterberg, South Africa ; and so termed from the promi- 
 nently-ridged sockets of the canine tusks so peculiar to the Dicynodont 
 family, which see. 
 
 Ptych61epis (Gr. ptyche, a fold or wrinkle, and lepis, a scale). Literally 
 " wrinkle-scale ; " a genus of sauroid fishes, of which several species occur 
 in the Lias of England. 
 
 Pudding-Stone. Now used as synonymous with conglomerate, but origi- 
 nally applied to a mass of flint pebbles, cemented by a siliceous paste, 
 from the resemblance of the imbedded pebbles to the fruit in a plum- 
 pudding. The plumpudding-stone of Herefordshire, so often sliced and 
 polished by lapidaries, is composed of black-flint pebbles imbedded in a 
 light- coloured paste ; hence the appropriateness of the name. 
 
 Pulley-Stones. A familiar term for the hollow casts or moulds of the 
 joints and stems of encrinites, as they occur in the cherts and rotten- 
 stones of the Carboniferous formation. Originally enclosed in the siliceous 
 matrix of chert, the calcareous stems of the crinoids have been subse- 
 quently dissolved, thus leaving their "screw-like" or "pulley-like" cast. 
 See ENCRINITE. 
 
 Pulverise (Lat. pulvis, pulveris, dust). To reduce to dust or powder ; 
 to crumble. Soil and rocks crumbled down by aqueous or atmospheric 
 agency are said to be pulverised. 
 
 Pumice (Ital. pomice, akin to spuma, froth). Volcanic froth or scum ; 
 a light spongy lava, so porous, vesicular, and fibrous, as to float on water. 
 It is usually of a whitish-grey colour, with a sub-pearly lustre, and con- 
 sists of about 75 silica and 17 alumina, with varying percentages of soda, 
 potash, and water. Used largely both in its natural and powdered state 
 as a polishing material. 
 
 Pumiceous. Having the nature and appearance of pumice; composed 
 of pumice. 
 
 Pumiciform. In the form of or resembling pumice. Applied to light, 
 377 
 
PUP PYR 
 
 porous rock-products, which seem, in some way or other, to be the results 
 of igneous action. 
 
 Pupa. The chrysalis shell ; a genus of small land-snails found all over 
 the world, but most abundantly perhaps in the northern hemisphere. 
 Upwards of forty species (fossil and sub-fossil) have been obtained from 
 Tertiary strata ; and one species, P. velusta, from the Lower Coal-measures 
 of Nova Scotia. 
 
 Purfoeck Beds. The uppermost members of the Oolite proper, or, ac- 
 cording to others, the basis of the Wealden formation. They derive their 
 name from the island or peninsula of Purbeck, on the coast of Dorset- 
 shire, where they are typically displayed ; and consist of argillaceous and 
 calcareous shales, and fresh-water limestones and marbles. They are 
 noted for their layers of fossil vegetable earth (dirt-beds), enclosing roots, 
 trunks, and branches of cycads and conifers. 
 
 Pustulopora (Lat.) Literally "pustule-pore;" a common tubular- 
 branched coral of the Chalk formation. The tubes are cylindrical ; their 
 apertures are arranged in spiral rows, and slightly projecting, thus giving 
 a pustulous appearance to the stem and branches. 
 
 Puy (Fr.) A provincial term for the conical hill-tops of Auvergne, in 
 Central France, which are for the most part the craters of extinct volca- 
 noes, as Puy de Dome, Puy de Come, &c. 
 
 P^cnodonts, Pycnodontidse (Gr. pyknos, thick, and odous, odontis, tooth). 
 Literally "thick-tooth ;" an extensive family of fishes, occurring in 
 Mesozoic strata. Their leading character consists in having the mouth 
 provided with a dense pavement of thick, round, and flat teeth, for the 
 purpose of crushing the shells and Crustacea on which they fed. 
 
 Pygocephalus (Gr. pygos, thick, solid, and kephale, head). A minute 
 stalk-eyed crustacean from the Coal-measures of Lancashire and Lanark- 
 shire, described by Mr Huxley in vols. xiii. and xviii. of * Geolog. Journal.' 
 
 Pyg6pterus (Gr. pyge, the rump, and pteron, a fin). Literally " rump- 
 finned ; " a genus of sauroid fishes (the Palceothrissum of Blainville) charac- 
 terised by the great development of their sub-dorsal and caudal fins, and 
 occurring throughout the Carboniferous and Permian formations. 
 
 Pyrites (Gr. pyr, fire, and ites for lithos). Sulphurets or sulphides of 
 iron, copper, cobalt, &c., are so termed, either from the hardness of iron- 
 pyrites, which strikes fire, or from its decomposing spontaneously with a 
 considerable evolution of heat. While we thus have " iron-pyrites," " cop- 
 per-pyrites," " cobalt-pyrites," &c., the term pyrite is restricted by miner- 
 alogists to the sulphuret of iron, which occurs in rocks of all formations, 
 and seems to be produced either by igneous action, or more commonly from 
 aqueous solution, especially under the influence of decomposing organic 
 matter. It is very liable to decomposition the sulphur sometimes separ- 
 ating and passing off as sulphuretted hydrogen, and the iron being changed 
 into the hydrated peroxide ; at other times it is converted into the sulphate 
 of iron. 
 
 Pyritiferous. Applied to rocks containing pyrites disseminated through 
 their mass, either in cubic crystals or in grains or irregular nodules e.g., 
 " pyritiferous shales," " pyritif erous vein-stone." 
 
 Pyr6genous (Gr. pyr, fire, and ginomai, I am formed). Fire-formed ; 
 produced by fire ; used as synonymous with igneous. 
 
 Pyrolusite (Gr. pyr, and lusis, decomposition). The mineralogical term 
 for the common binoxide or black oxide of manganese, in allusion to the facil- 
 
 378 
 
PYR QUA 
 
 ity with which it is resolved by heat into oxygen and a suboxide giving off 
 at a red heat from 10 to 12 per cent of oxygen. It occurs in various states 
 massive, disseminated, fibrous, earthy, or compact ; is of an iron-black or 
 steel-grey colour ; semi-metallic lustre ; streak black and soiling ; specific 
 gravity from 4.7 to 5 ; hardness from 2 to 2.5 ; and consists of 63.6 man- 
 ganese and 36.4 oxygen, with traces of baryta, 'silica, and water. "Pyro- 
 lusite was formerly confounded with Mauganite (the grey oxide), but 
 differs in crystallisation, and in containing no water. It is best distin- 
 guished by the colour of the streak, and its softness often so great as to 
 soil the fingers. It occurs chiefly in beds in gneiss, clay-slate, porphyry, 
 and the older rocks, or in veins often with calc-spar, heavy-spar, and ores 
 of iron and manganese. It sometimes has been produced by the de- 
 composition of the latter ; and crystals of manganite are found only par- 
 tially converted into pyrolusite." As an ore, pyrolusite is worked in 
 many places, and is employed in the manufacture of glass, in glass-paint- 
 ing and enamel, and in the glazing and colouring of pottery. 
 
 Pyrope (Gr. pyr, fire ; opsis, appearance). The mineralogical term for a 
 dark-red variety of iron-garnet (precious garnet) which is usually found in 
 rounded or angular fragments, loose or imbedded. The carbuncle of the 
 lapidaries ; both names having reference to the appearance of fire or 
 burning coal which it presents when held between the eye and the sun. 
 
 Pyrophysalite (Gr. pyr, fire, and physalite). Coarse columnar topaz ; 
 same as PHYSALITE, which see. 
 
 Pyroxene (Gr. pyr, fire, and xenos, a guest). A name used by Continen- 
 tal mineralogists for augite (which see), in allusion to its usual mode of oc- 
 currence in the igneous rocks. 
 
 Pyrrhotine (Gr. pyrrlwtes, reddish). A sulphide or sulphuret of iron 
 generally occurring massive and amorphous, having a granular structure, 
 and of a reddish or light bronze-yellow colour. Distinguished from com- 
 mon iron pyrites by its inferior hardness. 
 
 Pyxidiculum (Lat., a small box). A genus of Diatoms, whose minute 
 siliceous shields present the appearance of a saucer-shaped box ; whence 
 the name. Abound in existing waters, and in recent and Tertiary marls 
 or microphytal earths. 
 
 a 
 
 Quadersdndstein (Ger.) Literally square-stone or freestone ; the Ger- 
 man term for certain soft sandstones of the Chalk formation the Lower 
 Quadersandstein being apparently the equivalent of our Upper Greensand, 
 and the Upper being nearly in the same horizon as our Upper White Chalk. 
 See tabulations, "GEOLOGICAL SCHEME." 
 
 Quadr-, Quadri-, Quadru- (Lat. quatuor, four). A frequent prefix in 
 scientific compounds signifying four, or in fours ; as quadrangle, a figure 
 having four angles, and consequently four sides ; quadrilateral, four-sided ; 
 quadruped, an animal having four feet fcmr-footed ; quadricorns, fur- 
 nished with four horns or antennae ; quadripartite, divided into four parts, 
 or arranged in fours, &c. 
 
 379 
 
QUA 
 
 Quadnimana (Lat. quatuor, four, and manus, hand). Literally "four- 
 handed ; " a term applied to the monkeys and lemurs, as forming an order 
 distinct from the bimana or two-handed mankind. Though termed " four- 
 handed," and furnished with a more or less opposible thumb to each ex- 
 tremity, these animals walk on all-fours man with his perfectly opposible 
 thumb being in reality the only "handed" animal in creation. Quadru- 
 manous remains have been found in the lowest Eocene Tertiaries, if not in 
 the Upper Chalk formation. 
 
 Quagmire or Quakemire. Boggy or miry ground so saturated with 
 water that the surface quakes or shakes to a considerable extent under the 
 feet of the passer over. The growing surface of these quaking-bogs has 
 often considerable tenacity, but once broken, there is nothing beneath save 
 soft " mire " or mud, and that frequently to great and dangerous depths. 
 
 Quaquaversal (Lat. quaqua, on every side, and versus, turned). Dip- 
 ping on every side ; applied to strata that dip on all sides from a common 
 centre ; dome-shaped or encircling stratification. 
 
 Quarry- Water. A familiar term among quarrymen and builders for the 
 water which is contained in the interstices of a rock when newly raised 
 from the quarry, but which it gradually loses by evaporation when exposed 
 to the air. The majority of rocks, whether stratified or unstratified, are 
 softer and more easily dressed when newly quarried, but as they lose the 
 " quarry- wa ter " they become harder and more refractory, this water as it 
 evaporates apparently depositing within the minute pores the mineral 
 matter (carbonate of lime, iron, silex, &c.) which it previously held in 
 solution. 
 
 Quartz (Ger. quarz). A German miner's term for crystallised silica; 
 rock-crystal ; silica is its purest rock-form. As a mineral, quartz is pro- 
 perly colourless, but more frequently coloured in various shades of white, 
 grey, yellow, brown, red, blue, and even black ; hence numerous varieties 
 are distinguished by their colours as rock-crystal, the highly transparent 
 varieties ; amethyst, the violet blue ; siderite, the indigo or Berlin blue ; 
 topaz, the wine-yellow ; cairngorm, brown or cinnamon-yellow ; milk-quartz, 
 rose-quartz, and so forth. Common quartz, occurring massive and in veins 
 of various shades of white, is a well-known rock, and, according to its 
 colour and lustre, is spoken of as milk-quartz, glassy-quartz, and the like ; 
 or mixed with other mineral matter it passes into jasper, Lydiansto)ie, horn- 
 stone, chert, flint, chalcedony, agate, and numerous other rocks and minerals, 
 in all of which silica constitutes more than nine-tenths of the mass. The 
 Quartz family is usually arranged into three groups : 1. The Vitreous, or 
 those varieties which have a bright glassy lustre, as rock-crystal, rose- 
 quartz, siderite, cairngorm, amethyst, aventurine, &c. ; 2. The Chalcedonic, 
 or those which display the sub-vitreous or waxy lustre and the translucency 
 of chalcedony, as agate, carnelian, chalcedony, flint, hornstone, onyx, &c. ; 
 and, 3. The Jaspery, or those presenting the duller colours, lustre, and 
 opacity of jasper, as bloodstone, jasper, Lydianstone, touchstone, siliceous 
 sinter, silicified wood, &c. 
 
 Quartziferous. Literally, "quartz-yielding;" a term frequently but 
 somewhat loosely made use of in geology. Thus " quartziferous veins" 
 are those essentially composed of quartz, while "quartziferous sands and 
 sandstones" are those in which the particles of quartz are somewhat 
 large and readily discernible. 
 
 Quartzite. An aggregation of quartz grains ; granular quartz. The 
 
QUA RAD 
 
 term is generally applied to sandstones which have been indurated or 
 altered by heat so as to assume the aspect of quartz-rock. 
 
 Quartzose. Literally " abounding in quartz ; " a term applied to sands, 
 sandstones, and grits essentially composed of quartz, and in which the 
 component particles are distinct and palpable. 
 
 Quartz-Rock. A term'usually, and properly, applied to a stratified rock 
 of the metamorphic series, consisting almost entirely of silica, having a 
 granular-crystalline texture, and of a greyish or pinkish-grey colour from 
 the presence of a slight trace of iron. 
 
 Quaternary (Lat. quatuor, four). Applied to all accumulations above 
 the true Tertiaries ; equivalent to POST-TERTIARY, which see. 
 
 Quicklime. The well-known form of lime after any ordinary limestone 
 (or carbonate of lime) has been exposed to a red-heat in a kiln, so as 
 to expel its carbonic acid. It is a protoxide of calcium, and on being 
 sprinkled with water falls readily to powder, with a crackling noise and 
 great evolution of heat. It has obtained its name from its caustic and 
 corroding qualities. 
 
 Quicksilver. The familiar term for fluid mercury, in allusion to its 
 bright metallic lustre and silver-white colour. It occurs native in rocks of 
 all ages, chiefly with cinnabar (sulphuret of mercury) in veins and fissures ; 
 is fluid at ordinary temperatures, but congeals at 40 Fahr., and forms 
 tesseral crystals. See MERCURY. 
 
 Quincunx (Lat. quinque, five). Strictly speaking, that arrangement of 
 five objects in which they are made to occupy the four corners and the 
 point of intersection of the diagonals of a square. The term, however, is 
 generally applied to any number of objects so disposed in lines that the 
 members of each succeeding line shall stand immediately behind the inter- 
 spaces or openings in the preceding one. The leaf-scars of lepidodendron 
 and the conifer OK, and the punctures of stigmaria, are arranged in this 
 quincuncial order. 
 
 R 
 
 Radiaria. A term applied by Lamarck to such of the Radiata of Cuvier 
 as have a radiated form of the entire body. They are the rayed animals 
 proper, and include only the sea-urchins, star-fishes, and medusae or sea- 
 nettles. 
 
 Radiata (Lat. radius, a ray). Radiated ; arranged round a central axis 
 like the rays or spokes of a wheel. In zoology, Cuvier's fourth and lowest 
 division of the animal kingdom, including all those animals whose parts 
 are disposed round a central axis in a radiated form, like that of the star- 
 fish. The division embraces Echinodermata (star-fish, sea-urchins, &c.) ; 
 Intestina (intestinal worms) ; Acalepha (medusae or jelly-fish) ; Polypi 
 (sea-anemones, coral polypes, &c.); and the INFUSORIA. Since Cuvier's 
 time this arrangement has been somewhat modified ; and the lower groups 
 of animals which are "gobular" rather than "rayed" have been erected 
 into an independent class under the title PROTOZOA, which includes such 
 
 381 
 
RAD RAI 
 
 orders as the Rhizopods, Sponges, and Infusoria. See tabulations, " ANI- 
 MAL SCHEME." 
 
 Radiated (Lat. radiatus). Adorned with rays; diverging from a com- 
 mon centre like the spokes of a wheel, a form frequent among minerals, as 
 zeolite and radiated iron-pyrites; belonging to the division Radiata or 
 rayed animals. 
 
 Radiolftes. A genus of Cretaceous bivalves belonging to the curious 
 Hippurite family, and so called from the radiated structure of the outer 
 layer of their opercular-looking upper valves. The Radiolite has an in- 
 versely conical under- valve, with a deep straight cavity, rough and folia- 
 ceous in its outer layers, and smooth within, with a finely-striated margin. 
 It is fitted with a convex or sub-conical opercular-looking upper valve, 
 which gives to the entire shell a somewhat spherical shape ; hence the 
 occasional synonyme of Sphcerulile. See HIPPURITE. 
 
 Rag, Bags tone. A provincial English term for any hard coarse-textured 
 rock; as "Kentish rag," a tough siliceo-calcareous member of the Lower 
 Greensand, used for building purposes in Kent ; " Rowley rag," a hard 
 crystalline greenstone, constituting Rowley Hill, near Dudley, &c. 
 
 Rain, Rainfall. As a geological agent, rain is of prime importance 
 vitally as well as mechanically ; its mechanical effects, however, being the 
 most conspicuous, and that more especially in hilly regions. Every shower 
 that falls exerts a degrading or wasting influence on rocks, soils, and all 
 exposed surfaces. By entering the pores of rocks and soils, rain softens 
 and loosens their cohesion, and thus renders them more easily acted on by 
 currents of wind and water. Land-floods or freshets also arise from rains, 
 the melting of snow, and from hail-storms ; and the periodical rains of the 
 tropics produce inundations and similar phenomena. The fall of rain 
 varies in different countries, and of course will be attended with pro- 
 portional results. In the British Islands it ranges from 24 to 60 inches, 
 or has an average of about 36 inches ; while in tropical countries the 
 mean annual fall is upwards of 200 inches 229 inches having been noted 
 in Dutch Guiana, 276 in Brazil, 302 at an elevation of 4200 feet in the 
 Western Ghauts, south of Bombay ; and in the Khasia Mountains, at the 
 head of the river-flats or Jheels of Bengal, upwards of 600 inches, or 50 
 feet, have been registered by various observers. At the same place, Dr 
 Hooker has recorded 30 inches in twenty-four hours ; 21 inches have been 
 noted at Cayenne during the same period; and 23 inches are not uncom- 
 mon near Port Jackson in New South Wales. Accustomed to the gentle 
 rains of our own island, we can scarcely form an estimate of the changes 
 produced by such sudden and enormous falls on the surface-soil and river- 
 courses of tropical countries. 
 
 Rainbow Chalcedony. A variety of chalcedony consisting of thin con- 
 centric layers, which when cut across exhibit an iridiscence resembling the 
 colours of the rainbow. 
 
 Raiu-Gauge. An instrument, of which there are several kinds, for 
 ascertaining the amount of rainfall in any given locality. One of the 
 simplest and most convenient is a tube sunk into the earth so as to pre- 
 vent as much as possible the effect of evaporation, with a square or circular 
 receiver for the rainfall, and a graduated float to mark the rise or amount 
 of water within for any given period. 
 
 Rain-Prints. Every one must have observed the effects of a passing 
 shower on the surfaces of the half-consolidated muds and sands of our 
 
 382 
 
KAK RAU 
 
 tidal shores and estuaries how it pits and patters them according to the 
 size of the drops, the force with which they are borne by the wind, and 
 the slanting direction in which they impinge. Precisely similar appear- 
 ances are presented on the stratified surfaces of every formation, from the 
 lowest Silurian up to the latest Post-tertiary these surfaces having, 
 when soft, received the shower-fall, been subsequently sun-baked and 
 hardened, and then overlaid by new deposits which filled up the pits and 
 patters as so many moulds. These fossil pittings are more or less circular, 
 according to the vertical or slanting direction of the rainfall ; are often 
 large, as from a heavy shower ; not unfrequently large and small curiously 
 commingled ; and occasionally the same surface bears traces of showers 
 that must have fallen when it was soft and easily impressed, and of others 
 that fell subsequently and made a fainter impression on its partially-baked 
 crust. We have thus not only evidence of the intensity and continuance 
 of these primeval showers, but of the quarter from whence the wind blew 
 that drove them against the muddy flats of long-since obliterated shores 
 and estuaries. 
 
 Eake Vein. In mining, a rent or fissure, generally vertical or highly 
 inclined, and cutting indifferently through all the strata. Eake veins are 
 either simple fissures unaccompanied by any displacement of the strata, 
 and known as " gash veins ;" or accompanying a fault or dislocation, and 
 then termed " slip veins." 
 
 Ramphorhynchus (Gr. ramphos, a bird's beak, and rhynchos, beak or 
 snout. A genus of Pterosaurians or winged reptiles from the Oolites of 
 Europe, and characterised by their horny toothless mandibles, which 
 seem, however, to have been furnished with a pair of long prehensile 
 teeth in the front part. 
 
 Rams' Horns. A familiar term among the peasantry of England for 
 the curling or incurved shell of the Ammonites. 
 
 Rapids. In geography, those portions of a river-course where the cur- 
 rent moves with much greater rapidity than the ordinary flow of the 
 stream. When impeded with rocks, which is generally the case, rapids 
 greatly interfere with or altogether obstruct the navigation of a river. 
 
 Raptores (Lat. raptor, aseizer or snatcher). Birds of Prey; an order 
 of birds, so called from their habit of seizing and retaining their prey 
 with their powerful talons. They are partly diurnal, as the vultures, 
 eagles, falcons, &c., and partly nocturnal, as the owls. Remains of 
 Raptorial birds occur in the Tertiary strata of Europe e.g., Lithornis 
 vulturinus, &c. 
 
 Ras6res (Lat.) Literally Scratchers or Scrapers; an order of birds, so 
 called from their habit of scraping or scratching up the soil with their 
 feet in order to obtain their food e.g., the common barn-fowl, turkey, 
 partridge, and the like. Remains of Rasorial birds have been found in 
 the bone-caves of England and Germany. 
 
 Rastrites (Lat. raster, a rake). That division of Graptolites (Silurian 
 sea-pens) having the cells placed at wide intervals along the stem or axis, 
 and accordingly standing out bold and pointed like the teeth of a rake. 
 See GRAPTOLITES. 
 
 Rauchwacke (Ger. ranch, smoke, and wacke). The German term for 
 one of the upper members of the Permian zechsteinor magnesian limestone, 
 in allusion to its dark-grey colour. The Rawhwacke' seems to be the 
 equivalent of the upper brecciated limestones of Durham and Yorkshire. 
 
EAV EEI 
 
 Ravine (Lat. ramo, I sound hoarsely). A deep precipitous gorge ; 
 usually the narrow excavated channel of some mountain stream ; and so 
 called from the hollow murmur of its waters. 
 
 Realgar. Known also as red orpiment and red sulphur et of arsenic ; the 
 proto-sulphuret of arsenic (69 arsenic and 31 sulphur), occurring native in 
 various formations, either in the form of fine red prismatic crystals, or 
 massive and disseminated. It is also prepared artificially from the sesqui- 
 sulphuret or yellow orpiment, which see. 
 
 Recent (Lat. recens, fresh, still growing). In geological classification 
 the term Recent is applied to all accumulations and deposits which have 
 taken place during the human epoch, or are still in progress of formation. 
 All accumulations and deposits whose remains belong exclusively to species 
 still existing, are, geologically speaking, "recent," though chronologically 
 of vast antiquity. By most geologists the Recent or Current epoch is 
 regarded as commencing at the close of the Glacial or Boulder-drift period, 
 as manifested in the northern hemisphere. 
 
 Reddle. A provincial term for a red argillaceous ore of iron ; also 
 called red-clay and red-chalk. It is simply decomposed haematite, having 
 a compact earthy texture ; dry, meagre feel ; and strong clayey odour 
 when breathed on. 
 
 Bed Marl. A familiar designation for the upper members of the New 
 Red Sandstone or Trias, as developed in England. Known also as "varie- 
 gated marls ;" the " Keuper" of the Germans ; and the " Marnes irise"es" 
 of the French. See TEIASSIC SYSTEM. 
 
 Reef (Sax. ) A riff or ridge ; usually applied to a range or ledge of rocks 
 occurring in the sea, and only partially covered, or placed at no great 
 depth under the surface of the water ; as the " coral-reefs " of the South- 
 ern Ocean. Differs from a shoal or bank, which generally occupies a wider 
 area and is for the most part composed of soft material, as mud, sand, and 
 gravel. 
 
 Region. A term often loosely applied in geography, but applicable to 
 any large tract of sea or land which is characterised by some feature not 
 to be found in other areas ; hence the idea of botanical, zoological, and 
 similar "regions." 
 
 Regnosaiirus. Literally "royal saurian ;" a provisional appellation ap- 
 plied by Dr Mantell to the imperfect remains (portion of a jaw and teeth) 
 of a large saurian occurring in the Wealden strata of Tilgate Forest, and 
 probably allied to Megalosaurus or Iguanodon. 
 
 Regor. The native name for the cotton soil of India, which is said to 
 cover nearly a third part of the southern peninsula, and to range north- 
 ward to a great distance, and also into the Birman Empire. It occupies 
 nearly level plains ; is of a bluish-black or greenish-grey colour from 
 three to twenty feet in thickness ; is of marvellous fertility ; and consists 
 of 48.20 silica, 20.30 alumina, 16.00 carb. of lime, 10.20 carb. of magnesia, 
 about 5 of organic matter, and a little oxide of iron. Like the Tchornozem 
 of Russia and Loess of the Rhine it is evidently of alluvial origin, and may 
 probably be of Upper Pliocene age. 
 
 Reindeer Period. A term introduced by M. Lartet in 1863 to express 
 a period later than that of the mammoth and rhinoceros in Europe, and 
 when the reindeer was a prominent feature in the Post-tertiary fauna of 
 the continent. The human remains belonging to the Mammothian period 
 are the rudest form of flint implement ; those of the Reindeer period are 
 
 384 
 
EEL EET 
 
 more advanced, and accompanied by carved horns, bone-needles, and 
 the like. 
 
 Reliquiae (Lat.) Remnants; what is left behind. Usually applied to 
 the remains of living creatures; but in geology extended to all organic 
 remains, whether vegetable or animal. 
 
 Beniform (Lat. ren, kidney). Kidney shaped ; applied, for example, to 
 concretions of ironstone, limestone, &c., which assume a flattish-oblong or 
 kidney-shaped form. 
 
 Beptflia (Lat. repo, I creep). In zoological arrangements the third 
 great division of vertebrate animals, embracing the Batrachians or frogs, 
 the Ophidians or serpents, the Saurians or lizards, the Loricata or croco- 
 diles, and the Chelonians or tortoises. As a class the Reptiles are cold- 
 blooded ; some have the body naked, others have it covered with scales, 
 with plates or scutes, or enclosed in a horny shell ; they are oviparous, 
 but never hatch their eggs ; and are partly terrestrial, partly aquatic, 
 and partly amphibious. In one or other of the above orders they are found 
 fossil, from the Devonian formation upwards culminating as it were both 
 in magnitude and in specific variety during the Oolitic epoch, which is 
 sometimes styled "the age of Reptiles," or "reign of Reptiles." See 
 tabulations, " ANIMAL SCHEME." 
 
 Resin (Lat. resina). A well-known substance which exudes from many 
 trees, and in particular from the firs and pines. It is usually of a yellow- 
 ish or amber-brown colour, more or less transparent ; becomes hard and 
 brittle on exposure to the atmosphere ; has a disagreeable taste and 
 aromatic odour ; is electric when rubbed ; and has a specific gravity (1.0 
 to 1.3) little exceeding that of water. When heated it readily melts, and 
 if the heat be much increased it takes fire and burns (like other hydro- 
 carbons) with a whitish flame and much smoke. It is soluble in alcohol, 
 ether, and the volatile oils, but is insoluble in water ; and in this respect 
 may be distinguished as well as separated from gum. It has been defined 
 as " volatile oil rendered concrete by the oxygen of the atmosphere ;" and 
 as most plants contain some kind of volatile oil or other, the number of 
 resins is very great. Substances partaking of the nature of gum and of 
 resin (that is, partly soluble in water) are termed Gum-resins, Resins, 
 gums, and gum-resins, occur in Tertiary and Post-tertiary formations, 
 and in particular in connection with brown-coal and lignite. 
 
 Besin, Mineral. As a family in mineralogical systems, the Mineral 
 Resins include such hydro-carbons as petroleum, bitumen, asphalt, amber, 
 retinite, copaline, hatchetine, and many other pitchy, fatty, or resinous- 
 looking substances, which, with the exception of petroleum, asphalt, and 
 amber, occur in small and unimportant quantities. 
 
 Resinous. Resembling resin; containing or yielding resin ; possessing 
 the properties of resin. Hence we speak of certain minerals having a 
 ''resinous lustre/' a "resinous odour," and so forth. 
 
 Betep6ra (Lat. rete, a net, and par a, a pore). Literally net-pore ; the 
 name given by Lamarck to a genus of fossil Bryozoa or compound mol- 
 luscs, which, like the existing flustra, have their cell-pores arranged in 
 net-like order. They occur in all formations. 
 
 Beticulated (Lat. reticulum, a small net). Having the appearance of net- 
 work ; composed of fibres and veins or lines which interlace and cross 
 each other like the threads of a net. The veins of an apple-leaf, for ex- 
 ample, have this reticulated or net-like appearance. 
 
 385 2fi 
 
RET RHI 
 
 Retinite, Resinite. Known also as retinasphalt ; one of the mineral 
 resins occurring in brown-coal and peat formations, in roundish irregular 
 lumps, of a yellowish-brown colour, resinous lustre, easily broken, and 
 slightly transparent. It is an impure hydro-carbon or fossil resin, usually 
 melts at a low heat, and burns with an aromatic or bituminous odour. 
 According to Mr Hatchett, who first described it in 1804 from the lignite 
 of Bovey in Devonshire, it consists of 55 resin, 41 asphalt, and from 3 
 to 4 of earthy residuum. 
 
 Reversed (Lat. re, back again, and versus, turned). Turned upside 
 down ; turned side for side. A reversed shell, in conchology, is one whose 
 whorls run from right to left, or whose aperture is turned to the left hand 
 when the shell is placed before the spectator with its apex upwards. 
 
 Rhabdomancy (Gr. rhabdos, a rod, and manteia, prophecy). Divina- 
 tion by rod or wand, so as to indicate where metals, minerals, and water 
 may be obtained from the crust of the earth a superstitious practice not 
 altogether abandoned in some parts of Britain, and still to some extent 
 followed in the south of France and Italy, under the names of Metallascopy 
 and Hydroscopy. "The divining-rod," says Brande, "is a branch of a 
 tree, generally hazel, forked at the end, and held in a particular way, by 
 the ends, in the hand of the adept ; and is supposed to indicate the posi- 
 tion of the substance sought by bending towards it with a slow rotatory 
 motion the adept, according to modern practice, being placed in contact 
 with some metallic or other magnetic substance." 
 
 Rhaetic Beds. A term now generally applied to the "passage beds" 
 that lie between the Trias and Lias, from their extensive development in 
 the Rhaetic Alps. Known also as "Kossen Beds," " Gervillia Beds," 
 " Tabinguen Beds," "PenarthBeds," "Infra-Lias," and the "Avicula Con- 
 torta Zone," some authorities ranking them as Upper Triassic and others 
 as Lower Liassic. 
 
 Rhinoceros (Gr. rhis, rhinos, the nose, and keras horn). Literally 
 " snout-horned ; " a well-known pachyderm of Asia and Africa, deriving 
 its name from the solid fibrous horns (one or two in number according to 
 species) which arm its snout. The living rhinoceroses are strictly inhabi- 
 tants of the hotter parts of the Old World the one-horned of Asia, and 
 the two-horned and others of Africa ; and all are heavy, bulky animals, 
 delighting in marshy river-grounds, and feeding on leaves, soft roots, and 
 succulent branches. Several fossil species occur in the later Tertiaries of 
 Europe in lake-silts, bone caves, and breccias ; and more remarkable 
 still, carcasses of one of these species (R. tichorinus) have been found in 
 fair preservation in the frozen soil of Siberia. Though thus discovered 
 ranging over the whole of Europe and northern Asia, we have no authentic 
 instance of a fossil rhinoceros occurring either in America or Australia 
 a distribution that finds its parallel in the case of many other Tertiary 
 animals. 
 
 Rhizodus (Gr. rhiza, root, and odous, tooth). A genus of Carboniferous 
 sauroid fishes, of large size, and originally confounded with holoptychius, 
 but differing in the larger size of the species, in the form of the scales, which 
 are rounded and marked with concentric wavy folds, and notably in the 
 teeth, which are larger, compressed-conical, sharp at the compressed edges, 
 and deeply striated towards the roots. The teeth are of two sorts, the 
 large sauroid ones, often four and six inches in length, and placed at inter- 
 vals along the jaws, and the smaller fish ones, which fill up the intervals and 
 
RHI RHY 
 
 are less boldly striated. Little is yet known of Rhizodus beyond the teeth, 
 jaws, sculptured head-plates, and detached scales ; and many teeth at one 
 time regarded as those of Rhizodus, are now known to be those of 
 Labyrinthodont saurians, as anthrocosaurus, &c. 
 
 Rhizopoda, Rhizopods (Gr. rhiza, a root, and pous, podos, foot). The 
 lowest class of the Protozoa of modern zoologists. They are minute 
 cellular animals (either simple or aggregated), and are so called from their 
 motions being performed by processes or root-like extensions of the sub- 
 stance of which they are composed. They are interesting to the geologist, 
 from the fact that the so-called Foraminifera which compose a large bulk 
 of the Chalk, &c., are compound Rhizopods enclosed in a chambered shell- 
 like case each cell-body occupying its own chamber. See POLYTHALAMIA 
 and FORAMINIFERA. 
 
 Rhodium (Gr. rhodon, a rose). A rare metal discovered by Wollaston 
 in 1803, and usually associated with osmium, iridium, and palladium (other 
 rare metals) in the ores of platinum. It derives its name from the red 
 colour of one of its solutions, though its own colour is white or silver-grey. 
 It is extremely hard, and used as nibs for gold pens. 
 
 Rhodocririus (Gr. rhodon, a rose). Literally " rose-encrinite ;" a genus 
 of Palaeozoic encrinites in which the column is cylindrical and traversed by 
 a pentagonal canal ; the rays or arms arise by a single ossicle, and then 
 bifurcate ; the receptacle is formed of three, five, ten, or more numerous 
 series of plates, which are ornamented externally by fine radiating ridges. 
 Rhodonite (Gr. rhodon, a rose). A silicate of the protoxide of mangan- 
 ese ; known also as manganese spar ; and so named from its dark rose-red 
 colour. It occurs in various formations and variously associated, and con- 
 sists of 48 silica, 49 protoxide of manganese, with a little lime and iron. 
 
 Rhomb (Gr. rhombos). In mathematics and crystallography, a four- 
 sided figure whose sides are equal, but whose angles are not right angles ; 
 a compressed square, if one might so speak. Rhomboid. Rhomb-like, 
 lozenge-shaped ; a four-sided figure having its opposite sides equal, but all 
 its sides are not equal, nor are its angles right angles. Rhombohedron. 
 A solid figure contained within six equal rhombs. 
 
 Rhomb-Spar. A variety of dolomite or crystallised magnesian: lime- 
 stone, already described under the name of BlTTER-SPAR, which see. 
 
 Rhopalodon (Gr. rhopalon, a club, and odous, odontos, tooth). Literally 
 " club-tooth ; " the generic name applied by M. Fischer to certain reptilian 
 remains from the Permian deposits of Russia. These remains consist of 
 detached teeth and fragments of jaws with teeth, of thecodont reptiles, 
 apparently related to the saurians from the Permian conglomerates of 
 Bristol. See THECODONTOSAURUS. 
 
 Rhynchonella (Gr. rhynchos, a beak). Literally " little-beak ; " a genus 
 of brachiopodous bivalves, forming the type of the family Mhynchonellidce, 
 and so named from their acutely beaked umbones. In rhynchonella the 
 shell is somewhat trigonal, acutely beaked, usually plaited ; dorsal valve 
 elevated in front, depressed at the sides ; ventral valve flattened, or hol- 
 lowed along the centre ; hinge-plates supporting two slender curved 
 lamellae. Only two or three living species are known, from the deeper 
 waters of Arctic and Antarctic seas ; but upwards of two hundred fossil 
 species have been catalogued from the Lower Silurian upwards. 
 
 Rhynchosaums (Gr. rhynchos, a beak, and sauros, lizard). Literally 
 " beak-saurian ; " a remarkable genus of saurians from the New Red Sand- 
 
 387 
 
RHY R1V 
 
 stone of Warwickshire, combining the lizard type of skull with toothless 
 jaws. " The general aspect of the cranium," says T. K. Jones, " resem- 
 bles that of a bird or turtle, the intermaxillary bones being very long, and 
 curving downwards, thus imparting to the fore part of the head the profile 
 of a parrot. There are no teeth apparent in either jaw, and Professor 
 Owen supposes that this reptile may have had its jaws encased by a bony 
 or horny sheath as in turtles. Footmarks of a small reptile, with the print 
 of the hind-toe pointed backwards, occur on the surface of some of the 
 Warwickshire sandstones, and are, with much probability, conjectured to 
 have been impressed by the Rhynchosaurus." 
 
 Rhyncolites, Rhyncholites (Gr. rhynchos, a beak, and lithos, stone). 
 The Palceoteuthis and RhynchoteutMs of D'Orbigny. The fossil beak-like 
 mandibles of cephalopods (like the cuttle-fish and nautilus) which generally 
 occur detached in the Lias, Oolite, and Chalk formations. These calcare- 
 ous mandibles are of two forms ; those corresponding to the upper mandible 
 constitute the " Rhyncholites " proper ; whilst the lower mandibles form 
 the genus " Conchorhynchus " of De Blainville. 
 
 Rhytidolepis (Gr. rhytis, rhytidos, a wrinkle, and lepis, scale). The term 
 applied by Sternberg, Gotta, and others to the Sigillaria, in allusion to its 
 thick corrugated outer bark. See SIGILLAKIA. 
 
 Rhytina. A genus of phytophagous Cetaceans, or rather Sirenians, dis- 
 covered by Steller on Behring's Island in 1741, and since completely ex- 
 tirpatedthe last individual having been killed in 1768. Like the Dodo 
 and Dinornis the Rhytina is considered extinct, its remains (from 8 to 24 
 feet in length) being now eagerly sought after for our public museums. 
 Unlike the manatees or sea-cows, the Rhytina was edentate, having special 
 bony palatal apparatus for the crushing of its food. 
 
 Ripple-Mark. This term is applied by geologists to the ridgy or wavy 
 surface of many sandstones, from its resemblance to the ripple produced 
 on a sandy sea-shore by the receding tide. As this ripple is produced by 
 the passage of any gentle current over a movable surface, we have wind- 
 ripples, tide-ripples, current-ripples, and the like ; and it requires discrim- 
 ination on the part of the observer to determine the nature of the producing 
 cause in the ancient formations. 
 
 Rise. In mining, any vertical or upward opening from a lower to a 
 higher portion of a vein, or it may be to the surface. 
 
 River (Lat. rivus ; Gr. rheo, I flow). Geologically, streams and rivers act 
 chiefly in a mechanical way, and their influence depends partly on the 
 nature of the rocks over which they run, the rapidity of their flow, and their 
 size or volume of water. If the rocks over which they pass be of a soft or 
 friable nature, they soon cut out channels, and transport the eroded ma- 
 terial in a state of mud, sand, and gravel to the lower level of some lake, to 
 their estuaries, or to the bed of the ocean. Their cutting as well as trans- 
 porting power is greatly aided by the rapidity of their currents ; hence the 
 power of mountain torrents compared with the quiet and sluggish flow of 
 the lowland river. It has been calculated, for example, that a velocity of 
 three inches per second will tear up fine clay, that six inches will lift fine 
 sand ; eight inches, sand as coarse as linseed ; and twelve inches, fine 
 gravel ; while it requires a velocity of twenty-four inches per second to roll 
 along rounded pebbles an inch in diameter, and thirty-six inches per second 
 to sweep angular stones of the size of a hen's egg. During periodical rains 
 and land-floods the currents of rivers often greatly exceed this velocity ; 
 
 388 
 
RIV EOC 
 
 hence the tearing up of old deposits of gravel, the sweeping away of bridges, 
 and the transport of blocks many tons in weight an operation greatly faci- 
 litated by the fact that stones of ordiuary specific gravity (from 2.5 to 2.8) 
 lose more than a third of their weight by being immersed in water. Nor 
 is it the mere velocity of rivers which produces their eroding or cutting 
 power, but the amount and nature of the debris carried down by their tor- 
 rents every pebble and block of shingle rubbing and striking and grinding 
 still deeper and deeper the channels down which they are borne. The 
 geological effects of rivers on the crust is thus of a twofold nature viz., to 
 waste and wear down the higher lands, and then to bear along the waste 
 material and deposit it in valleys, in lakes, or in the ocean, in the state of 
 mud, clay, sand, or gravel. See DELTA. 
 
 Elver-Basin. In geography, the whole extent of valley-shaped or basin- 
 shaped country drained by any river and its tributaries e.g., the " Basin 
 of the Tay," the " Basin of the Severn." 
 
 Roadstead or Roads. Usually applied to an open and exposed anchorage 
 where ships may ride under the lee or shelter of the land, but from which 
 they must sail when the wind is about to blow strong from the sea. 
 
 Roches Montonnee. The name given by French geologists to those 
 rounded projecting eminences of Alpine rocks that have been worn down 
 and smoothed by glacier action. 
 
 Rock. The "crust," or external portion of the earth accessible to human 
 research, is composed of substances less or more solid, and all known to 
 the geologist by the name of Rocks these rocks the products, in the main, 
 of aqueous and igneous agencies. No matter whether in the state of 
 soft and yielding clay, of incoherent sand and gravel, of dull earthy chalk 
 or sparkling marble, of friable sandstone or the hardest granite all are 
 spoken of as "rocks "and "rock-formations." In this sense the term 
 rock is purely technical ; and it has even been proposed by German miner- 
 alogists to extend the term to ice and water as being principal constituents 
 of the earth's mass. 
 
 Rock-Basins. Curious basin-shaped cavities occurring in the granites of 
 high and exposed regions like that of Dartmoor in Devonshire, and varying 
 from one to many feet in diameter, and from a few inches to several feet in 
 depth, with edges more or less sloping, and generally containing pebbles 
 or other gravelly detritus whose motion, with the aid of water, seems to 
 have been the efficient cause of their formation. At one time superstition 
 ascribed the excavation of these " basins " or " pot-holes " to the Druids ; 
 but no one now for a moment doubts that, however these early priests 
 may have used them, they are the direct results of decomposition and 
 attrition on the softer portions of the felspathic granite. See vol. xv. of 
 ' Geological Journal ' for some interesting details of the Dartmoor basins, 
 by Mr Ormerod. 
 
 Rock-Butter. A soft, yellowish admixture of alum, alumina, and oxide 
 of iron, oozing out of rocks which contain alum. A product of decompo- 
 sition. 
 
 Rock- Cork. A variety of asbestus whose fine fibres are so interlaced and 
 matted as to give it the texture and lightness of cork. Occurs in veins and 
 crevices in serpentine and similar rocks, and often known as " mountain- 
 cork." See ASBESTUS. 
 
 Rock-Crystal. A familiar term for the transparent and colourless varie- 
 ties of crystallised QUARTZ, which see. Though usually colourless and 
 
 389 
 
ROC 
 
 transparent, "rock-crystal " occurs in various shades, and the term is even 
 extended to smoke-coloured and perfectly black varieties. It is customary, 
 however, to distinguish the coloured varieties by separate names ; hence 
 the purple are known as amethysts; the yellow, topazes; the amber-coloured, 
 cairngorms, and so on. Rock-crystal is found in veins, fissures, and other 
 cavities in every geological formation, but chiefly and most perfectly in the 
 older crystalline and granitic rocks. The primary form is rhombohedral, 
 but it usually occurs either in six-sided prisms, acutely terminated by six 
 planes ; in acute simple six-sided pyramids ; or in such prisms and pyramids 
 doubly terminated. The largest and finest specimens are obtained from 
 the Alps, Pyrenees, Siberia, Brazil, Ceylon, Madagascar, and in a less de- 
 gree from Saxony, Norway, and the Scottish Highlands. The purest sorts 
 consist almost entirely of silex, with a trace of alumina, lime, oxide of iron, 
 or other colouring matter ; have a fine vitreous lustre, a specific gravity 
 of from 2.5 to 2.8, and a hardness of 7, being in this respect only inferior 
 to corundum and diamond. 
 
 Rocking-Stones. Weather-worn rounded blocks, generally of granite or 
 tabular greenstone, so nicely poised on their basis that a very ordinary 
 force suffices to make them oscillate or "rock" from side to side. See 
 LOGAN-STONES. 
 
 Bock-Oil. The familiar as well as commercial term for Petroleum or 
 Mineral-Oil) which see. 
 
 Bock-Salt The familiar as well as scientific term for common salt 
 (chloride of sodium), when it occurs in the earth's crust as a solid rock- 
 mass. In the British Isles the great repository of rock-salt is the Trias or 
 Upper New Red Sandstone ; but deposits of equal magnitude are found 
 in connection with Oolitic strata, as in the Salzburg Alps, with Cretaceous 
 greensands as at Cordova in Spain, with Chalk and Tertiary rocks in the 
 valley of Cardona in the district of the Pyrenees, with Tertiary marls as in 
 Sicily and at Wielitska in Poland ; and salt springs are known to issue 
 from Carboniferous and older strata. It is thus a product of all epochs, 
 and must have been formed either by the gradual and long-continued de- 
 siccation of limited areas of salt-water alternately cut off and placed in con- 
 nection with the ocean, or by precipitation from saturated solutions, per- 
 haps brought about by the evaporating power of volcanic or other thermal 
 agency. The Cheshire deposits of rock-salt, which may be taken as a typi- 
 cal illustration, lie along the line of the valley of the Weaver, in small 
 patches, about Northwich. There are two beds lying beneath 120 feet of 
 coloured marls, in which no traces of animal or vegetable fossils occur. 
 The upper bed of salt is 75 feet thick ; it is separated from the lower one 
 by 30 feet of coloured marls, similar to the general cover ; and the lower 
 bed of salt is above 100 feet thick, but has nowhere been perforated. They 
 extend into an irregular oval area, about a mile and a half in length, by 
 three-quarters of a mile in breadth. The salt in these deposits is some- 
 times pure and transparent, and at other times is of a dirty reddish hue, 
 and mixed to the amount of half its bulk with earthy impurities. It is not 
 stratified or laminated, but divided into vertical prisms of various forms 
 and magnitudes, sometimes more than a yard in diameter the outer sides 
 of these rude crystallisations being generally pure and transparent. 
 
 Bock-Soap. Known also as mountain-soap ; one of the clays or silicates 
 of alumina, of a pitch-black or bluish-black colour, slightly greasy feel, 
 writes but does not soil, adheres strongly to the tongue, and falls to pieces 
 
ROC ROT 
 
 in water. Occurs in veins and fissures. The compactor sorts are cut into 
 crayons ; the softer are used as a fulling material. 
 
 Bock-Wood. A variety of absestus, of a brown colour, and occurring in 
 long compacted fibres which give it the aspect and texture of wood ; hence 
 the name. See ASBESTOS. 
 
 Rodeniia (Lat. rodo, I gnaw). Literally rodents or " gnawers ; " an ex- 
 tensive class of mammals, so called from their habit of gnawing or nibbling 
 their food, which generally consists of the harder and drier vegetable sub- 
 stances, and for which purpose they are provided with sharp chisel-shaped 
 incisors e.g., the rat, hare, beaver, squirrel, and porcupine. 
 
 Roestone. A familiar English term for Oolite, from its being composed 
 of an aggregation of small rounded grains or spherules, which, taken in 
 the mass, present considerable resemblances to the roes of fishes. The 
 larger-grained varieties are known as peastones or pisolites, and the irregu- 
 lar-grained as pea-grits, &c. See OOLITE. 
 
 Roof. In coal-mining, the stratum or material immediately overlying 
 the workable coal, from its forming, as it were, a roof or covering to the 
 operations of the miner. In metalliferous veins, the overhanging part or 
 wall of the vein. 
 
 Rosalina (Lat. rosa, a rose). A genus of many-celled foraminiferous 
 organisms, so called from the circular or rose-like disposition of the cham- 
 bers. In Rosalina the cells are arranged round a central spire in one or 
 more whorls, the outer chambers gradually becoming larger and more 
 inflated. The opening is on the under or depressed side, and the whole 
 external surface is minutely punctured. 
 
 Rose-Quartz. A more or less transparent variety of quartz of a fine 
 rose-red or pink colour ; massive ; and when sufficiently free from flaws is 
 cut and polished as an ornamental stone. 
 
 Rostellaria (Lat. rosteilum, a little beak). One of the Strombidae or 
 Wing-shells, of which five or six species inhabit the Indian and Chinese 
 seas at moderate depths, and of which upwards of seventy species occur 
 fossil, from the Lower Greensand inclusive. Shell with an elongated 
 spire ; whorls numerous and flat ; canals long ; outer lip more or less ex- 
 panded, with a single sinus close to the beak. The older Tertiary species 
 have the outer lip enormously expanded and smooth-edged ; those with 
 keeled and spiniferous whorls form the sub-genus Spinigera. 
 
 Rotalia, Rotalites (Lat. rota, a wheel). A genus of foraminiferous 
 shells, so called from their nautiloid wheel-like contour. They are ex- 
 tremely minute, and appear in the Lias, Oolite, and Chalk in immense 
 numbers and many species, and still swarm in the present seas. Though 
 nautiloid in their aspect, they are regularly turbinated, the cells de- 
 creasing in size towards the apex or centre. 
 
 Roth-todte-liegende. Literally " red-dead-liers ; " the name given by 
 German miners to the red sandstones and marls which lie under the 
 Kupfer-schiefer or copper- slate, because they are " dead " or non-metalli- 
 ferous. They seem to be the equivalents of the lowermost Permian sand- 
 stones of the north of England. 
 
 Rotifera (Lat. rota, a wheel, and fero, I bear). An order of infusorial 
 animalcules, so called from the revolving wheel-like motion of the rows of 
 vibratile cilia (hair-like processes) which surround their mouths, and by 
 which they move through the water, as well as create currents to bring 
 within their reach the organised atoms on which they feed. They are 
 
 391 
 
EOT RUS 
 
 divided into Nuda and Loricata the former having the body soft and 
 naked, the latter covered with a sheath. 
 
 Rotten-Stone. A siliceo-aluminous compound, resulting from the de- 
 composition of impure limestone by the percolation of carbonated waters. 
 Most of the rotten-stone of commerce (used for polishing metals, &c.) is 
 derived, like that of Derbyshire, from the decomposition of siliceous lime- 
 stones the lime being decomposed, and the silex remaining as a light 
 earthy mass. 
 
 Rowley-Rag. The hard, fine-grained crystalline greenstone constituting 
 Eowley Hill in the Dudley coal-field. "This trap-rock," says Mr T. R. 
 Jones, "supplied the materials for the important experiments by Gregory, 
 Watt, and Sir James Hall on the fusion and cooling of rocks ; and has of 
 late been employed by Messrs Chance, at Oldbury, near Birmingham, in 
 the manufacture of molten indestructible architectural materials." 
 
 Rabble. A quarryman's term for the loose covering of angular frag- 
 ments which appear at the outcrop of many sandstones. Applied also to 
 all accumulations of loose angular fragments not water- worn and rounded 
 like gravel and shingle. 
 
 Rubellite (Lat. rubeo, to flush with red). A mineralogical term for the 
 fine red varieties of TOURMALINE, which see. 
 
 Rubicelle. A lapidary's term for the fine yellow or orange-red varieties 
 of the spinel RUBY, which see. 
 
 Ruby (Lat. rubeo, I flush with red). A mineralogical and lapidary's 
 term for the fine red transparent varieties of Spinel and Corundum, which 
 see. The finest red and violet varieties are obtained from Ceylon, Ava, 
 and other parts of the East, hence known as the Oriental ruby, and which, 
 when uniform in colour, free from flaws, and large, ranks next to the dia- 
 mond among gems. It is customary to distinguish the rose-red varieties 
 as Jialas-ruby ; the yellow or orange-red as Rubicelle ; and the violet as 
 A Imandine ruby ; but of course there are many intermediate shades, as 
 there are diversities of composition, among the so-called " rubies " of the 
 lapidary and jeweller. The " corundums " proper consist almost entirely 
 of alumina, with a minute proportion of iron peroxide or other colouring 
 matter ; the " spinels," on the other hand, contain from 10 to 20 per cent 
 of magnesia, with minute but varying proportions of silica, lime, and 
 chrome. Both corundum and spinel are found in situ in gneiss and 
 granitic rocks; but the chief supply of the "rubies" of commerce is 
 obtained from the gravelly detritus of streams and mountain torrents. 
 
 Rugose (Lat. ruga, a wrinkle). Full of wrinkles ; having a coarse ir- 
 regular surface like the bark of an old oak or elm ; covered with many 
 wrinkles or minute folds, like the shell of the Buccinum undatum or com- 
 mon whelk. 
 
 Ruin. A term occasionally employed in familiar description for certain 
 minerals, whose sections or cut faces exhibit the appearance of ruined 
 buildings, as Ruin-agate, or brecciated agate, Ruin-marble, or Gotham 
 marble, &c. 
 
 Ruminantia (Lat. ruminare, to chew the cud). An important group of 
 quadrupeds, often referred to in zoology and palaeontology, and including 
 those which, like the ox, deer, goat, sheep, &c., ruminate, or chew the 
 cud. They are all vegetable-feeders, have cloven hoofs, and are void of 
 canine and incisive teeth in the upper jaw. 
 Rusophycus (Gr. rusos, wrinkled, and phucos, sea- weed). A genus estab- 
 
ItUS SAD 
 
 lished by Professor Hall for certain transversely- wrinkled impressions 
 found in rocks of the " Clinton Group" (Middle Silurian) of New York, and 
 supposed to be fossil sea-weeds, whence the name. These curious and 
 irregular markings have since been found in other Palaeozoic rocks of 
 America, and Dr Dawson suggests that they may be the casts of the im- 
 pressions of the laminated gill-feet of trilobites, and that they may have 
 been connected with the place of incubation at the end of burrows. 
 
 Rust (Sax.) The powdery oxide or tarnish which covers the surfaces of 
 metals exposed to the action of a moist atmosphere ; hence we have the 
 well-known "iron rust," "copper rust," and so on. 
 
 Rutile, Riitilite (Lat. rutilus, shining red). Native binoxide of titanium 
 coloured by the peroxide of iron, and so called from its deep and often 
 dark-red colours. It usually occurs in long prismatic or acicular crystals, 
 and is common in granite, gneiss, and mica-schist, often investing and 
 penetrating rock-crystal in these formations. It is used in porcelain- 
 painting to produce a yellow colour. 
 
 Ryacolite (Gr. ryax, ryakos, a stream, and lithos, stone). A species of 
 felspar, whitish, transparent, and of vitreous lustre ; so called from its 
 being found with augite, nepheline, and mica in the lava-streams of 
 Vesuvius. Many of the so-called "glassy felspars " belong to this species, 
 which consists of 50 silica, 30 alumina, 10.56 soda, and 6 potash, with 
 traces of lime and magnesia. 
 
 s 
 
 Saarbrnck, in Lorraine, whose coal formation abounds in beautiful 
 specimens of Palceoniscus, Amblypterus, and other allied fishes. These 
 organisms occur in the slaty shales and in the ironstone nodules. 
 
 Saccharite (Lat. sacckarum, sugar). A species of felspar occurring in 
 fine granular masses, of a vitreous lustre, and white or greenish - white 
 colour; whence the name. It is found in veins in serpentine, in the 
 chrysoprase mines, near Frankenstein in Silesia. 
 
 Saccharoid (Gr. sakcJiar, sugar, and eidos, likeness). Resembling loaf- 
 sugar in texture ; applied to crystalline limestones like the fine statuary 
 marble of Carrara. 
 
 Sacrnm, Sacral. In anatomy, the posterior bone of the pelvis, articu- 
 lated to the last lumbar vertebra, and firmly united on each side to the 
 hip-bones, forming, as it were, the "key-stone" of the pelvic arch. In 
 young animals the sacral vertebra (which are of variable number in differ- 
 ent groups) are generally distinct and separable, but become united or 
 anchylosed (less or more) into one piece, according to age and specialities 
 of structure. 
 
 Saddle-Back. A familiar term for anticlinal strata, from their sloping 
 or dipping right and left in saddle form. In mining phraseology, the 
 sides or slopes of a saddle-back or anticline are termed its "wings." See 
 ANTICLINE. 
 
 393 
 
SAF SAL 
 
 Safety Lamp. A lamp invented by Sir Humphry Davy to prevent the 
 explosion of fire-damp in coal-mines, familiarly termed by the colliers a 
 "Davy." It consists of a lamp completely surrounded by wire-gauze, 
 having a mesh from ^ to ^ of an inch in width, and through which the 
 explosive mixture cannot, under ordinary circumstances, be fired. There 
 are various modifications of this invention by Stephenson, Clanny, Meuse- 
 ler, and others ; but in all, the essential principle is the non-transmission 
 of flame through tubes or openings whose diameters do not exceed the 
 fortieth part of an inch the wire-gauze acting merely by its cooling power. 
 See DAVY LAMP. 
 
 Sahlite. A variety of augite, so called from its being discovered in the 
 silver-mines of Sahla in Sweden. It occurs in columnar, lamellar, or 
 granular concretions, usually of a light or greyish - green colour, of a 
 shining pearly lustre, and, for the most part, imbedded, as in iron and lead 
 ores, and in altered limestones. See AUGITE. 
 
 St Cuthbert's Beads. A North of England term for the detached bead- 
 like joints of the encrinite, from a legend alluded to by Sir Walter Scott 
 in 'Marmion/ 
 
 " On a rock by Lindisfarne, 
 St Cuthbert sits, and toils to frame 
 The sea-born beads that bear his name. " 
 
 St Peter's Finger. An old and familiar term of the English peasantry 
 for Belemnites, many of which are of a finger-like form. 
 
 Salamandroides (literally, salamander-like). The term originally ap- 
 plied by Dr Jager to certain salamander-like remains from the Upper 
 New Red Sandstone of Wirtemberg ; but since critically examined by 
 Professor Owen, and classed with LABYRINTHODON, which see. 
 
 Sal- Amm6niac. Muriate or hydrochlorate of ammonia ; so called from 
 the Temple of Ammon in Egypt, where it was originally obtained by burn- 
 ing camel's dung. It is now largely procured by other processes, and 
 occurs native in crusts, stalactites, and pulverulent masses, chiefly in the 
 rents and fissures near active volcanoes. It is of a greyish or yellowish 
 white, according to impurities of iron, sulphur, &c. ; has a saline pungent 
 taste ; is easily soluble in water ; and volatilises without fusing. Used in 
 medicine, dyeing, and various metallurgic operations. 
 
 Salamstein, Salamstone. A familiar term for the fine blue transparent 
 varieties of Oriental Sapphire, which see. 
 
 Saliferous (Lat. sal, salt, and fero, I yield). Containing or yielding 
 salt, as "saliferous strata," "saliferous deposits," &c. Saliferous System 
 was at one time used by English geologists as synonymous with Upper 
 New Red Sandstone, which is the great repository of rock-salt and brine 
 springs in England ; but as other formations in different countries are 
 equally rich in this mineral, the designation has been all but abandoned 
 for that of Trias or Triassic. See ROCK-SALT. 
 
 Salifiable (Lat. sal, salt, and/o, I become). Having the property of 
 becoming a salt ; capable of being converted into the form of a salt by 
 combination with an acid ; hence the " salifiable bases " of the chemist. 
 
 Salinas. The name given in South America to those superficial deposits 
 which often occupy extensive plains on the Pacific or rainless side of the 
 Andes, and which are usually covered with a white saline effloresence or 
 crystalline incrustation. They occur at all elevations, from a few feet to 
 several thousand feet above the sea-level, and are evidently the remains 
 
 394 
 
SAL SAN 
 
 of old sea-reaches and lagoons that have been desiccated by the upheaval 
 of the land. They extend for about 600 miles north and south, but find 
 their greatest development between latitudes 19 and 25 south, and at 
 distances varying from 10 to 40 miles inland. The usual salts occurring 
 in these " salinas," as in those near Iquique and the desert of Atacama, 
 are common salt, Epsom salt, Glauber-salt, thenordite, glauberite, soda- 
 alum, magnesia-alum, gypsum, anhydrite, along with chloride of calcium, 
 iodide and bromide of sodium, carbonate and nitrate of soda, and in some 
 places borate of lime and borax. 
 
 Saline (Lat. sal, salt). Containing or impregnated with salt ; as " saline 
 springs," "saline incrustations," &c. 
 
 Sal-Mirabile (Lat.) Literally "wonderful salt;" a term of the older 
 chemists for sulphate of soda or Glauber-Salt, which see. 
 
 Salses. Eruptions of hot acidulated mud from small orifices, generally 
 in volcanic districts, and often accompanied by steam and gases at a high 
 temperature, which act powerfully on the surrounding solid matters, dis- 
 integrating and decomposing them, and forming new compounds. In some 
 districts the gases are inflammable, and flames issue from the orifices. 
 
 Salt (Gr. lulls, Lat. sal). This term, though in ordinary language limited 
 to common salt or sea-salt, is in chemistry and mineralogy applied to all 
 combinations of acids with alkaline or salifiable bases ; hence we have 
 such terms as haloid salts, copper salts, had salts, and the like. "The 
 nomenclature of salts," says Brande, "has reference to the acids which 
 they contain; sulphates, nitrates, carbonates, &c., implying salts of the 
 sulphuric, nitric, and carbonic acids. The termination ate implies the 
 maximum of oxygen in the acids, and ite the minimum ; thus the salts of 
 sulphurous and nitrous acids are called sulphites and nitrites. When salts 
 contain one equivalent of acid and one of base, they are called neutral 
 salts ; where one equivalent of acid is combined with two of base, they are 
 termed basic salts, subsalts, or disalts ; and where there are two equivalents 
 of acid and one of base, the salt is a supersalt or bisalt. Thus the terms 
 subacetate of lead and diacetate of lead are synonymous ; so are supercar- 
 bonate and bicarbonate of potash. Many salts are hydrous that is, they 
 contain a definite proportion of water of crystallisation ; others are desti- 
 tute of water, and are dry or anhydrous salts. Some attract moisture 
 when exposed to the air, and are said to be deliquescent ; others suffer their 
 water to escape and become opaque or pulverulent, and are said to be 
 efflorescent" Common Salt, which is a chloride of sodium, is obtained 
 either by the evaporation of sea- water and brine-springs, or by the treat- 
 ment and purification of rock-salt. It is indispensable as a condiment or 
 article of food, and is largely employed in glass - making, enamelling, 
 glazing, bleaching, and other industrial processes. 
 
 Saltpetre (Lat. sal, salt, and petra, stone). A familiar term for nitrate 
 of potash, or Nitre (which see), from its being found native generally in 
 loose stony soils. 
 
 Sanadine (Gr. sanis, a board, in reference to the tabular form of the 
 crystals). An occasional synonyme for glassy felspar, a variety of Ortho- 
 clase, or potash-felspar, which see. 
 
 Sand (Sax.) Any aggregation of water- worn particles, derived from pre- 
 existing rocks and other mineral substances. Sand is generally composed 
 of quartz-grains (quartz being one of the hardest of simple minerals, and 
 longest resisting the processes of attrition) ; but it may also consist of the 
 
 395 
 
SAN SAP . 
 
 particles of shells, corals, &c. ; hence such terms as "shell-sand," " coral- 
 sand," and the like. 
 
 Sand- Drift. The general term for all wind-blown sands, whether occur- 
 ring in inland deserts or along the sea-shores. In both situations it pre- 
 sents much the same appearance, namely, ridges, hillocks, or sand-dunes 
 more or less parallel, and lying of course across the direction of the pre- 
 valent winds. Sand-drift occurs largely along the shores of our own 
 island, forming "Links" or "Dunes," generally covered with the sand- 
 reed and other coarse herbage, and rising in ridges from twenty to sixty 
 feet in height. 
 
 Sand-Pillars. The ordinary name for the sand-storms of desert tracts 
 like those of the Sahara and Mongolia, because they assume a whirling and 
 pillar-like form in their onward march. " They often come on," says Mr 
 Michie, who crossed Mongolia in 1863, "after a sultry day. A yellow 
 haze appears in the sky, darkening the sun ; then columns of fine dust 
 are seen spinning round in whirlwinds. At that stage every living thing 
 seeks shelter, and those who are afield are lucky if they are not caught in 
 the blinding storm before they reach their houses. It has been supposed 
 that they are due to some peculiar electrical condition of the atmosphere." 
 
 Sand-Pipes or Sand-Galls. The name given to those cylindrical or pipe- 
 like hollows, often of considerable depth, which occur in chalk rocks, and 
 which are usually filled up with sand and gravel and clay from above. 
 These "pipes" have been ascribed by some to the wearing, rotatory motion 
 of sand and pebbles which form the "pot-holes" of existing shores ; and 
 by others, with greater reason, to the percolation of water charged with car- 
 bonic acid the corroding action being often confined to a narrow tube a 
 few feet in diameter, and upwards of 20, 40, or 60 feet in depth. 
 
 Sand-Scratches. "The sands carried by the wind," says Professor 
 Dana, " when passing over rocks, sometimes wear them smooth or mark 
 the surface with scratches and furrows, as observed by W. P. Blake over 
 granite rocks at the pass of San Bernardino in California. Even quartz 
 was polished and garnets were left projecting upon pedicles of felspar. 
 Limestone was so much worn as to look as if the surface had beenjemoved 
 by solution." Such appearances are apt to be mistaken for those of glacial- 
 isation, and require careful observance. 
 
 Sandstone is simply consolidated sand the particles (whether siliceous 
 or calcareous) having been compacted by pressure, or being held together 
 by lime, clay, oxide of iron, or some other cementing material. Some 
 sandstones, like those of Edinburgh and St Andrews, contain upwards of 
 98 per cent of pure silica, the remainder being lime, alumina, and iron. 
 
 Saponaceous (Lat. sapo, soap). Feeling like soap to the touch ; having 
 a soapy feel, as steatite, and many other allied minerals. Also, capable of 
 being worked into a lather like soap, as the juice or mucilage of many 
 plants, aquatic and terrestrial. 
 
 Sapphire (Gr.) A highly transparent variety of corundum, with a very 
 imperfect cleavage and conchoidal fracture those of fine red colours being 
 often named "Oriental rubies ;" those of blue, " Sal am stein;" those of yel- 
 low or white, " Oriental topaz ; " those of green, " Oriental emerald," &c. 
 It consists of alumina, with a trace of peroxide of iron and other colouring 
 matter, and is the hardest of all known gems, except the diamond. The 
 "sapphire blue" of the Greeks and .Romans seems to have been the lapis- 
 lazuli, and not this gem. 
 
 396 
 
SAR SAU 
 
 Sarcode (Gr. sarx, flesh, and eidos, resemblance). The term applied by 
 Dujardin to the simple glutinous (or fleshy-like) substance which consti- 
 tutes the body or vital mass of the protozoa or lowest forms of animal 
 life e.g., the jelly-like substance which constitutes the body of the 
 amoeba, and the glairy coating which invests the horny framework of the 
 sponge. 
 
 Sdrcolite (Gr. sarx, flesh, and lithos, stone). An unimportant variety 
 of Analcime (one of the Zeolites) ; and so called from its fine flesh-colour. 
 
 SarcUSnyx. A variety of onyx (which see) ; and said by some to derive 
 its name from Sardes in Lydia, and by others from Sardo, the Greek name 
 for Sardinia both being localities from which it was obtained for cameo 
 manufacture. 
 
 Sarsen Stones. The name given in the south of England to those large 
 tabular blocks of sandstone which are scattered over the surface of the 
 chalk downs, and which, from their partially worn and weathered aspect, 
 are evidently the remains of the once superincumbent Eocene strata which 
 have been removed by denudation. Known also as Druid-stones and 
 Grey-wethers, which see. 
 
 Sassoline (from Sasso, near Sienna). The mineralogical term for boracic 
 acid, which occurs in thin, scaly, irregular six-sided cr3 r stals, of a whitish 
 colour, pearly lustre, and less or more translucent. The crystals have an 
 acidulous and slightly bitter taste, feel greasy, and are easily soluble in 
 boiling water. Boracic acid (or " hydrous boracic acid," as it is often 
 termed) occurs, with various impurities, in many volcanic regions ; in the 
 hot springs of Sasso, near Sienna ; and in the lagoni of Tuscany, where 
 many thousand pounds are annually obtained by evaporating the water. 
 
 Satin-Spar. A familiar term for the finely-fibrous, silky varieties of 
 A rragonite, or prismatic calc-spar, many of which are susceptible of a fine 
 polish, and exhibit the lustre of satin ; whence the name. 
 
 Saturated (Lat. saturate, full). Full to overflowing; water saturated 
 with salt, is water that can dissolve no more of that substance every addi- 
 tional particle that is added to this "saturated solution" falling to the 
 bottom undissolved. 
 
 Saurian (Gr. sauros, a lizard). Of or pertaining to the Saurians, or 
 scaly reptiles, of which the common lizard has been taken as the repre- 
 sentative. As a section, the Saurians comprehend the lizards, monitors, 
 iguanas, chameleons, &c., all well-known forms among living species ; and 
 the ichthyosaurus, plesiosaurus, deinosaurus, iguanodon, and numerous 
 other extinct and gigantic forms, some of which were marine, others 
 terrestrial some carnivorous, and others herbivorous. As an order, the 
 Saurians are characterised by their elongate rounded bodies, densely 
 covered with imbricated or granular scales ; by their elongate, tapering, 
 usually scaly tails; limbs four, but occasionally rudimentary, and com- 
 pletely concealed under the skin ; ribs distinct and movable ; sternum 
 distinct ; mouth not dilatable, jaws toothed ; eyes and ear-cavities promi- 
 nent and exposed ; eggs with a hard skin or crust ; and young not under- 
 going any metamorphosis. See tabulations " ANIMAL SCHEME." 
 
 Saurocephalus (Gr. sauros, lizard, aud kephale, head). Literally "lizard- 
 headed ;" a genus of fossil fishes of the Cycloid order of Agassiz, found 
 in the Chalk formation, and so named from the peculiar formation of the 
 head. 
 
 Saurodon (Gr. sauros, lizard, and odous, tooth). Literally "lizard- 
 397 
 
SAU SCA 
 
 toothed ;" a genus of fossil fishes of the Cycloid order, found in the Chalk, 
 and so termed from the sauroid character of their teeth. 
 
 Saiiroid (Gr. sauros, lizard, and eidos, likeness). Like or akin to the 
 Saurians ; a convenient term implying affinity or resemblance without 
 asserting absolute identity. 
 
 Sauroidei. One of Agassiz's orders of fossil fishes ; so called from their 
 exhibiting, in their structure and dentition, certain sauroid or reptilian 
 characters. They occur in the Carboniferous, Permian, Oolitic, and Chalk 
 systems ; and their remains (teeth, bones of the head, &c.) often indicate 
 fishes of great size and pre-eminently predaceous habits ; e.g. , megalichthys, 
 sauropsis, saurichthys, &c. 
 
 Sauroidei-Dipterfni. One of Agassiz's orders or sub-orders of fishes, 
 mainly characterised by having rows of true fish-teeth on the outer edges of 
 the jaws, and irregularly implanted reptilian teeth on the inner plates. 
 The forms are chiefiy Devonian, and embrace such genera as dipterus, 
 diplopterus, osteolepis, glyptolepis, &c. 
 
 Sauropsis (Gr. sauros, lizard, and opsis, appearance). A genus of 
 sauroid fishes occurring in the Oolitic system, and so named by Agassiz 
 from certain characteristics of their dentition. 
 
 Sauropterygia (Gr. sauros, a lizard, and pteryx, a wing or fin). One of 
 the thirteen orders into which Professor Owen proposes to arrange the 
 Keptilia, living and extinct. The fins in this order of marine reptiles (of 
 which the Plesiosaur may be taken as the type) do not include more 
 than five digits, and resemble those of turtles ; hence the name. There 
 are no post-orbital and supra-temporal bones ; there are large temporal and 
 other vacuities between the cranial ; there are two ante-orbital nostrils ; 
 teeth simple, in distinct sockets of the premaxillary, maxillary, and pre- 
 mandibular bones, the maxillaries being the larger ; limbs natatory, with 
 not more than five digits ; a sacrum of one or two vertebrae for the attach- 
 ment of the pelvic arch in some ; cervical vertebra numerous ; pleura- 
 pophyses have simple heads, those of the trunk being long and bent. See 
 tabulations, "ANIMAL SCHEME." 
 
 Saussiirite. An impure variety of Lalradorite, or Labrador felspar, 
 occurring in compact, sub-translucent masses, of a bluish or greenish grey, 
 in many hyperstbene rocks ; and so named in honour of the French 
 philosopher Saussure. 
 
 Savannah, Savanna (Fr.) An American term for any vast grassy plain 
 or prairie ; but usually applied to the great central plain of North Amer- 
 ica, which may be said to stretch, with little perceptible interruption, 
 from the Gulf of Mexico to the Arctic Ocean. 
 
 Scaglia (Ital., a scale or chip). An Italian calcareous rock, the equiva- 
 lent of our white chalk. In the north of Italy it contains nodules and 
 layers of flint ; yields ammonites, belemnites, and the like ; is of a red 
 colour, and has a fissile structure ; hence the name. 
 
 Scagliola (Ital., diminutive of scaglia). An artificial composition em- 
 ployed in architectural facings and ornamentation ; consisting of pure 
 finely-powdered Plaster-of- Paris, or calcined gypsum, Flanders glue, isin- 
 glass, &c. ; and made to resemble the natural scaglia limestone. Known 
 also as Mischia, from the mixture of colours employed in it, being made to 
 imitate marble. 
 
 Scalariform (Lat. scalaris, a ladder, and forma, form). Presenting the 
 appearance of a ladder ; applied by botanists and microscopists to certain 
 
 398 
 
SCA SCH 
 
 vessels in the woody structure of the cycads and conifers having an 
 elongated form, and crossed by connecting fibres, like the steps of a 
 ladder. 
 
 Scalent (Lat.) Climbing; the sixth of the fifteen series into which 
 Professor Rogers subdivides the Palaeozoic strata of the Appalachian chain 
 the "Climbing Day," of the North American Palaeozoics, and the equi- 
 valents in part of our Upper Silurians. See PALEOZOIC FORMATIONS. 
 
 Scapheus (Gr. skapheus, a digger). A genus of macrurous crustaceans 
 from the Lias of Lyme Regis, characterised by its spiny cephalo-thorax, 
 prominent rostrum, strong spiny limbs, hirsute abdominal segment, and 
 laminated telson or tail-plate. The fore-limbs are monodactylous or single- 
 fingered, and seem to indicate fossorial habits, whence the name. 
 
 Scaphite (Lat. scapha, a skiff). A genus of the Ammonite family, pecu- 
 liar to the Chalk formation, and so named from the boat-like contour of its 
 shell the inner whorls looking like an ancient reversed prow, and the last 
 chamber, which is free, produced horizontally, and then sharply recurved, 
 forming, as it were, the boat and stern. 
 
 Scapolite (Gr. skapos, a rod, and lithos, stone). A silicate of alumina 
 and lime occurring in long prismatic (rod-like) crystals which lie parallel, 
 diverge, or cross each other, and are either imbedded or in drusy cavities. 
 It is also found massive with a granular or columnar structure ; is less or 
 more transparent ; has a vitreous or resinous lustre ; and is colourless or 
 coloured pale-grey, greenish-yellow, or red. Its composition is vety un- 
 certain. It is found in metalliferous veins, in beds of crystalline lime- 
 stone, and usually associated with calc-spar, quartz, felspar, and mica. It 
 has been taken as the type of the Scapolite family, which includes several 
 closely-allied minerals palagonite, nepheline, prehnite, nephrite, &c. See 
 tabulations, "MINERAL SCHEME." 
 
 Scapula, Scapular Bone (Lat.) The shoulder-blade; a bone which, 
 from its size and position, is frequently found detached in a fossil state. 
 "It is broad and flat, generally triangular, sometimes sub-quadrilateral, 
 in Mammals ; narrow and commonly sabre-shaped in Birds ; narrow and 
 straight in Saurians ; a round, strong, and straight column in Chelonians ; 
 and variously shaped and articulated to the back of the skull in most 
 Fishes." 
 
 Scar or Scaur (Sax.) A bluff precipice of rock ; hence the term " Scar 
 Limestone," applied to the mountain limestone as it occurs in the hills of 
 Yorkshire and Westmoreland, occasionally corrupted into "score" and 
 "skaour." 
 
 Scar-Limestone. The name given by English geologists to the lower 
 group of the Carboniferous Limestone, as developed in bluff precipices 
 and lofty " scars " in the north-western districts of Yorkshire and in 
 Westmoreland. 
 
 Scarped (Fr. escarper, to cut steep). Having a steep face ; worn or cut 
 away so as to present a steep precipitous face. 
 
 Scheelite. Tungstate of lime ; consisting of 81 tungstic acid and 19 
 lime ; and occurring in the veins of the older rocks in imbedded four-sided 
 pyramidal crystals, or in reniform and amorphous-granular crusts, of a grey- 
 ish-white, yellowish, or brownish colour, vitreous lustre, translucent and 
 brittle. Named after the Swedish chemist Scheele, who first discovered 
 tungstic acid in this mineral. 
 
 Scheererite (after Von Scheerer, its discoverer, in 1822). One of the 
 
SCH SCO 
 
 
 
 mineral resins occurring in brown-coal and peat, in crystalline grains and 
 scales, and in minute acicular crystals, of a white or yellowish-green colour; 
 pearly lustre, soft and very friable, and without odour when cold. Melts 
 at 111 Fahr. into a colourless fatty liquid ; inflames readily, and burns 
 completely away, giving out much smoke and a faint aromatic smell. 
 
 Schiller-Spar (Ger. schillern, to change colour). A massive magnesio- 
 siliceous mineral (hydrated silicate of magnesia) of a greyish-green or 
 yellowish-brown colour, having a pearly metallic lustre, flat cleavage, and 
 exhibiting a slight play of colour. Is generally found in connection with 
 serpentine ; and is closely related to Bronzite and Diallage being softer, 
 and containing more water than the former, and more magnesia and less 
 lime than the latter. Thus an average of analyses gives 
 
 Schiller- ) 43 sm 2g m 3 u 13 iron t j mangan-) 2 alumina, 13 water. 
 
 spar, } 
 
 Diallage, 51 16 17 6 4 ,, 3 2 
 
 Bronzite, 56 30 2 8 1 ,,1 2 
 
 Schist (Gr. schisma, a splitting or division). This terra should be re- 
 stricted to such rocks as mica-schist, chlorite-schist, gneiss, and the like, 
 which have a foliated structure, and split up in thin irregular plates, not 
 by regular cleavage as in clay-slate, nor in large flat laminse as in flag- 
 stones. Hence we speak of the "crystalline schists," meaning thereby 
 gneiss, mica-schist, chlorite-schist, and the like, as distinct from the slates, r 
 whicff in this sense are retained for the Clay- slate formation. In the slates, 
 the splitting-up may be said to be perfect and indefinite ; the schists or 
 schistoze rocks, on the other hand, are only capable of an imperfect separa- 
 tion into layers and laminse. 
 
 Schizopteris (Gr. schiza, a cleft, and pteris, fern). An obscure genus of 
 Coal-measure ferns, so called from their palmated or deeply-cleft leaflets. 
 They have been found surrounding the stems of sphenopteris, and from 
 this circumstance are supposed to have been climbers, and indicative of a 
 tropical climate. 
 
 Schlerodus (Gr. schleros, rough, and odov.s, tooth). A provisional genus 
 of fishes found in the Ludlow bone-bed (Upper Silurian), and so named 
 from the minute pustules on the surface of their teeth. The jaws and 
 teeth are the only portions yet found. 
 
 Schorl (Swed. sliorl, brittle). Known also as Black Tourmaline, a pris- 
 matic, longitudinally-striated mineral, of a pitchy lustre and colour, brittle 
 texture, and capable of being rendered electric by heat or friction. It 
 occurs abundantly in the sparry cavities and veins of the granitic rocks, 
 often beautifully imbedded in the felspar and quartz. The term schorl 
 has been applied to several dissimilar minerals by foreign mineralo- 
 gists, as "schorl rouge," rutile; "schorl blanc," albite ; "schorl violet," 
 axinite, &c. 
 
 Scleretinite (Gr. sUeros, hard ; refine, resin). One of the mineral resins 
 occurring in the Palaeozoic Coal-formations, in roundish drops and pellets, 
 of a black colour, hard and brittle like asphalt, but nearly allied to amber 
 in composition. 
 
 Scolfthus, Scolites (Gr. sJcolios, tortuous). Applied to those tortuous 
 tube-like markings which occur in certain sandstones, and which seem to 
 have been the burrows of annelids, or, as some suppose, of minute fossorial 
 crustaceans. 
 
 Scoridceous. Resembling scoriae ; applied to loose, cindery debris, 
 400 
 
SCO SEC 
 
 having the aspect or character of scoriae. Scorified. Reduced to scoriae, 
 or cindery dross. 
 
 Sc6rise (Ital. scoria, dross). Applied to all accumulations of dust, ashes, 
 cinders, and loose fragments of rocks, discharged from active volcanoes. 
 Properly speaking, the term refers to the scum-like dross which floats on 
 the surface of molten masses, and which, when cooled down, breaks up 
 into loose cindery fragments and clinkers. We may have, thus, the scoriae 
 of a glass-furnace as well as the scoriae of a volcano ; though the term is 
 generally applied to the cindery products of the latter. 
 
 Scoriform. In the form of, or resembling scoriae. Applied to loose 
 cindery aggregates, which seem to owe their origin to igneous action. 
 
 Scotch Pebbles. A common term among mineralogists for varieties of 
 agate, carnelian, and the like, which are often found in the soils from 
 decomposed traps and in the gravels of rivers and the sea-shores, but 
 which were originally derived from the cavities of the amygdaloidal rocks 
 of Scotland. See AMYGDALOID. 
 
 Screw-Stones. A familiar term for the hollow siliceous casts of encri- 
 nite stems, frequently occurring in the cherts and rotten stones of the 
 Carboniferous limestone ; and so called from the resemblance of the numer- 
 ous interspaces of the jointed columns to the threads of a screw. See 
 PULLEY-STONES. 
 
 Sea-Breeze. In geography, the breeze or air-current that sets in from 
 the sea towards the land. This generally occurs during the day, when the 
 warmer air over the heated surface of the land ascends, and the colder air 
 over the sea sets in to supply its place. Within the tropics the sea and 
 laijd breezes occur with great regularity, the former from nine in the 
 morning till near sunset, and the latter from a little after sunset till near 
 sunrise the following morning. 
 
 Seal. In zoology, the familiar term for a well-known genus and family 
 (Phocidce) of marine carnivorous mammals frequenting our own shores, but 
 abounding especially on the sub-arctic coasts of Newfoundland, Labrador, 
 Greenland, and Spitzbergen, where they are hunted for their oil, and killed 
 in incredible numbers. The seal is not known in a fossil state earlier than 
 the close of the Glacial or Upper Pleistocene period, when apparently more 
 than one species occur in the brick-clays of the British Islands. 
 
 Seam. Strictly speaking, the line of separation between two strata, 
 which often differs in colour from the strata themselves, and looks like the 
 seam between two portions of a garment ; but loosely applied to subor- 
 dinate beds occurring in any series, as seams of coal in the Coal-measures, 
 which are in the main composed of sandstones, shales, and clays. 
 
 Secondary Strata. Originally applied to the fossiliferous strata lying 
 between the Transition and Tertiary of Werner ; now employed as equi- 
 valent to Mesozoic^-th&t is, comprehending the Trias, Lias, Oolite, Weal- 
 den, and Chalk formations. 
 
 Sectile (Lat. sectilis). Capable of being cut ; applied in mineralogy to 
 those rocks and minerals which can be cut with a knife without causing 
 the particles to spitter and fly about. Talc, mica, and steatite yield quietly 
 to the knife, and are thence said to be " sectile." 
 
 Section (Lat. sectus, cut through). Literally, a cutting through, as of 
 the trunk of a tree, to display its internal structure. A geological section 
 represents the structure of the earth's crust on any given line in a vertical 
 direction ; and is either natural, as seen in cliffs and precipices ; artificial, 
 
 401 2o 
 
SEC SEM 
 
 as in quarries, tunnels, and coal-pits ; or theoretical, when constructed from 
 a number of observations on the position of the strata in various adjacent 
 localities. As the earth is so vast, compared with any means of representa- 
 tion we have at our command, and as the thickness of the'strata is so small, 
 compared with the length of most lines of section, "theoretical sections" 
 are in general mere indications of what they are intended to represent, but 
 indications of vast utility when read with proper understanding. 
 
 Secular (Lat. saculum, an age). Applied in geology to great natural 
 processes, whose results become appreciable only after the lapse of ages : 
 thus we speak of the " secular refrigeration " of the globe from some hypo- 
 thetical state of original igneous fluidity ; of "secular contraction" of the 
 earth's mass, as resulting from its gradual refrigeration, and so on. 
 
 Sediment (Lat. sedere, to settle down). Matter settled down from sus- 
 pension in water. If the turbid muddy waters of a river be allowed to 
 stagnate, the mud will gradually fall to the bottom and form sediment. 
 Rocks which have been formed in this manner, as shale, clay, sandstone, 
 &c., are termed sedimentary ; that is, sedimented from mechanical sus- 
 pension in water. The term, however, is generally applied to all the stra- 
 tified rocks, whether produced exactly in this way, or generally by the 
 operations of water. 
 
 Seismdgraphy, Seismogrdphic (Gr. seismos, a shock, earthquake, and 
 graphe, description). Literally a writing about or description of earth- 
 quakes ; hence such accounts constitute a " seismography," and maps or 
 charts constructed so as to indicate the centres of convulsion, lines of 
 direction, areas of disturbance, and the like, are termed "seismographic." 
 
 Seism6logy (Gr. seismos, a shock or earthquake, logos, reasoning). The 
 science of earthquakes, in all that relates to their force, duration, lines of 
 direction, periodicity, and other characteristics. 
 
 Seism6meter (Gr.) Literally " shock -measurer ;" an instrument, or 
 rather apparatus, of which there are several modifications, for measuring 
 the force and direction of earthquake convulsions. 
 
 Seldchia (Gr. selas, a flash of light). The Cartilaginous order of fishes, 
 as the sharks, rays, and chimseroids ; said to be so called from their emit- 
 ting a phosphorescent light. See tabulations, " ANIMAL SCHEME." 
 
 Selenite (Gr. selene, the moon). Sulphate of lime- or gypsum, when it 
 occurs in fine transparent crystals ; so termed from its subdued lustre and 
 transparency. See GYPSUM. 
 
 Selenium (Gr. selene, in allusion to its lustre). An elementary acidifying 
 and basifying substance, discovered by Berzelius in 1818 in the iron pyrites 
 of Fahlun. In its general chemical habitudes it resembles sulphur, and is 
 said to form a connecting link between sulphur and the metals. When 
 precipitated it appears as a red powder, which, when heated, melts, and 
 on cooling forms a brittle black mass, but transmitting red light in thin 
 plates. It burns with a blue flame, and produces a gaseous substance 
 (oxide of selenium), which has a most penetrating and characteristic odour. 
 With sulphur, phosphorus, the earths and metals, it forms seleniurets; hence 
 " seleniurets " of lead, cobalt, silver, &c. 
 
 Semi- (Lat.) A frequent prefix in scientific compounds, literally sig- 
 nifying " half," but frequently implying merely defect or incompleteness ; 
 as semicircle, half a circle; semi-transparent, imperfectly transparent. 
 Same as the Greek hemi which see. 
 
 Semionotus (Gr. semeion, a mark or device, and noios, the back). Liter- 
 402 
 
SEM SER 
 
 ally ' ' stamped back ; " a genus of Liassic fishes belonging to the Lepidoid 
 order ; and so called by Agassiz in allusion to the peculiar character of the 
 dorsal scales. 
 
 Semi-Opal. Literally "half-opal;" a term applied to the duller and 
 less pellucid varieties of common Opal, which see. 
 
 Seneca Oil. A familiar term for the petroleum of Pennsylvania, from its 
 occurrence at Seneca Creek, and its use as a lubricant by the Seneca 
 Indians. See PETROLEUM and BITUMEN. 
 
 Sepals (Lat. sepes, a fence or enclosure). The leaf-like divisions of the 
 cup or calyx which encloses the corolla or blossom of a flower. The im- 
 pressions of sepals are not unfrequent in a fossil state ; those of the petals 
 or divisions of the blossom are exceedingly rare and doubtful. 
 
 Sepiadse (Gr. sepia, the cuttle-fish). A well-known family of cephalo- 
 podous molluscs belonging to the Decapod division of the Dibranchiate 
 order, and of which the common cuttle-fish (Sepia officinalis) has been taken 
 as the type. The family is characterised by an internal rudimentary shell, 
 in the form of a friable calcareous plate, imbedded in the back part of the 
 mantle, and from which the pounce of the chemist is derived. The family 
 includes several fossil forms Spirulirostra, Beloptera, Eelemnosis, &c. 
 See tabulations, " ANIMAL SCHEME." 
 
 Septarium, plural Septaria (Lat. septum, a fence or division). Flattened 
 nodules of calcareous clay, ironstone, or other matter, internally divided 
 into numerous angular compartments by reticulating fissures which are usu- 
 ally filled with calcareous spar, and show well against the darker matrix of 
 the nodule. The reticulating fissures or septa seem to have arisen from the 
 shrinkage of the mass while in the act of consolidating, and to have been 
 subsequently filled by infiltration. Such argillaceous, calcareous, and fer- 
 ruginous nodules are common in many clays and marls, as in the shales of 
 the Coal-formation, in the Oxford clay, in the London and Barton clays, 
 &c. ; are often arranged in lines or bands ; are always more or less flat- 
 tened ; generally contain some central organic nucleus round which the 
 matter has aggregated, such as a leaf, scale, coprolite, or the like ; and 
 when split up in the direction of the stratification, frequently exhibit very 
 curiously marked sections ; hence the names beetle-stones, turtle-stones, Ludi 
 Helmontii, and the like. Septaria, such as those derived from the Oxford 
 and London clays, when burnt and ground, are largely used for Roman 
 cements. See NODULAR STRUCTURE. 
 
 Septum, plural Septa (Lat.) A partition or division. The thin plates 
 which separate the chambers of the Nautilus and Ammonite are termed 
 septa ; so also the thin radiating divisions which give to the pores of corals 
 their star-like or rayed appearance. 
 
 Serai (Lat.) Late, the nightfall; the last or uppermost of the fifteen 
 series into which Professor Rogers subdivides the Palaeozoic strata of the 
 Appalachian chain the "Nightfall," metaphorically speaking, of the 
 North American Palaeozoics, and the equivalents of our upper or true Coal- 
 measures. See PALEOZOIC FORMATIONS. 
 
 Series. Applied to any number of allied objects arranged in sequence. 
 In geological classification, any set of strata possessing some common 
 mineral or fossil characteristic, as the Greensand series, Wenlock series, 
 &c. A subordinate group in some great formation or system. . 
 
 Serpentine. A siliceo-magnesian rock of granitic or metamorphic 
 origin ; so called from the resemblance of its variegated colours to the 
 
 403 
 
SER SET 
 
 skin of a serpent. Common or compact serpentine occurs in veins, dykes, 
 or imbedded masses ; is usually dark-coloured (green, grey, red, or brown), 
 and often spotted, striped, or veined ; is rather soft and sectile ; has a 
 dull splintery fracture ; and feels greasy. Though soft it is susceptible of 
 a fine polish, and being easily cut and turned on the lathe, it is fashioned 
 into various ornamental articles, as that of Lizard Point in Cornwall, and 
 Portsoy in Banffshire. Its average composition seems to be 44 silica, 43 
 magnesia, and 13 water. Besides the common serpentine, also known as 
 ophite, mineralogists distinguish noble serpentine, usually of some shade of 
 green, translucent, and having a resinous lustre when polished ; marmolite, 
 or foliated serpentine ; picrolite, or fibrous serpentine ; and chrysolite, or 
 asbestiform serpentine, of a fine oil-green colour and silky lustre, but con- 
 sidered by some as a distinct mineral. 
 
 Serpula, Serpulidae. A family and genus of annelids deriving their 
 name from the tortuous and twisted tubes they inhabit. The animals of 
 this family are fixed or sedentary ; and have elaborate calcareous tubes or 
 crusts for their protection. They have feathery or arborescent gills sur- 
 rounding their heads ; hence the occasional term Cephalobranchiate An- 
 nelidans. The shelly tubes of the Serpulce occur on every shore, incrust- 
 ing stones, rocks, shells, drift-wood, sea-weeds, &c. ; and are readily dis- 
 tinguished by their tortuous and irregular forms. In tropical seas some 
 species live in large colonies, their shelly exuviae forming banks resembling 
 coral-reefs in their solidity and extent. 
 
 Serpulites. The general palseontological term for all fossil tortuous 
 tubes and tube-like organisms apparently allied to those of the existing 
 Serpulae; and evidently the products of tube-forming Annelids. They 
 occur i all formations from the Silurian upwards, and in some of their 
 forms have often been mistaken for the shells of Mollusca. Whatever their 
 forms, they are always smooth within, have no chambers or divisions, and 
 exhibit no traces of muscular attachment. 
 
 Sertularia (Lat. set-turn, a wreath). A genus of hydroid polypes, so 
 called from their cells being arranged on the opposite sides of a fleshy or 
 horny axis, this giving to their stems a wreath-like appearance. The 
 Silurian graptolites, though similarly disposed, may have no real affinity 
 either to the sertularice, pennatulce, or virgularice of existing seas. 
 
 Sessile (Lat. sedeo, I sit). Applied to animals and organisms that are 
 closely attached to other objects, and not supported on a pedicle, foot- 
 stalk, or stem. Thus the balanus or acorn-shell is sessile when compared 
 with the lepas or goose-barnacle, which is supported on a fleshy pedicle ; 
 and the eyes of some crustaceans are attached to the carapace, while those 
 of others are surmounted on movable foot- stalks. Sessile and pedunculated 
 are thus opposing terms. 
 
 Seta, plural Setae (Lat., bristle, bristles). A term frequently and vari- 
 ously applied in natural history. In botany, the bristle-like stalk that 
 supports the theca or seed-case of mosses ; the awn or beard of grasses ; 
 the glandular points of the rose, &c. In zoology, the stiff short hairs that 
 clothe many caterpillars and insects ; the bristles that arm the rings of the 
 earth-worm and form its points of progression ; the stiff processes that 
 cover the limbs and mandibles of many crustaceans ; and the like. 
 
 Setaceous (Lat. seta, a bristle). Covered or armed with bristles; 
 bristle-like ; in form and character resembling a bristle ; bristly. 
 
 Setigerous (Lat. seta, bristle, and gero, 1 carry). Literally "bristle- 
 404 
 
SHA SHO 
 
 bearing ; " applied to the organs of plants and animals that are covered or 
 armed with short stiff processes resembling bristles. 
 
 Shale (Ger. schalen, to peel or shell off). Applied to all argillaceous 
 strata that exhibit a laminated structure, and consequently split up more 
 or less perfectly in the direction of their bedding. Clay, for example, is 
 massive or plastic and void of structure; marl is friable or crumbly; 
 shale always exhibits some degree of lamination and fissility. Being, in 
 fact, the solidified muds of former waters, the shales present endless vari- 
 eties in point of composition, and these are usually defined as calcareous, 
 arenaceous, bituminous, and so forth, according to the predominating or 
 most perceptible ingredient. 
 
 Shanklin Sand. A name occasionally given to the Lower Greensand of 
 the Chalk formation, from its being conspicuously developed at Shanklin, 
 in the Isle of Wight. 
 
 Shell (Sax.) Familiarly and loosely applied to any hard crust or cover- 
 ing; but in zoology restricted to the hard calcareous coverings of the 
 Mollusca or Testacea. According to Brande, the mineral or hardening 
 principle of shell is carbonate of lime nearly pure. The animal principle 
 in the porcellaneous shells (e. g., the cowries) is a small quantity of soluble 
 gelatine; in the mother-of-pearl or nacreous shells (e.g., the pearl-oyster) 
 it is albuminous. The latter, therefore, when steeped in dilute muriatic 
 acid, leave a membranous or cartilaginous residue ; but the former are 
 entirely soluble. 
 
 Shell-Marl. Applied to all deposits of marl that is, soft earthy depo- 
 sits of lime in the bottom of fresh- water lakes and other stagnant waters 
 in which shells are present in notable proportion. In British shell-marls 
 the most abundant shells are paludina, lymnea, planorbis, and cyclas ; and 
 in less proportion ancylus, unto, and the minute cases of entomostracous 
 crustaceans. See MARL. 
 
 Shell-Mounds. Better known, perhaps, as Kjokken-miidding or "kitchen- 
 middens," which see. These mounds, composed for the most part of 
 shells of the oyster, cockle, mussel, and other edible mollusca, are found 
 in many places along the shores of northern Europe, and point to an early 
 period when savage races, ignorant of the use of the metals, frequented the 
 sea-coast and fed upon the shell-fish in question, as well as upon the native 
 terrestrial fauna, imbedded bones of which are also not uncommon. 
 
 Shell-Sand. On certain coasts the tide- and wave-washed sands are in 
 a great measure composed of the broken and triturated shells of the 
 mollusca common to the locality. To such masses the term shell-sand is 
 usually applied; and where readily accessible it forms an available fer- 
 tiliser. 
 
 Shingle. Loose imperfectly-rounded stones and pebbles, as distinct 
 from gravel and sand. The " shingle beaches" which are piled along cer- 
 tain portions of our coasts, and the " shingle barriers" which occur at the 
 mouths of many rivers, are merely masses of rock debris in the process of 
 attrition to gravel and sand. 
 
 Sheading or Shoding. In mining, searching for fragments of ore in the 
 gravel of a stream or valley, so as to trace from these fragments the posi- 
 tion of the vein from which they have been derived. In general, the 
 shoad-stones, or fragments of ore, become more frequent the nearer the 
 original vein is approached. 
 
 Shoal (Sax.) In geography, any portion of the bottom of a sea, estuary, 
 
 405 
 
SID SIL 
 
 lake, or river where the water is of little depth. Shoals or banks are 
 usually composed of mud, sand, and gravel, which are accumulated by 
 opposing currents or sets of the tide ; and as they are much frequented by 
 marine animals for the purposes of food or procreation, they must become 
 in course of ages the receptacles of very heterogeneous matters organic 
 and inorganic. 
 
 Siderite (Or. sideros, iron). A name given to sparry iron-ore ; some- 
 times also to cube-ore ; and occasionally to a vitreous variety of quartz of 
 an indigo or Berlin-blue colour. The prefix sidero- is in frequent use in 
 mineralogy either to denote composition or iron-like aspect, as sidwomelane, 
 sideritine, &c. 
 
 Sienite, Sienitic, more frequently and properly SYENITE, which see. 
 
 Sierra (Span.) In geography, sierra signifies a ridge or range of moun- 
 tains, and refers to their saw-like outline ; cordillera, on the other hand, 
 means simply a connected mountain- chain ; and mauna, an isolated hill or 
 mount. 
 
 Sigillaria (Lat. sigillum, a seal). An extensive genus of Coal-measure 
 stems, characterised by their furrowed or channeled surfaces, and named 
 in allusion to the leaf-scars, which look like so many seal-impressions on 
 the ridges or raised flutings. In Sigillaria the scars of the leaves are 
 small, round, and much narrower than the ridges of the stem ; while in 
 Favularia, which has also a furrowed stem, the scars are square, and as 
 broad as the ridges. Sigillaria occurs in great profusion and many specific 
 forms (upwards of fifty species have been named), and of all sizes, from 
 stems the girth of the arm to trunks several feet in diameter, and upwards 
 of sixty feet in length. From the flattened state of many of the trunks, it 
 appears to have been a tree of little substance, and yet many of its charac- 
 ters forbid the supposition of its being hollow, like the reed or cane. In 
 many instances it is found growing in situ, and in whole forests ; and in 
 such instances it is always furnished with the dichotomising or forking 
 roots, known as stigmaria. Regarding the affinities of sigillaria, some 
 would refer it to the tree-ferns, others to the palms, and some again to the 
 coniferse ; but the truth is, that while it exhibits characters touching on 
 several existing orders, there is in reality no living family wherewith to 
 compare it. According to M. Brongniart, who has made it the subject of a 
 special memoir ('Archives du Muse'um d'Histoire Naturelle,' 1839), "Sigil- 
 laria constituted a peculiar extinct family, belonging to the great division 
 of gymnospermous dicotyledons. They were tall erect trees, with a regu- 
 lar and cylindrical stem, without side-branches, but dichotomous towards 
 the summit. Their superficial bark was hard and durable, channeled 
 longitudinally, bearing leaf-scars that are of a rounded form above and 
 below, and angular at the sides, often oblong in relation to the stem, and 
 having three vascular pits, one central and small, and two lateral of a large 
 size. The internal structure bears most analogy to that of the Cycadese, 
 and the foliage consisted of long, linear, carinated leaves. The Sigillariae, 
 therefore, differ essentially from the arborescent cryptogams, which they 
 somewhat approach in having scalariform vascular tissue, symmetrical and 
 regular leaf-scars, and branchless trunks." 
 
 Silex, Silica (Lat. Gr. chalis, a peeble). In chemical language, " the 
 earth of flints." This important substance (we abridge and modify from 
 Brande) constitutes the characteristic ingredient of a great variety of 
 siliceous minerals; among which rock-crystal, quartz, chalcedony, and 
 
 406 
 
SIL 
 
 flint, may be considered as silex nearly pure. It also predominates in 
 many of the rocky masses which constitute the crust of our globe, such as 
 granite, quartz-rock, and the numerous varieties of sandstone. Although 
 silica has none of the ordinary or more obvious acid properties, yet as it 
 combines in definite proportion with many salifiable bases, and expels 
 carbonic acid when fused with the carbonated alkalies, it is very commonly 
 termed Silicic acid, and its various compounds have been denominated 
 Silicates. When pure and colourless rock-crystal is heated red hot, and 
 quenched in water, it becomes opaque and friable ; and if in this state it 
 be reduced to powder, it presents one form of pure silica. If in this state 
 (in which it is perfectly insoluble in water) it be fused with three parts of 
 carbonate of potash, it forms a glass which is soluble in water, and from 
 this solution (formerly called liquor of flints] the concentrated acids throw 
 down the silica in the form of a gelatinous hydrate ; but if the solution be 
 diluted, and the acid gradually added, the alkali may be perfectly neutral- 
 ised without any deposition of silica, which, therefore, is thus exhibited 
 in a very soluble state : when, however, the solution is evaporated to dry- 
 ness, the silica remains in a state as insoluble as before. This solubility of 
 hydrated silica, whilst when dry t is perfectly insoluble, may serve to 
 explain the occasional occurrence of silica in mineral waters, and its depo- 
 sition in various chalcedonic incrustations. But silica presents another 
 very remarkable character ; which is, if we reverse the above proportions, 
 and fuse together a mixture of one part of carbonate of potash and three 
 of powdered rock-crystal or calcined flint, we then obtain a transparent 
 and fusible compound which is insoluble in water, and which in fact is 
 glass. See GLASS. 
 
 Siliceous (Lat. silex, flint). All rocks having a flinty texture, or into 
 whose composition silica enters as a notable ingredient, are said to be 
 siliceous. Rock-crystal and quartz "are the purest states in which silex 
 occurs in nature ; common flint is an impure variety ; and chert and horn- 
 stone are still more impure admixtures. 
 
 Siliceous-Sinter (see SINTER). A siliceous incrustation or deposit from 
 springs holding silica in solution, like the Geysers of Iceland. It has often 
 a mammillary surface, and exhibits internally numerous successive lines or 
 layers of deposit. According to Klaproth, that from the Geysers consists 
 of 98 silica, 1.50 alumina, and 0.50 iron. 
 
 Siliclfied (Lat. silex, flint, and^o, I am made). Converted into flinty or 
 siliceous matter ; petrified by the infiltration of silica in a state of solu- 
 tion, as the silicified stems from Antigua, the desert of Cairo, and Van 
 Diemen's Land. Silicification is a common process in the neighbourhood of 
 hot springs, which generally hold a notable proportion of silica in solution 
 e.g., the Geysers of Iceland, and the hot springs of the Azores and of 
 Tongariro in New Zealand. 
 
 Silicon. The base of silica, one of the elementary substances, of a dark 
 nut-brown colour, and now shown not to be a metal, but nearly allied to 
 boron and carbon in some of its properties. It is an non-conductor of 
 electricity, incombustible in air and oxygen, infusible by the blowpipe, 
 and not acted upon by any single acid, though readily soluble in a mixture 
 of the nitric and hydro-fluoric acids. Like carbon it will combine with the 
 metals, especially with aluminium, forming cast-aluminium, just as carbon 
 and iron form cast-iron. 
 
 Sill (Sax. syl, the flat stone forming the threshold or door-sill). Applied 
 
 407 
 
SIL 
 
 in mining to flat-bedded strata of sandstone or similar hard rocks ; hence 
 the "whin-sill" of the north of England an interstratified trap of the 
 mountain limestone. 
 
 Silt. This term is properly applied to the fine impalpable mud which 
 collects in lakes and estuaries, but is generally used to designate all calm 
 and gradual deposits of mud, clay, or sand ; hence we speak of " marine 
 silt," " tidal silt," and of harbours being partially filled or silled up with 
 tidal debris. 
 
 Silurian System. The name originally given by Sir Roderick Murchison 
 (and now adopted by all geologists) to that vast suite of fossiliferous strata 
 which lies between the partially fossiliferous Cambrian schists beneath and 
 the Old Red Sandstone above, from the fact of their being well developed, 
 and first worked out by him, in the district between England and Wales 
 anciently inhabited by the Silures under their chief Caractacus or Caradoc. 
 In the typical region of Shropshire, &c., the system, according to its in- 
 vestigator, consists of the following members : 
 
 UPPER SILURIAN. 
 
 /Finely laminated reddish and greenish sandstones, locally 
 T > 1 | known as "Tilestones." (In part, base of Devonian System). 
 ~ ' / Micaceous grey sandstone in beds of varying thickness. 
 series, | Argillaceous limestone (Aymestry limestone). 
 
 \Shale with concretions of limestone (Lower Ludlow). 
 
 f Concretionary limestone (Wenlock limestone). 
 Wenlock J Argillaceous shale in thick beds (Wenlock shale). 
 Series, j Shelly limestone and sandstone (Woolhope and Mayhill). 
 
 (.Gritty sandstones and shales (Upper Llandovery). 
 
 LOWER SILURIAN. 
 
 ferits and sandy shales (Lower Llandovery). 
 JThick-bedded whitish freestone (Caradoc sandstone). 
 (Bark calcareous flags and slates (Bala beds), 
 j Slaty flags and bands of limestone (Llandeilo and Lingula flags). 
 |Gritty flags and slates (Longmynd or "Bottom Rocks"). 
 
 In other regions the nature of the rocks may differ from the above ; but 
 in all whether Scotland, Scandinavia, Bohemia, Russia, or North America 
 the same facies of Life prevails, and the Silurian as a SYSTEM is distinc- 
 tively characterised by its graptolites ; its corals, heliolites, favosites, &c. ; 
 its echinoderms, actiniocrinites, cystidece, &c. ; its brachiopods, lingulce, 
 terebratulaz, and orlhidce ; its chambered shells, lituites and Maclurea ; its 
 serpulites and cornulites ; its Crustacea, calymene, asaplms, trinucleus, and 
 other trilobites, most of which are never found beyond the limits of 
 Silurian strata. Its fauna is eminently marine, and exhibits most of the 
 great forms of invertebrate life ; but as yet few fishes have been detected, 
 and these chiefly in the uppermost beds of the system. Its flora is still 
 imperfectly known -scattered and fragmentary sea- weeds, indistinct stems 
 of aquatic plants, and a few pinnules and spore-cases of lycopodaceous, 
 and twigs of lepidodendroid land-plants, being all that has yet been dis- 
 covered in strata unmistakably Silurian. 
 
 Silvas, Selvas (Lat. silva, a wood). A term applied to the woodland 
 region of the great Amazonian plain. Low-lying, damp, fertile in soil, and 
 under the influences of a tropical sun, these sil-vas present the rankest luxu- 
 riance of primeval forest-growth. 
 
 408 
 
SIL SIV 
 
 Silver. An early and well-known metal of a peculiar white colour 
 (silver-white), brilliant lustre, malleable, ductile, and soft when pure. Its 
 specific gravity is from 10.5 to 11 ; it melts at about 1000 Fahr. ; it is not 
 altered by air or moisture, but is readily tarnished or blackened by sul- 
 phuretted hydrogen. It occurs native in the older rocks, in threads and 
 strings, in arborescent, moss-like aggregates, and in plates and nuggets 
 often of considerable magnitude. In its native state it often occurs as an 
 alloy with gold, platina, copper, or arsenic more frequently perhaps with 
 platina than with any other metal. It is also largely obtained from ores, 
 generally as a sulphuret or sulphide, and often in intimate union with ores 
 of lead, antimony, bismuth, &c. so that the ores yielding silver are, 
 strictly speaking, ores of other metals. These ores are found chiefly in 
 the primary and transition strata ; though argentiferous lead ores occur 
 abundantly in secondary strata. 
 
 Simoom. An Arabic term signifying poison, and applied to a hot suffo- 
 cating wind, which occurs in most countries bordering on sandy deserts. 
 Coming from the arid desert, and laden with the minutest particles, it 
 often gives a red or reddish-dun colour to the atmosphere, and thus fore- 
 warns the traveller to take shelter from the approach of its pestilential 
 breath. In Turkey it is called the Samieli ; in Egypt, Khamsia (fifty), 
 because it usually continues fifty days ; and on the western coast of Africa, 
 Harmattan. 
 
 Sinter (Ger. sintern, to drop). Compact incrustations from siliceous or 
 calcareous springs are known as siliceous-sinter and calc-sinter. The 
 term is used in contradistinction to tuff or tufa, which is open and porous, 
 and wants the hard ringing sound of sinter when struck by the hammer. 
 
 Siphonia (Gr.) A genus of fossil sponges occurring abundantly in the 
 Chalk and Greensand of Europe. The Siphoniae consist of a pear-shaped 
 body, more or lesslobed, and mounted on a slender stalk, which terminates 
 below in several rootlets for attachment to the rocks or other bodies on 
 which they grow. Those occurring in the Upper Greensand of Farnham 
 are infiltrated with phosphate of lime, and have (along with other phos- 
 phatic nodules from the same strata) been used in agriculture. 
 
 Siphuncle (dim. of siphon, a tube). Any small tube or tubular passage ; 
 usually applied to the tube-like perforation which passes through the 
 septa and chambers of such shells as the nautilus, ammonite, and 
 ceratite. 
 
 Sirocco (Arab.) The name given to the hot parching wind which oc- 
 casionally passes over Sicily and adjacent districts during the latter part 
 of summer and autumn, and which is supposed to originate in the Sahara 
 or Great Burning Desert of Africa. 
 
 Sivalic or Sewalick Hills. A range of minor mountains skirting the 
 southern base of the Himalayas, and celebrated in geology chiefly through 
 the discoveries of Dr Falconer and Colonel Sir Proby Cautley. " It has 
 proved," says the former, " more abundant in genera and species than any 
 other region yet explored. As a general expression of the leading features, 
 it may be stated that it appears to have been composed of representative 
 forms of all ages, from the oldest of the Tertiary period down to the 
 modern, and of all the geographical divisions of the Old Continent grouped 
 together into one comprehensive Fauna in India." 
 
 Sivatherinm (Siva, an Indian goddess, and therion, beast). The generic 
 term applied by Dr Falconer to the skull and bones of a gigantic mammal 
 
 409 
 
SKO SME 
 
 found in the Sivalic Tertiaries, and forming, as it were, a link between the 
 ruminants and large pachyderms. " It was larger than a rhinoceros, had 
 four horns, and was furnished with a proboscis ; thus combining the horns 
 of a ruminant with the characters of a pachyderm. When living it must 
 have resembled an immense antelope or gnu, with a short and thick head, 
 and an -elevated cranium crested with two pairs of horns the front pair 
 being small and the hinder large, and set quite behind, as in the Aurochs. 
 With the face and figure of the rhinoceros, it had small lateral eyes, great 
 lips, and a nasal proboscis." See ' Fauna Antiqua Sivalensis,' by Falconer 
 and Cautley. 
 
 Skorodite (Gr. skorodon, garlic). A hydrous arseniate of iron, of a leek- 
 green colour, inclining to brown ; and supposed to be a secondary produc- 
 tion from the decomposition of ores containing arsenic and iron. It fuses 
 before the blowpipe, giving out a strong smell of garlic ; whence the name. 
 
 Slate (Sax.) Any thin plate of rock ; any rock that can be split (schlittsen) 
 into thin liminae or plates, like roofing-slate. This term is now generally, 
 and should be, restricted to argillaceous rocks, like common roofing-slate, 
 whose lamination is not produced by bedding, but is due to a metamorph- 
 ism called cleavage, which often traverses the rock at right angles to the 
 lines of stratification. Foliated rocks, like gneiss and mica-schist, are 
 termed schists, not slates ; and thinly-bedded sandstones are flagstones and 
 tilestones. See CLAY -SLATE and CLEAVAGE. 
 
 Slate-Spar. A variety of calcareous spar ; so called from its occurring 
 in thin slaty lamellae, often with a shining white pearly lustre, and greasy 
 feel. See CALC-SPAR. 
 
 Slaty. Resembling slate ; having the cleavable or fissile structure of 
 clay-slate. Somewhat loosely applied to all hard thinly-laminated rocks ; 
 as " slate-clay" or slaty clay, a hard fissile shale ; "slate-coal" or slaty 
 coal, a hard laminated variety of bituminous coal. 
 
 Slide. A miner's term for a minor slip or dislocation of the strata, the 
 fissure being usually filled with fine unctuous clay, which makes the one 
 side appear to slip or slide away from the other. 
 
 Slikensides. In mining, the smooth striated surface of a fault or fissure 
 apparently produced by convulsive friction, and subsequently coated with 
 a siliceous or calcareous glaze by the passage of water or heated vapours. 
 Also provincially applied to an ore of galena occurring in Derbyshire. 
 
 Slime (Sax., akin to the Lat. limus, mud). The familiar as well as 
 scientific term for all soft adhesive mud ; hence the slimy silt of compara- 
 tively stagnant waters, the slimy oaze or ooze of the deep sea-bottom 
 brought up by the sounding-rod. 
 
 Slip. A familiar term for a faitlt or dislocation, as if the one portion of 
 strata had slipped or slid away from the other. See FAULT. 
 
 Slope and Counter-Slope. The majority of mountain-chains present on 
 one side a long and gentle slope, and on the other a short and rapid one 
 the former is termed the slope, the latter the counter-slope. Thus the 
 slope of the Andes is towards the Atlantic, the counter-slope or steep side 
 towards the Pacific. 
 
 Smaltine. Arsenide of copper; one of the most important ores of 
 Cobalt, being, along with cobaltine, that from which the greater part of 
 the Smalts of commerce is derived. See COBALT. 
 
 Smerdis (Gr.) A genus of ctenoid fishes often occurring in shoals in the 
 Tertiary marls of Aix in Provence. They are of small size rarely exceed- 
 
 410 
 
SMI SOD 
 
 ing three or four inches in length and the species are generally charac- 
 terised by their dorsal fins and widely-forked tails. 
 
 Smithsonite (after the chemist Srnithson). Silicate of zinc, occurring in 
 detached crystals, and in stalactitic, botryoidal, granular, and compact 
 masses, of various colours, vitreous lustre, brittle, phosphorescent when 
 rubbed, and electric by heat. Consists of 67.4 oxide of zinc, 25.1 silica, 
 and 7.5 water. See KALAMINE. 
 
 Smudge-Coal. An English miner's term for coal that has been partially 
 de-bituminised, or converted by contact with trap-dykes, &c., into a sort 
 of natural coke or impure anthracite. Known also as " blind-coal," 
 " stone-coal," and other similar provincial designations. 
 
 Snow- Blanket. The name given by farmers and others to any consider- 
 able thickness of snow which covers the ground during winter, and helps 
 to protect its vegetation from the severity of the frost. In continental 
 countries, like central and northern Europe, this blanket is of essential ser- 
 vice during severe and long-continued frosts in early spring. 
 
 Snow- Light or Snow -Blink. The name given by Voyagers and travellers 
 in the arctic regions to the peculiar reflection that arises from fields of ice 
 or snow. An experienced seaman, it is said, can readily distinguish by 
 the Uink whether the ice is newly formed, heavy, compact, or open. The 
 blink or snow-light of field-ice is the most lucid, and is tinged with yellow; 
 of packed ice it is pure white ; ice newly formed has a greyish blink ; and 
 a deep yellow tint indicates snow on land. 
 
 Snow-Line. That line or limit of elevation at which the air permanently 
 attains the temperature of freezing water, and at and above which the 
 surface is perpetually covered with snow and ice. The snow-line is, of 
 course, highest towards the equator, and gradually descends as we approach 
 either pole. It has also its summer and winter limits, coming lower in 
 winter, and rising higher in summer. 
 
 Soapstone. A soft sectile variety of steatite ; so called from its soapy 
 or saponaceous feel when rubbed between the fingers a characteristic 
 possessed by most magnesian minerals. See STEATITE. 
 
 Soda. The oxide or rather protoxide of sodium ; one of the alkalies, 
 obtained from the ashes of marine plants, and largely and inexhaustibly 
 from sea-salt. Several of its compounds are well-known constituents of 
 the earth's crust ; as the muriate (common or rock salt) ; the cabonate 
 (natron); the nitrate (nitratine) ; the sulphate (Glauber-salt); the borate 
 (borax), &c. Its compounds also occur as notable ingredients in many 
 rocks and minerals ; e.g., the felspars and zeolites. 
 
 Sodium. The metallic basis of soda, discovered by Davy in 1809. 
 Sodium has a bright lustre, and a white silvery colour, with a tinge of red. 
 It is soft and readily moulded at 60, melts at 194, and rises in vapour at 
 a red heat. It is lighter than water, its specific gravity being only 0.972. 
 It is rapidly oxidised on exposure to the air, and on being thrown into 
 water floats about upon the surface and quickly disappears being con- 
 verted into soda, which is dissolved in the water. Its affinity for oxygen 
 prevents its occurrence in nature as sodium ; but the compounds of soda 
 are sufficiently abundant forming rock-masses in the solid crust, occur- 
 ring in the ocean and other saline waters, entering into the composition of 
 many rocks and minerals, being present in all marine and many land 
 plants, and appearing likewise in the structure of the higher animals, which 
 all instinctively swallow large quantities of its chloride. See SODA. 
 
 411 
 
SOI SPA 
 
 Soil (Lat. solum). The usual term for that superficial earthy covering 
 of our planet, in which plants grow and flourish, and which we cultivate, 
 for their artificial growth, in our fields and gardens. It is an intimate 
 admixture of disintegrated rock-matter (clay, sand, &c.) with decomposed 
 vegetable and animal substances; and is readily distinguishable by its 
 dark loamy colour from the inorganic " subsoil" of clay, sand, or gravel 
 that lies beneath. Agriculturists distinguish soils partly by their pre- 
 vailing constituents, as loamy, sandy, clayey, &c. ; and partly by their 
 fitness for the growth of certain crops, as turnip soils, clover soils, and 
 the like. 
 
 Solano (Lat. sol, the sun). A hot south-west wind which occasionally 
 visits the Spanish peninsula, and, blowing from the direction of the African 
 deserts, is regarded as a modified sirocco, which see. 
 
 Solenhofen, near Aichstadt in Germany, a locality celebrated for its fine 
 lithographic slate, which has yielded to the palaeontologist many of the 
 rarest and most perfect specimens of reptiles and mammals peculiar to the 
 upper Oolites. 
 
 Solenites (Gr. solen, a tube or pipe). A genus of Oolite stems or leaves, 
 so called from their fistular or tubular nature. They occur in matted 
 masses, are narrow, regularly striated, taper-pointed, and not unlike, in 
 general aspect, the leaves of the common quill-wort, isoetes lacustris. 
 
 Solfatara (Ital. solfo, sulphur). A volcanic fissure or other orifice from 
 which sulphureous vapours, hot mud, and steam are emitted. Akin to 
 thefumaroles, hornitos, and salses that occur in most volcanic areas. See 
 VOLCANOES. 
 
 Solstices (Lat. sol, the sun ; sto, I stand). The two extreme points of 
 the sun's apparent course north and south of the equator, and where he 
 appears to make a stand, going neither northward nor southward. These 
 are the first points of Cancer and of Capricorn, and the two corresponding 
 seasons of the year are known as the Summer and Winter Solstices. 
 
 Sombrero Guano. Sombrero, one of the West India Islands so called 
 from its resemblance to a "sombrero," or low-crowned Spanish hat, and 
 situated about 130 miles east of Porto Rico is about two and a half 
 miles long, one-half to three-fourths of a mile wide, and rises from 20 to 
 30 feet above the level of the ocean. It is a barren rock, and appears to 
 be entirely composed of the rich phosphatic mineral known in commerce 
 as Sombrero Guano. This substance imbeds numerous bones of turtles and 
 other marine animals ; and from its composition, which resembles bones 
 deprived of their cartilage, it has been supposed (with every degree of 
 probability) that the island was once a shoal swarming with turtles and 
 other vertebrate animals, whose accumulated remains of ages have been 
 cemented together, and gradually elevated above the ocean level to the 
 present position of the island. See OSITE. 
 
 Spalacotherium (Gr. spalax, mole; therium, beast). A mole-like insec- 
 tivorous marsupial, whose teeth and jaw-bones have been found in the 
 Upper Oolites (Purbeck Beds) of England. 
 
 Spar (Ger. spath).A mineralogical term applied to those crystals or 
 minerals which break up into rhombs, cubes, plates, prisms, &c., with 
 smooth cleavage faces. Hence we have calc-spar, felspar, brown-spar, 
 Iceland-spar, and the like. The term is often used as synonymous with 
 crystal, as "sparry cavities," " sparry fosures," &c., meaning thereby that 
 the cavities and fissures are studded with crystals. 
 
 412 
 
SPA SPH 
 
 Spatangidse. A tribe of fossil echinites or sea-urchins peculiar to the 
 Chalk and Greensaud, and distinguished by the following characters : 
 Case oblong or heart-shaped ; mouth elongated traversely and destitute 
 of proper jaws, situated in front of the centre of the base and near the 
 anterior border of the periphery ; ventral outlet towards the posterior 
 margin ; tubercles and spines all very small. The tribe has been sub- 
 divided into spatangus proper (in which the ambulacra are petaloid, the 
 external row of pores slightly elongated, and the inner rows round), 
 ananchytes, micraster, and holaster, which see. 
 
 Spathic (Lat. spatha, a blade). Applied in mineralogy to minerals 
 having an even-lamellar or flatly-foliated structure. 
 
 Spathose (Gr. spathe, a flower-sheath). Occurring in broad plates or 
 lamellae, foliated in texture, as some varieties of gypsum, and other cal- 
 careous minerals. 
 
 Species (Lat.) In natural history, an assemblage of individuals whose 
 likeness to one another is sufficient to justify the conclusion that they all 
 have sprung, or may have sprung, from a common stock. According to 
 this notion, one species is distinguished from another species by sound de- 
 finite characters, which are transmissible from generation to generation, 
 and only liable to such unimportant changes as constitute temporary varie- 
 ties. According to other notions, a species, if at all liable to variations, 
 may vary indefinitely, and thus in course of time pass into an altogether 
 new and different species. 
 
 Specific Centre. "The term specific centre " (we quote the late Edward 
 Forbes) "has been used to express that single point upon which each 
 species had its origin, and from which its individuals become diffused. 
 Tn the course of their diffusion, and during the lapse of time, the species 
 may become extinguished in its original centre, and exist only on some 
 one or several portions of the area over which it became diffused. Groups 
 of the individuals of a single species may thus become isolated, and if they 
 be placed far apart, may present the fallacious aspect of two or more 
 centres for the same species. To get at the causes of such phenomena, we 
 must trace the history of the species backwards in time, and inquire into 
 its connection with the history of geological change ; in other words, endeavour 
 to connect its history in space with its history in time." 
 
 Specular (Lat. speculum, a mirror). Having a smooth brilliant surface 
 that reflects light more or less perfectly ; hence "specular iron ore," and 
 the like. 
 
 Speeton Clay. A deposit frequently alluded to by English geologists. 
 It occurs at Speeton, near Scarborough in Yorkshire, and appears by its 
 fossils to represent the Lower Greensand of the south of England, but is 
 exceptional in its appearance, as it consists of a dark-blue laminated bed, 
 with nodules of clay ironstone. 
 
 Sphsereda (Gr. sphaira, a sphere or globe). The name given to certain 
 vegetable organisms from the Oolite, consisting of a striated stem bear- 
 ing numerous branchlets, each of which is terminated by a globular berry- 
 like body hence the name. 
 
 Sphse'rodus (Gr. sphaira, a sphere, and odous, tooth). Literally "globe- 
 tooth ; " a genus of Oolitic fishes belonging to the Pycnodont family, and 
 so called from the globular shape of their teeth. 
 
 Sphseroid or Spheroid (Gr. sphaira, a sphere). A figure having a shape 
 nearly resembling that of a perfect sphere or globe. The earth, being 
 
 413 
 
SPH SPI 
 
 flattened at either pole to the extent of some thirteen miles, is not a per- 
 fect sphere, but an oblate spheroid. Spheroidal. Having the outline or 
 figure of a spheroid ; globular. 
 
 Sphserosiderite (Gr. sphaira, a globe, and sideros, iron). A mineral ogi- 
 cal term applied to the botryoidal or reniform concretions of siderite, or 
 sparry carbonate of iron, in allusion to their rounded forms. The " Kid- 
 ney iron-ore " of the miner. See SIDERITE. 
 
 Sphsemlites (Gr. sphaira, sphere, and lithos, stone). A genus of thick 
 sub-conical chalk shells, externally striated, and furnished with a concen- 
 trically arranged opercular-looking upper valve. They belong to the 
 Hippurite family, from which genus they differ in having only one internal 
 longitudinal ridge, and in having the external surface roughened by irre- 
 gularly raised sheathing-plates of successive growths. Same as RADIO- 
 LITES, which see. 
 
 Sphenacdnthns (Gr. sphen, a wedge, and akantha, a thorn or spine). 
 A provisional genus of ichthyodorulites or fin-spines belonging to some 
 unknown cestraciont of the lower Coal-measure period. Occur abundantly 
 in Scotland. 
 
 Sphenophyllum (Gr. sphen, sphenos, a wedge, and phyllon, leaf). The 
 Rotularia of Sternberg ; a genus of Coal-measure plants having verticillate 
 (or whorled) wedge-shaped leaves the leaves dilating at the apex, and 
 being furnished with dichotomous veins. From these characteristics, Dr 
 Lindley "has scarcely any doubt that Sphenophyllum was one of those 
 plants which in the ancient world represented the Pine tribe of modern 
 floras." M. Brongniart, on the other hand, regards them as herbaceous 
 plants related to the Marsiliacese or Pepper- worts. 
 
 Sphen6pteris (Gr. sphen, a wedge, and pteris, fern). A genus of fossil 
 ferns, so named from the prevailing form of the leaflets ; occurring pro- 
 fusely in the Carboniferous system, less abundantly in the New Red Sand- 
 stone and Oolite, and dying out in the Greensand. The genus is charac- 
 terised by its twice or thrice pinnated leaves ; leaflets contracted at the 
 base, not adherent to the rachis, lobed ; lower lobes largest, diverging and 
 somewhat palmate ; veins one or more strongly marked in each leaflet. 
 
 Spiculum, plural Spicula (Lat.) Literally, a point or sting; in zoology 
 the term is usually applied to those minute needle-shaped siliceous or 
 calcareous particles which are imbedded in the fibrous mass of sponges, 
 recent and fossil. They occur in the gelatinous sarcode or investing vital 
 membrane of living sponges, or frequently project beyond the mass, as 
 if intended for organs of defence. According to Owen, some of the rag- 
 stones of the Greensand are so full of siliceous spicules as to irritate the 
 hands of the workmen employed in quarrying them. 
 
 Spider. Remains of the Spider order (Arachnida) have been found in 
 the lower Oolites ; and circumstances render it probable that they existed 
 as early as the Carboniferous era. 
 
 Spiniferites (Lat. spina, a spine, and/ero, I bear). A term employed by 
 Dr Mantell to designate those minute spherical bodies beset with spines, 
 which occur in the chalk and flint, and which were at one time regarded as 
 identical with the microscopic xanthidia of Ehrenberg. " The real nature 
 of these fossils," says the author of the term, " must be regarded as still 
 undetermined." Their prevalence in the chalk-flints, whose forms are 
 derived from zoophytes, seems to countenance the supposition that the 
 Spiniferites are the gemmules or early state of animals of this family ; but 
 
 414 
 
SPI SPR 
 
 I have never detected any organic connection between them and the Pori- 
 fera with which they are associated." 
 
 Spirifer (Lat. spira, a spire or coil, and fero, I bear). A genus of bra- 
 chiopods whose broad-hinged deeply-striated bivalves occur abundantly in 
 Silurian, Devonian, and Carboniferous strata. The Spirifers occur in 
 many specific forms, and are so termed from the spiral calcareous processes 
 which in the living state supported the ciliated brachia or arms. These 
 processes being internal, are only observable by carefully laying open finely- 
 preserved specimens. 
 
 Spirolina, Spirolinite (Lat. spira, a coil or spire). A genus of minute 
 many-chambered foraminiferal organisms occurring in the Chalk ; and so 
 termed from the spiral or whorl-like termination of their crosier-like forms. 
 
 Splint or Splent Coal. A Scotch term for a hard laminated variety of 
 bituminous coal, intermediate in texture between cannel and common pit- 
 coal. The name is derived from its splitting (or splenting] up in large flaggy 
 or board-like laminae. The Splints form a very valuable variety their 
 hardness fitting them for any kind of carriage, and their "dryness" 
 enabling them to burn open, with great heat, and without caking 
 together. 
 
 Spongillopsis. Literally spongilla-lilce ; a genus of spongiform organ- 
 isms belonging to the Permian of Germany, and so named by Dr Geinitz 
 from their near alliance to the living Spongilla flumatilis, or fresh- water 
 sponge of Blainville. 
 
 Spongltes. This term, says Mantell, is applied generically to those 
 fossils which appear to be identical in structure with the ordinary marine 
 sponges that consist of a fibro-reticulated porous mass, destitute of regular 
 tubes or canals ; the form exceedingly various. In the living sponge, the 
 mass consists of a framework of horny interlacing fibres, in which are im- 
 bedded numerous " spicula" or needle-shaped calcareous or siliceous par- 
 ticles, the whole being invested by a glairy gelatinous "sarcode" or vital 
 membrane. The outer surface is studded with "pores" which imbibe 
 water, and convey it by numerous "canals" to the interior, whence it is 
 ejected by larger and more prominent orifices termed " oscula. " Existing 
 sponges are usually divided into the homy, flinty, or limy or "ceratose," 
 " siliceous," and " calcareous " according to the substance of their hard 
 sustaining parts, which are commonly "spicules." The siliceous abound 
 in the Oolite and Chalk, attaining their maximum of development in 
 the latter formation ; and are now almost extinct, or are represented by 
 other families with calcareous spicula. The horny, on the other hand, 
 appear to be more abundant now than in ancient seas but their remains 
 are only recognisable in those instances where they were charged with 
 siliceous spicula. 
 
 Spoondrift. During storms at sea, the violence of the tempest is some- 
 times so intense as to quell the billows, and scatter the water in a heavy 
 shower, called by the sailors spoondrift. On such occasions saline particles 
 have impregnated the air to the distance of fifty miles inland. 
 
 Spore, Sporule (Gr. spora, seed). The reproductive germ of crypto- 
 gamic plants, as the ferns and club-mosses. Such spora are often found 
 attached to their fronds, as in the Devonian Cydopteris Hibernica ; or in 
 drifted masses as in the Coal-measures ; and even (according to Dr Hooker) 
 as early as the Ludlow rocks of the Upper Silurian era. 
 
 Springs. In geography, discharges of water from the earth's crust, and 
 415 
 
SQU STE 
 
 so called from their "springing/' as it were, from below to the surface. 
 They are usually distinguished as perennial and intermittent, surface and 
 deep-seated, Iwi and cold, pure and mineral, and so forth, according to 
 their more obvious characteristics. As geographical agents they are of 
 vast importance in administering to the wants of vegetable and animal 
 life, and in fertilising the districts through which they flow ; and as geo- 
 logical, they are ever dissolving and transporting mineral matter, and are 
 intimately connected with the formation of veins, crystallisation, and the 
 metamorphism of rock-masses. 
 
 Squaloid (squalus, shark, and eidos, like). Shark-like ; resembling, 
 appertaining to, or having something in common with, the Shark family. 
 The Squaloids embrace the True sharks or Squalodonts, having sharp-edged 
 teeth and the mouth on the under surface of the head ; the Hybodonts, 
 having teeth nearly like the preceding, but with edges less acute ; and the 
 Cestraciouts, having a rough pavement of bony and usually enamelled pieces 
 in the mouth, and the mouth situated at the extremity of the head, like 
 the cestracion or " Port- Jack son " shark of Australia. 
 
 Squamous, Squamose (Lat. squama, a scale). Scaly ; covered with scales ; 
 having a scale-like aspect, structure, or arrangement. 
 
 Staarenstein (Ger.) Literally " star-stone ;" the popular German 
 designation of Psarolites or silicified fern-stems, in allusion to the star-like 
 markings produced by sections of the vessels that compose their tissues. 
 See PSAROLITES. 
 
 Stahlstein, Steelstone. The German name for some pure crystalline 
 carbonates of iron, because a kind of steel is readily made from such ores 
 without passing through the process of cementation. Such carbonates, 
 though rare in Britain, abound in some parts of Europe. 
 
 Stalactite (Gr. stalasso, I drop). Applied to those icicle-like incrusta- 
 tions of lime, chalcedony, &c., which often fret the roofs of caverns and 
 fissures, and which arise from the dropping of water holding these rock- 
 matters in solution. 
 
 Stalagmite (Gr. stalagma, a drop). The same mineral matter as stalac- 
 tite, but applied to the incrustation that covers the floor of the cavern. 
 The stalactites and stalagmites frequently meet each other, and form 
 pillar-like masses in limestone caverns ; and occasionally a linear fissure 
 in the roof, by the direction it gives to the dropping of the lapidifying 
 water, forms a perfectly transparent curtain or partition of purest ala- 
 baster. 
 
 Stalagmitic. Having the texture or structure of stalagmite. Applied 
 to limestones which, like those of the Tertiary fresh-water basins of Au- 
 vergne, have an open, porous, and somewhat concretionary structure. 
 
 Stanniferous (Lat. stannum, tin). Yielding or containing tin ; applied 
 to veins, rocks, and superficial deposits containing the ores of tin ; hence 
 we have " stanniferous gravels," as well as " stanniferous vein-stones." 
 
 Station. The region occupied by any particular plant is called its station, 
 and that of any particular animal its habitat each being the locality which 
 presents the conditions most favourable to its growth and development. 
 
 Steatite (Gr. stear, fat). A soft magnesian or talcose mineral having a 
 smooth, soapy, or greasy feel ; hence the name. It is a mere massive talc 
 or talc-stone, occurring in subordinate beds in serpentine and chlorite- 
 schist ; usually of a greyish or yellowish-green colour ; having a fibro- 
 laminated texture ; soft and easily sectile. Soapstone, potstone, and other 
 
 416 
 
STE 
 
 talcose rocks (silicates of magnesia), are mere varieties. Steatite has been 
 recently employed in France in the manufacture of buttons, cameos, &c., 
 by exposing it after its fabrication for several hours to a white heat. By 
 this strong calcination it acquires sufficient hardness to strike fire with 
 steel, and to resist the hardest file. It can be polished, however, with 
 emery, tripoli, &c., and may likewise be coloured by different organic and 
 mineral substances. 
 
 Stegodon (Gr. siege, roof, and odous, tooth). One of the sub-genera into 
 which Dr Falconer divides the Elephants, fossil and existing. The term 
 has reference to the gable-end form presented by a section of their molars 
 taken longitudinally through the ridges of the crowns. " The Stegodons " 
 (Dr Falconer in ' Geological Journal,' vol. xiii.) ' ' constitute the intermedi- 
 ate group of the Proboscidea, from which the other species diverge, through 
 their dental characters, on the one side into the Mastodons, and on the 
 other into the typical Elephants." 
 
 Stellated (Lat. stella, a star). Star-like ; having the fibres, crystals, or 
 other members diverging in all directions from a common centre. 
 
 Stemples. In Derbyshire, says Professor Jukes, the shafts of the vein 
 mines are often ascended and descended, not by ladders, but by pieces of 
 wood, called stemples, fixed in the side of the shaft. 
 
 Steneosaurus (Gr. stenos, narrow, and sauros, lizard). A genus of Cro- 
 codilians found in the Chalk and Greensand, and characterised by their 
 long, narrow, beak-like muzzles ; whence the name. They are closely 
 allied to Teleosaurus, but differ in the nasal orifices (which are situated 
 at the extreme tip of the muzzle) being semicircular instead of widely- 
 circular. 
 
 Stephanite. Sulphide of silver and antimony; a brittle sulphuret of 
 silver, occurring principally in veins in the older rocks, either in crystals, 
 massive, or disseminated. It is a valuable ore of silver ; consists of 70.4 
 silver, 14 antimony, and 15.6 sulphur ; and is named after the Archduke 
 Stephan of Austria. 
 
 Steppe Limestone. A Pliocene limestone of brackish-water origin, and 
 so named by Sir R. Murchison and M. de Verneuil, because, with its asso- 
 ciated sandy beds, it underlies large areas of the steppes of eastern Europe 
 and Asia. See ARALO-CASPIAN FORMATION. 
 
 Steppes. A Tartar term, adopted by geographers for those extensive 
 flats or plains which occupy so large a portion of northern Asia and 
 Siberia. In summer they are largely covered with long rough grass, are 
 but partially wooded, and consist of alluvial deposits (sand, gravel, black- 
 earth, bog-earth, &c.), all of comparatively recent formation. Though the 
 Steppes form the great pasture-grounds of the nomade Tartars, they are 
 in many parts barren and shingly, and in others so flat and boggy that 
 during winter these portions become frozen and inhospitable morasses. 
 
 Stereodus (Gr. stereo, solid; odous, tooth). Literally "solid-tooth ;" a 
 provisional genus of cycloid fishes with "sauroid" dentition, from the Mio- 
 cene Tertiaries of Malta. In this genus, which somewhat resembles 
 pachyrhizodus in the circular scales covered with minute asperities, the 
 teeth are rounder, more strongly conical, and set more widely apart, with 
 a slight curvature towards the inner side of the jaw. 
 
 Sternbergia (after Sternberg). An assemblage of singular stems occur- 
 ring in the sandstones of the Coal-measures, and presenting the appear- 
 ance of a vast number of plates or short joints held together by a central 
 
 417 2D 
 
STE STI 
 
 axis. Some of them are striated longitudinally, others not ; and many are 
 evidently the detached central piths of other plants, and not independent 
 stems. 
 
 Sternum (Lat.) The breast-bone ; whose form in most vertebrate 
 families is a good anatomical criterion. Sternal. Of or belonging to the 
 breast. Sterno-costal. Belonging to the region of the ribs attached to the 
 sternum. 
 
 Stibnite (Lat. stibium, antimony). Tersulphide of antimony, consisting 
 of 72.88 antimony, and 27.12 sulphur. " This ore (we quote the ' Glossary 
 of Mineralogy ') usually occurs crystallised in variously modified and ter- 
 minated rhombic prisms, which are sometimes closely aggregated laterally ; 
 also disseminated ; massive, with a long columnar structure ; and fibrous, 
 with a plumose, woolly, or felt-like appearance. Colour and streak lead- 
 grey, inclining to steel-grey ; sometimes blackish and dull externally, and 
 with an irridescent tarnish. Lustre, metallic, sectile ; very brittle ; yields 
 to the pressure of the nail ; and leaves a mark like black-lead when rubbed 
 on paper." This ore is the source of most of the antimony of commerce ; 
 and may be distinguished from a similar ore of manganese by its easy 
 fusibility, crude antimony being obtained from it by simple fusion. See 
 ANTIMONY. 
 
 Stigmaria (Lat. stigma, a dot or puncture). An extensive assemblage 
 of root-stems, characteristic of and peculiar to the Carboniferous system, 
 and so named from their regularly pitted or dotted surfaces each punc- 
 ture or areola representing the attachment of a long, slender, succulent 
 radicle. For a long time the true nature of stigmaria was unknown, and 
 as there is nothing analogous in existing nature, the earlier observers 
 busied themselves with ingenious speculations, which ended only in a 
 name ; hence the numerous designations ficoidites, variolaria, phytolithus, 
 lithophyllum, &c. by which the organism has been successively known. 
 Stigmaria is now ascertained to be the root of sigillaria, lepidodendron, &c. , 
 and usually occurs in the shale or ancient mud in which it grew, as an 
 underground stem less or more cylindrical, generally compressed, studded 
 with circular pittings or areolse arranged in spiral order round the stem ; 
 these areolse often denuded, but frequently having the long succulent tubu- 
 lar radicals attached. In most instances the main roots have central or 
 sub-centrical piths, or woody axes, and where the matrix is sufficiently pre- 
 servative, a thick finely-corrugated bark makes its appearance though 
 generally converted into a film of coal. When found in attachment with 
 the sigillaria trunk, four or more main roots strike down into the soil, 
 these speedily bifurcate and spread out horizontally, bifurcating again and 
 again, till they terminate at a distance (often of 20 or 30 feet) in an 
 obtuse-growing point. Where the underground root and aerial stem meet, 
 the peculiar markings both of stigmaria and sigillaria'are usually indistinct, 
 and it is not till beyond the first bifurcation that the regular areolse and 
 their attached radicles make their appearance. As there are several 
 species of sigillaria and lepidodendron, so we are presented with several 
 stigmaria the specific distinctions consisting chiefly in the forms of the 
 areolse and the attached radicles. In some the areolae are distinctly stel- 
 late or star-shaped ; in others they are so elevated as to become tubercular 
 (hence Brongniart's term mammillaria) ; and in all there is a central speck 
 which passes inwards and connects the succulent radicle with the central 
 woody axis. 
 
 - 418 
 
STI STE 
 
 Stilbite (Gr. stilbe, lustre). A mineral of the Zeolite family occurring in 
 fissures or druses of granite and primary rocks, but most frequently in 
 traps and amygdaloids. Occurs in broad pyramidal crystals, often in fas- 
 cicular or diverging groups ; also massive, in radiating broad columnar 
 aggregates; or macled. Has a vitreous lustre; is colourless, or more 
 frequently white, red, grey, yellow, and brown. Consists of silica 55.07, 
 alumina 16.58, lime 7.58, soda 1.30, and water 19.30. 
 
 Stinkstone (Ger. stinkstein}. A name given to fetid limestones that is, 
 those which, on being struck or rubbed, emit an odour of sulphuretted 
 hydrogen. They are usually of a dark colour, and are often less or more 
 bituminous. Known also as Swi'Mstone. 
 
 Stiper Stones. A celebrated ridge in Shropshire, whose stony masses, 
 says Murchison, " appear to the artist like insulated Cyclopean ruins jut- 
 ting out upon a lofty moorland, at heights varying from 1500 to 1600 feet 
 above the sea." They are fragments of a thick band of siliceous sandstones, 
 which, though in parts veined, altered, and fractured, and occasionally 
 passing into crystalline quartz rock, yet form an integral portion of the 
 overlying schistose formation, and contain fragments of lingulae. They 
 belong to the Primordial or Protozoic Zone of palaeontologists. See SILU- 
 RIAN SYSTEM. 
 
 Stomapoda (Gr. stoma, the mouth, and pous, podos, the foot). An order 
 of Crustaceans, so called from the arrangement of their thoracic or true 
 feet in connection with the mouth, which is usually furnished with one or 
 more pairs of jaw-feet the whole of the thoracic segments being covered 
 or enclosed by the carapace. It includes three families, the Phyllosomidce, 
 the Squillidce, and the Mysidce. 
 
 Stone Lilies. A popular term for the Enerinites, in allusion to the 
 resemblance which their rayed receptacles mounted on slender columns 
 bear to the flower and stalk of the lily (Gr. krinon, a lily). 
 
 Stonesfield Slate. A member of the lower Oolites, occurring immedi- 
 ately beneath what is known as the "Great Oolite," and celebrated for 
 its being the rock in which English geologists first detected mammalian 
 remains (Phascolotkerium, &c.) of Secondary epoch. It is a thin calcareous 
 flagstone occurring in two beds, separated by a calcareous sandstone, and 
 is worked for pavement and tiles near the village of Stonesfield in Oxford- 
 shire. 
 
 Stourbridge Clay. A celebrated fireclay occurring in the Coal-measures 
 of Stourbridge in Worcestershire, and largely employed in the manufac- 
 ture of fire-bricks, pipes, retorts, furnaces, and the like. It is found in a 
 bed about 4 feet thick, and consists of about 64 silica, 23 alumina, 2 oxide 
 of iron, and 10 water. 
 
 Strahlstein (Ger.) Literally "ray-stone;" the German synonyme of 
 A ctinote or Actinolite (which see). A variety or sub-species of Hornblende, 
 so called from its occurring in long prismatic crystals, or in radiated 
 columnar masses. 
 
 Stratification (Lat. stratum, and facio, I make). The general arrange- 
 ment or condition of all rocks or other matters deposited from suspen- 
 sion in water this arrangement being in layers or strata more or less hori- 
 zontal and parallel to each other. Inclined, vertical, or contorted strati- 
 fication is the result of convulsions subsequent to the deposition and con- 
 solidation of the originally flat strata, and though altering their position, 
 does not aflect their character as stratified masses. Stratification is thus 
 
 419 ' 
 
SIR 
 
 a mere mechanical arrangement, and not to be confounded with jointing 1 , 
 cleavage, foliation, crystallisation, or other structure arising from the 
 action of chemical or other subtle forces. What is termed "false stratifica- 
 tion " (that is, when a thick stratum is made up of minor layers, either 
 placed obliquely, waving, or thinning out and thickening irregularly) is a 
 structure arising from currents in the water of deposit the sedimentary 
 matter being here and there shifted and redeposited, being carried over 
 the sloping edges of submarine banks, layer after layer, or, it may be, 
 blown about and redistributed in minor layers, as we see in sub-aerial sand- 
 hills, or on the shifting banks of rivers and tidal estuaries. See LAMINA- 
 TION. 
 
 Stratum, plural Strata (Lat. stratum, strewn or spread out). When 
 rocks lie in layers, one above another, each layer forms a stratum, the whole 
 a series of strata. The term evidently implies the idea of being strewn or 
 spread out by some smoothing, levelling, or equalising action, as that of 
 water. Rocks lying in parallel layers are said to be stratified; those 
 among which there is no appearance of this arrangement, unstratified. 
 Layer, bed, seam, band, &c., are less or more used as synonymous with 
 stratum ; but strictly speaking, each has its own proper significance in 
 correct geological description. 
 
 Streak. In mineralogy, that appearance which the surface of a mineral 
 presents when scratched by a hard instrument ; or that appearance which 
 a mineral leaves on a rough porcelain slab when forcibly drawn or stroked 
 along its surface. The streak, often differing from the colour, and being 
 pretty persistent, supplies the mineralogist with an easily applied physical 
 characteristic. 
 
 Stream-Tin. A term applied to the rolled fragments of tin-stone or 
 oxide of tin, which occur mingled with gravel and other stony detritus in 
 the gullies and water-courses of Cornwall. See Tra-STONE. 
 
 Stream- Works. The usual designation for metalliferous workings in the 
 loose clays, sands, gravels, and general " drift " which covers the valleys 
 of a country, and from which the metal or ore is obtained by repeated 
 " washings," in contradistinction to "mine- works," which are carried on 
 in the veins that traverse the solid rocks. These metalliferous drifts are 
 but the debris worn down in course of ages from the veins of the higher 
 hills. 
 
 Streptospond^lus (Gr. streptos, turned back or reversed, and spondylos, 
 vertebra). A crocodilian saurian of the Wealden epoch, so called in 
 allusion to the peculiar articulating surfaces of the vertebrae. In existing 
 crocodiles the bones of the back or vertebrae are concavo-convex, that is, 
 united to each other by a ball-and-socket joint, the convexity being be- 
 hind. Some of the fossil crocodiles of the Tertiary have also this structure 
 of the spinal column ; but in every crocodilian of the Secondary formations 
 the articulating surfaces of the vertebrae are either flat or concave, except 
 in the streptospondylus, whose vertebrae are convexo-concave ; that is, the 
 convexity is directed forwards a position the reverse of the ordinary type. 
 Striated (Lat. stria, a streak). Streaked or marked with fine thread-like 
 lines running parallel to each other. When the striae become very marked 
 and decided, the surfaces are said to be grooved, furrowed, or channeled. 
 
 Strike (Ger. streiclien, to stretch or extend). The direction or line of 
 outcrop of any stratum. The strike of a stratum is always at right angles 
 to its dip, and vice versa. Thus, if the strike of a stratum run east and 
 
 420 
 
STE 
 
 west, it must dip either to the north or south ; or if we find any stratum 
 dipping to the east, we may be sure that its outcrop has a north and south 
 direction. 
 
 String. In mining, a small narrow branch of a metalliferous vein ; hence 
 certain ores are spoken of as occurring in "threads and strings." 
 
 Strobilites (Gr. strobilos, a fir-cone). A generic term for certain coni- 
 ferous cones, with tapering truncated scales, occurring in the Coal, Lias, 
 and other formations. The term may be held, in the mean time, for the 
 reception of all fossil fruits that are evidently coniferous. 
 
 Stromat6logy (Gr. stroma, stratum). A term proposed to embrace "the 
 history of the formation of the stratified rocks," with all that relates to 
 their succession and organic remains, in contradistinction to PETRALOGT 
 and LITHOLOGY, which see. 
 
 Str6mnite. Known also as Barystrontianite ; a variety of Strontianite 
 or carbonate of strontian, so called from Stromness in Orkney, where it 
 occurs in yellowish-white, semi-translucent masses, with a faint pearly 
 lustre and crystalline structure. Consists of 68.6 carbonate of strontian, 
 27.5 sulphate of baryta, and 2.6 carbonate of lime. Supposed to be a mere 
 admixture of strontianite and barytes. 
 
 Strongyl6ceros (Gr. strongylos, rounded, and keras, horn). A species of 
 gigantic deer, found in Pleistocene Tertiaries and bone-caves, rivalling 
 the megacerosi or gigantic Irish deer, in bulk ; but having, as the name 
 indicates, antlers not palmated, but of the type of the existing red-deer. 
 
 Str6ntia, Strontian, Strontites. One of the alkaline earths of which 
 strontium is the metallic base. It occurs in a crystalline state, as a car- 
 bonate (strontianite) in the lead-mines of Strontian in Argyleshire, whence 
 the name. It was discovered by Dr Hope in 1792 ; but has since been 
 found in other countries, though strontitic minerals are rather rare. Jt is 
 a greyish-white powder, infusible in the furnace; nearly as heavy as 
 baryta ; has an acid burning taste, but not so corrosive as baryta. Stron- 
 tianite is the carbonate, and celestine the sulphate, of strontia, which see. 
 
 Strontianite. Carbonate of strontia, so called because first found at 
 Strontian in Argyleshire. It occurs "in variously-modified hexahedral 
 prisms ; also in fibrous, globular, and granular masses ; colour apple- green, 
 white, and yellowish-brown ; lustre shining, pearly ; streak white, yields 
 readily to the nail, and brittle, with uneven fracture. Usually consists of 
 about 94 carbonate of strontia, 6 carbonate of lime, with a small trace of 
 iron. 
 
 Strontium. The metallic base of strontia, procured from the carbonate 
 of strontia (strontianite) by Davy in 1806. It is analogous to barium, but 
 has less lustre ; is fused with difficulty, and is not volatile. When exposed 
 to the air it attracts oxygen, and becomes converted into strontia or prot- 
 oxide of strontian. Strontium is harmless, while barium and all its com- 
 pounds are poisonous. 
 
 Str6phodus (Gr. strophao, I twist, and odous, tooth). A genus of large 
 flat, oblong cestraciont fish-teeth, much resembling Psammodus, but hav- 
 ing a twisted instead of a punctated or sandy appearance on the grinding 
 surfaces. They are common in the Lias, Oolite, and Chalk. 
 
 Structure. A term applied in geology and mineralogy to denote the 
 form or condition in which the component parts of rock-masses are 
 arranged. Thus we say that certain sandstones have a fissile or laminated 
 structure, that certain basalts have a columnar structure, and that the 
 
 421 
 
STU SUB 
 
 structure of granite is tabular or cuboidal. Structure, in fact, refers to 
 the mode in which a rock is aggregated in the mass ; texture, on the other 
 hand, refers to the manner in which its component particles are internally 
 arranged. Thus, on examining a granite quarry, we find the rock arranged 
 in large tabular or square-like masses this is its structure ; on breaking 
 one of these blocks we find it hard, close-grained, and crystalline this is 
 its texture. 
 
 Stucco (Ital.) When the white powder of calcined gypsum (plaster-of- 
 Paris) is mixed with thin glue instead of water, it forms stucco, which is 
 extensively used for casts, mouldings, statuettes, &c. 
 
 Stufa. Anlcelandic term for those fissures or orifices in volcanic districts 
 (like Hecla), from which jets of steam issue often at a temperature much 
 above the boiling-point of water. 
 
 Stylastritse (Gr. stylos, a column, and astron, star). Literally "column- 
 stars ; " the name suggested by Mr Martin of Derbyshire for the Encrin- 
 ites, in allusion to their form, which is that of a feathery star-fish sur- 
 mounted on a long jointed stalk or column. The term was rarely or never 
 used, and may now be regarded as obsolete. 
 
 Stylontirns (Gr. stylos, a writing-style, and oura, the tail). A genus of 
 Crustaceans occurring in the passage-beds between the Upper Silurian and 
 Lower Old Red Sandstone, and exhibiting forms intermediate between the 
 xiphosurous and phyllapod families. They belong to the family Eurypter- 
 idce; have the cephalo- thorax much rounded ; the eyes centrical or sub- 
 centrical ; are furnished with four or five pairs of organs for swimming 
 and prehension ; those organs springing from the basal joint of the jaw- 
 feet are long and slender in the two swimming pairs, and short and 
 covered with spines in the prehensile pairs. The thoracico-abdominal seg- 
 ments (twelve in number) are destitute of appendages, and the last termi- 
 nates in a long caniculated pointed (or style-like) tail ; hence the name. 
 The only specimens yet discovered are from the Upper Silurian beds of 
 Lesmahagow, and the flagstone beds of the Old Bed in Forfarshire. 
 
 Stythe (Sax.) A miner's term for fire-damp, or rather for the stifling, 
 suffocating odour of choke-damp that follows an explosion of the former. 
 
 Sub- (Lat* sub, under). In geology, as in other branches of natural 
 science, the prefix sul) is employed to denote a less or inferior degree; 
 as sub-crystalline, less than crystalline ; sub-columnar, not distinctly col- 
 umnar ; sub- calcareous, somewhat calcareous. It also applies to position, 
 as sub- cretaceous, under the chalk ; sub-aqueous, under the water ; sub- 
 aerial, under the open air, &c. 
 
 Sub-aerial. Literally "under the air;" applied to phenomena which 
 take place on the earth's surface or under the open air, in contradistinc- 
 tion to sub-aqueous, or under the water. 
 
 Sub-aqueous (Lat. sub, under ; aqua, water). Applied to phenomena 
 that take place in or under the water, in contradistinction to sub-aerial, or 
 those that take place under the open air. 
 
 Sub-Apennines. An extensive suite of Older and Newer Pliocene beds, 
 which are amply developed along the whole extent of Italy on both flanks 
 of the Apennines, and form a line of low hills between the older chain and 
 the sea. They consist of light-brown and blue marls, covered by yellow 
 calcareous sand and gravel, and frequently attain a thickness of from 1500 
 to 2000 feet. They were first described by Brocchi under the term " Sub- 
 Apennines ; " and though chiefly composed of Older Pliocene strata, the 
 
 422 
 
SUB SUL 
 
 numerous shells they contain demonstrate that they belong in part both to 
 older and newer members of the Tertiary series. 
 
 Submarine (Lat. sub, under, and mare, the sea). Under the sea; applied 
 to objects that have their place at some depth in the waters of the sea, at 
 the bottom of the ocean, or covered by the waters of the ocean ; as " sub- 
 marine forests," "submarine volcanoes," and other analogous pheno- 
 mena. 
 
 Submergence (Lat. submerge, I plunge under water). Applied in geology 
 to all sinkings of the land whereby its surface is brought under the waters 
 of the ocean. Thus we have "submerged forests," " submerged islands," 
 and so forth. 
 
 Subsidence (Lat. sub, under, and sido, I sink or settle down). The act 
 of sinking or settling down to a lower level. Applied in geology to sinkings 
 of portions of the earth's crust, which may be either gradual and scarcely 
 perceptible over a long lapse of years, or sudden and destructive as arising 
 from earthquake convulsions. 
 
 Subterranean, Subterraneous (Lat. sub and terra). Lying under the 
 surface of the earth ; imbedded at some depth in the earth, as subterranean 
 forests ; concealed beneath the surface of the earth, as subterranean pas- 
 sages, &c. 
 
 Subterposition (Lat. subter, under, and positus, placed). The order of 
 arrangement in which strata are placed below each other, as stiper-positiou 
 is the order in which they are arranged above one another. 
 
 Suchosaurus (from suchus or suchis, the name given by Strabo to the 
 sacred crocodile of the Nile). A provisional genus of Crocodilians founded 
 on certain teeth occurring in the Wealden strata of Tilgate Forest, 
 and distinguished by their form, which is about an inch long, slender, 
 pointed, gently recurved, and compressed laterally with a sharp edge in 
 front and behind. 
 
 Sugar Limestone. A local term, applied in Yorkshire to the metamor- 
 phosed mountain limestone that rests on the thick trappean mass of the 
 " Whin Sill." " It is in fact," says Phillips, "converted to a crystalline 
 white rock of very large grain, which easily disintegrates into loose crys- 
 talline sand." 
 
 Sulcated (Lat. sulcus, a furrow). Furrowed ; deeply furrowed or chan- 
 neled ; having a deeply-furrowed surface. 
 
 Sulphur (Lat.) One of the elementary substances, occurring in nature 
 as a greenish-yellow, brittle solid ; crystalline in structure, and exhaling a 
 peculiar odour when rubbed. It has a specific gravity of from 1.98 to 2.12 ; 
 is insoluble in water, but dissolves in other liquids, as oil of turpentine and 
 the fixed oils, and especially in the bisulphuret of carbon. It is a non- 
 conductor of electricity, but acquires negative electricity by friction. It 
 melts at a low temperature (234) ; and burns with a bluish flame and 
 most suffocating odour. Sulphur occurs abundantly in a free state, chiefly 
 in volcanic districts, where it appears in veins, amorphous masses, in 
 drusy cavities, or mingled with clay and other earthy impurities. It is 
 also extensively diffused throughout the globe in combination with other 
 substances. With the metals it forms their principal ores, as sulphurets 
 or siilphides of silver, lead, zinc, antimony, iron, &c. ; and with the earths, 
 as sulphates of lime or gypsum, of baryta, magnesia, soda, and the like. 
 It is largely diffused throughout the waters of the ocean in combination 
 with soda, magnesia, &c. ; and is present in the structure both of plants 
 
 423 
 
SUM SUT 
 
 and animals. It is largely and variously employed in- the arts, for which 
 it is obtained from volcanic districts in a crude state ; from deposits such 
 as those of Poland and Gallicia, where it occurs as an ore in combination 
 with clay ; or from pyrites, in which it is in chemical union as a sulphuret 
 of iron. 
 
 Sump. In coal-mining, that portion of the shaft or pit which extends 
 downwards beyond the seam to be worked, and consequently forms the 
 receptacle to which the waters of the mine flow, and from which it is 
 pumped by the engine. The "sump" may vary from a few feet to sev- 
 eral fathoms in depth. 
 
 Sunstone. A familiar term for Avanturine felspar ; a resplendent variety 
 of Oligoclase, deriving its play of colours from minute imbedded flakes or 
 crystals of iron-glance. 
 
 Superficies, Superficial (Lat.) The external surface of anybody; the 
 exterior parts ; hence the term " Superficial Accumulations" is applied to 
 those loose and irregular accumulations of soil, sand, gravel, clay, peat- 
 moss, and other detritus, which cover the solid and regularly stratified 
 crust of the earth. See tabulations, "GEOLOGICAL SCHEME." 
 
 Superposition (Lat. super, above, and positus, placed). The order of 
 arrangement in which strata and formations are placed above each other. 
 Thus, we speak of the Chalk occurring above the Oolite "in order of 
 superposition," and of the Muschelkalk being in order of superposition 
 above the Bunter-Sandstein. The idea intended to be conveyed is, that 
 every formation is more recent than that on which it lies, and that there is 
 a certain sequence of formations which is never reversed or found out of 
 order, though occasionally some of the members may be absent or wanting 
 in certain localities. 
 
 Supra- (Lat. supra, above). A prefix occasionally made use of to denote 
 mere position above; as SUPRA-CRETACEOUS, above the Chalk, a term 
 employed by Sir H. de la Beche to embrace all the stratified deposits 
 which occur above the Chalk, and equivalent to TERTIARY, which is now 
 universally adopted. 
 
 Surbed. In architecture, to set stones on edge, or contrary to their 
 natural bedding in the quarry. Many stones, when surbedded, yield to the 
 weather, and fall off in thin plates or laminae. 
 
 Surf. The name given to the " broken water " of waves that roll and 
 break on comparatively flat shores. The surf along certain shores in the 
 southern hemisphere is often very violent and almost incessant. 
 
 Surgent (Lat. ) Mounting up ; the fifth of the fifteen series into which 
 Professor Rogers subdivides the Palaeozoic strata of the Appalachian chain 
 the " Mounting Day" of the North American Palaaozoics, and the equiva- 
 lent in part of our Middle Silurians. See PALAEOZOIC FORMATIONS. 
 
 Surtur-Brand. An Icelandic term for a peat-like variety of brown-coal 
 or lignite occurring in the Pliocene deposits, and sometimes under the 
 volcanic overflows of that island. 
 
 Sussex Marble. A fresh-water limestone of the Wealden formation, 
 occurring in thin bands in various parts of Sussex (whence the name), and 
 almost wholly composed of the shells of Paludiyice, or river-snails. Known 
 also as Petworth Marble, which see ; and occasionally also as Bethersden 
 Marble, from its occurring in that locality in the Wealds of Kent. 
 
 Sliture (Lat. sutura, a seam ; from suo, I sew). A seam ; a line of junc- 
 tion. Applied in anatomy to the lines of junction between the several 
 
 424 
 
SWA SYR 
 
 portions of the cranium these lines presenting a jagged or zigzag appear- 
 ance like the cross stitches of a seam. Sutural junctions are common in 
 the hard structures of animals ; e.g., the bones of the head, the chambers 
 of cephalopod shells, &c. 
 
 Swamp. In geography, low, spongy land generally saturated with 
 moisture, and unfit either for agricultural or pastoral purposes. The term 
 is commonly used as synonymous with bog and morass ; but a swamp may 
 be here and there studded with trees, like the Dismal Swamp of Florida, 
 while bogs and marshes are destitute of trees, though frequently covered 
 with grasses and aquatic vegetation. 
 
 Swamp Ore. A familiar term for bog- iron ore, which occurs in swampy 
 tracts, in bands or cakes of considerable thickness, but of inferior quality 
 as an ore, from its containing phosphoric acid, which renders the iron 
 made from it brittle or of slender tenacity. 
 
 Swanage Crocodile. The popular term for the Goniopholis, whose re- 
 mains were first discovered in the Purbeck beds of Swanage. See GONIO- 
 
 PHOLIS. 
 
 Swiuestone. The name given by Kirwan to those fetid varieties of 
 limestone better known as STINKSTONE, which see. 
 
 Syenite (from Syene in Upper Egypt). A granitic rock composed of 
 felspar, quartz, and hornblende ; and so called from its being obtained by 
 the ancient Egyptians for their monumental purposes from Syene. Any 
 granitic rock in which hornblende predominates is termed syenitic, as 
 syenitic or primitive greenstone. 
 
 Syepoorite. A sulphuret of cobalt, of a steel-grey or yellowish colour, 
 found in primary rocks along with pyrite and chalcopyrite at Syepoor, near 
 Rajpootanah, in North- West India. It consists of 64.64 cobalt, and 35.36 
 sulphur; and is employed by the Indian jewellers to give a rose colour to 
 gold. 
 
 Sylvanite. The name originally given to native Tellurium, from its 
 being first found in Transylvania. Also a valuable ore of gold and silver 
 ^X e telluride of gold and silver consisting of 13.8 silver, 20.5 gold, and 
 59.7 tellurium, with traces of copper, lead, and antimony. It is found 
 in veins in the older rocks, and occurs in indistinct and minute circular 
 crystals, of a steel-grey or brass-yellow colour, metallic lustre, soft, and 
 very sectile. 
 
 S^nchronal, Synchronous (Gr. syn, together, and chronos, time). Occur- 
 ring at the same time ; contemporaneous ; of the same date or epoch. 
 
 Sy^icline, Synclinal (Gr. syn, together, and clino, I bend). Applied 
 to strata that dip from opposite directions inwards, like the leaves of 
 a half-opened book ; or which incline to a common centre, forming a 
 trough or basin-shaped hollow. Synclinal axis, the line of direction in 
 which such a trough or basin trends ; the converse of Anticlinal axis, 
 which see. 
 
 Syringodendron (Gr. syringx, a pipe or channel, and dendron, tree). 
 The generic term applied by Sternberg to the Sigillaria (which see), in 
 allusion to the channeled or pipe-like flutings of its trunk. 
 
 Syringop6ra (Gr. syringx, a pipe, and pora, pore). Literally "pipe- 
 pore ; " a genus of palaeozoic corals abounding in the Carboniferous lime- 
 stone, and bearing a general resemblance to the Organ-pipe Coral of 
 Australian seas. The polypidom consists of a cluster of long, cylindrical, 
 vertical tubes, distant from each other, and connected by transverse 
 
 425 
 
SYS TAB 
 
 tubular processes ; the cells are deep and radiated by numerous lamellae. 
 Formerly known as Tubipora or Tubiporites. 
 
 System (Gr. syn, together, and stemi, to stand). Groups of objects or 
 occurrences, having such relations as permit them to be classed together, 
 constitute a system. In geology, the term is usually applied to such 
 series or groups of strata as are in intimate relation, chronologically 
 speaking, and are characterised in the main by a marked similarity of 
 fossil forms. Thus the various groups Lower Coal, Mountain Limestone, 
 Millstone Grit, and Upper Coal which compose the Carboniferous System, 
 though each lithologically very distinct, are yet intimately connected in 
 .unbroken sequence ; and though each has forms of life peculiar to itself, 
 yet over the whole there runs such a facies of resemblance that there can 
 be no doubt of their all belonging to one great Life period or System. 
 
 Tabasheer (Persic). Literally "bamboo milk;" a siliceous secretion 
 occurring at the joints of the bamboo, and so called from its being occa- 
 sionally found of a white milky consistence. It occurs more frequently 
 in starch-like concretions (called by the Indians " bamboo camphor"), and 
 is a pure silex, like the thin pellicle which forms the outer coating of the 
 bamboo and many of the grasses. 
 
 Table-Land. In geography, any flat or comparatively level tract of 
 land considerably elevated above the general surface of a country. While 
 plains and valleys are low-lying expanses but little broken by elevations 
 and depressions, table-lands and plateaux are similar tracts, often of great 
 altitude ; as the table-land of Mexico, rising about 6000 feet above the 
 sea ; the table-land of Central Spain, 2200 feet in height ; and the plateaux 
 of Central Asia, rising successively from 3000 to 6000, 12,000, and 16,000 
 feet above the sea-level. Such elevated plains are accompanied by im- 
 portant physical and vital results, conferring on areas under the tropics 
 the climate, flora, and fauna of temperate regions, and bequeathing to 
 temperate areas all the phenomena of arctic regions. 
 
 Table-Layers. That peculiar structure in certain granites, greenstones, 
 porphyries, and other igneous rocks, which gives to their sections the 
 appearance of stratification, and which is termed by some geologists 
 pseudo-strata, and by others the stratiform structure. In many instances 
 this division into parallel planes seems to be the result of jointing, or some 
 analogous structure, on a large scale ; in others, it is merely the mark of 
 the successive overflows of igneous matter which constitutes the mass. 
 
 Tabreez Marble. A beautiful transparent limestone, composed of in- 
 numerable laminae, thin as paper, and formed by deposition from a cele- 
 brated calcareous spring near Maragha. 
 
 Tabular. Composed of, or arranged in, square blocks or table-like masses, 
 as many granites and greenstones. The " tabular " frequently passes into 
 the " columnar" structure, and vice versa. 
 
 426 
 
TAB TAL 
 
 Tabular Spar. The prismatic augite spar of Mobs, the Schaalstein of 
 Werner, and Wollastonite of other mineralogists. See WOLLASTONITE. 
 
 Tachylite (Gr. tachys, quick, and lithos). A black vitreous mineral of 
 the hornblende family, occurring in amorphous fragments in the softer 
 trap-rocks, and nearly related to obsidian and isopyre. The name has 
 reference to the ease with which it fuses under the blowpipe ; same as the 
 hyalomelan or black -glass of Hausmann. 
 
 Tac6nic. A term applied by the late Professor Emmons to the rocks 
 east of the Hudson (from the Taconic range lying along the western slope 
 of the Green Mountains), and which consist of slates, quartz-rock, and lime- 
 stones of Lower Silurian or perhaps more properly of Upper Cambrian age. 
 
 Taeni6pteris (Gr. tainia, a ribbon, and pteris, fern). A genus of elegant 
 ferns occurring in the Lias and Oolite, and so named from their long, 
 narrow, tapering, riband-like leaves, which are furnished with a strong 
 midrib, and have secondary bifurcating veins almost at right angles to 
 the midrib. On some specimens the sori or seed-specks are still visible, 
 thus bringing them in pretty close affinity with the simple-leaved aspid- 
 iums and polypodies of our own day. 
 
 Talc (Ger. Talk). A. common magnesian mineral occurring in masses, 
 composed of thin crumpled laminae or folise, or in scaly aggregates like 
 mica, which it also often resembles in colour. It is easily distinguished, 
 however, from mica in being much softer, and, though flexible, not elastic. 
 Like other magnesian minerals, it feels greasy ; and, though varying in 
 colour, its prevalent hue is a greenish or yellowish white, lustre pearly, 
 transparent in very thin plates, and infusible. Its chemical composition is, 
 63.9 silica and 36.1 magnesia ; but a part of the latter is often replaced by 
 iron protoxide. Talc occurs not only as a simple mineral, but enters with 
 quartz, mica, chlorite, and felspar into the composition of many of the 
 crystalline rocks, as talc-schist, chlorite-schist, steatite, serpentine, &c. 
 Common talc is used for crayons, for polishing stones, for crucibles, as a 
 fulling material or absorbent of grease, and also in porcelain mixtures. 
 See the following compounds, and STEATITE. 
 
 Talcite. An occasional synonyme of Phollerite or Nacrite, a hydrated 
 silicate of alumina, occurring chiefly in granitic veins. See NACRITE. 
 
 Talcose. Applied to rocks which have a talc-like aspect, or which con- 
 tain talc as a notable ingredient of their composition ; e.g., chlorite-schist, 
 talc-schist, steatite, serpentine, potstone, and the like. 
 
 Talcose Granite. A granitic rock composed of felspar, quartz, and talc 
 or chlorite ; known also as PROTOGENE, which see. 
 
 Talc-Schist. A glistening schistose rock of the metamorphic series, 
 consisting of talc and quartz, arranged in foliaa more or less crumpled ; 
 of various colours, but greenish hues prevail ; has a greasy feel, and gene- 
 rally associated with mica-schist, chlorite-schist, steatite, and serpentine. 
 
 Tallow, Mineral. One of the mineral resins, or hydrocarbons ; a light, 
 soft, fatty substance of a greenish-yellow colour, and usually known as 
 HATCHETINE, which see. 
 
 Talpa. The mole; remains of species of this well-known insectivorous 
 mammal have been found from the Miocene Tertiaries upwards. 
 
 Talus (Lat.) In fortification, the outside of a wall or rampart which 
 slopes inward and upward, the wall diminishing in thickness as it rises in 
 height. Adopted in geology to designate the sloping mounds of detritus 
 which accumulate at the bases of cliffs and precipices, being derived from 
 
 427 
 
TAM TAR 
 
 their weathered and wasted surfaces. In many instances, where the cliffs 
 are high and the rocks of a wasting nature, the talus in the course of ages 
 assumes gigantic dimensions, and its long sloping surface becomes a char- 
 acteristic feature of the landscape. 
 
 Tamping. A term employed in rock -blasting to signify the clay, sand, 
 or other rubbish rammed or stamped down on the powder in the bore-hole 
 for the purpose of preventing the charge from being blown from the hole 
 as from a gun-barrel, and thus compelling it to burst the rock in which it 
 has been lodged. 
 
 Tannin. Impure or crude tannic acid, occurring in the bark of oak and 
 other trees. It is a powerful antiseptic, hence this property in peal-mosses, 
 &c., derived mainly from the accumulated decay of vegetable substances. 
 
 Tantalite. Known also as columbite; the ore of the metal tantalum or 
 columbium, occurring in prismatic crystals, or in granular masses, in the 
 granites of Finland. When recently broken, tantalite is of a dark bluish- 
 grey or iron-black colour ; has a specific gravity from 7 to 8 ; and con- 
 sists of about 84.5 tantalic acid, 14.5 iron protoxide, and 1 protoxide of 
 manganese, with a trace of oxide of tin. Those varieties which contain 
 upwards of 5 per cent tin oxide are termed Cassitero-tantalites. 
 
 Tantalum. The metal extracted from tantalite and yttro-tantalile. It 
 is of a dark-grey colour, very dense, and difficult of fusion. Said to 
 derive its name from the insolubility of its oxide in acids, in allusion to the 
 fable of Tantalus, who, though up to the chin in water, could not drink. 
 
 Tapiridae. The tapir family ; a group of pachydermatous animals, hav- 
 ing thick massive bodies, short semi -prehensile trunks, three pair cutting 
 and one pair canine teeth, very .short tails, four-toed fore-feet and three- 
 toed hind-feet ; having much the aspect of a pig, but about the size of an 
 ass ; and represented by the tapir of South America. They are sometimes 
 marked as a sub-family of the Elephantidce, under the term Tapirina, 
 which includes only two or three living species, but embraces numerous 
 fossil congeners from the Tertiaries of Europe, as Palceotherium, Lopkiodon, 
 Coryphodon, &c. 
 
 Tapirotherium. Literally "tapir-beast;" a gigantic quadruped of the 
 Eocene period, having intimate structural relationship to the existing 
 tapirs, whence the name. 
 
 Tap-Boot. In botany, the main root of a plant, which passes directly 
 downwards, as a continuation of the aerial stem or trunk. 
 
 Tar, Mineral. A variety of bitumen or inspissated petroleum, found 
 oozing from the rocks of different formations, but often from limestones 
 in connection with lignite or coal, and occasionally in volcanic districts. 
 See BITUMEN. 
 
 Taragmite Series (Gr. taragma, disturbance). A term employed by 
 Dr Fleming in his ' Lithology of Edinburgh,' to embrace the Boulder 
 Clay, or lowest stage of the modern epoch, as " having been formed 
 when violent aqueous movements were taking place, and probably at a 
 period when the state of our island was widely different from the pre- 
 sent." The Brick-clays which lie above he terms the Alcumite or tran- 
 quil series ; and the more superficial deposits, the P/ianerite or evident 
 series. See MODEEN EPOCH. 
 
 Tarai. "This name," says Dr Hooker in his 'Himalayan Journal,' "is 
 loosely applied to a tract of country at the very foot of the Himalayas : is 
 Persian, and signifies damp. Politically the Tarai generally belongs to the 
 
 428 
 
TAR TEB 
 
 hilly states beyond it ; geographical!}- it should belong to the plains of 
 India ; and geologically it is a sort of neutral country, being composed 
 neither of the alluvium of the plains nor of the rocks of the hills, but for 
 the most part of alternating beds of sand, gravel, and boulders brought 
 down from the mountains. The Tarai soil is generally light, dry, and 
 gravelly, and varies in breadth from 10 miles along the Sikkim frontier, to 30 
 and more at the Nepaulese. The gravel-beds extend uninterruptedly upon 
 the plains for fully 20 miles south of the Sikkim mountains, the gravel 
 becoming smaller as the distance increases, and large blocks of stone not 
 being found beyond a few miles from the rocks of the Himalaya itself, even 
 in the beds of livers, however large and rapid. Throughout its breadth 
 this formation is conspicuously cut into flat-topped terraces, flanking the 
 spurs of the mountains, at elevations varying from 250 feet to nearly 
 1000 feet above the sea. These terraces are of various breadth and 
 length, the smallest lying uppermost, and the broadest flanking the 
 rivers below. The isolated hills beyond are also flat-topped and terraced. 
 This deposit, which is of recent formation, contains no fossils; and its 
 general appearance and mineral constituents are the only evidence of its 
 origin, which is no doubt due to a retiring ocean that washed the base of 
 the Sikkim Himalaya, receiving the contents of its rivers, and wearing 
 away its bluff spurs." 
 
 Tardigrada (Lat. tardus, slow, and gradus, a step). Literally "slow 
 walkers;" a term variously employed by zoologists, but first used by 
 Cuvier to designate the Sloths of South America, in allusion to their slow 
 and difficult mode of progression while on the ground. See BRADYPID.E. 
 
 Tarnowitzite. A variety of Arragonite from Tarnowitz in Upper Silesia, 
 containing from 3 to 4 per cent of carbonate of lead. 
 
 Tastes of Minerals. As a means of distinguishing many of the soluble 
 minerals, the taste has been employed ; hence mineralogists speak of the 
 astringent, like vitriol ; sweetish astringent, like alum ; saline, like common 
 salt ; alkaline, like soda ; cooling, like saltpetre ; bitter, like Epsom salts ; 
 sour, like sulphuric acid, and so on. 
 
 Taxites (Lat. taxus, the yew-tree). The generic term for such conifer- 
 ous remains as are evidently allied to the yew-tree. They occur in the 
 Oolite, but chiefly in the Tertiary lignites. 
 
 Taxodites. Fossil plants found in Tertiary deposits, and allied to the 
 Taxodium, or deciduous cypress of North America ; a tree which often 
 attains most gigantic dimensions in the southern swamps of that country. 
 Tax6xylon (Lat. taxus, and xylon, wood). A name given by Unger to 
 certain yew- like twigs and branches from the upper Tertiaries of Europe. 
 
 Tchornozem or Tchornen Sem (Tart.) Literally, "black mould ;" a local 
 name for the black earth of the south of Russia, which covers the whole 
 of the Aralo- Caspian plain a range of country embracing not less than 
 100,000,000 acres. It varies from 4 to 20 feet in thickness ; is remarkable 
 for its fertility ; and consists chiefly of silica with a little alumina, lime, 
 and oxide of iron, and about 7 per cent of carbonaceous or vegetable mat- 
 ter, of which no less than 2.45 is nitrogen gas ! This remarkable deposit 
 covers every other in the district, and is evidently of alluvial origin. 
 
 Tebbad (Pers.) Literally, " fever- wind ;" the name given to the hot, 
 scorching winds that sweep across the dry sandy plains of Central Asia, 
 carrying clouds of impalpable sand along with them, which are said to fall 
 like " flakes of fire" on the skins of the unfortunate travellers. 
 
 429 
 
TEE TEL 
 
 Teeth (Teut. tunth; allied to the Latin dens, and Greek odous). From 
 their hardness and durability the teeth of animals are generally well pre- 
 served in stratified deposits, and are not unfrequently the only fossilised 
 remnants of the creatures to which they belonged ; hence their importance 
 to the palaeontologist. They consist of three tissues dentine, which 
 forms the body of the tooth ; cement, which constitutes the harder outer 
 coating ; and enamel, which lies between the dentine and cement, and is 
 the hardest of all known animal tissues. The teeth of different classes 
 differ in composition, size, form, structure, and so forth, according to the 
 habits and requirements of the animal ; some being fitted for cutting and 
 tearing flesh, others for gnawing and crunching bones ; some for grinding 
 and pounding the harder vegetable substances, others for crushing softer 
 tissues ; some for seizing and retaining such slippery prey as fishes, while 
 others are fitted for rasping and nibbling the bark of trees, transfixing 
 insects, crushing shell-fish, or it may be serving as organs of offence and 
 defence, or assisting in progression, climbing, anchoring, and the like. 
 Whatever their function, it is usual to divide them into incisors or front 
 cutting teeth, canines or side seizing and tearing teeth, premolars and 
 molars, or true grinding teeth ; and according to the requirements of the 
 animal, one or other, or even all, of these divisions may be suppressed, or 
 one set enormously developed into " tusks," at the expense of the rest. 
 This idea of answerable teeth in the different classes of animals has given 
 rise to what is termed "dental formulae" for each class; i standing for 
 incisor, c for canine, p for premolar, and m for molar. Thus in man, the 
 number of these teeth on each side of the jaws is represented by the 
 
 22 11 22 33 
 following brief formula : i ^- c r^ ; p .rr ; m ~ = 32. Hence, know- 
 
 2..L 1.1 Z.'2 6.6 
 
 ing the functional characteristics the size, form, structure, &c. of 
 each class of animals, the palaeontologist can often, by microscopic 
 sections and rigid comparisons, arrive at sound conclusions as to the 
 affinity of extinct animals, whose sole remains consist of a few teeth, or, it 
 may be, even the fragment of a single tooth. Thus fish teeth are readily 
 separable from reptilian teeth, and reptilian from mammalian ; while each 
 great family of fishes, reptiles, and mammals have their permanent dental 
 characteristics which the skilful odontologist can easily detect. For the 
 specialties of the subject see Owen's 'Odontography,' and his article 'Odon- 
 tology' in 'Encyclopaedia Britannica.' 
 
 Tele6logy (Gr. teleos, complete, brought to an end, and logos). The doc- 
 trine of final causes. Teleologist. One who seeks for the final causes of 
 phenomena. 
 
 Teleosaurus (Gr. teleos, complete, and sauros, lizard). A genus of Cro- 
 codilian reptiles belonging to the Oolitic period, and characterised by their 
 having (like the recent Gavial) long slender muzzles, with numerous 
 pointed teeth, but differing in having the nasal apertures terminating in 
 two orifices in front of the nose, and not blended into one opening as in the 
 recent species. The osseous scutes of the dermal covering, the skull and 
 jaws with teeth, the vertebral column, and many other bones, have been 
 found, indicating four or five species at least, the individuals of which 
 varied from three to fifteen or eighteen feet in length. See STENEOSAURUS. 
 
 Telerpeton (Gr. tele, afar off, remote, and herpeton, reptile). A small 
 lizard-like reptile from the white sandstones of Lossietnouth in Morayshire, 
 and so named in allusion (palaeontologically speaking) to its remote anti- 
 
 430 
 
TEL TEM 
 
 quity. Its osteology seems to denote a blending of Lacertian characters 
 with those of the Batrachians. The Triassic affinities of telerpeton, stag- 
 onolepis, and other reptilian remains from the sandstones of Lossiemouth, 
 have recently suggested the possibility of these strata being Triassic or 
 Liassic, and not Old Red Sandstone, as has hitherto been supposed. The 
 lithological evidence is still, however, incomplete, though tending gene- 
 rally towards the idea of their Triassie origin. 
 
 Tellurium (Lat. Tellus, the goddess of the earth). A rare metal of a 
 brilliant tin-white colour ; very easily fusible, and usually found massive 
 and disseminated along with quartz, gold, and iron-pyrites, in some of the 
 mines of Germany and Hungary. It was discovered and named by Klap- 
 roth in 1782, but has not been applied to any useful purpose. The native 
 metal is rarely found pure, but contains a minute percentage of gold or of 
 iron, and the ores enumerated by mineralogists are complex and uncertain 
 admixtures, as graphic tellurium, consisting of tellurium, gold, silver, and 
 lead; white tellurium, of tellurium, gold, silver, lead, and sulphur; and 
 black tellurium, of copper in addition to the preceding constituents. 
 
 Temperature of the Earth. As one of the orbs of the solar system, the 
 Earth has a variable and irregular surface temperature ; it has also a tem- 
 perature peculiar to the rocky crust ; and judging from volcanic action, hot 
 springs, and the like, there is also a higher and more remarkable interim" 
 or central temperature. Without entering upon any questions as to the 
 exact proportions that exist between the solid rocky crust accessible to 
 our investigations, and the inaccessible interior, of which we can know 
 nothing by direct observation, we know enough of the Earth's Tempera- 
 ture to warrant the following general conclusions : 1. That the surface 
 temperature is mainly derived from the sun, and that, though variable and 
 irregular during any one season, it is, on an average of many seasons, 
 capable of being laid down with considerable certainty ; 2. That the tem- 
 perature of the crust, as depending on external heat, is also variable to 
 the depth of from 60 to 90 feet, but that at this limit it remains station- 
 ary ; 3. That downwards from this invariable stratum the temperature in- 
 creases (as has been proved by experiments in mines and Artesian wells) 
 at the ratio of one degree for every 60 feet, and that at this rate a tempera- 
 ture would soon be reached sufficient to keep in fusion the most refractory 
 rock-substances ; 4. That this high internal temperature is apparently the 
 cause of hot springs, volcanoes, earthquakes, and other igneous pheno- 
 mena, which make themselves known at the surface ; and, lastly, That 
 intense as the interior heat may be, the surface of the globe is scarcely, if 
 at all, affected by it (according to Fourier, only iVth of a degree), owing to 
 the weak conducting properties of the rocky crust. 
 
 Temperature of the Ocean. Respecting the temperature of the ocean, 
 though as yet few observations have been made, we know it is more 
 equable than that of the land ; that at the depth of 60 fathoms or so it is 
 pretty constant ; that it is colder in summer than the surrounding atmo- 
 sphere of any contiguous district, while in winter it is always several de- 
 grees higherthus exercising the function of a great storehouse of heat 
 for modifying and equalising the climates of the adjacent lands. Its mean 
 temperature, from such experiments as have been made, is estimated at 
 39^ or 7-i above the freezing-point of pure water, and as nearly as pos- 
 sible at the point of its mean density. Its surface temperature varies of 
 course with the latitude shading off from about 80 or 82 at the equator 
 
 431 
 
TEN TER 
 
 to 40 at the 56th parallel, and thence down to perpetual ice at either pole ; 
 that is, laying aside the problematical existence of an open sea surround- 
 ing the north pole, as has been affirmed by some of our arctic voyagers. 
 
 Tenacity (Lat. tenaz, tough, capable of holding together). The degree 
 of force with which particles of bodies cohere or are held together. Ap- 
 plied especially to metals which can be drawn into wire, as gold, silver, 
 copper, iron, &c. 
 
 Tennantite (after Mr Tennant, the London mineralogist). A variety of 
 grey copper ore (sulphuret of copper) occurring in the mines of Cornwall 
 along with common copper-pyrites. It is distinguished perhaps by its 
 large percentage of arsenic ranging from 10 to 20 per cent of the whole. 
 
 Tentacula (Lat. tentaculum, from tento, I feel by touching frequently, 
 and that from Undo, I stretch forth). Feelers ; slender, flexible, and 
 often jointed organs, possessed by many tribes of animals, and used for 
 the purposes of feeling, exploring, prehension, locomotion, or for attach- 
 ment to other bodies e.g., the tentacula of polypes, sea-anemones, cuttle- 
 fishes, and the like. 
 
 Tentaculites (Lat. tentacula, feelers). A genus of annulated feeler-like 
 organisms occurring in Silurian strata ; of annelid origin, and probably 
 allied to Serpula. " They were annulated, shelly tubes, of a highly com- 
 plex structure," says Mr Salter, " and not jointed tentacles or stems." 
 See COBNULITES. 
 
 Tephroite (Gr. tephros, ash-coloured). Anhydrous silicate of mangan- 
 ese, occurring in distinct crystalline and granular masses, of an ash-grey 
 colour (whence the name), and consisting of 30 silica and 70 protoxide of 
 manganese, with traces of iron and lime. 
 
 Teratosaurus (Gr. teras, teratos, a prodigy, and sauros, lizard). Literally 
 " wonderful lizard ;" a singular reptile from the Upper Keuper Sandstone 
 of Stuttgart, figured and described by Von Meyer in his ' Palseonto- 
 graphica.' The only remains of the genus at present known are a portion 
 of the head (consisting of the maxillary, nasal, and orbital bones), two 
 detached teeth, and probably a coracoid. The teeth resemble those of 
 Megalosaurus, but, according to Von Meyer, the remains indicate, on the 
 whole, a true Lacertain type, having some affinities to the existing genera 
 Stellion and Uromastix. 
 
 Terebratella. A genus of brachiopods resembling terebratula; having 
 the shell smooth, or radiately plaited ; dorsal valve longitudinally im- 
 pressed ; hinge-line straight or not much curved ; beak with a flattened 
 area on each side of the deltidium ; foramen large ; deltidium incomplete ; 
 loop attached to the septum. About twenty species are found fossil from 
 the Lias upwards, and about the same number still exist in the seas of the 
 higher latitudes in both hemispheres at from 90 to 95 fathoms' depth. 
 
 Terebratula (diminutive of terebratus, perforated, in allusion to the per- 
 foration of the beak). A genus of brachiopod bivalves, of which about 
 100 species have been enumerated from the Silurian system upwards, and 
 a few species of which are still existing as deep-sea molluscs (from 90 to 
 250 fathoms). The genus has been taken as the type of the .family Tere- 
 bratulidce, which is characterised by the shell being minutely punctate ; 
 usually round or oval, smooth or striated ; ventral valve with a prominent 
 beak and two curved hinge-teeth ; dorsal valve with a depressed umbo ; a 
 prominent cardinal process between the dental sockets, and a slender 
 shelly loop. The family embraces such genera as Terebratula, Terebratella, 
 
 432 
 
TER 
 
 Argiope, Thecidium, and Stringocephalus, together with many doubtful 
 sub-generic or merely specific forms. 
 
 Teredina. An extinct genus of boring molluscs, whose perforations are 
 common in the drift-wood of the London Clay. " The calcareous tube of 
 the teredina was united, and, as it were, soldered on to the valves of the 
 shell, which cannot therefore be detached from the tube, like the valves 
 of the recent Teredo," which see. 
 
 Teredo (Gr. teredon, from tereo, I bore). A genus of marine bivalves 
 belonging to the Pholas family, and so called from their habit of boring 
 into and taking up their lodgment in wood. The animal is elongate and 
 worm-like ; hence the familiar designation of ' 'ship- worm ;" and the shell 
 is somewhat globular, open in front and behind, and lodged at the inner 
 extremity of a tubular, straight, or flexuose burrow, partly or entirely 
 lined with shell. About twenty living species of teredines are known ; and 
 about the same number have been found fossil from the Lias upwards. 
 Fragments of drift-wood drilled by the Teredina, (an extinct genus) are 
 common in the London Clay. . 
 
 Terra Cotta (Ital.) Literally "baked earth ;" a term applied to a kiln- 
 burnt ware prepared from the purest kinds of fire-clay, and usually 
 employed for vases, mouldings, and other architectural ornaments. " The 
 best terra cottas," says Ansted, " are made in France, and the manufacture 
 has there attained a high state of perfection. Various attempts in Eng- 
 land have met with partial success ; the unequal contraction of the mate- 
 rial being a difficulty rarely surmounted." 
 
 Terra Ponderosa (Lat.) Literally "heavy earth," another name for 
 heavy-spar or Barytes, which see. 
 
 Terra Sienna. A yellow-coloured ochraceous earth or bole, used as a 
 pigment ; and so called from its being brought from Sienna, in Italy. In 
 its natural state it is known as Raw Sienna ; and when roasted and ren- 
 dered redder in colour it is called Burnt Sienna. 
 
 Terrace. Any shelf or bank of land having a uniformly flat or level sur- 
 face. Such terraces are produced by the operations of water, and are either 
 ancient sea-margins (raised beacJtes), formed by gradual upheaval of the 
 land ; or lake and river terraces that point to a time when the valleys in 
 which they occur were either occupied by lakes at these heights, or had 
 their whole surfaces at these levels, and before their rivers had worn their 
 channels down to lower depths. In this way we may have terraces of depo- 
 sition as well as terraces of denudation. 
 
 Terratolite. Glocker's term for Hard litkomargethe terra miraculosa 
 Saxonice of old authors. See LlTHOMARGE. 
 
 Terricola (Lat. terra, the earth, and colo, I inhabit). An order of Anne- 
 lids which, like the earth-worms, burrow in the earth ; hence the name. 
 How far some of the "annelid tracks" and "annelid burrows" of the 
 stratified systems may have resulted from the operations of terrestrial 
 worms, palaeontology has not yet determined. 
 
 Tertiary (Lat. tertius, third). Of or belonging to the Tertiary system 
 the third or upper great division of the stratified systems, as distinguished 
 from Secondary and Primary; hence we speak of "Tertiary epoch," 
 "Tertiary fossils," "Tertiary strata," &c. See TERTIARY SYSTEM. 
 
 Tertiary System. --The earlier geologists, in dividing the stratified crust 
 into primary, secondary, and tertiary formations, regarded as Tertiary all 
 that occurs above the Chalk. The term is still retained, but the progress 
 
 433 2E 
 
TES TET 
 
 of discovery has rendered it necessary to restrict and modify its meaning. 
 Even yet the limits of the system may be said to be undetermined some 
 embracing under the term all that lies between the Chalk and Boulder- 
 drift, others including the Drift and every other accumulation in which no 
 trace of man or his works can be detected. Palseontologically speaking, 
 much might be said in favour of both views ; but the difficulty of unravel- 
 ling the relations of many clays, sands, and gravels, makes it safer to 
 adopt, in the mean time, a somewhat provisional arrangement, and to 
 regard as TERTIARY all that occurs above the Chalk till the close of the 
 Drift, and as POST-TERTIARY every accumulation which appears to have 
 been formed since that period. Adopting this view, we have the following 
 intelligible synopsis : 
 
 nr\am rr-rir>mT * T> v f RECENT and SUPERFICIAL ACCUMULATIONS OCClir- 
 
 TERTIARY. - rin aboye the Bou ] der _drift. 
 
 TERTIARY. 
 
 PLEISTOCENE... Boulder or Glacial Drift. 
 
 PLIOCENE Mammaliferous, Red and Coralline 
 
 Crag of Suffolk, &c. 
 
 MIOCENE Faluns of Touraine, Molasse of Swit- 
 zerland, and part of Vienna Basin. 
 
 EOCENE Strata of London and Paris Basins. 
 
 As in other systems, so in the Tertiary, the fossils of the older strata differ 
 considerably from those of the newer ; and thus the whole might be con- 
 veniently grouped into Lower, Middle, and Upper. Palaeontologists, how- 
 ever, have chosen a somewhat different nomenclature, and, taking the per- 
 centage of fossil shells as their guide, have adopted the scientific divisions 
 above tabulated. Thus Eocene (eos, the dawn, and Tcainos, recent) implies 
 that the strata of this group contain only a small proportion of existing 
 species, which may be regarded as indicating the dawn of existing things ; 
 Miocene (melon, less) implies that the proportion of recent shells is less 
 than that of extinct ; Pliocene (pleion, more), that the proportion of recent 
 shells is more or greater than that of the extinct ; and Pleistocene (pleiston, 
 most), that the shells of this group are mostly those of species inhabiting 
 the present seas. This nomenclature is now in general use by English 
 geologists, though it must be confessed that the progress of fossil dis- 
 covery has long since rendered the divisions lower, middle, and upper, 
 more appropriate, and much less liable to mislead. For further details 
 and foreign equivalents, see tabulations, " GEOLOGICAL SCHEME." 
 
 Tessellated (Lat. tessela, dim. of tessera, a cube or small square of wood 
 used in chequer-work). Divided into squares or chequers, either by differ- 
 ent colours, or by the crossing of striae ; chequered ; arranged in square or 
 lozenge-shaped compartments. 
 
 Testacea (Lat. testa, a shell). A general designation for those molluscous 
 animals that are furnished with a shelly covering, as the oyster, peri- 
 winkle, &c., in contradistinction to those which are naked or merely 
 covered with a tough coriaceous tunic (tunicala). 
 
 Tetra (Gr., four). A frequent prefix in scientific nomenclature, as tetra- 
 gonal, four-cornered ; tetradactylous, having four toes, &c. 
 
 Tetracaulodon (Gr. tetra, four ; caulos, stalk ; and odous, tooth). Liter- 
 ally "four tusk-teeth ;" a name proposed by Dr Godman as a generic 
 distinction for some elephantine jaws of the Tertiary period, which have 
 two short tusks in the lower jaws in addition to the long tusks of the 
 
 434 
 
TET THE 
 
 upper jaws. Professor Owen and others regard the tetracaulodon of Dr 
 Godman as the immature state of the MASTODON GIGA NTEUS the lower 
 tusks being merely milk-teeth, which were lost as the animal became 
 adult. Some palaeontologists, however, still retain the distinction, and 
 enumerate several species of the genus Tetracaulodon. 
 
 Tetrddymite (Gr. tetradymos, fourfold). Sulphotelluride of bismuth ; so 
 called from the quadruple macles in which its crystals usually appear. It 
 also occurs massive and granular foliated ; of a brilliant steel-grey colour ; 
 and consists of 60.00 bismuth, 34.60 tellurium, and 4.80 sulphur. 
 
 Tetragonolepis (Gr. tetra, four ; gone, corner ; and lepis, scale). Literal- 
 ly "four-cornered scale;" a Liassic fish somewhat similar to the DAPEDIUS 
 (which see), but differing in the characters of its scales and teeth, and be- 
 longing to the Pycnodont family. 
 
 Tetralophodon (Gr. tetra, four, and lophos, ridge). Literally "four- 
 ridged ;" one of Dr Falconer's sub-genera of Mastodons, which he divides 
 into trilophodoti and tetralophodon, according as the crowns of their molar 
 teeth exhibit three or four pap-like transverse ridges with intervening 
 depressions. 
 
 Tetrapodichnftes (Gr. tef.ra, four; pom, podos, foot ; and i-chnon, a foot- 
 print). The footprints of four-footed creatures, as batrachian reptiles, and 
 other terrestrial saurians. See ICHNITES. 
 
 Tetrdpterus (Gr. tetra, four, and pteron, wing or fin). Four-finned ; a 
 genus of fossil fishes peculiar to the Chalk formation, and characterised, 
 according to Agassiz, by the close apposition of their pectoral and ventral 
 fins. 
 
 Thalactroides. Fossil fruits belonging to plants of the order Ranuncu- 
 lacece, and related to Thalictrum (Meadow- Rue) ; hence the name. They 
 have been found in the Eocene strata of France and England. 
 
 Thalassiophytes (Gr. thalassios, belonging to the sea, and phyton, a 
 plant). Literally "sea-plants;" a term occasionally employed to embrace 
 the entire vegetable productions of the ocean its deep waters, its rocks, 
 and its shores. 
 
 Thecodont (Gr. iheke, a sheath, and odous, odontos, tooth). In express- 
 ing the leading modifications in the mode of attachment of the teeth 
 among the inferior or squamate saurians, Professor Owen makes use of the 
 following terms : viz., acrodont (akros, the summit), those which have the 
 teeth anchylosed to the summit of the alveolar ridge ; pleurodont (pleuron, 
 the side), those which have them anchylosed to the bottom of an alveolar 
 groove, and supported by its side ; and thecodont, those which have the 
 teeth implanted in sockets, either loosely or confluent with the bony walls 
 of the cavity. 
 
 Thecodontia (Gr. iheke, a case or sheath, and odous, tooth). One of 
 the thirteen orders into which Professor Owen proposes to arrange the- 
 Reptilia, living and extinct. The name has reference to the implantation 
 of the teeth in distinct sockets ; and the genera of the order seem peculiar 
 to Permian and Triassic strata. In the Thecodonts the vertebrae are 
 biconcave ; the ribs long and bent, the anterior ones with a bifurcate head ; 
 the sacrum consists of three vertebrae ; and the limbs ambulatory, the 
 femur having a third trochanter. The teeth have the crowns compressed, 
 pointed, with trenchant and finely serrated margins; and implanted in 
 distinct sockets. 
 
 Tliecodoutosaurus (Gr. theke, a sheath or socket, and odous, odontos, 
 
 435 
 
THE THO 
 
 tooth). Literally "socket-tooth saurian;" a type of reptile apparently 
 peculiar to the Permian epoch ; and so called from having the teeth im- 
 planted in distinct sockets, as in the crocodile. The remains were first 
 discovered by Dr Kiley and Mr Stutchbury in the dolomitic conglomerate 
 of Somersetshire, and consist of jaws, teeth, vertebrae, and bones of the 
 extremities ; but similar forms have since been obtained from the Per- 
 mians of Russia, Germany, and Chatham in North Carolina. " The 
 teeth," says Dr Mantell, "are pointed, compressed laterally, trenchant, 
 and finely serrated on the edges. These reptiles, in their thecodont type 
 of dentition, biconcave vertebrae, double-headed ribs, and proportionate 
 size of the bones of the extremities, are nearly related to the Teleosaurus 
 of the Oolite ; but combine a lacertian form of tooth and structure of the 
 pectoral arch with these crocodilian characters ; and the bodies of the 
 vertebrae have a series of ventricose excavations for the spinal chord, in- 
 stead of a cyclindrical canal." 
 
 Thelodus (Gr. thele, a little nipple, and odous, tooth). A fish of the 
 Silurian bone-bed ; so called from its peculiar mammillated teeth. No- 
 thing is yet known of its true affinities. 
 
 Thenardite (after M. Thenard). Anhydrous sulphate of soda occurring 
 in crystalline crusts, of a vitreous white colour, at the salt-springs of 
 Espartinas, near Madrid, where it is deposited from the waters during the 
 summer months. It occurs also in Peru, and is used for preparing soda. 
 
 Thermal (Gr. therme, heat). Warm; applied to hot springs and other- 
 waters whose temperature exceeds 60 Fahrenheit. The term HYDRO- 
 THERMAL is frequently used to express the action of heated waters and 
 steam in contradistinction to that of volcanoes or of dry combustion. 
 
 Thermondtrite (Gr. therme, heat, and natron, crude carbonate of soda). 
 Haidinger's term for prismatic carbonate of soda, consisting of 50.1 
 soda, 35.4 carbonic acid, and 14.5 water, with slight earthy impurities. 
 It occurs with natron in the lakes of South America, the Egyptian desert, 
 &c., and is deposited from their waters during the warm season ; whence 
 the name. According to Haidinger, a saturated solution of soda at a tem- 
 perature of 77 to 99 Fahr., and cooling slowly, forms crystals of thermo- 
 natrite ; whereas a less saturated solution at a iosver temperature forms 
 crystals of natron. 
 
 Thin-out. A stratum is said to "thin-out" when it becomes thinner 
 and thinner, as you trace it in any direction, till it finally disappears, and 
 its place is taken by some other stratum. A thin-out is, in fact, the natu- 
 ral termination of every stratum, unless its edge has been brought to the 
 surface by subterranean disturbance, and then it is said to crop-out. 
 
 Th6msonite (after Dr Thomson, the well-known chemist). A mineral 
 of the zeolite family, occurring in rectangular prisms in druses, in fan- 
 shaped or in radiated aggregates of a whitish colour ; and found with 
 calc-spar and other zeolitic minerals in cavities in amygdaloid, basalt, 
 greenstone, and old lavas. Known also as Comptonite, and consists of 
 silica 38.5, alumina 30.6, lime 12.6, soda 4.8, and water 13.15. 
 
 Thorina. The protoxide of the metal thorium, an earth discovered by 
 Berzelius in the mineral thorite ; thorium being named after the Scandina- 
 vian deity Thor. 
 
 Th6rite. A hard, brittle, reddish-brown, massive mineral occurring in 
 the Syenites of Norway, and yielding to analysis about 58 per cent of the 
 earth thorina. 
 
 436 
 
THE TIL 
 
 Thrisson6tus (Gr. thrix, thrissos, bristle, and notos, back). Literally 
 " bristle-back ; " a genus of fishes peculiar to the Lias and Lower Oolite, 
 and characterised by the peculiarity of their dorsal fin. 
 
 Thrissops (Gr. thrix, bristle, and opsis, appearance). One of Agassiz's 
 genera of fossil fishes, occurring in the Lias and Oolite, and so named from 
 the long bristle-like character of their fin-rays. 
 
 Throw. A miner's term for fault, because of its displacing the strata 
 " throwing " them up on one side and down on the other. The " throw " 
 is the amount of vertical displacement occasioned by a fault ; hence the 
 fault is said to be an upthrow or downthrow, an upcast or downcast, accord- 
 ing to the side from which it is viewed. 
 
 Thrust. Applied in mining to the breaking-down of the roof of a gallery 
 or any similar opening, by the pressure or thrust of the superincumbent 
 rocks. See CRUSH and CREEP. 
 
 Thuites. A genus of coniferous plants occurring in fragments in the 
 shale and coal of the Oolite, and so called from the resemblance of their 
 imbricated stems and terminal twigs to those of the modern Thuja or 
 Thuya, better known as the Arbor-vitce. 
 
 Thiilite. A rare variety of epidote of a rose or peach-blossom colour, 
 occurring in granular masses in the granites of Svuland in Norway. 
 
 Thummerstone or Thummerstein. The Axinite of other mineralogists ; 
 so called by Werner from its occurring in the crystalline rocks of Thum in 
 Saxony. 
 
 Thunderbolts. A familiar term of the English peasantry for Belemnites, 
 the majority of which are straight, round, and tapering, or of a bolt-like 
 form. 
 
 Th^lacoleo (Gr. thylakos, pouch, and leo, lion). Literally "pouched 
 lion ; " a carnivorous marsupial mammal from the Pleistocene or upper- 
 most Tertiaries of Australia ; and so called from the trenchant dentition of 
 its skull (the only portion yet found), which rivals that of the lion in size. 
 
 Thylacotherium (Gr. thylakos, a pouch, and therion, animal). A small 
 marsupial mammal of the Oolite. Apparently the same as Amphitherium, 
 which see. 
 
 Tides. The name given to those regular oscillations, or risings and 
 fallings of the water of the ocean, which are occasioned by the attraction 
 of the moon and sun, and which occur twice in the course of the lunar day 
 (24 hours, 50 minutes). The flow, or rising towards the shore, is called 
 flood tide, and the falling away ebb tide. The highest point to which the 
 flood tide attains is called high-water, and the lowest to which the ebb tide 
 sinks is low-water. During high and low water there is a short period of 
 rest, or no current either way, and this is called slack-water. When the 
 sun and moon act in the same direction (that is, at full moon), the greatest 
 tidal rise will take place, and these are known as spring-tides ; but when 
 these luminaries are in opposition (that is, during the third and first 
 quarters of the moon), the rise is least, and then we have neap-tides. As 
 geological agents, the tides are of vast importance in scouring away, trans- 
 porting, and reasserting the debris of the ocean. 
 
 Tile-Ore. A variety of red oxide of copper, of a reddish-brown colour, 
 occurring massive or incrusting, earthy or more or less indurated. It 
 consists of sub-oxide of copper, mixed with much peroxide of iron and 
 other substances. 
 
 Tilestone. Any thinly- laminated sandstone suitable for roofing; applied 
 
 437 
 
TIL TIN 
 
 specially to the flaggy beds at the base of the Old Ked Sandstone. The 
 " Tilestones " as a group are regarded as the " passage or transition beds '' 
 between the Silurian and Devonian systems ; and have been ranked by some 
 geologists with the one system, and by others with the other. As developed 
 in Hereford, Lanark, and Forfar, lithologically and palseontologically, we 
 are inclined to consider them as the true basis of the Old Ked Sandstone. 
 
 Tilgate Forest, in Sussex, situated on the clays, sandstones, and calci- 
 ferous grits of the Wealden formation ; a district rendered classical by the 
 discoveries of the late Dr Mantell. See his ' Fossils of Tilgate Forest,' 1 
 vol. 4to, 1827. 
 
 Till. A provincial Scotch term for the stiff unstratified clays of the 
 Boulder formation ; and now beginning to be used by geologists for any 
 thick unstratified alluvia. 
 
 Tilted Up. Applied to strata that are suddenly or abruptly thrown up 
 at a high angle of inclination. Tilts of this nature are usually accom- 
 panied by fractures and crushings of the strata. 
 
 Tin (Lat. stannum], A well-known metal of a silver-white colour, 
 slightly tinged with grey, having a peculiar taste, and an odour which 
 may be readily recognised when held for a while in the warm hand. It is 
 considerably harder than lead ; has a specific gravity of 7.3 ; and fuses at 
 442 Fahr. a temperature 170 below the melting point of lead. It is 
 very malleable when heated to about 200, and is readily beaten into leaf 
 or tin-foil : but it is not very ductile, though it may be drawn into wire of 
 feeble tenacity. It is flexible, bending with a crackling noise, apparently 
 the result of its crystallised structure the fused metal crystallising in 
 regular octahedrons. As a metal that does not readily tarnish, it is 
 employed for coating sheet-iron (tin-plate) and copper ; and its foil, 
 alloyed with quicksilver, forms the reflecting surface of glass mirrors. It 
 also unites with other metals and forms valuable alloys, as bronze, bell-metal, 
 specidum-metal, and the like ; and its salts, dissolved in muriatic acid, are 
 used in dyeing and calico-printing. It has not been found native (or at least 
 very doubtfully so), but it is obtained from cassitei'ite, pyramidal tin-ore or 
 oxide of tin, which occurs in veins in the granitic and crystalline rocks 
 of Cornwall, Saxony, Spain, the East India Islands, and other localities. 
 
 Tin-Ore, Tin-Stone. The familiar name given to the oxide of tin, or 
 Cassiterite, as being the only ore from which the tin of commerce is derived. 
 It occurs in veins in the granitic and crystalline rocks, and is xisually 
 associated with wolfram, copper, iron-pyrites, and other minerals. It is 
 found either in blackish-brown pyramidal or prismatic crystals ; or massive 
 in granular aggregates ; and not unfrequently in rounded fragments in 
 gravelly detritus. The name wood-tin is given in Cornwall to the kidney- 
 shaped masses which have a finely fibrous or radiated structure ; toad's-eye- 
 tin, to the same variety when the concretions are small and berry-like ; 
 and stream-tin, to the gravel-like ore found with detritus in the gullies and 
 water-courses of metalliferous districts. As an ore, it consists of 77.50 
 tin, 21.50 oxygen, with traces of iron and silica ; and being disseminated 
 through the veinstone, the rock must be pounded and washed before the 
 ore can be smelted. As a geological generalisation, it is asserted that in 
 Cornwall tin usually occurs in the upper portion of the veins, while copper 
 is found below. 
 
 Tin-Pyrites. Known also as Slannine or Bell-metal ore; a sulphuret 
 of copper, tin, and iron the iron sometimes replaced by zinc. It is a 
 
 438 
 
TIN TOP 
 
 mineral of a steel-grey or sometimes of a coppery-yellow colour : occurring 
 massive, granular, and disseminated, rarely crystallised ; and is usually 
 associated with tin -ore in the veins of Cornwall and Bohemia. See STAN- 
 NINE. 
 
 Tincal, Tinkal (the Oriental term for borax). Crude borax, as it is 
 imported from the East Indies in dirty-yellow crystals. When refined it 
 constitutes the Borax of commerce, which see. 
 
 Tirolite (occurring in many parts of the Tyrol). Known also as Copper- 
 froth ; a fine verdigris-green or azure-blue carbonate of copper and arsenic, 
 occurring in reniform or mammillary aggregates, with a radiating foliated 
 texture and drusy surface. It is found in beds and veins with other copper 
 ores. 
 
 Titaniferous. Containing or yielding titanic acid and titanium ; as 
 titaniferous cerite, a blackish-brown mineral, consisting of the oxides of 
 cerium, iron, manganese, and titanium ; titan-schorl, known also as rutile 
 or ingrine, a mineral consisting of oxide of titanium and peroxide of iron ; 
 titaniferous iron-sand, or iserine, occurring in roundish grains generally in 
 connection with Tertiary volcanic districts, and sometimes in such abun- 
 dance as to be used for the production of steel, of which it produces a tough 
 and very superior kind. 
 
 Tltanite. Prismatic titanium ore; a silico-titanite of lime; better 
 known to English mineralogists as SPHENE, which see. 
 
 Titanium (Gr. titanos, falling to a calx or lime). One of the elementary 
 substances, discovered by the Rev. Mr M'Gregor in 1789 ; it is of a dark 
 copper-red colour, with a strong metallic lustre, which readily tarnishes 
 on exposure to the air. As titanic acid, it is a constituent of several 
 minerals, as Menekite, Sphene, Brookite, Rutile, and Anatase. 
 
 Titanotherium. Literally "gigantic beast ; " a large herbivorous mammal 
 occurring in the Lower Miocene beds of the Missouri district, and having 
 some relations to the modern Tapirs, but more perhaps to the extinct 
 Palseotheres of Europe. Judging from the teeth and jaws, it probably 
 attained a size about twice that of the existing horse. 
 
 Tiza. The name by which borate of lime (Nayesine) is called in southern 
 Peru, where it occurs on the dry plains or salinas in the neighbourhood of 
 Iquique in white reniform masses, in size from a hazel-nut to a potato. 
 
 loadstone. A term applied by the Derbyshire miners to certain 
 trap-rocks which occur interstratified, or in connection, with the moun- 
 tain limestones of that country. Some of these toadstone beds are com- 
 pact and basaltic, others are earthy, vesicular, and amygdaloidal. By 
 some (and with every degree of probability) the term is said to be from the 
 German todt-stein or dead-stone the rock being dead or unfruitful of lead- 
 ore as compared with the associated limestones ; according to others, the 
 rock obtains its name from the resemblance of its amygdaloidal spots to 
 those on a toad's skin. 
 
 Topaz (Gr. topazion, though it is doubtful whether the topazion of the 
 ancients were the same as our topaz). One of the gems ; occurring in 
 finely striated prismatic crystals, massive with indistinct crystalline struc- 
 ture, or disseminated in rounded fragments ; transparent, vitreous, electric 
 when heated or rubbed, and of various colours or colourless. It is found 
 chiefly in the granitic and crystalline rocks, and frequently associated with 
 rock-crystal, tourmaline, beryl, and euclase, or with fluor-spar and other 
 minerals containing fluorine. It is harder than quartz, has a specific 
 
 439 
 
TOP TOU 
 
 gravity of about 3.5, consists of alumina, silica, and fluoric acid, and is 
 hence a fluo-silicate of alumina. Topaz is highly valued as an ornamental 
 stone, and the chief supplies are obtained from Brazil and Siberia, though 
 found in many other countries. Those from Brazil have deep yellow tints, 
 but became pale pink or red on exposure to heat ; those from Siberia have 
 a bluish tinge ; the Saxon topazes are of a pale wine-yellow, but become 
 limpid by exposure to heat ; and those found in the Scotch Highlands are 
 of a sky-blue colour. The purest from Brazil are termed Goutte d'Eau 
 (drops of water), and, when cut in facets, closely resemble the diamond in 
 lustre and brilliance. A common or coarse columnar topaz named Pyrophy- 
 salite is not to be confounded with the Precious Topaz above described. 
 
 Topazolite. A pale yellow, nearly transparent, variety of garnet, found 
 in Piedmont, and consisting of 37 silica, 2 alumina, 29 lime, 4 glucina, 25 
 iron, and 2 manganese. 
 
 Topaz-Hock. The name given to a granular slaty mixture of quartz, 
 schorl, and topaz, occurring at Schneckenstein, near Auerbach in Saxony. 
 
 Top6graphy (Gr. topos, a place, and grapho, I describe.) A particular 
 account of any locality, city, town, or village ; in contradistinction to the 
 general geography of the country in which it is situated. 
 
 Tornado (Span, tournar, to turn). A whirlwind ; any violent storm or 
 hurricane of wind, usually accompanied with thunder, lightning, and rain. 
 Tornadoes, though excessively violent and destructive, are for the most 
 part limited in area and of short duration. 
 
 T6rrelite (after Dr Torrey). A red-coloured variety of Columbite or 
 Niobite from New Jersey, consisting of niobic acid, protoxide of iron, and 
 manganese. 
 
 Torrid Zone (Lat. torridus, burning, scorching). The middle zone or belt 
 of the earth's surface, extending on each side the equator to the tropics 
 of Cancer and Capricorn respectively ; and so called from its high tempe- 
 rature. See ZONE. 
 
 Tosca-Rock. A name given by the inhabitants of Buenos Ayres to a 
 marly arenaceous rock found imbedded in layers and nodular masses 
 among the ai'gillaceous earth or mud of the Pampas. The term is used by 
 Mr Darwin in his interesting descriptions, and has been adopted by sub- 
 sequent observers. See PAMPEAN FORMATION. 
 
 Touchstone. A variety of. flinty slate, so called from its being used for 
 testing the purity of gold the quality of the metal being judged of by the 
 colour of the streak which it leaves on the stone. See LTDIAN STONE. 
 
 Tourmaline. A mineral occurring in the granitic and metamorphic 
 rocks of most countries, and so complex and variable in composition as to 
 be usually divided into three groups Schorl, Achroite, and Rubellite. It 
 occurs in long prismatic crystals, generally striated vertically, and im- 
 bedded or attached. It is most frequently black, but is found of various 
 colours, and occasionally colourless ; is about the hardness of felspar ; spe- 
 cific gravity 3.3; and becomes electrical by heat or by friction. Tourma- 
 line is ranked under the Gem family, though not greatly prized as a 
 precious stone the red varieties being known as Rubellites or Siberites 
 (from Siberia) ; the dark-blue as Indicollites ; the black opaque varieties 
 as Schorl; and the white or colourless as Achroite. "Though a wide- 
 spread mineral, tourmaline,'' says J. Nicol, "is not of high geological 
 importance, as it only forms an essential constituent of schorl-rock and 
 topaz-rock, both very limited masses. It has hitherto been found only in 
 
 440 
 
TOX TEA 
 
 the older plutonic and metamorphic rocks, and never either in the newer 
 stratified or in the recent trap or volcanic formations. It is very com- 
 mon in granite, where it sometimes replaces the mica, and is frequently 
 associated with quartz, orthoclase, albite, mica, lepidolite, chlorite, topaz, 
 and beryl, either in druses or in subordinate beds, or with their crystals 
 enclosed or intermixed with each other." 
 
 Tox6ceras, Toxoceratite (Gr. toxon, a bow, and keras, horn). A genus 
 of the Ammonite family, peculiar to the Green sand or Lower^Chalk forma- 
 tion, and so named from the bow-shape of its shell like an ammonite 
 uncoiled. " Between toxoceras, crioceras, and ancyloceras," says Wood- 
 ward, " there are numerous intermediate forms." 
 
 Toxodon (Gr. toxon, a bow, and odous, tooth). A large quadruped, of 
 unknown affinity, from the Upper Tertiary or Pampean formation of 
 South America, and so named by Professor Owen from the singularly 
 curved form of its two outer incisors. Th^ skull is twenty-eight inches 
 long and sixteen broad, and presents a blending of the osteological charac- 
 ters of several existing natural orders, as the Rodents, Pachyderms, and 
 Cetacea. 
 
 Toxdster (Gr. toxon, bow, and astron, star). A genus of fossil sea-urchins 
 peculiar to the Neocomian or Lower Chalk formation, characterised by 
 their somewhat semicircular contour (hence the name) ; by their unde- 
 pressed ambulacra, which converge towards the summit of the case ; by 
 their horizontally-elongated pores ; by the odd ambulacrum being in a 
 deep groove, the mouth transverse, and the vent in the posterior face. 
 
 Trachyte (Gr. trachys, rough). The name given to the felspathic class 
 of volcanic rocks which have a coarse cellular paste, rough and gritty to the 
 touch. " This paste," says Lyell, "has commonly been supposed to con- 
 sist chiefly of albite, but according to M. Delesse, it is variable in compo- 
 sition, its prevailing alkali being soda." Through the base are dissemin- 
 ated crystals of glassy felspar, mica, and sometimes quartz and hornblende, 
 although in the trachyte properly so called there is no quartz. The varie- 
 ties of felspar which occur in trachyte are trisilicates, or those in which 
 the silica is to the alumina as in the proportion of three atoms to one. 
 
 Trachytic Porphyry. This rock, according to Abich, has the ordinary 
 composition of trachyte, with quartz superadded, and without any augite 
 or titaniferous iron. ' 
 
 Transition (Lat., going between, intermediate). The passage from one 
 state or period to another ; hence we speak of the Tilestones as "transition 
 beds" between the Silurian and Devonian systems that is, partaking in 
 some measure of the character of both systems. 
 
 Transition Rocks or Strata. In the classification of Werner and his 
 school the transition strata were separated from the primary as being less 
 crystalline, affording unmistakable evidence of their mechanical or sedi- 
 mentary origin, and containing occasional remains of plants and animals. 
 For these reasons it was assumed they were deposited at a period when 
 the earth and sea were passing into a state fit for the reception of organ- 
 ised beings ; and hence the term Transition. It comprised the Greywacke 
 formation of the older geologists ; which has since been subdivided into 
 the Cambrian and Silurian systems. 
 
 Transliicency (Lat. trans, through ; luceo, I shine, from lux, light). 
 Literally " shining through ; " that property of minerals and other sub- 
 stances which permits light to pass through them, but not in sufficient 
 
 441 
 
TEA 
 
 quantity to show distinctly the forms and colours of objects placed on their 
 other side. A mineral is therefore said to be translucent when light evi- 
 dently passes through its substance, though objects cannot be distinguished 
 through it by the eye. See TRANSPARENCY. 
 
 Transmutation (Lat.) A change from one place to another, or from 
 one thing into another. A term adopted by Lamarck and his followers to 
 express their hypothetical views of the derivation of existing species from 
 preceding species, by slow and gradual Transmutations of one form of 
 organisation into another form, independent of the interference of any 
 creative agent, and merely by the influence of external or physical condi- 
 tions, or by the internal impulses of the organism as affected by extraneous 
 caiises. 
 
 Transparency (Lat. trans, through, and pareo, I appear). Literally 
 " appearing through ; " that property of bodies which permits light to 
 pass through them so freely that the forms, hues, and distances of objects 
 can be distinctly seen on the other side. Air, water, the purer kinds of 
 glass, and many minerals, are therefore said to be transparent; and this 
 property varies in intensity till it passes into mere translucency ; and trans- 
 lucency also varies in degree till no light pass through, and the substance 
 is said to be opaque. 
 
 Trap, Trappean (Swedish trappa a stair). Tabular greenstone and 
 basaltic rocks, from their rising up in step-like masses, were originally so 
 termed ; but the name is now extended to all igneous rocks which are not 
 either strictly Granitic or decidedly Volcanic. Others derive the origin of 
 the term from the terrace-like aspect of Secondary hills, generally com- 
 posed of interstratified greenstones, basalts, amygdaloids, &c., which stand 
 out in ledges from the softer strata that have yielded to denudation. What- 
 ever the original idea, the term is now employed by geologists to embrace 
 all the multifarious igneous rocks that belong to the Palaeozoic and Secon- 
 dary epochs, as distinct from the more ancient granites on the one hand, 
 and the recent volcanic rocks on the other. The Trappean series thus 
 embraces basalt, clinkstone, basaltic clinkstone, greenstone, greenstone- 
 porphyry ; compact felspar or felstone, felspar- porphyry ; hornstone, pitch- 
 stone, pitchstone- porphyry ; claystone, claystone porphyry ; amygdaloid, 
 trap-tuff, wacke, trap-breccia, and the like. As a class, they are mainly 
 composed of felspar, augite, and hornblende, the varieties differing accord- 
 ing to the predominance of one or other of these ingredients. 
 
 Trass, Tarass. A provincial German term for a Tertiary tufaceous 
 alluvium or volcanic earth, which occupies wide areas in the Eifel district 
 of the Rhine. Its basis consists almost entirely of pumice, in which are 
 included fragments of basalts and other lavas, pieces of burnt shale, slate, 
 sandstone, and numerous trunks and branches of trees. Tt seems to have 
 originated either as a volcanic mud, like that thrown out by the craters of 
 the Andes ; or as volcanic dust and ashes deposited in the fresh- water 
 lakes of the period. When pulverised it is used as a hydraulic cement, 
 like the pozzolana of Italy. 
 
 Travertin. A whitish concretionary limestone deposited from the water 
 of springs holding lime in solution ; abundantly formed by the waters of 
 the Anio, at Tibur, near Rome ; hence the name Tiburtinus, Travertinus, 
 or Travertin. It is usually compact, hard, and semi-crystalline, and in 
 this respect is distinguished from Gale-tuff or tufa, which is a loose and 
 porous surface-deposit. 
 
 442 
 
TEE TRI 
 
 Tremadoc Slates. A series of coloured slates and grits about 1000 feet 
 thick, occurring at Tremadoc in North Wales, and constituting a portion 
 of the Cambrian system of Sedgwick or the Lower Silurian of Sir Koderick 
 Murchison. 
 
 Trembldres. The name given by the Spanish settlers of South America 
 to the surf ace- tremors which, in some volcanic districts, are almost of daily 
 occurrence. 
 
 Tremolite (named from Val Tremola). A variety or sub-species of horn- 
 blende, known also as grammatite and calamite, of a white or greenish-grey 
 colour, occurring in long prismatic crystals or in columnar aggregates 
 the crystals often bent and striated longitudinally, pearly and semi- 
 transparent. Is found in dolomite, granular limestone, and other subor- 
 dinate beds in the crystalline rocks. 
 
 Tretosternon (Gr. tretos, perforated, and sternon, the breast-bone). 
 The generic term applied to the fossil bones of a turtle-like animal from the 
 Wealden and Purbeck beds. It seems to be related to the river-turtles 
 (Trionyx and Emys) of the hotter regions of Asia, Africa, and America. 
 
 Tri- (Gr. treis, Lat. ires, three). A frequent prefix of scientific terms 
 signifying thrice, or in threes ; as tripartite, divided into three parts ; tri- 
 sected, cut into three segments ; trilobate, three-lobed ; tripinnate, three 
 times pinnate, &c. 
 
 Trias, Triassic System. This system derives its name Trias or triple 
 series from its being composed in Germany, where it is very fully deve- 
 loped, of three main members : viz., the Keuper, the Muschelkalk, and the 
 Bunter-sandstein. These, as far as they can be compared, are lithologi- 
 cally and palaeontologically the equivalents of the Upper New Red Sand- 
 stone of England, and may be intelligibly co-ordinated as follows: 
 
 1. KEUPER. 
 
 2. MUSCHELKALK. 
 
 3. BUNTER SAND- 
 STEIN. 
 
 Germany. 
 
 ( Saliferous and gypseous 
 ) shales, with beds of varie- 
 ) gated sandstones and car- 
 \ bonaceous laminated clays. 
 
 J" Compact greyish limestone, 
 
 < with beds of dolomite, gyp- 
 ( sum, and rock-salt. 
 
 ( Various coloured sandstones, 
 
 < dolomites, and red clays ; 
 ( occasional pisolites. 
 
 England. 
 
 Saliferous and gyp- 
 seous marls, with 
 grey and whitish 
 sandstones. 
 
 (Wanting.) 
 
 Reddish sandstones 
 and quartzose con- 
 glomerates. 
 
 Or extending the co-ordination to France, we have the following rela- 
 tions : 
 
 England. 
 Variegated Marls. 
 
 Variegated Sandstone. 
 
 Germany. 
 Keuper. 
 Muschelkalk. 
 Bunter Sandstein. 
 
 France. 
 Marnes irise*es. 
 Calcaire coquillier. 
 Gres bigarre". 
 Gres des Vosges. 
 
 The TRIAS is thus in all its relations the Upper New Red Sandstone of the 
 earlier English geologists, and has been separated from the Lower New 
 Red or PERMIAN, because its flora and fauna are essentially Mesozoic, and 
 akin to those of the Oolite and Chalk, while those of the Permian are essen- 
 tially Palaeozoic in their facies, and related to those of the Carboniferous 
 
 . 443 
 
TRI 
 
 below. In England the system is sparingly fossiliferous, but in Germany 
 
 and France, as well as in Southern Africa and North America, where there 
 is a large development of Red Sandstones, supposed to be of Triassic age, 
 there is a fuller (though by no means exuberant) exhibition of Life, vege- 
 table as well as animal. The flora embraces equisetums, calamites, ferns, 
 cycadaceous and coniferous plants; the fauna, corals, star-fishes, shell- 
 fish, crustaceans, reptiles, numerous footprints of reptiles and birds, and 
 
 indications of marsupial mammals. Economically, the system is the 
 
 great repository of rock-salt and brine-springs in England and Ireland. 
 See NEW RED SANDSTONE, and tabulations, " GEOLOGICAL SCHEME." 
 
 Tributary. Applied to any stream which, directly or indirectly, contri- 
 butes water to another stream. One stream falling directly into another 
 stream becomes an affluent to that stream ; but both may be tributaries to 
 some larger current. An affluent is thus necessarily a tributary, but a 
 tributary is not necessarily an affluent. 
 
 Tricarpellites (Gr. treis, three, and karpos, fruit). Fossil nut-like fruits 
 from the London Clay, so called from their consisting of three carpels or 
 seed-cells. 
 
 Trichecodon. A provisional genus of marine mammals, founded by 
 Mr E. R. Lankester on some tusks from the Red Clay of Suffolk, which 
 show affinities to the Walrus (Trickecus) though apparently of much larger 
 dimensions. 
 
 Triconodon (Gr. ) Literally "three-coned tooth;" a provisional genus 
 of small marsupials, founded on some remains of teeth and jaws from the 
 Purbeck or Upper Oolitic beds of England. Nothing is yet known of these 
 Oolitic marsupials (plagiaulax, triconodon, &c.) beyond their teeth and 
 lower jaws. 
 
 Trigonellites (Gr. treis, three, and gone, corner). A shell -like organism 
 consisting of two plates or valves, and so called from its triangular form. 
 " The real nature of the shell," says Lyell, " of which there are many 
 species in Oolitic rocks, is still a matter of conjecture. Some are of opinion 
 that the two plates formed the gizzard of a cephalopod ; for the living 
 Nautilus has a gizzard with horny folds, and the Bulla is well known to 
 possess one formed of calcareous plates." 
 
 Trigonia (Gr. treis, three, and gone, corner). A dimyariau bivalve of 
 the Oolite and Chalk, so called from its three-cornered shape. The fossil 
 trigonia} are thick, tuberculated, ribbed shells the ribs either radiating 
 or arranged concentrically : but the shell having been almost entirely 
 nacreous, it is generally wanting, and only the cast remains the ' ' horse- 
 heads " of the Portland quarrymen. About 100 species are catalogued from 
 the Trias to the Chalk inclusive ; none have yet been found in Tertiary 
 strata, but one or two species occur in Australian seas. 
 
 Trigoniadse. A family of conchiferous molluscs, of which Trigonia is 
 the type, having equivalve, close, three-cornered shells, with the umbones 
 directed backwards ; interior nacreous ; ligament external ; hinge-teeth 
 few and diverging. The family is chiefly fossil, and includes trigonia, 
 myophoria, aximis, and lyrodesma. 
 
 Trigonocarpon (Gr. treis, three ; gone, corner ; and carpos, fruit). A genus 
 of thick-shelled fruits occurring in the Coal-measures, and so called from 
 the three projecting ribs or corners which mark the surface of the shell. 
 They vary considerably in size, and are regarded as palm-nuts, to which 
 they bear a striking resemblance. 
 
 444 
 
TKI TRO 
 
 Trilobite, Trilobitidse (Gr. treis, three, and lobos, lobe). An extensive 
 family of Palaeozoic crustaceans, deriving- their name from the obvious 
 three-lobed-like aspect of their bodies. The trilobites, in numerous generic 
 forms, as asaplius, ampyx, calymene, homalonotus, ilcenus, ogygia, olenus, 
 phacops, trinucleus, &c., are especially characteristic of the Silurian system ; 
 about a dozen genera range through the Devonian epoch ; only three or 
 four make their appearance in Carboniferous strata ; and not a single 
 specimen has been found in any later formation. The skeleton of the 
 trilobite consists of a cephalic shield or plate (cephalo-thorax), furnished 
 with prominent many-facetted sessile (very rarely pedunculated) eyes on 
 the upper or dorsal aspect, and beneath a labrum or " hypostome" which 
 would indicate foot-jaws; a three-lobed body in segments less or more 
 numerous ; and a caudal plate or appendage (pygidium) variously termi- 
 nated. As yet no indications of antennae or limbs have been detected ; 
 " still," says Owen, "there can be no doubt they enjoyed such locomotive 
 power as even the limpet and chiton exhibit when requisite." Many of 
 them are extremely minute, and in all likelihood the larval forms of larger 
 so-called genera ; a considerable number attain a size of from one to six 
 inches ; and it is rarely indeed that fragments are found indicating 
 species exceeding twelve or fifteen inches long. For the subdivisions of 
 the group, and its place among the Crustacea, see tabulations, " ANIMAL 
 SCHEME." 
 
 Trilophodon (Gr. treis, three, and lopkos, ridge). Literally "three- 
 ridged ; " one of Dr Falconer's sub-genera of Mastodons, which are divided 
 by him into trilophodon and tetralophodon, according as the crowns of their 
 molar teeth exhibit three or four pap-like transverse ridges with inter- 
 vening depressions. 
 
 Trionyx (Gr. treis, three, and onyx, claw). Literally "three-clawed ;" a 
 fossil tortoise or chelonian occurring in Tertiary strata ; and doubtfully 
 (from three-clawed imprints of footsteps) in any earlier formation. 
 
 Trlplite (Gr. treis, three). A phosphate of manganese occurring in mas- 
 sive or coarsely granular aggregates, and so called from its being cleav- 
 able in three directions, at right angles to each other. Consists of 34 
 iron protoxide, 33 manganese protoxide, and 33 phosphoric acid. 
 
 Tripoli. A polishing powder originally brought from Tripoli in Africa, 
 but newfound in many other places. It is a kind of "rotten-stone," 
 composed of the siliceous shields of microscopic infusoria, and diato- 
 macese ; an infusorial or microphytal earth of a whitish-grey or yellow 
 colour ; soft, light, and friable. 
 
 Tristychius (Gr. treis, three, and stychos, row). A genus of cestraciont 
 fin-spines or ichthyodorulites from the Carboniferous formation, indicative 
 of shark-like fishes of great size ; and so called from the triple row of barbs 
 or tooth-like processes with which they are armed. 
 
 Trochitse (Gr. trockos, a wheel). A name given by the earlier palaeon- 
 tologists to the small detached joints of the encrinite. See ENTROCHI. 
 
 Trochdceras (Gr. trockos, a hoop, and keras, horn.) A genus of nauti- 
 lites found in the Upper Silurians of Bohemia. Shell nautiloid, spiral, 
 depressed. 
 
 Troclras (Lat. trockus, a hoop). An extensive genus of living and fossil 
 univalves belonging to the family Turbinidce, and characterised by their 
 pyramidal-shaped numerous-whorled shells, which are nearly flat at the 
 base, and have an oblique rhombic aperture which is pearly inside ; hence 
 
 445 
 
TRO TUN 
 
 the common designation of "silver shells." They are found fossil from 
 the Devonian upwards, the fossil being more numerous than the existing 
 
 Trogontherium (Gr. trogo, I gnaw, and therion, beast). Literally 
 " gnawing beast ;" an extinct rodent found in the fresh-water Pleistocenes 
 or uppermost Tertiaries of Europe, and so closely allied to the existing 
 beaver that it is by some palaeontologists regarded as a mere specific or 
 sub-generic form. Its bones indicate a size about a fourth larger than the 
 largest known species. 
 
 Trona (Arabic). A crude carbonate of soda, occurring in crystalline in- 
 crustations in the deserts of Africa and Asia, and in the dried-up lakes and 
 river-courses of South America. Consists of about 38 soda, 40 carbonic 
 acid, and 22 water. 
 
 Tropics, Tropical (Gr. tropikos, from trepo, I turn). Those two circles 
 on the earth's surface over which the sun seems directly to pass when he is 
 at the greatest distance from the equator viz., 23 g degrees ; hence the one 
 is called the northern tropic or Tropic of Cancer, and the other the southern 
 or Tropic of Capricorn. The zone or belt of the earth within these circles is 
 said to be " within the tropics " or " tropical" and constitutes the Torrid 
 Zone of climatologists. Plants, animals, climate, and other phenomena 
 occurring within this region, are said to be Tropical ; those on the extreme 
 temperate verges of the region, Sub-tropical. 
 
 Trdpifer (Gr. tropis^ keel, and fero, I bear). A minute crustacean from 
 the Lias bone-bed of Aust Passage ; so called from its keeled carapace. 
 
 Trouble. A mining term for any faulting or shifting of the strata of a 
 coal-field by which the regular and continuous working of its minerals is 
 interrupted. A field so faulted is said to be troubled. See FAULT. 
 
 Trough. A familiar term for any sudden depression of strata by which 
 they are made to assume the basin-shaped or synclinal arrangement. 
 Generally used as synonymous with basin or syncline. 
 
 Trough- Joint. The fissure or joint which frequently accompanies the 
 abrupt bending of strata passing through the middle of the curvature. 
 
 Tubbing. The technical term for the lining of a shaft with wood or 
 iron, for the purpose of preventing the falling in of loose incoherent strata 
 or of excluding the water that may flow in from the sides. In many 
 instances this casing requires to be of iron, water-tight, and of the most 
 substantial description. 
 
 Tubiporites (Lat. tubus, a tube, and porus, a pore). Parkinson's term 
 for a genus of fossil corals composed of closely-united calcareous tubes 
 each tube having been the abode of an individual polype. Now known as 
 Syringopora, which see. 
 
 Tuff, Tufa (Ital. tufo, Gr. tophos). Originally applied to a light porous 
 rock composed of cemented scoriae and ashes ; but now used for any porous 
 vesicular compound, as calc-tuff, trap-tuff, volcanic tufa, &c. ; which see. 
 
 Tungsten (Swedish, heavy-stone). A hard brittle metal, of a light steel- 
 grey colour and brilliant metallic lustre, having a specific gravity of 17.5. 
 It is barely fusible at the greatest heat of the smith's forge, but when 
 heated to redness in the open air it is converted into the peroxide (tungstic 
 acid). Its ores, tungstates of lime, iron, and manganese, are very fre- 
 quently associated with those of tin, which they greatly injure. These 
 are wolfram, tungstate of iron and manganese ; stolzite, tungstate of lead ; 
 scheelite, tungstate of lime ; and t^lngst^c ochre. The metal is not used in 
 
 446 
 
TUN TUR 
 
 the arts ; but tungstic acid is employed in dyeing. It was discovered by 
 Scheele in 1781 ; hence the occasional early synonyme of Scheelium or 
 Scheelite. 
 
 Tunicate (Lat. tunica, a coat or tunic). A class of headless molluscs, 
 which have no shells, but are protected instead by an elastic, leathery- 
 looking tunic ; hence the name. The tunicaries have no organs of locomo- 
 tion, but are found floating freely in the ocean, or fixed to rocks, shells, 
 sea- weeds, and the like. They are hollow, and have two orifices from which 
 they squirt the water after it has served the purposes of respiration and 
 nutrition, and this forcible ejection assists in propelling those that are free 
 floaters. They are divided into two great groups the fixed or Ascidians; 
 and the free-floating or Salpians, which see. 
 
 Turbinated (Lat. turbo, a whipping-top). Top-shaped ; generally ap- 
 plied to those univalve shells which, like the winkle and garden-snail, have 
 a spiral top-like form. 
 
 Turbinidse (Lat. turbo, a whipping-top). An extensive family of gastero- 
 pod molluscs, of which the common turbo or " top-shell " has been taken 
 as the type. The Turbinidae (which include the genera turbo, phasianella, 
 trochus, euomphalus, &c.) have spiral, top-shaped, or pyramidal shells; 
 more or less pearly inside; and furnished with a calcareous or horny 
 operculum. They are marine, littoral in their habits, feed on sea-weeds, 
 and have a world-wide distribution. 
 
 Turbo (Lat., a whipping-top). The common top-shell, a genus of gaster- 
 opod molluscs, embracing about 60 living species found in all seas ; and 
 upwards of 360 fossil species (including littorina) found from the Lower 
 Silurian upwards. See TURBINID^:. 
 
 Turin Nuts. A familiar term for the fossil fruits of a species of Walnut 
 which occurs in the newer Tertiary deposits in the neighbourhood of Turin. 
 "The ligneous envelope," says Mantell, "has perished, but the form of its 
 surface, and of the enclosed kernel, is preserved in calcareous spar. 
 
 Turkey-Slate, Turkey-Stone. A familiar term for whetslate, novaculite, 
 or honestone, some of the best varieties being imported from Turkey, where 
 it occurs of a remarkably fine and even grain, and of a greenish-grey or 
 slightly yellowish colour. 
 
 Turquois. The uncleavdbk azure-spar of Mohs, and the Calaite of other 
 mineralogists ; a phosphate of alumina with a little phosphate of iron and 
 copper ; occurring amorphous, reniform, stalactitic or incrusting ; and 
 usually of a beautiful sky-blue or greenish-blue colour. It takes a fine 
 polish, and is highly prized as an ornamental stone. It is found in veins 
 in flinty slate, but many of the finest Oriental turquoises are gathered as 
 pebbles from the alluvium of Persia and Syria ; and it is said that fossil 
 teeth and bones coloured by hydrated copper oxide or phosphate of iron 
 from Nuash in Siberia and Trevaux in France, and known as Odontolite, 
 are often substituted for the true mineral. See ODONTOLITE. 
 
 Tiirrilite (Lat. turris, a tower, and lithos). An extinct genus of cham- 
 bered shells belonging to the Ammonite family, and characterised by 
 their straight, spiral, turreted contour. They seem restricted to the Chalk 
 formation, in which from twenty to thirty species have been detected. 
 
 Turritella (Lat. dim. of turris). A genus of marine gasteropods, the 
 type of the family Turritellidce, and so called from their turriculated 
 shape, the shell being elongated, many-whorled, spirally striated ; aper- 
 ture rounded, margin thin ; operculum horny, many-whorled ; with a 
 
 447 
 
TUR UMB 
 
 fine briated margin. The living species, familiarly known as screw-shells, are 
 about fifty, in number, and have a world-wide distribution; the fossils, more 
 than one hundred and fifty, are found from the Lower Greensand upwards. 
 They are inhabitants of deepish water ranging from three to one hundred 
 fathoms. 
 
 Turtle-Stones. A familiar appellation for those nodular concretions 
 commonly known as Ludi ffelmontii, septaria, and the like. See SEPTARIA. 
 
 Tympanophora (Gr. tympanon, a cymbal, and phoreo, I bear). A term 
 applied to certain fossil plants, chiefly from the Oolite, having minute 
 branching stems, each branchlet being terminated by a rounded or globu- 
 lar appendage resembling a seed-vessel. Nothing is known of their nature, 
 or of that of Sphcereda, which they somewhat resemble. 
 
 Typhoon (Gr.) Literally, a tempest or whirlwind. Typhoons, the name 
 given by navigators to the hurricanes that visit, generally from June to 
 November, the seas of Southern China, and the adjacent archipelagoes of 
 the Philippines and Moluccas. 
 
 Tl 
 
 U'lmannite (after Ulmann). An ore of nickel and antimony found 
 chiefly in the copper-mines in the transition rocks of the Westerwald. It 
 is of a bluish-grey colour, and consists of 26.8 nickel, 58.6 antimony, and 
 14.6 sulphur, but part of the antimony often replaced by arsenic. 
 
 Ulodendron (Gr. hule, a wood, and dendron, tree). A genus of Coal- 
 measure trunks, often of considerable size, and characterised by their 
 stems not being furrowed, but covered with rhomboidal scales, and having 
 on opposite sides two vertical rows of large circular scars, to which cones 
 had been attached. In Bolhrodendron (which see) the stem is dotted ; and 
 the cone-scars are obliquely oval. 
 
 Ulna, Ulnar (Lat. ulna, the cubit or large bone of the fore-arm). The 
 two bones that form the fore-arm, or that portion between the wrist 
 and elbow, are termed the ulna and radius, the ulna being the larger of 
 the two. 
 
 Ultramarine. Literally "beyond the seas ; " a well-known blue pigment 
 of great beauty and permanence, and until lately prepared from the lapis 
 lazuli the finest specimens of which were brought from China and Further 
 Asia ; hence the name. It is now artificially prepared by the chemist, 
 after a mode originally discovered by Gmelin. The artificial, which can 
 be made cheaply and in any quantity, consists of 46.60 silica, 3.83 sul- 
 phuric acid, 23.30 alumina, 21.48 soda, 1.06 peroxide, with traces of lime, 
 magnesia, and sulphur. See LAPIS LAZULI. 
 
 Umber (Lat. umbra, shade, hue). A well-known pigment of various 
 shades of brown ; occurring either naturally in veins and beds, or pre- 
 pared artificially from various admixtures. The " umber" proper of the 
 mineralogist is a soft earthy combination of the peroxides of iron and 
 manganese, with minor proportions of silica, alumina, and water. It is 
 usually found in veins in the transition and crystalline strata, and appears 
 
 448 
 
UMB UNI 
 
 to be a product of decomposition. Much of the umber of commerce, how- 
 ever, is a mere ochraceous admixture ; and that from Cologne is said to 
 be only brown-coal finely pulverised. 
 
 Umbo, plural Umbones (Lat.) A boss or protuberance. In conchology, 
 that knob-like point of a bivalve shell which is situated immediately above 
 the hinge. Umbonated. Bossed ; knobbed in the centre. 
 
 Umbral (Lat. ) Shady, belonging to the dusk; the fourteenth of the 
 fifteen series into which Professor H. D. Rogers subdivides the Palaeozoic 
 strata of the Appalachian chain the ' ' Dusk " of the North American 
 Palaeozoics, and the equivalent, in part, of our Carboniferous Limestone 
 and Lower Coal-measures. See PALEOZOIC FORMATIONS. 
 
 Unconformable. Strata lying parallel on each other are said to be con- 
 formable ; but when one set is laid on the upturned edges of another set, 
 they are un conformable. Unconformability is generally taken as evidence 
 of a break in geological sequence the underlying set having been depo- 
 sited, consolidated, and upturned, before the deposition of the unconform- 
 able or overlying strata. 
 
 U'nctuous (Lat. unctus, anointed, greasy). Many minerals, such as 
 steatite, talc, serpentine, and the like, when rubbed between the fingers, 
 have an unctuous or greasy feel a character which is often useful in dis- 
 criminating species. Most of the naagnesian minerals have ihisfeel, which 
 is altogether different from that produced by mere smoothness. 
 
 Underclay. A term now generally applied to those argillaceous beds 
 which immediately underlie seams of coal. These underclays are usually 
 tenacious, more or less bituminous, and almost always interpenetrated by 
 stigmaria roots. Every seam of coal has not an underclay ; but where 
 they exist they seem to have been the ancient soil or mud on which the 
 vegetation of the coal-bed flourished. 
 
 Undercliff. The term applied to a cliff when the upper part has fallen 
 down along a considerable line of coast, and forms a subordinate terrace 
 between the sea and the original shore. 
 
 Underlie, Underlay. In mining, the dip or inclination of a mineral 
 vein viewed from above downwards. 
 
 Under-tow. A nautical term for any decided under-current of water. 
 Thus, in the ordinary breaking of waves, the wave advances, crests, makes 
 its plunge, and then its waters flow back beneath those of the next wave 
 in general, producing a strong under-current or under-tow. 
 
 Undulation (unda, a wave undula, a little wave). Alternate elevations 
 and depressions of strata are spoken of as undulations ; ridged or wavy 
 surfaces are said to be undulated. 
 
 Ungulite Grit. A series of greenish-coloured shales and grits occurring 
 near St Petersburg (probably of Lower Silurian age) ; and so termed be- 
 cause their prevailing shell is the Obolus or Ungula, a nail-shaped brachio- 
 pod of the Lingula family. 
 
 Uniclinal. In most instances when strata are bent or curved a syncline 
 or trough accompanies an anticline or saddle ; but in some instances there 
 is simply one great elevation or depression, after which the rocks regain 
 their normal inclination, and to this solitary bending the term uniclinal 
 has been applied by Mr Darwin and others. 
 
 Uniformitarian. In geology, one who holds the doctrine that the laws 
 of nature have acted uniformly throughout all time past, and that the 
 appearances in the earth's crust, however difficult of solution, are to be 
 
 449 2F 
 
UNI URA 
 
 ascribed to the uniform action of these laws, and not to revolutionary or 
 cataclysmal operations. 
 
 Unionidse (Gr. unio, a pearl). The family of River-mussels, found in 
 the ponds and streams of all parts of the world. They have a solid, pearly 
 shell, with two principal and two lateral teeth on the hinge ; and their 
 umbones or bosses are generally smooth or longitudinally laminated. 
 Those which have no cardinal teeth are arranged under the genus Anodon. 
 Of the Unio, which is taken as the type of the family, there are about 250 
 living species; and about fifty species have been found fossil from the 
 Carboniferous formations upwards. There is considerable doubt, how- 
 ever, whether the Carboniferous shells really belong to the genus Unio ; 
 some geologists refer them to Cardinia, and commence the Uniones with 
 the Wealden. 
 
 Univalve (Lat. unus, one, and valva, a lid or valve). Applied to mollusc- 
 ous animals or " shell-fish " whose shell consists of a single piece, as the 
 periwinkle, limpet, &c.; in contradistinction to bivalves, like the cockle 
 and mussel, whose shell consists of two valves or pieces. According to the 
 Linnean arrangement shells consisted of three orders, univalves, bivalves, 
 and multivalves; but these divisions are now little attended to except in 
 popular description. The univalves are usually spoken of as " turbinated " 
 or those having a spire, and those without a spire. Palaeontologically, the 
 gasteropods or true univalves have been on the increase since palaeozoic 
 times, till now in the current epoch they constitute the most numerous 
 class of mollusca both in genera and species. 
 
 Unstratified. Applied to rocks which do not occur in layers or strata, 
 but in amorphous masses ; and as this is a feature of igneous rocks, the 
 term is usually regarded as synonymous with igneous. Hence we speak of 
 aqueous or stratified rocks, and of igneous or unstratified rocks ; though, 
 strictly speaking, many igneous products, as flows of lava and trap, 
 showers of dust and ashes, &c., occur in stratiform or sheet-like accumu- 
 lations. " The terms stratified and unstratified," says De la Beche, " have 
 been commonly considered as respectively synonymous with aqueous and 
 igneous. Practically this division is highly valuable ; but theoretically it 
 is not so satisfactory, at least if we are to infer that all rocks divided into 
 tabular masses, one resting on another, must have been deposited either 
 chemically or mechanically from water. We should be careful not to 
 couple too far stratification with aqueous deposition, as sheets of igneous 
 rocks may cover pre-existing sheets of similar rocks, and the result be 
 stratification." 
 
 Upheave, Upheaval, Uplift. A lifting up of strata by some expansive 
 or elevating power from below. The terms upthrow and downthrow are more 
 generally used to designate such subterranean movements. 
 
 U'ranite. Known also as uran-mica, uran-glimmer, and lime-uranite ; a 
 mineral occurring in flat tabular crystals of a sulphur-yellow to siskin- 
 green colour, and consisting, according to Berzelius, of 15.5 phosphoric 
 acid, 62.6 peroxide of uranium, 6.2 lime, and 15.7 water. It is found 
 chiefly in granitic rocks, and occasionally in veins and beds in the crystal- 
 line strata with other ores. It is a calcareo-phosphate of uranium, and 
 differs from chalcolite, which is a cupreo-phosphate, only in containing lime 
 instead of copper. 
 
 Uranium. A metal discovered by Klaproth in 1789, and so named by 
 him after the planet Uranus, which was discovered in the same year. It 
 
 450 
 
URA VAL 
 
 is obtained from several mineral species, and is, when separated, a pow- 
 dery substance of a greyish black colour, with a metallic lustre, very com- 
 bustible, and burning with a white light. It is separated with great diffi- 
 culty ; is infusible ; and has a specific gravity of 9.0. Preparations of 
 uranium are used for imparting fine orange tints to glass and porcelain 
 enamel ; and the uranite of potash affords a splendid orange to the artist. 
 The various minerals containing uranium are in general easily distin- 
 guished by the hues of yellow they communicate to glass. The following 
 are the principal : 1. Uranium ore, pechurane, or pitchblende; 2. Uranite, 
 wan-mica, uran-ghmmer, or lime-uranite ; and, 3. C/ialcolite, or copper- 
 uranite. 
 
 Uran Ochre or Uranium Ochre. Earthy oxide of uranium, occurring in 
 soft friable masses, disseminated or encrusting, along with pitchblende or 
 protoxide of uranium, in the granites of Saxony and France. It has vari- 
 ous hues of yellow and orange, and seems derived from the decomposition 
 of the protoxide. 
 
 Urao. A native term for the carbonate of soda found in crystalline 
 crusts on the dried-up lakes and river-courses of South America ; same as 
 the Trona of the Arabs, which see. 
 
 Urchin (Lat. erinacem, the hedgehog). The name of " sea-urchin" has 
 been given to the echinus, on account of its prickly ambulacra! spines. 
 See ECHINIDA. 
 
 Urosthenes (Gr.) Literally " strong- tail ;" a genus of fishes from the 
 Carboniferous strata of New South Wales, and so named by Professor 
 Dana from its powerful heterocercal tail. In general form of the body, 
 the large size and backward position of the dorsal and anal fins, the genus 
 resembles Pyqopterus ; but differs in having these organs placed directly 
 opposite to each other, in their being shorter and nearer the tail, and also 
 in having the scales smooth. See PTGOPTERUS. 
 
 U'rsidse (Lat. ursus, a bear). The Bear tribe ; a well-known family of 
 carnivorous mammals, having a wide range both in the old and new worlds, 
 and particularly in the northern hemisphere. The remains of several 
 species (U. spelceus, priscui, &c.) have been found in the caves breccias, 
 and alluvia of the Pleistocene period. 
 
 Urns. The Ure-ox or Bos iirus, described by Caesar in his ' Commenta- 
 ries,' and stated to abound during his invasion in the forests of Gaul and 
 Germany. It has been long quite extinct in all parts of Europe, and is 
 supposed to be the same as the Bos primigenius, whose remains occur in 
 Post-tertiary deposits. Often confounded with the Auroch or Bison of 
 northern Europe, which still lingers in a protected state in the Imperial 
 forests of Russia. 
 
 Valentinite (after Valentine). White oxide of antimony; a mineral oc- 
 curring crystallised, or massive and disseminated in granular, columnar, 
 and foliated aggregates ; usually of a whitish-grey colour, and consisting 
 of 84.32 antimony and 15.6*8 oxygen. It is found in veins in the primary 
 rocks along with other ores of antimony, lead, and zinc. 
 
 451 
 
VAL VAR 
 
 Valley (Lat. vallis).A.ny hollow or low-lying tract of land bounded by 
 hill or mountain ranges ; and usually traversed by a stream or river which 
 receives the drainage of the surrounding heights. We have thus " circular 
 valleys," " longitudinal valleys," and " cross valleys," according to the 
 configuration and disposition of the bounding heights ; though, generally 
 speaking, longitudinal valleys, taking their names from the rivers which 
 flow through them, are the most characteristic and common. A level 
 tract of great extent, and traversed by more rivers than one, is, properly 
 speaking, not a valley, but a plain ; and deep narrow river-courses, on 
 the other hand, are more correctly designated glens, ravines, and gorges. 
 Geologically speaking, valleys take their rise from original inequalities of 
 the surface produced by subterranean movements ; or they are the result 
 of long-continued erosion by river-currents, and thence known as " Valleys 
 of Erosion." (See EROSION.) Occasionally we meet with such terms as 
 " Valley of Elevation," and " Valley of Denudation " the former being a 
 huge fracture or rent produced by subterranean upheaval, and from which 
 the strata dip away on either side ; the latter being a mere valley of ero- 
 sion scooped out by the action of water without disturbing the original 
 position of the strata, which are continuous on both sides. 
 
 Vanadinite. The vanadiate of lead, a rare mineral occurring in crusts 
 of small hexagonal prisms, of a yellowish-brown colour and resinous 
 lustre, chiefly along with other ores of lead, as at Wanlockhead, Matlock, 
 Wicklow, and in auriferous veins in Siberia and Mexico. It consists, ac- 
 cording to Thomson, of 66.3 oxide of lead, 7.06 lead, 23.44 vanadic acid, 
 and 2.45 chlorine. 
 
 Vanadium. A rare metal of a greyish silvery colour, discovered by 
 Sefstroem in 1830, in the iron prepared from the iron-ore of Taberg in 
 Sweden, and named after Vanadis, a Scandinavian deity. It has since 
 been found in the form of vanadiate of lead or vanadinite, a mineral occur- 
 ring in many localities. As a metal, the properties of vanadium are yet 
 little known. 
 
 Variables. Near the equator the trade- winds, north and south of it for 
 a certain distance, completely neutralise each other, and the zone of calms 
 and light breezes so formed is known as the Variables. 
 
 Variegated Sandstone. The New Red Sandstone of English geologists ; 
 the gres ligarre of the French ; and the bunter sandstein of the German. It 
 is also termed by some 1 the Poikilitic (variegated) System, in allusion to 
 its mottled and particoloured shales and sandstones. 
 
 Variety (Lat. varius, changeable). In natural history, a subordinate 
 division of a species, distinguished by some accidental or unimportant dif- 
 ferences, not considered essential to the main and permanent characteristics 
 of the species. Some slight difference in colour, in size, or in the greater 
 or less development of some particular organ, may constitute a variety, 
 while it may not affect the permanent characteristics of the species. 
 
 Variolite (Lat. variola, small spots). The name given to those varieties 
 of compact amygdaloid or amygdaloidal porphyry, in which the enclosed 
 crystals are numerous, small, and round, giving to the rock a spotted 
 appearance. This appearance is often rendered more striking from the 
 matrix of the rock being of a different colour from the enclosed crystals. 
 
 Variolitic. Spotted ; thickly marked with small round specks. Ap- 
 plied to rocks having the aspect of Variolite, or small-grained amygdaloidal 
 porphyry. 
 
 452 
 
VAS VEI 
 
 Vascular (Lat. vasculum, a little vessel). Composed of small vessels, 
 like the woody tissue or substance of flowering plants ; and used in con- 
 tradistinction to cellular, which denotes that the substance is built up 
 of uniform cells, and consequently softer and less durable in structure. 
 Vascularity indicates a higher degree of organisation than simple cel- 
 lularity. 
 
 Vasodentine (Lat. vas, a vessel, and dens, tooth). An anatomical term 
 employed to express that modification of dentine (see TEETH) in which 
 capillary tubes of the primitive vascular pulp remain uncalcified, and 
 carry red blood into the substance of the tissue. They form the so-called 
 vascular or medullary canals, arid are usually more or less parallel in their 
 course. A large proportion of the central part of the tooth of the sloth 
 and megatherium consists of vaso-dentine, and a smaller proportion of the 
 same part of the tusks of the elephant and of the chisel-like incisors of 
 the rodents. 
 
 Vauquelinite (after Vauquelin the chemist). A chromate of lead and 
 copper occurring in veins with other ores, in minute tabular crystals, or 
 in mammillary crusts, of a dark olive-green colour, and resinous lustre. 
 Consists of 60.87 lead protoxide, 10.80 copper protoxide, and 28.33 
 chromic acid. 
 
 Vein (Lat. 'vena). Applied in geology to all fissures and rents in the 
 earth's crust filled with mineral or metallic matter, differing from the 
 rock-mass in which they occur these subsequently filled fissures tra- 
 versing and ramifying through the solid rock, like the veins through the 
 living system. When such fissures are filled with granite, greenstone, 
 claystone, or with other massive rock-matter, whether igneous or other- 
 wise, they are all usually termed "dykes ;" but when containing metalli- 
 ferous ores or crystalline minerals, they receive the name of "veins" or 
 "lodes;" and "false veins" when they are merely rents or fissures filled 
 with debris from above. The subject of veins is one of the most difficult 
 and complicated and interesting because difficult and complicated with- 
 in the whole range of geology. It embraces the following questions or 
 branches of research : 1. The nature of the substances occurring in min- 
 eral veins ; 2. The mode or modes in which these substances were aggre- 
 gated ; 3. The situations of their occurrence, and the nature and age of 
 the rock formations in which they occur ; 4. Their frequency in any given 
 district, and the directions they take that is, whether they all trend in 
 one way, or cross and intercross ; 5. Their relative ages, so as to erect 
 them into separate " Systems," and thus be enabled to apply such 
 knowledge to their economical exploration. Such an inquiry involves, 
 of course, much patient observation in geology, an intimate acquaint- 
 ance with mineralogy, and, above all, a knowledge of those chemical 
 and electrical forces which are continually acting, and must have simi- 
 larly acted in all time past, in decomposing, dissolving, segregating, 
 and reconstructing the mineral and metallic constituents of the earth's 
 crust. For a brief and intelligible review of the theory of mineral and 
 metallic veins, see Professor Phillips's ' Manual of Geology,' in ' Ency- 
 clopedia Metropolitana,' together with the various authorities therein 
 referred to. 
 
 Veined. Streaked ; marked, like some marbles, with lines or veins of 
 colour, either parallel to, or crossing each other. 
 
 Veinstone. The stony or mineral matter occupying a vein, in contra- 
 453 
 
VEI VER 
 
 distinction to the metallic or metalliferous ores of which it forms the 
 matrix. Known also as Veinstuff. 
 
 Veinstuff. The usual mining term for the rock-matter technically the 
 matrix or gangue which fills a vein, and through which the ore is dis- 
 seminated in crystals, nests, strings, ribs, and other forms. This vein- 
 stuff or matrix may be either crystalline or amorphous. 
 
 Ventral (Lat. venter, the belly). Of or belonging to the belly; e.g., the 
 ventral or belly fins of fishes, as distinguised from the dorsal or back 
 fins. 
 
 Ventricose (Lat. venter, the belly). Bellying ; swelling or bulging out 
 in the middle ; generally applied to hollow bellying forms. 
 
 Ventriculite (Lat. ventricultis, a ventricle or sac). The name given 
 to certain fossil zoophytes of the Chalk, usually appearing as fungiform 
 flints, and well known to the inhabitants of Kent and Sussex as " petrified 
 mushrooms." Palaeontologists are not agreed as to the precise nature of 
 the ventriculites, which seem to have been of a spcngiform flexible texture, 
 and to have consisted of a hollow cup-like expansion, tapering to a point 
 below, and attached by fibrous rootlets to other bodies. 
 
 Verd Antique (Ital. verde antico). A clouded green marble, consisting 
 of an admixture of serpentine and limestone, found at Genoa and in 
 Tuscany, and much prized for its beauty. 
 
 Verde di Corsica Duro. A rock found in the island of Corsica, of a 
 changing green colour, composed of Diallage and Labrador felspar, and 
 used for vases, inlaying, and other ornamental purposes. 
 
 Verdigris (Fr. verde-gris, green-grey). A sub-acetate of copper, formed 
 by bringing the surface of the metal in contact with acetic acid ; and so 
 called from its peculiar green colour. A rust of copper, or jErugo, which 
 see. 
 
 Verditer. A blue pigment, prepared by adding finely- levigated chalk or 
 "whiting" to a solution of copper in aquafortis. 
 
 Vergent (Lat.) Drawing to a close ; the eleventh of the fifteen series 
 into which Professor Rogers subdivides the Palaeozoic strata of the Appa- 
 lachian chain the "Descending Day" of the North American Palaeozoics, 
 and the equivalents of our middle Devonians. See PALAEOZOIC FORMA- 
 TIONS. 
 
 Vermiculite (Lat. diminutive of vermis, a worm). A minerai substance 
 composed of minute micaceous plates disseminated through a mealy mag- 
 nesian matrix, and having a soapy lustre and greasy feel. It consists 
 of silica, magnesia, iron peroxide, alumina, and a trace of manganese. 
 When heated to redness it swells out with a vermicular motion, as if it 
 were a mass of small worms ; hence the name. 
 
 Vermicnlites (Lat. vermis, a worm). Applied to the smaller and shorter 
 worm-tracks which appear on the surfaces of many flaggy sandstones. 
 
 Vermiform (Lat. vermis, a worm, and forma, shape). Worm-like ; 
 worm-shaped. Vermiform casts and impressions occur in the sandstones 
 of various formations ; some apparently the true rejectamenta of annelids, 
 like the earth- and lob-worm ; others their tortuous tubes and burrows ; 
 and many their mere superficial tracks or trails. See ARENICOLTTES, FORA- 
 
 LITES, SCOLITES, &C. 
 
 Vermilion. A well-known brilliant red pigment, prepared by pulveris- 
 ing the red sulphuret of mercury, or Cinnabar, which see. 
 Vertebra (Lat., from verto, I turn). A single bone of the backbone or 
 454 
 
VER V1V 
 
 spinal column. The different vertebrae comprising the backbone are 
 usually divided into cervical or those of the neck, dorsal or those of the 
 back, lumbar or those of the loins, and caudal or those prolonged into a 
 tail in many classes of animals. Important distinctions are also founded 
 upon the mode in which the several vertebrae are attached or jointed to 
 each other some being concave before (procceliari), others being concave 
 at both ends (amphiccelian), and others flat in front and concave behind 
 (platycoelian). 
 
 Vertebrata (Lat. vertebra, the joint of a backbone). One of the two 
 grand divisions of the animal kingdom, including all those animals fur- 
 nished with vertebrae or backbones. In Cuvier's arrangement the Verte- 
 brata embrace the Mammals, Birds, Reptiles, and Fishes; the Inverte- 
 brata the Articulata, Mollusca, and Radiata. See tabulations, "ANIMAL 
 SCHEME." 
 
 Vesicular (Lat. vesicula, a little bladder). Full of bladder-like cavities ; 
 composed of cells or vesicles. Applied to rocks full of little cavities, as 
 vesicular lava, vesicular trap-tuff, &c. these cavities having arisen from 
 the disengagement of gases when the rock-matter was in molten a state. 
 
 Vespertine (Lat.) Of or belonging to the evening; the thirteenth of 
 the fifteen series into which Professor H. D. Rogers subdivides the Palaeo- 
 zoic strata of the Appalachian chain the "Evening'' of the North 
 American Palaeozoics, and the equivalents of our Lower Coal-measures or 
 Carboniferous slates. See PALEOZOIC FORMATIONS. 
 
 Vesuvian. A reddish-brown mineral of the Garnet family ; so called 
 from its being found in volcanic rocks, and in particular those of Vesuvius. 
 Same as pyramidal garnet or Idocrase, which see. 
 
 Vibratile Organs (Lat. vibro, I move quickly or vibrate). A common 
 designation for those hair-like organs of motion with which so many of the 
 lower aquatic animals are furnished ; and termed CILIA, which see. 
 
 Vitreous (Lat. vitrum, glass). Having the lustre or aspect of glass ; 
 glassy. Vitrify. To melt or convert into glass. Vitrified. Having the 
 surface coated with or partially converted into glass by the action of 
 heat. 
 
 Vitrification (Lat. vitrum, glass, and^o, I become). The conversion of 
 any mineral substance into glass ; hence we speak of " vitrified forts," of 
 the " vitrification of rocks," &c., when by the action of heat their surfaces 
 are covered with a glaze or glassy coating, produced, as glass is, by the 
 fusion of silica along with an alkaline flux. 
 
 Vitriol (Lat. vitrum, glass). A term applied by the earlier chemists to 
 all crystalline bodies having a certain degree of transparency, but now 
 mainly restricted as a familiar designation for the following substances : 
 viz., blue vitriol, sulphate of copper or cyanose ; green vitriol, sulphate of 
 iron, copperas, or melanterite ; white vitriol, sulphate of zinc or goslarite ; 
 red vitriol, sulphate of the proto -peroxide of iron and magnesia or botryo- 
 gene ; and oil of vitriol, or sulphuric acid, so called because originally 
 distilled from green vitriol or copperas. 
 
 Vivianite. A mineralogical term for phosphate of iron, which occurs in 
 prismatic crystals, in fibrous reniform crusts, also massive, disseminated, 
 and earthy ; usually of a fine indigo blue ; found in metalliferous veins, as 
 well as a recent formation in connection with decomposed animal matter. 
 It is sometimes used as a pigment. 
 
 Viviparous (Lat. vivus, alive, and pario, I bring forth). Animals 
 455 
 
VOL 
 
 which bring forth their young alive and perfect, are said to be viviparous, 
 in contradistinction to the oviparous, or those which produce their young 
 in the egg. 
 
 Volcanic ( Vulcanus, god of fire). Igneous action apparent at the surface 
 of the earth, in contradistinction to Plutonic (which see), or that taking 
 place at great depths in the interior. Volcanic, as applied to rocks, em- 
 braces all igneous products of recent or modern origin, as distinct from 
 Trappean and Granitic. Cosmically speaking, volcanic activity seems to 
 have been most manifested in the northern hemisphere. See IGNEOUS 
 ROCKS. 
 
 Volcanic Bombs. Bomb -like masses of lava, frequently occurring in 
 great numbers in the vicinity of active volcanoes. Speaking of those on 
 the island of Ascension, Mr Darwin remarks : " They vary in size from 
 that of an apple to that of a man's body ; they are either spherical or 
 pear-shaped, or with the hinder part (corresponding to the tail of a comet) 
 irregular, studded with projecting points, and even concave. Their sur- 
 faces are rough, and fissured with branching cracks ; their internal struc- 
 ture is either irregularly scoriaceous and compact, or it presents a sym- 
 metrical and very curious appearance, which is very simply explained, if 
 we suppose a mass of viscid, scoriaceous matter to be projected with a rapid 
 rotatory motion through the air" 
 
 Volcanic Cones. The name usually given to volcanic hills of active or 
 of recent eruption. These cones are generally spoken of as lava cones, 
 having a gentle slope and pit-like crater of eruption ; tufa cones, having a 
 steep slope and saucer-shaped crater ; cinder cones, having a still steeper 
 slope and narrow crater ; and mixed cones, formed partly of lava and partly 
 of tufa and cinders, and varying in aspect according as one other ingredient 
 predominates or has been the latest erupted. 
 
 Volcanic Foci (Lat. focus, a fire, the point of greatest intensity). 
 Subterranean centres of igneous action, from which minor exhibitions 
 diverge. 
 
 Volcanic Mud, The foetid sulphureous mud discharged by volcanoes, 
 especially those of South America. See CANGANA and MOT A. 
 
 Volcano (Lat. Vulcanus, the god of fire). A volcano has been described 
 by Sir Charles Lyell as " a more or less perfectly conical hill or mountain, 
 formed by the successive accumulations of ejected matter in a state of 
 incandescence or high heat, and having one or more channels of communi- 
 cation with the interior of the earth, by which the ejections are effected." 
 Mr Scrope, who has directed much attention to volcanic phenomena, re- 
 marks that "a volcanic 'cone of eruption,' in its normal form, with a 
 ' crater ' or cup-shaped hollow at its summit, is the result of the accumu- 
 lation round the volcanic orifice or vent of the scoriae, and other fragmen- 
 tary matters projected into the air by the series of explosive discharges of 
 elastic vapour and gases which usually characterise an eruption. The 
 fragments which fall back into the vent are, of course, thrown up again 
 and again, and triturated into gravelly sand or fine ashes by the friction 
 attendant on this violent process. Those which fall on the outside of the 
 vent are heaped up there in a circular bank, the sides of which, both 
 within and without, slope at an angle rarely exceeding 33. And this 
 bank, viewed externally, has of course the shape of a truncated cone the 
 crater being a hollow inverted cone contained within it." 
 
 Volkmaimia (after Volkmann). A provisional genus of Coal-measure 
 456 
 
VOL WAG 
 
 stems having verticillate or whorled leaves, and bearing cones on their 
 extremities. They are regarded as asterophyllites in fructification. 
 
 V6ltzia (after Voltz of Strasburg). A genus of coniferous plants 
 peculiar to the Permian and Triassic formations. They greatly resemble 
 araucarla in the form and imbrication of their leaves, which are inserted 
 all round the pinnated branches, are sessile, slightly dilated at the base, 
 and almost conical. Fruit in spikes or loose cones. 
 
 V6ltzine or Voltzite (after Voltz). Oxysulphuret of zinc, occurring in 
 small hemispherical incrustations, in quartz veins, and usually coloured 
 brown or brownish-red by the presence of a small percentage of iron per- 
 oxide. 
 
 V6raulite. An occasional synonyme for the ferro-magnesian silicate of 
 alumina, better known as blue-spar, azurite, or lazulite from its occurring 
 at Vorau in Styria. See LAZULITE. 
 
 Vulcanism or Vulcanicity (Lat. Vulcanus, the god of fire). A general 
 term adopted by Humboldt, and made use of in his 'Cosmos,' to embrace 
 "the entirety of those telluric phenomena which are to be ascribed to the 
 constantly active reaction of the interior of the earth upon its external crust or 
 surface" Thermal springs, gas and mud volcanoes, burning springs and 
 salses, and the large burning mountains or volcanoes proper, are thus 
 brought under one category ; and he regards it "as advantageous to avoid 
 the separation of that which is casually connected, and differs only in the 
 strength of the manifestation of force and the complication of physical 
 processes." The term has not yet been adopted by English geologists ; 
 and it must be confessed that there is considerable difficulty in associating 
 phenomena which seem to depend on some deep-seated source of heat 
 within the globe, with those that may arise from heat, chemically or other- 
 wise generated, in the mere exterior or superficial crust. 
 
 Vulcanists. Applied to those geologists who opposed the Wernerian 
 or Neptunian doctrine, that all rocks were of aqueous origin, and who con- 
 tended for the presence of igneous action in the formation and modification 
 of the earth's crust. 
 
 Vulcanite. An occasional synonyme of Pyroxene or Volcanic garnet, from 
 its occurrence in ejected blocks and lavas. 
 
 Viilpinite. A granular variety of anhydrous sulphate of lime or gypsum, 
 so called from its being found at Vulpino in Italy, where it is polished for 
 ornamental purposes, under the name of marmo bardiglio. 
 
 W 
 
 Wacke". A German miner's term for a soft earthy variety of trap-rock, 
 resembling indurated clay, but generally containing crystals peculiar to 
 the Trap series. It is usually of a greyish-green colour, from the amount of 
 earth it contains, is sometimes amygdaloidal, and readily crumbles down 
 when exposed to the weather. It seems to be, in some instances, a com- 
 pacted mass of volcanic dust and ashes ; in others, an indurated volcanic 
 mud. See GREY WACKE. 
 
 457 
 
WAD WAT 
 
 Wad or Wadd. A miner's term for an earthy oxide of manganese, 
 occurring in beds and in crusting veins and fissures in the older rocks. It 
 is used chiefly as a coarse pigment in oil-painting ; for colouring and 
 glazing pottery ; and in the manufacture of glass. When mixed with lin- 
 seed oil, the ochrey variety often takes fire spontaneously. 
 
 Wignerite (after Dr Wagner). The fluophosphate of magnesia, a trans- 
 parent mineral, having a vitreo-resinous lustre, wine-yellow or honey- 
 yellow colour, and at one time confounded with the Brazilian topaz. It is 
 very rare, and has been found only near Werfen in Salzburg, in quartz- 
 reins in the Clay-slate formation. 
 
 Wdlchia (after Walch). A genus of coniferous plants occurring in the 
 Carboniferous and Permian systems. According to Sternberg, who erected 
 the genus, they have numerous closely-set, regularly-pinnated branches, 
 resembling those of Araucaria excelsa, and which are thickly beset with 
 foliage. In many instances the branches are terminated by oblong cones, 
 composed of imbricated, oval, or lanceolate pointed scales. 
 
 Warp. A provincial term for the muddy deposit from waters artificially 
 introduced over low lands, as those adjoining the Trent, Ouse, &c. The 
 process of warping consists in causing water loaded with silt to enter low 
 flats at flood-tides, there to remain till it has deposited its mud, and after- 
 wards allowing it to run off clear when the tides are low. It is an im- 
 portant means of fertilising, as well as of raising the general level of large 
 low tracts. 
 
 Waste. In mining, the old neglected workings of a coal-mine ; so called 
 from their being unattended to in ventilation, drainage, and other par- 
 ticulars. 
 
 Water. In chemical nomenclature water is the protoxide of hydrogen, 
 consisting of two volumes of hydrogen and one of oxygen, or of eight parts 
 of oxygen to one of hydrogen by weight 88.9 oxygen, and 11.1 hydrogen. 
 When pure and at ordinary temperatures, it is fluid and amorphous, with- 
 out taste or smell, colourless in small quantities, but in large masses of a 
 peculiar green or blue. The specific gravity of pure or distilled water, at 
 62 Fahr., is assumed at 1.000, and is taken as the standard of gravity 
 for all other bodies ; but sea-water varies according to locality, and the 
 depth from which it is taken, from 1.027 to 1.029. When heated to the 
 temperature of 212 Fahr., at the level of the sea and under the ordinary 
 pressure of the atmosphere, water boils and is converted into steam ; 
 and this boiling-point (as it is termed) becomes less in proportion as 
 we ascend above the sea-level. At 40 Fahr. water is at its minimum 
 volume, expanding as it rises above that temperature till it is wholly 
 converted into vapour, and also, as it falls below it, till it is converted 
 into ice a transparent, brittle, crystalline solid. Water, as found on 
 the earth, is never absolutely pure, but contains more or less of vari- 
 ous substances, as atmospheric air, carbonic acid, nitrogen gas; silica, 
 alumina, and salts (carbonates, sulphates, nitrates, phosphates) of lime, 
 magnesia, soda, potash, protoxide of iron and manganese ; or chlorides 
 and fluorides of their metallic bases ; and in the sea and some saline 
 springs, also iodine and bromine. As a geological agent, water may 
 be regarded in three main lights viz., vitally, as indispensable to 
 the life and growth of plants and animals ; chemically, as entering less 
 or more into the composition of, all inorganic or mineral bodies ; and 
 mechanically, as abrading, transporting, and reasserting the materials of 
 
 458 
 
WAT WEA 
 
 the earth's crust, by its operations in rain, rivers, waves, tides, and other 
 currents. 
 
 Water of Crystallisation. Many substances, in passing from a state 
 of solution to the solid crystalline form, combine chemically with a 
 certain portion of the water, which in a dry state forms an essential part 
 of their crystals, and seems, in some cases, to give the peculiar determina- 
 tion to their constituent molecules ; the amount of this water is the "water 
 of crystallisation." 
 
 Watershed. In physical geography, the ideal line which separates two 
 river-basins or systems of natural drainage all the springs and streamlets 
 " shedding off," like the roof of a house, as it were, to their respective 
 basins. The watershed is not necessarily a mountain-chain, and in some 
 rare instances it is broken by a water-communication connecting two great 
 river-systems. 
 
 Waterspout. " The waterspouts so frequently seen in the ocean origi- 
 nate," says Mrs Somerville, " in adjacent strata of air of different tempera- 
 tures, running in opposite directions in the upper regions of the atmo- 
 sphere. They condense the vapour and give it a whirling motion, so that 
 it descends tapering to the sea below, and causes the surface of the water 
 to ascend in a pointed spiral till it joins that from above, and then it looks 
 like two inverted cones, being thinner in the middle than either above or 
 below. When a waterspout has a progressive motion, the upper and 
 under part must move in the same direction and with equal velocity, 
 otherwise it breaks, which frequently happens." 
 
 Water- worn. Worn away, smoothed and rounded by the action of 
 water, as the "shingle" in the bed of a river, or the "pebbles" on the 
 sea-shore. Water-worn blocks are generally smooth and rounded in form ; 
 weat/ier-wom, rough, and more or less honeycombed. 
 
 Wavellite (after Dr Wavel, its discoverer). Phosphate of alumina ; a 
 transparent yellowish-grey or greenish-grey mineral, occurring in minute 
 acicular crystals, which unite in hemispherical masses, with a radiated 
 fibrous texture and drusy surface. It is found in various formations, but 
 chiefly in clay-slate and other older rocks ; and is sometimes confounded 
 with Hydrargillite, which is a pure hydrate of alumina. 
 
 Wayboards. A mining term, now pretty generally employed by geolo- 
 gists to designate any thin layers or bands that separate or define the 
 boundaries of thicker strata ; thus we speak of thick beds of limestone 
 separated by "wayboards" of slaty shale, of sandstones separated by 
 "wayboards" of clay these thin layers indicating the lines of junction at 
 which the strata separate or give way. 
 
 Weald (Sax. wold, a woodland). The low country lying between the 
 North and South Downs of Kent and Sussex ; and from this locality being 
 the chief area in Britain of a formation that lies between the Oolite and 
 the Chalk, the term Wealden or Weald has been applied to the strata of 
 that formation. See WEALDEN GROUP. 
 
 Wealden Group. In the tabulations of English geologists, that series of 
 strata which occurs between the uppermost beds of the Oolite and the lower 
 ones of the Chalk formation. By some it is regarded as a fresh-water or 
 estuarine group of the Oolitic system ; by others it is classed as the lowest 
 member of the Cretaceous system ; but as a subordinate "group," litholo- 
 gically and palseontologically, it is sufficiently distinct from either. Dr 
 Mantell, to whom we are indebted for the most detailed account of the 
 
 459 
 
WEA WEN 
 
 Wealden, describes it as "a series of clays and sands with subordinate beds 
 of limestone and shale, containing fresh-water shells, terrestrial plants, 
 and the teeth and bones of reptiles and fishes ; univalve shells prevailing 
 in the upper, bivalves in the lower, and saurian remains in the intermedi- 
 ate beds ; the state in which the organic remains occur manifesting that 
 they have been subject to the action of river-currents, but not to attrition 
 from the waves of the ocean." As a group, the Wealden is of limited ex- 
 tent in England and on the continent of Europe, while in other regions its 
 precise equivalents have not yet been detected. As typically developed in 
 Kent and Sussex, it seems to occupy the site of an ancient estuary, which 
 received the clay and mud of some gigantic river, whose waters occasion- 
 ally bore down the spoils of land plants and land animals, to be entombed 
 along with those of aquatic origin. Regarding it as the upper group of 
 the Oolitic system, it may be said to consist of two main members the 
 Weald Clay and Hastings Sands, which, when analysed, exhibit the follow- 
 ing particulars, taken in descending order : 
 
 Weald Clay. Thick blue clays, having in the upper part septaria of 
 argillaceous ironstone, and in the lower parts beds of the shelly 
 fresh-water limestone (paludina limestone) known as " Sussex, Pet- 
 worth, or Bethersden marble." 
 
 Hastings Sands. Fawn-coloured sand and friable sandstone (Horsham 
 beds) ; calciferous sandstones, alternating with friable and conglome- 
 rate grits (Tilgate beds) ; white sand and friable sandstone alternating 
 with clay (Worth Sandstone) ; bluish limestone alternating with blue 
 clay and sandstone shale, and some beds of calciferous sandstone ( Ash- 
 burnham beds). See tabulations, " GEOLOGICAL SCHEME." 
 "Weathering. The wasting or wearing away of rock-surfaces by exposure 
 to the atmosphere or weather. Geologists speak of the " fresh fracture " 
 in contradistinction to the " weathered surface," which is often merely 
 discoloured or covered by a pellicle of lichens. 
 
 Weather-worn. Applied to rocks and cliffs whose faces are less or more 
 wasted and worn away by the action of the water. Many rocks being of 
 unequal hardness, their weather-worn surfaces present very fantastic shapes, 
 and are often deeply pitted and honeycombed. 
 
 Websterite (after Dr Webster). Hydrous subsulphate of alumina ; 
 known also as Aluminite; a snow-white or yellowish-white earthy mineral 
 occurring in soft reniform masses, with a very fine scaly or fibrous structure. 
 It seems to arise from the decomposition of clays in recent formations, and 
 consists of 30.26 alumina, 23.37 sulphuric acid, and 46.37 water. 
 
 Wenlock Limestone and Shale. A characteristic group or section of the 
 Upper Silurian strata, typically developed near Wenlock, in Shropshire. 
 Near Wenlock the limestone (formerly well known to collectors as the 
 "Dudley Limestone") consists of thick masses of grey sub-crystalline 
 strata, replete with corals and encrinites. It is essentially of a concretion- 
 ary nature, the concretions being locally known as " bell-stones," and con- 
 sisting of pure carbonate of lime. The shale, which is a mass of fine argil- 
 laceous matter, imbedding numerous calcareous concretions, is by far the 
 largest member of the group, ranging from 600 to 1000 feet in thickness, 
 and replete with corals, encrinites, trilobites, shells, and other marine 
 exuviae. Near Coalbrookdale the shale is known as " die-earth," because 
 it lies beneath all the mining ground the minerals "dying out," as it were, 
 at this stage of descent. See SILURIAN SYSTEM. 
 
 460 
 
WER WIL 
 
 Wernerite (after Werner). A rare mineral, occurring in long prismatic 
 crystals, translucent, colourless, pale-grey or greenish-yellow ; and found 
 chiefly in veins in the crystalline rocks. Chemical and crystallographic 
 constitution somewhat uncertain, but now regarded as a variety of SCAPO- 
 LITE, which see. 
 
 Wetherellia (after Mr Wetherell). One of Mr Bowerbank's genera of 
 fossil fruits from the London Clay. They seem to have been pulpy fruits 
 divided into two lobes by the expansion of the ripe seeds ; and from the 
 appearance which their section presents, are popularly known as "petri- 
 fied coffee-berries." 
 
 Wheal. In Cornwall a very frequent designation for a mine; being a 
 modern form of the old Cornish word Hud, a mine. 
 
 Whet-stone. Known also as " Whet-slate" and " Novaculite ;" a very 
 hard, fine-grained siliceous slate, used for sharpening knives, joiners' tools, 
 and other instruments. See HONE. 
 
 Whim. In mining, a machine consisting of a winding barrel or cylinder, 
 usually worked by horse or water power, and used for raising ore, coal, or 
 other stuff from a mine. 
 
 Whin, Whinstone. Used in Scotland as synonymous with greenstone ; 
 but applied by miners and quarrymen to any hard resisting rock that comes 
 in the way of their operations. 
 
 Whirl or Whorl. In conchology, a wreath or single turn of the spire of 
 a univalve shell, such as the helix or garden snail. The axis of revolution 
 is termed the columella, and the turns of the spiral are denominated whirls 
 or whorls. In some shells the whirls are few, in others they are numerous 
 and distinct ; in some they are arranged in a long, tapering, screw-like 
 spiral ; in others they form a short, pointed cone ; while in many they are 
 coiled round each other on a horizontal plane in wheel- like or discoid form. 
 In most univalves, when the aperture is turned towards the spectator, and 
 the apex upwards, the whirls run from left to right to the apex ; in a few 
 this order is reversed ; hence we speak of reversed or sinislral shells. 
 
 Whirlpool. Any rotatory or circular motion of water produced by op- 
 posing winds and tides. The whirlpool of Maelstrom, on the coast of 
 Norway, is occasioned by the meeting of tidal currents round the islands 
 of Lofoden and Moskoe. It is a mile and a half in diameter, and so violent 
 that its roar is heard at the distance of several leagues. 
 
 Whirlwind. The name given to aerial currents that assume a rotatory, 
 whirling, or spiral motion. They are often of great violence, but fortu- 
 nately of short duration, and are most frequently caused by the meeting 
 of two contrary winds, though sometimes by obstructions of the land, as 
 precipitous mountains, narrow gorges, and the like. Their occurrence at 
 sea produces waterspouts ; on the loose sands of the desert, sand-pillars 
 and kindred phenomena. 
 
 Whitby Snakes. A provincial, and now obsolete, term for the coiled-up 
 snake-like shells of the ammonite, found abundantly in the Lias of Whitby, 
 in Yorkshire. 
 
 Whitestone. A variety of felspathic granite ; the Weiss-stein of Werner ; 
 and the Eurite of French mineralogists. See EURITE. 
 
 Wichtisite or Wichtyne. One of the Garnet family, nearly allied to 
 Glaucophane (which see) ; and so called from its being found at Wichtis in 
 Finland. 
 
 Williamite (after Prof. Williams). A siliceous oxide of zinc, nearly 
 461 
 
WIN WOL 
 
 related to Galmei or electric calamine, and usually found along with it. 
 See ZINC. 
 
 Wind (Sax.) The general name for aerial currents caused by the unequal 
 heating of the atmosphere the heated and more rarefied portions ascend- 
 ing, and the colder and denser flowing downwards to supply their place. 
 Winds are divisible into three great categories permanent, like the trade- 
 winds ; periodical, like the monsoons and the sea and land breezes ; and 
 accidental, when the times of their occurrence cannot be determined. 
 
 Windward. In nautical phraseology, all objects on the weather-side of a 
 vessel, or that against which the wind blows, are said to be to the wind- 
 ward that is, in the direction from which the wind blows. See LEEWARD. 
 Win, Winning. In mining phraseology, the term "winning" is applied 
 to the whole series of operations boring, sinking, excavating, &c. by 
 which any mineral is actually procured or " won " from the crust of the 
 earth. Most frequently used in coal-working. 
 
 Wings. In mining phraseology, the sides or slopes of an anticline or 
 saddle-back. 
 
 Wissenbach Slates. A series of slaty schists, impure limestones, and 
 quartzose beds, which lie at the base of the Devonian system as developed 
 in the country along the Rhine. 
 
 Withamite (after Dr Witham). A variety of epidote, found in porphyry 
 in Glencoe, and occurring in minute bright- red crystals. See EPIDOTE. 
 
 Witherite (in honour of Dr Withering, its discoverer). Carbonate of 
 barytes (80 barytes, 20 carbonic acid) ; known also as barolite, and found 
 abundantly in veins traversing the older formations. It occurs massive of 
 a somewhat fibrous structure, or in distinct crystals ; whitish or yellowish 
 grey, and strongly translucent. See BARYTES. 
 
 W6hlerite (in honour of Wohler the chemist). A translucent, vitreous, 
 yellowish-brown mineral, occurring in tabular crystals, or in strongly stri- 
 ated six- or eight-sided prisms in the zircon- syenite, near Fredericksvarn 
 and Brevig in Norway ; and containing, according to Scheerer, 30.62 silica, 
 14.47 niobic acid, 15.17 zirconia, 26.19 lime, 7.78 soda, and the protoxides 
 of iron and manganese. 
 
 t Wolchite. The prismatoidal copper-glance of Phillips ; a mixed ore of 
 copper, lead, antimony, arsenic, and sulphur, occurring in the iron mines 
 of Wolch, in Carinthia. 
 
 Wolchonskoite, Volchonskoite. A variety of chrome-ochre, occurring 
 as an emerald-green or blackish-green massive mineral, and containing 
 from 20 to 35 per cent of chrome-oxide. 
 
 Wolfram (Ger. wolf, wolf, and rahm, froth). The name given by Wer- 
 ner to the tungstate of iron and manganese, a mineral occurring in short 
 prismatic crystals, or in granular froth-like aggregates of a blackish- 
 brown colour, metallic adamantine lustre, and having a specific gravity of 
 from 7 to 7.5, and a hardness about 6. It occurs, for the most part, asso- 
 ciated with ores of tin in the primary and transition rocks, and occasion- 
 ally in such abundance as to render the tin-ore worthless. According 
 to Berzelius, it consists of 74.67 tungstic acid, 18 protoxide of iron, and 
 6 manganese, with a trace of silicia. 
 
 Wolfsbergite. Antimonial copper ; a double sulphuret of copper and 
 antimony, found crystallised, massive, or granular, in quartz at Wolfsberg, 
 in the Harz Mountains. 
 
 Wdllastonite (after Wollaston the chemist). The tabular spar of Phillips; 
 462 
 
WOO XAN 
 
 a silicate of lime, with traces of magnesia and iron, occurring chiefly in 
 granular limestone, but also in the trap and volcanic rocks. It is ranked 
 as one of the Hornblende family, but is rarely crystallised occurring 
 mostly in broad prismatic or tabular masses, of a greyish-yellow or reddish- 
 brown colour, having a vitreous or pearly lustre. Specific gravity, 2.8 ; 
 hardness, 4.5. 
 
 Wood-Coal. A synonyme for Lignite or Broicn-coal, in allusion to its 
 woody texture, which is often as distinct and well-preserved as the texture 
 of recent timber. See LIGNITE. 
 
 Wood-Opal. A variety of opal, known also as litkoxylon or opalised wood, 
 in which the form and texture of the wood is still distinctly visible. Beau- 
 tiful specimens are obtained from Hungary, and from near Hobart Town 
 in Van Diemen's Land. 
 
 Woodstone. A familiar term for silicified wood, such as that from An- 
 tigua, the Desert of Cairo, and Van Diemen's Land. 
 
 Wood-Tin. Fibrous oxide of tin ; a variety of tin-ore so called from its 
 fibrous texture resembling that of wood. It is usually of a brown or yel- 
 lowish-grey colour, and occurs in rounded fragments, having an internal 
 fibro-radiating texture. It is found in Cornwall, Mexico, and other tin- 
 yielding countries ; and consists, according to Vauquelin, of 91 oxide of 
 tin, and 9 peroxide of iron. See TIN. 
 
 Woolwich Beds. A name occasionally employed by English geologists 
 to designate those beds of plastic and mottled clays, sands, and rolled flint- 
 pebbles which lie between the " Thanet Sands " and the " London Clay." 
 Next to the Thanet Sands they form the lowest beds of the London Terti- 
 ary Basin. 
 
 Wrae Limestone. A limestone of the Lower Silurian series, occurring at 
 Wrae Hill, near Innerleithen, in Peeblesshire. 
 
 Wulfenite. A mineralogical term for the molybdate of lead ; a mineral 
 of a wax or orange-yellow, occurring in short prismatic or pyramidal crys- 
 tals collected in druses, and found in beds and veins in Secondary and tran- 
 sition limestones. Consists of 60 protoxide of lead, and 40 molybdic acid. 
 
 Wych or Wich. A Celtic word signifying salt spi'ing; hence the termi- 
 nation of such English towns as Droitwich, Nantwich, Middlewich, &c., 
 where salt springs exist. 
 
 Xanthidium (Gr. xanlhos, yellow). A genus of Diatoms, whose micro- 
 scopic case or fristule consists of a hollow, siliceous globe, beset with 
 spines ; and whose endochrome or colouring matter, in recent species, is 
 of a deep yellowish-green ; whence the name. They abound in recent, 
 Tertiary, and upper Secondary formations ; and from their increase by 
 self-division, usually appear as twin spherules. 
 
 Xdnthite (Gr. xanthos, yellow). A mineral of the Garnet family, occur- 
 ring in small, greenish-yellow, translucent, loosely-connected grains, in a 
 bed of limestone near Amity in New York. It seems, from its compo- 
 sition, to be a variety of idocrase, which is found in the same locality. 
 
 463 
 
XAN YEL 
 
 Xdnthokon. A sulpho-arsenite of silver, occurring in rhombohedric 
 crystals, or in small reniform masses ; and so called from its orange-yellow 
 or yellowish-brown colour. It consists of 63.4 silver, 14.7 arsenic, and 21.9 
 sulphur. 
 
 Xanthophyllite (Gr. xanthos, yellow ; phyllon, leaf; and lithos}. The 
 rhombohedric pearl-mica of Mohs, occurring in mica and talc schists, and 
 so named from its yellowish colour and foliated texture. 
 
 Xiphosura (Gr. xiphos, a sword, and oura, a tail). Literally "sword- 
 tail ;" a division of the entomostracous crustaceans, in which the last seg- 
 ment of the body forms (in the adult animal) a long, three-edged, sharp- 
 pointed weapon, as in thelimulus, or king-crab. The xip/iosura differ from 
 other crustaceans in having the basal joint of their thoracic feet furnished 
 with spines which serve as masticatory organs (foot-jaws) ; in having their 
 branchiae or gills composed of membranous folds attached to the basal 
 portion of the abdominal legs ; in having the head and breast united into 
 one buckler-like plate (the cephalo-thorax) ; and in having the abdominal 
 buckler terminating in the long sharp-pointed spine which gives them 
 their name. The thoracic feet, which generally terminate in pincer-like 
 claws, are used for prehension and mastication ; the abdominal, which 
 are foliaceous or leaf-like, subserve the purposes of swimming and respir- 
 ation. The existing species are all marine, and inhabitants of warmer 
 regions ; the fossil species range from the Upper Silurian and Lower 
 Old Red, and appear to have been of much more gigantic dimensions than 
 their living congeners. 
 
 X^lite (Gr. xylon, wood). A mineralogical term for those varieties of 
 amianthus which have a woody-like texture ; and better known, perhaps, 
 as " mountain-wood," "rock-wood," &c. They consist essentially of silica, 
 magnesia, and iron protoxide. 
 
 Xyl6bius (Gr. xylon and bios). Literally " timber-liver ;" a small 
 chilognathous myriapod discovered by Dr Dawson in the interior of sigil- 
 larise in the Lower Coal-measures of Nova Scotia ; and so termed from its 
 supposed habit of burrowing in the decayed trunks of trees, such as those 
 in which its remains were found petrified. If indeed a myriapod, it is the 
 earliest of its kind yet known to palaeontology. 
 
 Xyldretine (Gr. xylon, wood, and retine, resin). Literally " wood-resin ;" 
 a sub-fossil resinous substance occurring in connection with the pine-trunks 
 of certain peat-mosses, and evidently the slightly-altered resins of these 
 
 Ydnolite. The name given by Lametheric to the Thummerstein of Wer- 
 ner, and the Axinite of Haiiy. One of the Garnet family, consisting of 
 silica, alumina, lime, iron, and manganese. 
 
 Yellow Earth, Yellow Ochre. A massive earthy mineral of the Clay 
 family, of an ochre-yellow colour, somewhat greasy feel, adheres to the 
 tongue, and pulverises in water. It seems to be a mixture of hydrous 
 
 464 
 
YEN ZAF 
 
 silicate of alumina, with hydrous peroxide of iron ; and is perhaps a decom- 
 posed clay-ironstone. When burnt and prepared it is sold by the Dutch 
 as a pigment under the name of " English Red." 
 
 Yenite. A double silicate of lime and iron, occurring in crystalline 
 strata, along with quartz, magnetic ironstone, copper pyrites, and other 
 ores ; and known also as Lievrite or Ilvaite. It was named Yenite in com- 
 memoration of the battle of Jena, in 1806 ; Ilvaite, from Elba, where it 
 occurs ; and Lievrite, after its discoverer, Le Lievre. 
 
 Yoredale Eocks. The name given by English geologists to the upper 
 group of the Carboniferous Limestone, as developed in the north-western 
 parts of Yorkshire the Scar Limestone forming the lower group. The 
 Yoredale Rocks consist of several beds of limestone alternating with free- 
 stones, flagstones, shales, and thin seams of coal, and attain a thickness of 
 about 1000 feet. 
 
 You-Stone. A familiar term for Chinese Jade, or Nephrite, which see. 
 
 Y'ttria. The name given by Ekeberg to a new earth discovered by 
 Gadolin, in 1794, in the quarry of Ytterby in Sweden ; hence the name. 
 It has also been called Gadolinite (which see), after its original discoverer. 
 
 Y'ttria-Spar. According to Hartmann, this occurs as a white incrusta- 
 tion, as Gadolinite, and other minerals from Ytterby in Sweden. 
 
 Yttrium. The metallic basis of the earth yttria. When separated 
 from the silica, lime, iron, and manganese with which it is associated in 
 yttria, it appears as a fine white powder, tasteless, inodorous, infusible, 
 and insoluble in water. 
 
 Yttro-Cerite. A rather rare mineral substance, occurring in granular 
 incrustations of a violet-blue to a whitish-grey colour ; and consisting, 
 according to Berzelius, of about 47 lime, 18 peroxide of cerium, 10 yttria, 
 and 25 hydro -fluoric acid. 
 
 Yttro-Columbite. The name given by Brochant and Dana to yttrious 
 oxide of columbium ; Yttro-tantalite, which see. 
 
 Yttro-I'lmenite. Same as Lamarskite, which see. 
 
 Yttro-Tantalite. Yttrious oxide of tantalum ; a mineral occurring in 
 kidney-shaped masses, of a shining metallic lustre, at Ytterby in Sweden. 
 Berzelius distinguishes the black, brown, and yellow varieties ; which 
 consist of somewhat varying proportions of tantalic and tungstic acids, 
 yttria, lime, and peroxides of uranium and iron. 
 
 Yttro-Titanite. Known also as Keilhauite; a blackish-brown translucent 
 mineral, having a resinous fracture, and much resembling garnet, but 
 distinguished by its greater specific gravity. It is a silicate of lime, iron, 
 and alumina, with titanic acid and yttria ; and occurs in the granitic and 
 crystalline rocks of Norway. 
 
 Zaffire. In mineralogy, the impure oxide of cobalt, being the residuum 
 of the native arseniuret of cobalt, after the arsenic, sulphur, and other 
 volatile matters have been expelled by calcination. Melted with silica and 
 potash, and reduced to powder, it becomes the "powder-blue" of commerce. 
 
 465 2 a 
 
ZAM ZEU 
 
 Zami6strobus. The generic term applied to fossil cone-like fruits, appar- 
 ently those of plants allied to the zamia and cycas. They occur chiefly in 
 the Upper Oolite, Wealden, and Chalk formations. 
 
 Zamites. The general term for all fossil plants apparently allied to the 
 existing zamia. They make their appearance in the Upper Oolites, and 
 continue throughout the Secondary and Tertiary formations. The existing 
 zamias (see order Gycadacece) being natives of the tropical parts of Asia 
 and America, and of the Cape of Good Hope and Australia, their occur- 
 rence in ancient formations gives evidence of tropical or sub-tropical con- 
 ditions of climate in the areas of deposit. 
 
 Zeagonite (Gr. zeo, I swell or bubble up, and gone, an angle). A mineral 
 of the Zeolite family, and so named from its tetragonal crystals, which are 
 chiefly arranged in spheres or bundles. Known also as Gismondine and 
 Abrazite ; but not very decidedly separable from the lime or potash harmo- 
 tomes or cross-stones, to which it is often referred. 
 
 Zechstein (Ger.) Literally "mine-stone;" because it has to be mined 
 or cut through to reach the copper-slate (Kupfer-schiefer) which lies imme- 
 diately beneath it. Von Buch suggests that the word was probably de- 
 rived from the Italian zeccMno or sequin, formerly a well-known coin in 
 Germany, because this calcareous rock was the cover which, being pierced, 
 led to the bed of ore from which the miner derived his profit. The German 
 " Zechstein " upper and lower is the equivalent of the Permian or Mag- 
 nesian Limestone of England. See PERMIAN SYSTEM. 
 
 Zellania. A sub-genus of Terebratulse occurring in the Oolitic forma- 
 tion, and characterised by their small, triangular, distinctly punctate shells, 
 which are rounded in front, taper towards the beak, are thickest at the 
 umbo, and have the sides somewhat flattened. 
 
 Zenith (Arabic.) In astronomy, that point in the heavens which is ver- 
 tically or right above the bead of the spectator ; the term nadir being that 
 which denotes the opposite point, or that perpendicularly or right under 
 his feet. In popular language, the term Zenith is used to denote the high- 
 est or culminating point of any subject referred to ; as the " zenith of the 
 poet's fame," the " zenith of saurian development." 
 
 Zeolite (Gr. zeo, I boil or bubble up, and lithos, stone). An extensive 
 family of minerals silicates of lime and alumina so called from their 
 frothing or intumescing into a whitish spongy enamel under the blowpipe. 
 The family includes hexahedral zeolite or analcime, prismatic or natrolite 
 and mesotype, prismatoidal or stilbite, hemiprismatic or Heulandite, pyra- 
 midal or apophyllite, rhomboidal or chabasite, diprismatic or laumonite, 
 paratomous or harmatome, &c., all of which are noticed under their respec- 
 tive names. The zeolites occur most abundantly in the amygdaloidal trap- 
 rocks ; frequently in basalt and greenstone ; occasionally in the granitic 
 and crystalline rocks ; and more rarely in the trachytes and lavas. 
 
 Zero. A word of Arabic origin signifying emptiness or extreme depri- 
 vation, and usually represented by a cipher or 0. It is variously used in 
 science ; but may be generally defined as the neutral point between any 
 ascending and descending scale or series. In familiar language it is used as 
 synonymous with nothing, or the extreme point of depression. The zero 
 of Fahrenheit's thermometric scale is 32 below freezing ; the real or abso- 
 lute zero would be the point at which caloric was entirely exhausted. 
 
 Zeuglodon (Gr. zeugos, a yoke, and odous, tooth). Literally "yoke- 
 tooth ; " a Tertiary mammal of the whale kind, so called by Professor Owen 
 
 466 
 
ZEU ZIR 
 
 from the peculiar form of its molar teeth. Remains of a skeleton between 
 seventy and eighty feet in length were first discovered in the Eocene strata 
 of Alabama and Arkansas, and described by Dr Harlan under the title 
 BASILOSAURUS (king of the lizards], under the supposition that they be- 
 longed to an enormous reptile a belief that has since been set aside by 
 the more correct investigations of our great English anatomist. 
 
 Zeiixite (Gr. zeuxis, connection or union, because found in the united 
 mines, Cornwall). A mineral of the Scapolite family, occurring in fibrous 
 masses of acicular crystals of a greenish-brown colour, and evidently 
 allied to Prehnite. Chemically, it is a ferro-silicate of alumina. 
 
 Zianite. Werner's synonyme for kyanite or cyanite, one of the Garnet 
 family, which see. 
 
 Zinc (Ger. zink). One of the simple or elementary bodies ; a metal of a 
 bluish-white colour, with a fine granular fracture, foliated structure, spe- 
 cific gravity about 7, harder than lead, but may easily be cut with a knife. 
 At common temperatures it is tough and intractable under the hammer ; 
 but when heated to between 220 and 320 it becomes malleable and duc- 
 tile, so that it can be beaten into plates, or rolled into sheets and leaves, 
 and drawn into wire. If heated, however, to 500 or so, it becomes brittle, 
 and fuses at 770. It tarnishes on exposure to the air, but is little oxidated, 
 the first-formed film of oxide long resisting the action of air and water, 
 and thus preventing further decay. Being a cheap and light metal, zinc 
 is largely used as a substitute for lead ; alloyed with copper, it forms the 
 well-known compound brass; and its salts are extensively used in medicine 
 and the arts. As a metal, zinc does not occur native ; and its chief ores 
 a,recalamine, or the carbonate, occurring most abundantly in limestones 
 along with calc-spar, ores of lead and iron, and other ores of zinc ; blende, 
 or the sulphuret, found also in veins with other ores ; Goslarile, or the sul- 
 phate, arising apparently from the decomposition of blende ; zincite, or the 
 red oxide ; and galmri or the siliceous oxide, usually found in connection 
 with calamine. The ores of zinc are readily determined by first roasting 
 and then fusing by the blowpipe on charcoal with copper filings. If zinc 
 is present the copper will be converted into a button of brass. 
 
 Zincite.- The mineralogical term for the native ferriferous oxide of zinc, 
 which see. 
 
 Zlnckenite, properly Zinkenite. A native sulphuret of antimony and 
 lead (35 lead, 43.4 antimony, and 21.6 sulphur), occurring in narrow ver- 
 tically-striated prisms, or in massive and columnar aggregates in veins, 
 along with sulphuret of antimony and quartz, at Wolfsberg, &c., in the 
 Harz, and so named after its discoverer, Zinken. 
 
 Zircon. One of the gems ; a heavy, hard, sparkling mineral, more or 
 less transparent ; doubly refractive ; and occurring colourless, or of vari- 
 ous colours, as yellow, green, and reddish-brown. It is found in prismatic 
 crystals, or in rounded grains, chiefly in the granitic and crystalline rocks; 
 and consists, according to Berzelius, of 33 silica and 67 zirconia. The 
 colourless varieties named jargon are often sold for diamonds ; the brilli- 
 antly-coloured are termed hyacinth, though many "hyacinths" are merely 
 garnets, and easily detected by their inferior gravity, hardness, fusibility, 
 and want of double refraction. 
 
 Zirc6nia. The oxide of zirconium; a white tasteless earth, discovered 
 by Klaproth in 1789, in zircons from Ceylon zircon being a silicate of 
 zirconia more or less highly coloured by oxide of iron. 
 
 467 
 
ZIR ZON 
 
 Zirc6nium. The metallic basis of zirconia, obtained in the form of a 
 black powder, resembling that of charcoal, but lustrous when rubbed. 
 
 Zoantharia (Grr. zoon, animal, and anthos, flower). Animal -flowers ; in 
 De Blainville's arrangement, the third class of zoophytes, including the 
 hydras, coral-polypes, sea-anemones, and the like, whose bodies or digestive 
 sacs are furnished with tentacula, which radiate from the mouth like the 
 petals of a flower. 
 
 Zodiac (zodion, a little animal). The name given by astronomers to the 
 zone within which the apparent motions of the sun, moon, and all the 
 greater planets are performed. It constitutes a belt nine degrees on either 
 side of the ecliptic, and is so named from its containing the figures of the 
 animals, &c., which represent the twelve signs. 
 
 Zoisite. A variety or sub-species of epidote, or prismatoidal augite spar, 
 of a yellowish or light-grey colour, occurring in granite, diorite, and other 
 crystalline rocks, and named after its discoverer, Baron von Zois. 
 
 Zone, in geography (Gr. zona, a girdle). One of the five great belts into 
 which the earth is supposed to be divided in respect to temperature ; viz., 
 the torrid, two temperate, and two frigid zones. The torrid includes all 
 the space that lies between the tropics, or 23^ degrees on each side of the 
 equinoctial line ; the temperate from that limit to the arctic circle (66g 
 degrees) in each hemisphere ; and the frigid zones from the arctic circles 
 to either pole. 
 
 Zone, in botany. With a view to generalise their observations on the 
 geographical distribution of indigenous plants, botanists are in the habit 
 of dividing the horizontal range of vegetation into zones, bounded by annual 
 isothermal lines, as 1, the equatorial ; 2, tropical ; 3, sub-tropical ; 4, 
 warmer temperate ; 5, cooler temperate ; 6, sub-arctic ; 7, arctic ; and, 8, 
 the polar. These zones, being applicable to either hemisphere, express 
 the climatic facies of vegetation within more precise limits than the three 
 great zones torrid, temperate, and frigid of the geographer. 
 
 Zone, in zoology. Every zone, from the shore daily covered by the tides 
 to the greatest vital depths, being characterised by its own peculiar sea- 
 weeds and shell-fish, in a manner very analogous to the changes in the 
 forms and species of vegetation observed in the ascent of a tropical moun- 
 tain, zoologists are in the habit of speaking of certain bathymetrical 
 zones or "zones of life regulated by depth." Thus, in the British seas, 
 naturalists (following the late Edward Forbes) point out four great belts 
 of life the Littoral, the Laimnarian, the Coralline, and the Coral (which 
 see) ; or, applying the principle to the life of the ocean in general, they 
 distinguish five belts of depth viz., 1, the Littoral; 2, Circum-littoral ; 
 3, Median ; 4, Infra-median ; and, 5, the Abyssal or Deep-sea zone. 
 " The life-forms of these zones," says Professor Owen, "vary, of course, 
 according to the nature of the sea-bottom ; and are modified by those 
 primitive or creative laws that have caused representative species in distant 
 localities under like physical conditions species related by analogy. Very 
 much (he continues) remains to be observed and studied by naturalists in 
 different parts of the globe, under the guidance of the generalisations thus 
 sketched out, to the completion of a perfect theory ; but in the progress 
 to this the results cannot fail to be practically most useful. A shell or a 
 sea-weed, whose relations to depth are thus understood, may afford im- 
 portant information or warning to the navigator. To the geologist, the 
 distribution of marine life according to the zones of depth has given the 
 
 468 
 
ZOO ZYG 
 
 clue to the determination of the depth of the seas in which certain forma- 
 tions have been deposited." 
 
 Zo61ogy (Gr. zoon, an animal, and logos, discourse). The science of liv- 
 ing beings in all that relates to their structure, habits, distribution, and 
 classification. Zoological, appertaining to the science of animal life ; 
 zoologist, one devoted to the study of zoology, or the knowledge of animal 
 forms in all their relations structural, functional, and gradational. For 
 systematic arrangements, see tabulations, " ANIMAL SCHEME." 
 
 Zo6nomy (Gr. zoon, an animal, and nomos, law). The science which treats 
 of the laws of organic life, in as far as these relate to the A nimal kingdom. 
 
 Zoophagous (Gr. zoon, an animal, and phago, I eat). Animal-eating ; 
 applied to certain tribes of animals (e. g., " zoophagous molluscs") which 
 prey on other animals : in contradistinction to those that are phytopftagous 
 or vegetable-feeders. 
 
 Z6ophyte (Gr. zoon, animal, and phyton, plant). A nimal- plants ; an 
 early and popular division of the animal kingdom, including the sponges, 
 corals, and other allied aquatic creatures, which, from their manner of 
 growth and appearance, were supposed to be intermediate between plants 
 and animals. Being wanting in scientific precision, the term is only 
 loosely and popularly applied to those polypes, polyzoa, &c., which secrete 
 plant-like substances, as sponges, corals, corallines, and so forth. 
 
 Zoophyt6logy (Gr. zoophyton, a zoophyte, and logos, discourse). That 
 department of natural history which treats of the structure, mode of 
 growth, habits, and distribution of zoophytes. 
 
 Zosterites. A genus of fluviatile plants occurring in the Wealden and 
 Lower Greensand formations, and so called from their resemblance to the 
 existing zostera marina or sea-wrack. In zosteriies the leaves are linear, 
 marked with few veins, and these not connected by transverse veins. 
 
 Ziindererz (Ger.) Tinder-ore ; an ore of antimony occurring in the Saxon 
 mines in soft, flexible, tinder-like masses, of a blackish-red colour and 
 little lustre. From analysis it appears to be an admixture of silver, lead, 
 iron, antimony, arsenic, and siilphur. 
 
 Zwieselite. A fluo-phosphate of iron and manganese, so called from 
 being found at Zwiesel, in Bavaria. 
 
 Zygomaturus. A large marsupial mammal the most extraordinary yet 
 discovered in the Post-tertiary deposits of Australia, and so named from 
 the great width of the zygomatic arches of the skull. Judging from the 
 size of the head, which was the only portion found in 1858, it seems to 
 have been as large as an ox, and to have had a face somewhat resembling 
 that of the existing wombat. It also appears to make a near approach to, 
 though differing generically from, the Diprotodon, another large marsupial 
 from the same ancient alluvial beds. 
 
III. 
 
 SPECIFIC APPELLATIONS 
 
NOTE. 
 
 THE following List contains the greater portion of those terms employed 
 by palaeontologists to distinguish their so-called species of fossil plants and 
 animals.* Most of them are Latin, or Latinised forms, and refer chiefly to 
 external aspect ; not unfrequently to the name of the discoverer, or other 
 individual eminent in the branch of natural history to which the object 
 belongs ; and in many instances to the locality where it was first detected, 
 or in which it is exclusively found. Thus, Pecten quinqiwcostatus, the 
 five-ribbed pecten ; P. Woodwardii, after S. P. Woodward, the eminent 
 conchologist ; and P. PurbecJcensis, a species apparently peculiar to the 
 Purbeck beds of the Oolite. Whatever their origin (and it is greatly to be 
 desired that describers would in every instance endeavour to adopt such 
 terms as refer to some palpable characteristic), these designations follow 
 the usual inflexion of Latin words ; rotundus, rotunda, roturidum pulcher, 
 pulchra, pulchrum or brevis, brevis, breve, being respectively applied just 
 as the generic word to which they refer may be masculine, feminine, or 
 neuter ; while the names of discoverers, &c., are thrown into the possessive 
 case, as Lyellii, Murchisoni; and those of localities converted into adjec- 
 tives, as Hibernians, Purbeckensis, and the like, but this, it must be con- 
 fessed, not always in the most classical or most euphonious forms. Our 
 present business, however, is more with their meanings than with their 
 origin, and these we have endeavoured to render in the simplest and brief- 
 est language, consistent with the comprehension of the fact or character 
 which the original term was intended to express. 
 
 * We say " so-called species ; " for, in the emphatic words of Professor Carpenter, 
 " there are still too many who are far too ready to establish new species, upon 
 variations of the most trivial character, without taking the pains to establish the 
 value of these ditferences, by ascertaining their constancy through an extensive 
 series of individuals, thus, as was well said by the late Prince of Canino, ' de- 
 scribing specimens instead of species,' and burdening science not only with a use- 
 less nomenclature, but with a mass of false assertions. It should be borne in mind 
 that every one who thus makes a bad species, is really doing a serious detriment 
 to science ; whilst every one who proves the identity of species previously ac- 
 counted distinct, is contributing towards its simplification, and is therefore one of 
 its truest benefactors." 
 
SPECIFIC APPELLATIONS. 
 
 A 'celensis, is, e; found at Aalen in Wirtemberg. 
 abbrevidtus, a, um; shortened ; comparatively short. 
 abductus, a, um; removed. 
 aVies;' the fir-tree ; fir-tree-like. 
 abjectus, a, um; worthless. 
 
 abndrmis, is, e; out of the usual order ; abnormal. 
 abrfiptus, a, um; abrupt ; terminating suddenly. 
 Acadianus, a, um; of, or belonging to, Nova Scotia. 
 acd^dis, is, e; stalkless ; stemless. 
 
 acciptnseroldes; sturgeon-like ; resembling the sturgeon. 
 acerdsus, a, um; of the maple-tree ; resembling the maple. 
 acetdbulum; slightly concave, like a cup or calyx. 
 aciculdtus, a, um; needle-pointed ; furnished with sharp points. 
 aciedentatus, a, um; needle-toothed ; sharp-toothed. 
 acinaci/6rmis, is, e; scimitar-shaped. 
 actinura; star- tailed ; prickly- tailed. 
 aculedtus, a, um; prickly ; armed with sharp points. 
 acumin&tus, a, um; pointed ; terminating sharply. 
 acutdngulus, a, um; acute-angled ; sharp-cornered. 
 ac&tifolius, a, um; sharp-leafed ; having pointed leaves. 
 acutirdstris, is, e; sharp-nosed;- sharp-beaked. 
 acuiiusculus, a, um; rather sharp ; somewhat acute. 
 adelphinus, a, um; brotherly ; in brotherhoods ; closely related. 
 aduncdtus, a, um; hooked ; formed like a hook. 
 aduncus, a, um; crooked ; shaped like a hook or claw. 
 cegagrdpilo'ides; shaggy ; like the wild goat's hair. 
 cequilaterdlis, is, e; equal-sided ; having equal sides. 
 cequiseptdtus, a, um; equally divided by septa or partitions. 
 cequisulcdlus, a, um; equal-furrowed ; having furrows of equal size. 
 cequivalvis, is, e; equal- valved ; valves of the same size. 
 djfinis, is, e; adjoining ; contiguous. 
 agaridf6rmis, is, e; shaped like a mushroom. 
 agaricoldes; mushroom-like. 
 
 Agassizi; in honour of Agassiz, the distinguished naturalist. 
 agglutindns; glued to, or joined to one another. 
 agrgstis, is, e; belonging to the fields ; field-dwelling. 
 
 473 
 
ALA API 
 
 aldtus, a, um; winged ; having wing-like appendages. 
 
 albo-gdtitrus; white-hat ; white-helmet shape. 
 
 aliformis, is, e; wing-shaped ; in the form of wings. 
 
 Allani; after Mr Allan, of Edinburgh, mineralogist. 
 
 Alnwicensis, is, e; found at Alnwick in Northumberland. 
 
 alpfetris, is, e; alpine ; growing at great elevations. 
 
 alternans; alternating ; following one after another. 
 
 alterndlus, a, um; alternating ; following at intervals. 
 
 alutdceus, a, um; tanned ; like tanned leather. 
 
 alveoldris, is, e; hollowed like a trough or channel. 
 
 ambiguus, a, um; ambiguous ; doubtful. 
 
 ammono'ides; ammonite-like ; curved like a ram's horn. 
 
 amphibius, a, um; amphibious ; living on land or in water. 
 
 amphSra; a flaggon ; flaggon-shaped. 
 
 amplidtus, a, um; enlarged ; spread out. 
 
 amplus, a, um; full ; full-sized. 
 
 ampulla; a flask or flagon ; flask-shaped. 
 
 ampulldceus, a, um; bottle-shaped ; flagon-like. 
 
 ampullosus, a, um; puffed out ; flagon-like. 
 
 amygdalceformis, is, e; almond-shaped. 
 
 amygdaloldes; almond-like ; in the form of almonds. 
 
 anastomosans; veined ; running one into another like the veins of a leaf. 
 
 andstomdsus, a, um; anastomosing ; running one into another like the 
 
 veins of a leaf. 
 (tnfltlnus, a, um; duck-like. 
 ancfys; doubtful ; undetermined. 
 ancyloldes; shield-like ; formed like a shield. 
 Andersdni; after the Rev. Dr Anderson of Newburgh, Fife. 
 angeioldes; vessel-like ; flagon-shaped. 
 Angftcus, a, um; English ; found in England. 
 anguilla; an eel ; eel-like in form. 
 angust&tus, a, um; narrowed ; constricted. 
 angustidens; narrow- toothed ; compressed tooth. 
 angustifolius, a, um; narrow-leaved. 
 angustifrons; narrow-fronted ; having a narrow forehead. 
 annfclens; connecting ; approaching ; akin to. 
 Anningice; after Miss Anning of Lewes, collector of fossils. 
 annuldtns, a, um; annular ; ring-shaped ; ringed. 
 an6malus, a, um; anomalous ; irregular. 
 anomolopdra; having unusual pores. 
 
 anthrac6philus, a, um; coal-loving ; found chiefly in the Coal-measures. 
 anserinus, a, um; goose-like ; of or pertaining to the goose. 
 Anstedi; after Professor Ansted of London, geologist. 
 anthracinus, a, um; coaly ; found in or belonging to coal. 
 antiquior, or, us; more ancient ; of earlier date. 
 antiquus, a, um; ancient ; of early date. 
 aperturdtus, a, um; full of apertures ; fissured. 
 apicdlis, is, e; sharp-pointed ; tapering to a slender point. 
 apicicurvdtus, a, ^lm; curved at the top or apex. 
 
 474 
 
API AXI 
 
 apiculdtus, a, um; pointletted ; slender-pointed. 
 
 approximdtus, a, um; approximating ; close upon one another. 
 
 aqulla; an eagle ; curved like an eagle's beak. 
 
 ardchnoldes; cobweb-like ; cobwebby. 
 
 ardchnoldeus, a, um; in the form of a cobweb ; in slender meshes. 
 
 ardneus, a, um; spider-web-like ; lightly netted. 
 
 arborescens; arborescent ; branching like a tree. 
 
 archetfipa; original ; the original type. 
 
 ardgerens; arch or bow bearing ; bow-shaped. 
 
 arctos; belonging to the arctic regions ; northern. 
 
 arcudrius, a, um; arched ; bent like a bow. 
 
 arcudtus, a, um; bent ; arched ; bow-shaped. 
 
 arculdtus, a, um; coffer-like. 
 
 arendrius, a, um; sandy ; belonging to the sand. 
 
 arenicolus, a, um; sand-dwelling ; burrowing in the sand. 
 
 areoldtus, a, um; areolate ; divided into a number of irregular squares or 
 
 small angular spaces. 
 arguttis, a, um; clear ; decided ; pretty. 
 armdtus, a, um; armed ; furnished with defences. 
 arthriticus, a, um; jointed ; furnished with joints. 
 articuldtus, a, um; articulated; closely jointed. 
 articuldsus, a, um; jointed ; full of joints. 
 arvensis, is, e; field-inhabiting ; belonging to the fields. 
 asper, a, um; rough ; rough-surfaced. 
 aspergillifdrmis, is, e; brush-shaped. 
 
 asjxrgillus; a brush for sprinkling holy water ; brush-like. 
 aspGrrimus, a, um; extremely rough ; harsh with points. 
 asperulus, a, um; roughish ; somewhat rough. 
 astacoldes; lobster-like; crayfish-like. 
 asleriscus, a, um; star-like ; in the form of an asterisk. 
 asthenodeirus, a, um; weak-necked ; slender-necked. 
 qstro'ides; star-like ; rayed like a star. 
 astrdphorus, a, um; star-bearing ; starred. 
 auloporoldes; pipe-pore-like ; resembling the aulopore coral. 
 a^ll6ticon; pipe-shaped ; pipe-like. 
 aurdntium; an orange ; like an orange. 
 auricula; an ear ; like an ear. 
 auriculdris, is, e; ear-shaped. 
 
 auriculdtus, a, um; eared ; having ear-like appendages. 
 auritus, a, um; long- eared ; decidedly eared. 
 Austtni; after Mr Godwin Austen, geologist. 
 avelldna; filbert; like a filbert. 
 
 avenifdrmis, is, e; oat-pipe-shaped ; like an oaten straw. 
 aviculo'ides; bird-shaped ; in the form of a little bird. 
 axincef6rmis, is, e; axe-shaped ; axe-like. 
 
 475 
 
BAG BOV 
 
 B 
 
 baccdtus, a, um; berried ; furnished with berry-like excrescences. 
 lacilldris, is, e; staff-like ; straight like a staff. 
 bacillum; a staff; staff-like. 
 baculiformis, is, e; staff-like ; staff-shaped. 
 baltedtus, a, um; belted. 
 
 Bdlticus, a, um; from the Baltic shores ; belonging to the Baltic Sea. 
 Banksii; after Mr Banks of Kington, Ludlow. 
 barbdtus, a, um; bearded ; having hair-like appendages. 
 Barrandei; in honour of M. Barrande, geologist and palaeontologist. 
 Bechei; after Sir Henry de la Beche, geologist. 
 BecJclesii; after Mr Beckles, geologist and palaeontologist. 
 bellicinctus, a, um; beautifully bound or wound round. 
 bellistriatus, a, um; beautifully striated ; covered with fine striaa. 
 bellulus, a, um; pretty ; neat. 
 Mllus, a, um; beautiful ; elegant. 
 Beudantii; after M. Beudant, French geologist. 
 bicalcardtus, a, um; two -spurred ; armed with two spurs. 
 bicarindtus, a, um; having two keels or ridges. 
 bicatenatus, a, um; marked with two chain-like lines or ridges. 
 bicorddtus, a, um; in the form of two hearts ; twin-hearted. 
 bicordna; double-crowned ; twin-crowned. 
 bicostdlis, is, e; having two ribs, or rib-like processes. 
 bidens; having two teeth ; bidentate. 
 bidorsdtus, a, um; having a double back. 
 bifascidtus, a, um; doubly banded ; two-striped. 
 bifrons; doubly fronted ; two-fronted. 
 bifurcdtus, a, um; bifurcated ; branching in two ; forked. 
 bilinedtus, a, um; two-lined ; marked with two lines. 
 Ulobus, a, um; two-lobed ; bilobed. 
 
 Binneyi; after Mr E. W. Binney of Manchester, geologist. 
 linus, a, um; double ; in pairs ; twinned. 
 bioculdtus, a, um; double-eyed; twin-eyed. 
 bipartitus, a, um; bipartite ; divided into two ; two- cleft. 
 biplex; double ; two-fold. 
 bipunctdtus, a, um; doubly punctured. 
 bispin6sus, a, um; doubly spined. 
 bisujfarciandtus, a, um; doubly stuffed ; swollen. 
 Blainvillii; after Blainville, the French zoologist. 
 Blumeribdchii; in honour of Blumenbach, German naturalist. 
 Bollensis, is, e; found at Boll in Wirtemberg. 
 b6ops; ox-eyed ; large or full-eyed. 
 boredlis, is, e; boreal ; belonging to northern latitudes. 
 botuliformis, is, e; sausage-shaped. 
 
 Bouchardiamis, a, um; after M. Bouchard, palaeontologist. 
 bovinus, a, um; ox-like ; allied to the ox family. 
 
 476 
 
BOW CAN 
 
 Bou-erbanki; after Dr Bowerbank of London, microscopist. 
 
 brachycephalus, a, urn; short-headed. 
 
 brachydeirus; short-necked. 
 
 brachypy&opterus, a, um; short sub-dorsal finned. 
 
 brachyurus, a, um; short-tailed. 
 
 breviceps; short-headed. 
 
 brevicollis, is, e; short-necked ; closely attached. 
 
 brevifolium; short-leaf; short-leaved. 
 
 brevir6stris, is, e; short-nosed ; short-beaked. 
 
 brevis, is, e; short. 
 
 brevispinus, a, um; short-spined. 
 
 JSridreus, a, um; many-armed, like the fabled Briareus. 
 
 Bristovii; after Mr Bristow, mineralogist, Geological Survey. 
 
 JBroderipii; in honour of Mr Broderip, geologist. 
 
 Brodiei; after Mr Brodie, author of ' Fossil Insects.' 
 
 Brongniarti; after Brongniart, the French fossil botanist. 
 
 Brownii, Browniana; after R. Brown, the celebrated botanist. 
 
 bucdrdium; ox-heart ; shaped like an ox-heart. 
 
 buccinHus, a, um; trumpet-like. 
 
 buccinoldea; like the shell buccinum. 
 
 Bucklandi; after Dr Buckland, geologist. 
 
 bulldtus, a, um; bossed ; round like a nail-head ; studded with small round 
 
 knobs. 
 
 bulloldes; shaped like the shell bulla. 
 bursa; a purse ; purse- or pouch-shaped. 
 byssdceus, a, um; having a " byssus," or appendage of fine filaments, like 
 
 flocks of wool. 
 
 cceldtus, a, um; carved in relief; sculptured. 
 ccespit6sus, a, um; turf -like ; turfy. 
 
 calcardtus, a, um; spurred ; spur-shaped ; furnished with spurs. 
 calcarifdrmis, is, e; spur-shaped ; in the form of a spur. 
 ceUcfofaj sandal ; like a sandal or slipper. 
 
 calligramma; beautiful writing ; beautifully marked with lines. 
 calopt>ra; beautiful-pored. 
 cdlvus, a, um; bald ; smoothly bare. 
 calyculdris, is, e; cup-like ; like the calyx of a flower. 
 calfaulus, a, um; like a little cup ; calyx-like. 
 Cambrensis, is, e; of or belonging to Wales ; occurring in Wales. 
 campanuldtus, a, um; bell-shaped. 
 campy~lodon; curved or crooked tooth. 
 canaliculdtus, a, um; channeled ; grooved. 
 canaliferus, a, um; furnished with channels or canals. 
 cancelldria; latticed ; furnished with cross-bars. 
 cancelldtus, a, um; latticed ; cancellated. 
 cancriformis, is, e; crab-formed ; crab-like. 
 
 477 
 
CAN C1N 
 
 cdndidus, a, um; white. 
 
 cannceformis, is, e; cane-shaped ; having a cane-like stem. 
 
 canteridtus, a, um; railed ; staked. 
 
 caperdt^(,s, a, um; shrivelled ; puckered in wrinkles. 
 
 capilldceus, a, um; hairy ; covered with fine hairs. 
 
 capilldris, is, e; hair-like ; capillary ; in tubes like hairs. 
 
 capistrdtus, a, um; haltered ; muzzled. 
 
 capitdtus, a, um; headed ; furnished with small heads. 
 
 cdprZSlus; the roebuck ; roebuck-like. 
 
 caput-serptniis; shaped like a serpent's head. 
 
 carbondcens, a, um; carbonaceous ; found in the Coal-measures. 
 
 carbondrius, a, um; of or belonging to the Coal-measures. 
 
 cardio'ides; cardium- or cockle-like. 
 
 carindria; having a keel or ridge. 
 
 cariiidtus, a, um; keeled ; furnished with ridges more or less elevated. 
 
 carintlla; a little keel or ridge. 
 
 cariniferus, a, um ; keel-bearing ; furnished with a keel or projecting ridge. 
 
 -carpom6rpha; fruit-shaped ; in the form of a fruit. 
 
 caryophyllus, a, um; clove-like ; clove-leaved. 
 
 cassinoides; helmet-like. 
 
 cdssis; a helmet ; in the form of a helmet. 
 
 castdnfus, a, um; chestnut-like. 
 
 catendtus, a, um; chained or connected together. 
 
 catSnifer, a, um; chain-bearing ; linked like a chain. 
 
 catenuldtus, a, um; chained ; formed of little links. 
 
 cathedrdlis, is, e; spire-like ; tapering and spire-like. 
 
 catillus; a little dish. 
 
 cdtus; the cat ; cat-like. 
 
 cauda-galli;-\ik.e the tail of a cock ; arranged like the plumes in a cock's 
 
 tail. j 
 
 cauddlis, is, e; tailed ; having a prominent tail. 
 cauddtus, a, um; tail-pointed ; furnished with a tail. 
 caulincefolia; stalk-leaved. 
 cavdtus, a, um; hollowed out ; hollow. 
 caitifrons; hollow-fronted. 
 celluldris, is, e; cell-like ; cellular ; full of cells. 
 cellulosus, a, um; full of cells ; abounding in cells. 
 centrdlis, is, e; central ; in the middle. 
 centrochir; goad-hand ; goad-fin. 
 
 centrStus, a, um; knotted ; having prominent tubercles. 
 cepcefdrmis, is, e; onion-shaped ; like an onion. 
 cervicornis, is, e; shaped like a stag's horn. 
 cervinus, a, um; deer-like ; allied to the deer kind. 
 chamceformis, is, e; cockle-shaped ; like the shell chama. 
 champsoides; crocodile-like ; allied to the Nilotic crocodile. 
 ckarceformis, is, e; like the fresh-water plant chara. 
 Cliarlesworthii; after Mr Charlesworth of London, naturalist. 
 dnctus, a, um; girdled ; encircled with lines. 
 cintreus, a, um; ash-coloured ; ashy. 
 
 478 
 
CIN CON 
 
 cinguldtus, a, urn; girdled ; encircled with lines. 
 
 circindtus, a, um; compassed ; encircled ; whorled. 
 
 circumvhtens; surrounding some other object. 
 
 circumsulcdtus, a, um; furrowed all round. 
 
 cirrhosus, a, um; cirrhous ; terminated by a curled filiform appendage. 
 
 cirrofcdes; cirrus-like ; having a curled appendage. 
 
 citharSlla; little lute. 
 
 clathratulus, a, um; slightly latticed ; slightly cross- barred. 
 
 clathrdtus, a, um; cross- barred ; latticed. 
 
 datkroldea; bar-like ; lattice-like. 
 
 clava; a knotty branch ; knob-like. 
 
 davaroides; club-like. 
 
 davdtula; little club. 
 
 davdtus, a, um; club-like ; club-shaped. 
 
 daviculdris, is, e; collarbone-shaped ; clavicle-like. 
 
 ddvlge>', a, um; club-bearing. 
 
 disioides; chamber-like ; separated into small chambers. 
 
 duniculdris, is, e; haunch-like. 
 
 dypedtus, a, um; shield-like ; furnished with a shield. 
 
 coddearella; little screw ; spiral-shaped. 
 
 coddedtus, a, um; screw-shaped ; spiral. 
 
 C6lei; after Lord Cole, now Earl of Enniskillen, paleontologist. 
 
 colubrinus, a, um; snake-like. 
 
 columUlla; a little dove. 
 
 columelldris, is, e; little-pillar-like. 
 
 combtistus, a, um; burnt up ; parched ; withered-like. 
 
 communis, is, e; common ; of frequent occurrence. 
 
 comdsus, a, um; bushy ; shaggy like hair. 
 
 complandtus, a, um; smoothed ; smooth-surfaced. 
 
 compUxus, a, um; complex ; in many folds ; not simple. 
 
 compressir6stris; flattened beak ; pressed together. 
 
 compressus, a, um; flattened ; flattened as if by pressure. 
 
 comptus, a, um; elegant ; adorned. 
 
 concdvus, a, um; hollow ; depressed ; concave. 
 
 concGntricus, a, um; arranged in concentric lines. 
 
 conchiticus, a, um; shelly ; shelly in aspect. 
 
 continnus, a, um; handsome ; pretty; neat. 
 
 cdnfluens; confluent ; running together ; running into one. 
 
 coi&cus, a, um; conical ; tapering to a point. 
 
 conifer, a, um; cone- bearing ; bearing cones like a fir-tree. 
 
 conjungens; immediately joining ; approximating. 
 
 cono^dens, a, um; shaped like a cone ; somewhat conical. 
 
 conophthalmus; conical eyed ; the eye projecting like a cone. 
 
 consobrinus, a, um; a cousin ; nearly allied. 
 
 constrictus, a, um; bound closely together ; constricted. 
 
 contiguus, a, um; near ; close to. 
 
 contwtidens; twisted tooth ; twist-tooth. 
 
 contdrtuplicdt'its, a, um; folded and much twisted. 
 
 contdrtux, a, um; twisted. 
 
 479 
 
CON CRE 
 
 contractus, a, um; contracted ; drawn together. 
 conitlus; a little cone. 
 convfaus, a, um; convex ; bent round. 
 convolutus, a, um; convoluted ; rolled as it were together. 
 Conybearii; after the Kev. Dr Conybeare, English geologist. 
 corallo'ides; coral-like ; having the aspect or structure of coral. 
 corbWa; a little basket. 
 corddtus, a, um; heart-like ; heart-shaped. 
 cordiformis, is, e; heart-shaped. 
 cornZus, a, um; horny ; having a texture like horn. 
 corniculdtus, a, um; horned ; furnished with horn-like processes. 
 cornu; a horn ; horn-like in form. 
 cornu-arietis; ram's horn ; curled like a ram's horn. 
 Cornubicus, a, um; of, or belonging to, Cornwall. 
 cornu-bovis; ox-horn ; ox-horn-like. 
 cwnu-pastoris; shepherd's horn. 
 
 cornutus, a, um; horned ; having horn-like appendages. 
 corolldris, is, e; corolla-shaped ; blossom-like. 
 cordna; a crown. 
 cwdn&la; little crown. 
 
 corrugdtus, a, um ; corrugated ; much wrinkled. 
 corticdtus, a, um; having a coat of bark ; coated. 
 coi-tilum; darling ; term of endearment. 
 corymbdsus, a, um; ivy-berried ; in clusters. 
 coryphcenoldes; diadem-like. 
 
 costdtus, a, um; ribbed ; having prominent ridges. 
 costeldtus, a, um; having very faint ribs. 
 
 costelliferus, a, um; marked with little ribs ; bearing faint ribs. 
 costuldtus, a, um ; having little ribs. 
 Cotteswoldice; from the Cotteswold Hills, Gloucestershire. 
 crassatinus, a, um; thickish. 
 crassicatida; thick tail. 
 
 crassicaulis, is, e; thick stalked or stemmed. 
 crassiconus, a, um; thick-coned; bluntly-tapering. 
 crdssldens; thick-tooth; thick-toothed. 
 crassin$rvus, a, um; thick-nerved ; fleshy-nerved. 
 crassirostris, is, e; thick-beaked ; thick-snouted. 
 crassispinus, a, um; thick-spined ; strong-spined. 
 crassissimus, a, um; very thick ; the thickest. 
 crassiusculus, a, um; thickish ; somewhat thick. 
 crassiventer; thick-bellied ; deep-bellied. 
 crassosteum; dense-boned ; thick-boned. 
 crdssus, a, um; thick ; stout. 
 crateriformis, is, e; goblet-shaped. 
 
 crendto-stridtus, a, um; convex- striated ; marked with convex lines. 
 crendtula; having small convex teeth. 
 crendtus, a, um; having convex teeth ; crenulated. 
 crenuldris, is, e; marked like the lines of a battlement. 
 crenuldtus, a, um; slightly crenulated ; zigzagged. 
 
 480 
 
CRE DAV 
 
 crepidula; a slipper ; slipper-like. 
 
 cretdceus, a, urn; chalky ; belonging to the Chalk formation. 
 
 cribrosus, a, um; sieve-like ; full of openings. 
 
 crispus, a, um; curled. 
 
 crista-gdlli; cock's comb ; like a cock's comb. 
 
 cristdtus, a, um; crested ; peaked. 
 
 ci*ist$lla; little crest. 
 
 cruentdtus, a, um; bloody. 
 
 crumetia; a purse. 
 
 crustuttntus, a, um; thin-crusted ; wafer-like. 
 
 cryptopdra; hidden-pored ; having the pores concealed. 
 
 cubicSdon; solid tooth ; cubical teeth. 
 
 cuculldea; hood ; hood-like. 
 
 cuculldtus, a, um; hooded ; furnished with a hood. 
 
 cultridefis; knife-tooth ; knife- or sharp-toothed. 
 
 Cummingce; after Lady Gordon-Gumming of Altyre, Morayshire. 
 
 cunedtus, a, um; wedged ; wedge-shaped. 
 
 cuneiceps; wedge- headed. 
 
 cuneiformis, is, e; tapering in the form of a wedge. 
 
 cuniculus; the rabbit ; cony-like. 
 
 cupressif6rmis, is, e; cypress-shaped ; like the cypress-tree. 
 
 cupuliformis, is, e; cup-shaped ; like an acorn. 
 
 curtansdtus, a, um; shortened ; curtailed. 
 
 curtdcerus, a, um; short-horned. 
 
 curtus, a, um; short. 
 
 curvicdrnis, is, e; bent-horned. 
 
 ctirvidens; bent-toothed ; having the teeth bent inwards. 
 
 curwn6dusi a, um; bent at the joints. 
 
 curvirostris, is, e; bent-beak ; bent-jaw. 
 
 cuspiddtus, a, um; pointed like a spear. 
 
 Cuvieri; in honour of Cuvier, the celebrated French naturalist. 
 
 cyathiformis, is, e; cup-shaped ; goblet-shaped. 
 
 cyclostdma; circular-mouthed ; circle-mouth. 
 
 cyclus; a circle ; round or circular-shaped. 
 
 cygrilpes; swan-footed ; like the swan's foot. 
 
 cylindricSdon; cylindrical tooth. 
 
 cyllndricus, a, um; cylindrical ; cylinder-shaped. 
 
 cymlifdrmis, is, e; boat-shaped ; like a skiff. 
 
 cambium; a skiff or boat. 
 
 cy-mbZla; a little skiff. 
 
 cyphus, a, um; crooked ; humped ; convex. 
 
 Doed&leus, a, um; beautifully worked, as if by Daedalus. 
 dama; the fallow-deer ; fallow-deer-like. 
 damcecornis, is, e; deer's-horn-like. 
 Davidsonii; after T. Davidson, palaeontologist. 
 
 481 
 
DEC DOL 
 
 decaddctylus, a, urn; ten-fingered ; ten-rayed. 
 
 decipiens; deceptive ; doubtful. 
 
 declivis, is, e; sloping ; bending downwards. 
 
 decordtus, a, um; decorated ; ornamented with figure-work. 
 
 decurrens; running down along ; extending. 
 
 decussdtus, a, um; arranged in pairs that alternately cross each other. 
 
 definUus, a, um; definite ; determined. 
 
 defdssus, a, um; deeply buried ; sunken. 
 
 Delabechii; after Sir Henry Delabeche, geologist. 
 
 delicdtulus, a, um; rather delicate ; slender. 
 
 deltoldea; shaped like the Greek letter A, delta ; trowel-formed. 
 
 dendrius; a coin ; in form of a coin. 
 
 dendrinus, a, um; tree-like ; branching like a tree. 
 
 dendropkyllo'ides; tree- leaf-like ; reticulated like the leaf of a tree. 
 
 dent&lium; resembling the tooth-shell or dentalium. 
 
 dentdlus, a, um; toothed ; notched. 
 
 denticuldtus, a, um; denticulated ; small-toothed. 
 
 dentifer, a, um; toothed ; furnished with teeth-like processes. 
 
 depttxus, a, um; wound round ; folded round. 
 
 deprissus, a, um; depressed ; slightly hollow. 
 
 Derbiensis, is, e; of or belonging to Derbyshire. 
 
 Deslongchampsii; in honour of M. Deslongchamps, geologist. 
 
 desmophflllus, a, um; bundle-leafed ; in leaf-like clusters. 
 
 destructor; a destroyer ; feeding on others. 
 
 D' Urlani; in honour of D' Urban the naturalist. 
 
 Dev6ni$nsis, is, e; of or belonging to Devonshire. 
 
 dicMlomus, a, um; dividing into two ; branching into two ; forked. 
 
 dwrandcerus, a, um; having two-forked horns. 
 
 dictyota; set with netting. 
 
 didymus, a, um; double ; twinned. 
 
 difformis, is, e; shapeless ; ill-formed. 
 
 digitalifdrmis, is, e; finger-like ; fingered. 
 
 digit&lus, a, um; finger-like, as the leaves of the horse-chestnut. 
 
 digona; two-cornered. 
 
 dilatdtus, a, um; dilated ; widened ; spread out. 
 
 dimididlus, a, um; halved ; divided in two. 
 
 discoideus, a, um; quoit-shaped ; disc-like. 
 
 discretus, a, um; divided. 
 
 discus; a quoit ; in the form of a quoit. 
 
 dispar; unlike; unequal. 
 
 diss&tus, a, um; dissected ; cut asunder. 
 
 dissimilis, is, e; unlike ; unsymmetrical. 
 
 distans; distant ; standing apart. 
 
 distichus, a, um; in two rows ; double-rowed. 
 
 distdrtus, a, um; distorted ; irregular in shape. 
 
 divaricdtus, a, um; straggling ; wide apart. 
 
 Dixoni; after Dixon, the author of ' Fossils of Sussex.' 
 
 dtilabra; an axe ; in the form of an axe. 
 
 dolalriformis, is, e; axe-shaped. 
 
 482 
 
DOL EUG 
 
 dolidris, is, e; tun-shaped ; barrel-like. 
 
 dolickodeirus; long-necked. 
 
 dolium, a cask ; doliSlus, a little cask. 
 
 donax; a reed. 
 
 dorsdlis, is, e; belonging to the back ; dorsal ; having a dorsal ridge. 
 
 dorsdtus, a, um; high-backed. 
 
 draconoc&phala; dragon's head. 
 
 dulius, a, um; doubtful ; uncertain. 
 
 dumet6sus, a, um; bushy ; tufty. 
 
 duplicates, a, um; doubled ; folded in two. 
 
 duriusculus, a, um; rather hard ; hardish. 
 
 E 
 
 elurneus, a, um; ivory-like ; having the texture of ivory. 
 
 echindtus, a, um; spiny ; covered with spines like the hedgehog. 
 
 echin6phorus, a, um; thorny ; bearing spines. 
 
 edtntulus, a, um; toothless. 
 
 editus, a, um; lofty. 
 
 edulinusy a, um; edible ; capable of being eaten. 
 
 ediilis, is, e; edible ; used as food. 
 
 effossus, a, um; dug out. 
 
 Egertonl; after Sir Philip Egerton, fossil ichthyologist. 
 
 Eggensis, is, e; from the Isle of Egg, Hebrides. 
 
 EhreribSrgii; after Ehrenberg, the great German microscopist. 
 
 Eifelensis, is, e; from Eifel, in Germany Lower Rhine. 
 
 elitphus; the stag or red-deer ; stag-like. 
 
 eUgans; elegant ; handsome in form. 
 
 elephantoldes; elephant-like. 
 
 ElginZnsis, is, e; found at or belonging to Elgin, in Morayshire. 
 
 ellipticus, a, um; in the form of an ellipse (oval). 
 
 elongdtus, a, um; lengthened ; drawn out. 
 
 emargindtus, a, um; emarginate ; having a notch at the end, as if a piece 
 
 had been taken out. 
 empleura; full-sided. 
 
 enormis, is, e; enormous ; unusually large. 
 ensifer, a, um; sword-bearing ; having pointed processes. 
 ensis; a sword ; tapering like a sword. 
 eoccenus, a, um; found in the Eocene or Lower Tertiaries. 
 ephippium; a saddle ; like a saddle. 
 
 equisetif6rmis, is, e; mare's-tail-shaped ; like the marsh plant equisetum. 
 erindceus, a, um; hedgehog-like ; resembling the hedgehog. 
 ermineus, a, um; like the ermine or weasel. 
 er6sus, a, um; gnawed ; bitten away. 
 
 erugdtus, a, um; not wrinkled ; smooth, from marks having been worn away. 
 escha.ra'ides; like a chafing-dish ; grate-shaped. 
 esodnus, a, um; pike-like ; relating to the pike-fish. 
 euglj/phus, a, um; well-carved ; distinctly marked. 
 
 483 
 
EUO FIL 
 
 euSdus; well-toothed. 
 
 eudmphalus, a, urn; well centred or bossed. 
 
 eupterygius, a, urn; well finned or winged. 
 
 eurygndtkus; wide-jawed; broad-jawed. 
 
 evulsus, a, urn; torn out. 
 
 exaltdtus, a, um; raised ; prominently elevated. 
 
 exardtus, a, um; defaced as to marks previously existing ; worn off. 
 
 excavdtus, a, um; hollowed out ; scooped out. 
 
 exdlsus, a, um; lofty ; high in stature. 
 
 excisus, a, um; cut off; cut out ; erased. 
 
 exertus, a, um; projecting. 
 
 exesus, a, um; corroded ; worn in holes. 
 
 exolttus, a, um; worn out ; defaced. 
 
 expdnsildbrum; broad-lipped ; spreading out at the lip. 
 
 expdnsus, a, um; widely spread ; spread out. 
 
 explaitdtus, a, um; spread out ; clearly seen. 
 
 exsculptus, a, um; deeply sculptured ; sculptured out. 
 
 extenudtus, a, um; thinned away ; drawn out into a thin edge. 
 
 exutus, a, um; stripped off ; removed. 
 
 F 
 
 f&ba; a bean ; like a bean. 
 
 fabagtlla; little bean ; like a little bean. 
 
 falcdtus, a, um; falcate or sickle-shaped. 
 
 fdlcifer, a, um; sickle-bearing ; armed with sickle-like processes. 
 
 fallax; fallacious; deceptive. 
 
 fasci&rius, a, um; bandage-like ; band-shaped. 
 
 fasicdtus, a, um; bandaged ; striped. 
 
 fasciculdtus, a, um; faggot-like ; in bundles. 
 
 fasciculus; a faggot or bundle ; in tufts. 
 
 fastigidtus, a, um; pointed ; peaked like a roof. 
 
 favoso'ides; honeycomb-like. 
 
 favosus, a, um; arranged like a honeycomb ; honeycombed. 
 
 fenestrdtus, a, um; window-paned ; reticulated. 
 
 flrox; fierce ; fitted for fierce work ; sharp-pointed. 
 
 ferMis, is, e; fertile ; bearing seed. 
 
 fibrdsus, a, um; fibrous ; full of fibres. 
 
 fibuldtus, a, um; broach- like. 
 
 ficoldes; fig-like. 
 
 ficulneus, a, um; belonging to the fig-tree. 
 
 Julicula; a little fiddle or kit. 
 
 filiciformis, is, e; fern-shaped ; fern-like. 
 
 Jiliformis, is, e; filiform ; thread-like. 
 
 filipendris, is, e; thread-finned or winged ; having thread-like fins. 
 
 filitextus, a, um; woven like threads ; formed of interlacing filaments. 
 
 filogrdnus, a, um; thread-grained ; fine-grained. 
 
 fildsus, a, um; thread-like ; thready. 
 
 484 
 
FIM GAL 
 
 fimbridtus, a, um; fringed. 
 
 fissicostdtus, a, um; having divided ribs ; cleft- ribbed. 
 fissura; a cleft ; having a cleft. 
 fissurttla; a little cleft. 
 fistula; a pipe or tube. 
 
 fisluldsus, a, um; pipe-like ; composed of small tubes. 
 Fittoni; after Dr Fitton, the geologist. 
 flabelldtus, a, um; spread out like a fan. 
 flabelliformis, is, e; fan-shaped ; flabelliform. 
 flaUllulus; a little fan. 
 flabellum; a f an ; fan-like. 
 flagelliformis, is, e; whip-shaped ; thong-like. 
 Flemingii; after Professor Fleming of Edinburgh, naturalist. 
 flezicostdius, a, um; bent-ribbed. 
 flexu6sus, a, um; bent ; crooked. 
 jtocc6sus, a, um; wool -like ; fleecy. 
 floredlis, is, e; flowery ; flower-like. 
 fl6riceps; flower-headed ; like a head of flowers. 
 florigemma; flowery-gemmed. 
 fluctudtus, a, um; waving ; wavy. 
 fddiens; digging ; burrowing in the earth. 
 folidceus, a, um; leaf -like ; leafy. 
 folidsus, a, um; leafy ; abounding in leaves. 
 fdlium; a leaf or thin plate. 
 fonticola; fountain-dwelling ; living in springs. 
 fontindlis, is, e; of or belonging to fresh-water springs. 
 foramin6sus, a, um; full of small holes. 
 Forbesii; in honour of the late Edward Forbes. 
 formicdtus, a, um; ant-like. 
 formdsus, a, um; fair, beautiful. 
 fornicdtus, a, um; arched. 
 
 fossUis, is, e; fossil or extinct, in contradistinction to recent or living. 
 foveoldtus, a, um; pitted ; covered with pit-like markings. 
 fronddsus, a, um; branching ; branchy. 
 frontdlis, is, e; having a large front or forehead. 
 fundlis, is, e; rope-like ; rope-shaped. 
 fungifdrmis, is, e; fungus-shaped ; mushroom-like. 
 fungoldes; fungus-like. 
 funiculdtus, a, um; cord-like ; corded. 
 furcdtus, a, um; forked ; branching in two. 
 furcilldtus, a, um; marked with slightly bifurcating lines. 
 fuscdtus, a, um; dark ; tawny. 
 fusiformis, is, e; spindle-shaped ; tapering at both ends. 
 
 gagateus, a, um; agate-like ; formed of agate. 
 gdttus; a helmet ; helmet-like. 
 
 485 
 
GAL GYR 
 
 galivides; like the plant galium, or "ladies' bed-straw." 
 
 Gaultianus, a, um; of or belonging to the Gault. 
 
 Gaultinus, a, um; belonging to, or peculiar to, the Gault. 
 
 geminans; doubling ; twin-form. 
 
 gemindtus, a, um; doubled ; in twins. 
 
 gemmdtus, a, um; studded with gems ; beaded. 
 
 geomStricus, a, um; arranged in geometrical order. 
 
 gibMrrulus, a, um; somewhat humped ; convex, or gibbous.' 
 
 gibb6sus, a, um; gibbous ; humped ; tumid. 
 
 Gibbsii; after Mr Gibbs, collector to the Geological Survey. 
 
 gibbus, a, um; humped ; having a hump or sudden rise. 
 
 gigdnteus, a, um; gigantic ; unusually large. 
 
 gigas; a giant. 
 
 gl&ber, a, um; smooth. 
 
 glabrispinus, a, um; smooth-spined. 
 
 gldndifer, a, um; acorn-bearing ; gland-bearing. 
 
 globiceps; globe-headed ; round-headed. 
 
 globdsus, a, um; globular ; globose. 
 
 globuldris, is, e; globular; globe-shaped. 
 
 glomerdtus, a, um; gathered in a mass ; wound up like a clue. 
 
 glyphurus, a, um; carved tail ; sculptured tail. 
 
 Goldfussi; after Goldfuss, the celebrated naturalist. 
 
 gongyloldes; knob-like. 
 
 gonioddctylus, a, um; corner-fingered. 
 
 Gothlandicus, a, um; of or from Gothland (Sweden). 
 
 grdcilis, is, e; slender ; slight in form. 
 
 graddtus, a, um; step by step ; graduated. 
 
 graminoldes; grass-like ; resembling the grasses. 
 
 grandispinus, a, um; great-spined ; having large spines. 
 
 grandcevus, a, um; ancient ; of great age ; primeval. 
 
 grandis, is, e; great. 
 
 Grantoni; from Granton quarry, near Edinburgh. 
 
 granuldtus, a, um; granulated ; having the surface dotted with small grains. 
 
 granuldsus, a, um; covered with small granules ; granular. 
 
 grdphicus, a, um; written on ; inscribed with lines like writing. 
 
 Grdyii; after Dr Gray of the British Museum. 
 
 Greenockii; after the Earl of Greenock, mineralogist. 
 
 Greenoughii; after Mr Greenough, English geologist. 
 
 gregdrius, a, um; gregarious ; occurring in flocks, or masses. 
 
 Griestoniensis, is, e; from Grieston quarry (Silurian) in Peeblesshire. 
 
 Griftkii; after Sir Richard Griffith, the Irish geologist. 
 
 grossic6nws, a, um; thick-coned. 
 
 grumdsus, a, um; grumous ; in the form of small clusters of grapes. 
 
 gryphceo'ides; gryphsea or gryphite-like ; like the beaked shell gryphsea. 
 
 guttdtus, a, ^lm; studded with guttse, or small drops. 
 
 gyr6sus, a, um; circular ; twisted-like ; greatly twisted. 
 
 486 
 
HAL HUT 
 
 haliotoldes; shaped like the haliotis or ear-shell. 
 Hallianus, a, urn; after Professor J. Hall of New York. 
 haldcyon; sea-dog ; sea-dog-like. 
 hamdtus, a, um; hooked ; hooked-like. 
 
 Hantoniensis, is, e; belonging to or found in Hampshire (Hants). 
 harpceformis, is, e; harp-shaped ; in the form of a harp. 
 harpftla; a little harp. 
 hastdlis, is, e; spear- like ; spear-shaped. 
 hastdtits, a, um;' formed like a dart or spear. 
 hastifdrmis, is, e; dart-shaped. 
 
 Hastingsice; after the Marchioness of Hastings, collector. 
 hausUllum; a little bucket ; bucket-like. 
 hebetdtus, a, um; blunt. 
 
 Hebi-idicus, a, um; of or belonging to the Hebrides. 
 helianthella; like a little sunflower said of certain corals. 
 helianthvides; sunflower-like ; rayed like the sunflower. 
 helicinus, a, um; whorled like the snail-shell (helix). 
 heUeoldes; snail-shell-like. 
 helicteres; ear-rings ; ear-drops. 
 helecter aides; ear-ring-like ; ear-drop-like. 
 helvellwdes; cabbage-like ; shaped like a head of cabbage. 
 hemicidaroldes; hemicidaris-like (a fossil sea-urchin). 
 kemisphericus, a, um; hemispherical in form. 
 hemisldma; half- mouthed. 
 
 Hensldvii; after Professor Henslow of Cambridge, botanist. 
 heterddon; irregular- toothed. 
 
 heterogSneus, a, um; irregular in composition or parts. 
 heteromdrphus, a, um; irregular in form. 
 heterophl/llus, a, um; irregular-leaved. 
 ketei-urus, a, um; irregular-tailed. 
 hexdgonus, a, um; six-cornered or six-sided. 
 hians; gaping. 
 
 HibMrtii; after Dr Hibbert of Edinburgh, geologist. 
 Hiternicus, a, um; found in, or belonging to Ireland ; Irish. 
 hierogltfphicus, a, um; marked as if with hieroglyphics. 
 hippoc&stanum; horse-chestnut. 
 hippocrepis; horse-shoe. 
 
 hippopddium; horse-hoof ; like the horse-hoof. 
 hippSpus; horse-hoof (in the form of). 
 hirudo; a leach ; leach-like. 
 hispidulus, a, um; somewhat rough or bristly. 
 hispidus, a, um; rough ; covered with long rigid hairs. 
 hiulcus, a, um; gaping. 
 
 humer6sus, a, um; broad-shouldered ; humped. 
 Huttoni; after Dr Hutton, the celebrated Scotch geologist. 
 
 487 
 
HUT JUB 
 
 Huttonianus, a, um; after Mr Hutton of Newcastle, fossil botanist. 
 
 hyalatus, a, um; glassy ; having the lustre of glass. 
 
 hyltridus, a, um; hybrid ; intermediate between two species. 
 
 hymenophylld'ides; membranous, leaf-like. 
 
 hypocraterifdrmis, is, e; salver-shaped. 
 
 hypnaides; hypnum-like ; like the common moss hypnum. 
 
 hystrix; a porcupine ; covered or beset with spines. 
 
 Ibbetsoni; after Captain Ibbetson, geologist. 
 
 icosiddctylus, a, um; twenty-fingered. 
 
 imbricatdrius, a, um; covered with tiles ; tile-like. 
 
 imbricdtus, a, um; imbricated ; overlapping like tiles. 
 
 impar; unequal ; having unequal parts. 
 
 impressus, a, um; impressed ; stamped. 
 
 incequdlis, is, e; unequal ; not having equal parts. 
 
 incequicostdtus, a, um; unequally ribbed. 
 
 indnis, is, e; void ; empty. 
 
 indsus, a, um; incised ; cut in ; slashed. 
 
 inconslans; inconstant ; not always of one size or form. 
 
 incrassdtus, a, um; thickened. 
 
 incrustans; incrusting other substances, as coral-growth, &c. 
 
 inc&rvus, a, um; incurved ; bent in. 
 
 infldtus, a, um; inflated ; swollen, as if blown up. 
 
 infdrmis, is, e; shapeless ; without form. 
 
 infundibulifCrmis, is, e; funnel-shaped. 
 
 ingens; huge ; unusually large. 
 
 inter cellulosus, a, um; intercellular ; cell within cell. 
 
 intermtdius, a, um; intermediate (in size or form). 
 
 inter stinctus, a, um; divided. 
 
 intertextus, a, um; interwoven ; ramifying. 
 
 intortus, a, um; twisted inwards. 
 
 intumescens; swelling up. 
 
 irrddians; not radiating from a common centre. 
 
 ir>-eguldris, is, e; irregular ; not disposed in regular order. 
 
 isocdrdia; equal heart (regularly heart-shaped). 
 
 isogonotdes; equiangular-like. 
 
 jac&lum; a dart ; dart-shaped. 
 
 Jamesii; after Colonel James of the Government Survey. 
 Jamesoni; after Professor Jameson of Edinburgh, geologist. 
 Jardinii; after Sir William Jardine, naturalist. 
 Jewettii; after Mr Jewett, American geologist. 
 jubdtus, a, um; maned ; having a mane-like fringe. 
 
 488 
 
JUG LEI 
 
 jugdlis, is, e; yoked together ; conjoined. 
 jugosus, a, um; yoked together ; closely conjoined. 
 Julcesii; after Mr Jukes of the Geological Survey of Ireland. 
 junceus, a, um; rush-stem-like. 
 juniperinus, a, um; juniper-like ; like the juniper-berry. 
 
 Kenperinus, a, um; belonging to the Keuper, or Upper Trias. 
 Konigii; after Konig, the Belgian palaeontologist. 
 
 labidtus, a, um; labiate ; having lips. 
 
 Ldbraddricus, a, um; of or belonging to Labrador ; occurring in Labrador. 
 
 Idbyrinthicus, a, um; labyrinthine ; full of intricate windings. 
 
 Idcerus, a, um; torn ; ragged. 
 
 lacini&lus, a, um; slashed. 
 
 lacleus, a, um; milky ; white as milk. 
 
 Iacun6sus, a, um; having deep depressions. 
 
 Iceviceps; smooth-head. 
 
 Iceoigdlus, a, um; smoothened ; polished. 
 
 Icevis, is, e; smooth ; polished. 
 
 lavissimus, a, um; very smooth ; exceedingly smooth. 
 
 Iceviusculus, a, um; slightly smooth. 
 
 Lamdrckii; after Lamarck, French naturalist. 
 
 Iamell6sus, a, um; in very thin plates. 
 
 lamindtus, a, um; laminated ; in thin plates. 
 
 lanceoKttus, a, um; lanceolate ; spear-shaped. 
 
 Landsburgii; after the Rev. Dr Landsborough, algseologist. 
 
 laquealus, a, um; carved ; adorned with fretted work. 
 
 latecduda; broad-tailed. 
 
 lateseptdtus, a, um; widely divided ; having septa or partitions wide apart. 
 
 laticostdtus, a, um; broad-ribbed. 
 
 Idtidens; broad-toothed. 
 
 latifolius, a, um; broad-leaved. 
 
 latifrons; broad front ; broad-fronted. 
 
 latim&nus, a, um; broad-handed ; broad-finned. 
 
 latipSnnis, is, e; broad-finned or winged. 
 
 latissimus, a, um; broadest ; very broad. 
 
 latiusculus, a, um; broadish ; somewhat broad. 
 
 lotus, a, um; broad. 
 
 lautus, or lavdtus, a, um; washed. 
 
 laxus, a, um; loose ; loosely arranged. 
 
 leiodus; smooth- tooth. 
 
 leiopleurus; smooth-ribbed. 
 
 leiosdmus; smooth-bodied. 
 
 489 
 
LEM LON 
 
 lemniscdtus, a, urn; labelled. 
 
 lenticuldris, is, e; lenticular; lens-shaped. 
 
 lenticuldtus, a, urn; lens-shaped, having a double-convex surface. 
 
 lenticulinus, a, um; lentil-like. 
 
 lentifdrmis, is, e; lens-shaped ; in the form of a lens. 
 
 lentus, a, um; slow. 
 
 lepiddtus, a, um; leprous ; covered with small peltate scales. 
 
 leporinus, a, um; resembling; the hare ; hare-like. 
 
 leptocephalus, a, um; slender-headed. 
 
 Uptodus; slender-tooth, slender- toothed. 
 
 Iept6gndthus; slender-jawed. 
 
 Iept6pterus, a, um; slender-finned. 
 
 leptorhinus, a, um; slender-nosed ; slender-snouted. 
 
 leptbsoma; slight-bodied ; slender-bodied. 
 
 leptbsteus, a, um; slender-boned. 
 
 Liasianus, a, um; of or belonging to the Lias formation. 
 
 Lidsswus, a, um; of or belonging to the Lias formation. 
 
 lichenoldes; lichen-like. 
 
 ligndrius, a, um; wood-like ; of wood. 
 
 liguldtus, a, um; ligulate ; strap-shaped. 
 
 lima; a file (like a file). 
 
 limbdtus, a, um; bordered. 
 
 limularus, a, um; limulus-tailed ; having a pointed tail like the king-crab. 
 
 linctus, a, um; licked ; smoothened as if by licking. 
 
 Lindleyi, Lindleyanus, a, um; after Dr Lindley, the eminent botanist. 
 
 linedtus, a, um; marked with lines, striated. 
 
 lineoldtus, a, um; marked with little lines. 
 
 lingua; the tongue ; tongue-like. 
 
 Iingua-b6vis; ox-tongue ; shaped like an ox's tongue. 
 
 linguiformis, is, e; tongue-shaped. 
 
 linguldtus, a, um; in the form of a tongue. 
 
 liratus, a, um; lyre-shaped ; in the form of a lyre. 
 
 Listeri; after Dr Lister, geologist. 
 
 litter&tus, a, um; lettered ; marked as if inscribed with letters. 
 
 lituifdrmis, is, e; trumpet-shaped. 
 
 loMtus, a, um; lobate ; divided by a determinate number of segments. 
 
 lobifolius, a, um; lob-leafed. 
 
 loculosus, a, um; partitioned. 
 
 Logani; after Sir William Logan, State Geologist for Canada. 
 
 lonchiodon; long tooth, slender-toothed. 
 
 lonchitis; the fern "adder's tongue;" like the adder's tongue. 
 
 longibractedtus, a, um; furnished with long bracts. 
 
 longiceps; long-headed. 
 
 Iongic6llis, is, e; long-necked. 
 
 I6ngidens; long tooth ; long-toothed. 
 
 longifdlius, a, um; long-leafed ; having long leaves. 
 
 longimanus; long-handed. 
 
 longirbstris, is, e; long-beaked ; long-snouted. 
 
 timus, a, um; the longest ; of unusual length. 
 490 
 
LON MAR 
 
 longitudin&lis, is, e; lying lengthwise ; long and narrow. 
 Lonsdaleii; after Mr Lonsdale, palaeontologist. 
 lophiodon; crested- tooth. 
 
 loricdtus, a, urn; loricated ; resembling a coat of mail. 
 Ludensis; from or belonging to Ludlow, in Shropshire. 
 lundtus, a, urn; moon-shaped ; crescent-formed. 
 lunuldtus, a, um; lunulate ; half-moon-shaped. 
 lycopodoldes; lycopodium-like ; club-moss-like. 
 LySKi; after Sir Charles Lyell, the geologist. 
 lyrdtus, a, um; lyrate ; lyre-shaped. 
 
 M'Coyamts, a, um; after Mr M'Coy of Melbourne, geologist. 
 M'Clintocki; after Sir L. M'Clintock the Arctic voyager. 
 macilentus, a, um; lank ; meagre ; scraggy. 
 macrocaulis, is, e; long-stemmed ; long-stalked. 
 macrocheirus, a, um; long-handed ; having long pectoral fins. 
 macroddctylus, a, um; long-fingered. 
 macrodiscus, a, um; long-disked ; having long leaf-scars. 
 mdcrodus; long tooth ; long-toothed. 
 macrolepiddtus, a, um; long-scaled ; large-scaled. 
 mda-omus, a, um; long shoulder-blade ; slender-shouldered. 
 macr6nyx; long claw; long-clawed. 
 macrophthdlmus, a, um; long- or large-eyed. 
 maa'ophgilus, a, um; long-leaved. 
 macropdmum; long cheek ; long-jawed. 
 macrdpterus, a, um; long-winged ; long-finned. 
 macropyg6pte / )'us } a, um; long tail-finned. 
 maci'ospondl/lus, a, um; long- backboned ; long-spined. 
 macrostSmus, a, um; long- or large-mouthed. 
 macrdtus, a, um; long- or large-eared. 
 macfurus, a, um; long-tailed. 
 
 mactro'ides; like, or having the form of the shell mactra. 
 maculdtus, a, um; spotted ; mackled. 
 major, or, us; the greater. 
 
 Malcolmsoni; after Dr Malcolm of Elgin, Morayshire. 
 mdlleus; a mallet, or hammer ; the shell malleus, 
 mammilldris, is, e; mammillated ; pap-shaped. 
 mammilldtus, a, um; nipple-shaped ; mammillary. 
 mammillifei-us, a, um; pap-bearing ; covered with pap-like points. 
 mancus, a, um; imperfect ; defective. 
 
 mandibuldris, is, e; beaked ; bill-like ; mandibular ; furnished with man- 
 dibles. 
 
 mandibuldtus, a, um; bill-shaped ; furnished with a mandible. 
 Mantelli; after Dr Mantell, the geologist. 
 Marcoudnus, a, um; after M. Jules Marcou, geologist. 
 margaritdceus, a, um; pearly ; having the lustre of pearl. 
 
 491 
 
MAR MON 
 
 margaritulus, a, urn; little pearl ; seed-pearl. 
 margindtus, a, urn; bordered ; having a distinct border. 
 marginalia; little margin (a genus of shells). 
 Martini; after Martin, the palaeontologist of Derbyshire. 
 mastod6nteus, a, urn; nipple-toothed ; teeth with tubercles. 
 maximus, a, urn; greatest ; the largest. 
 meandrinus, a, um; meandering ; serpentine. 
 meandroldes; like the meandrina or brain-coral. 
 medium, a, um; intermediate ; middling. 
 medulldris, is, e; medullary ; having a pith. 
 megdlodon; large tooth ; large-toothed. 
 megalophi/ttus, a, um; large-leaved. 
 megaldtis, is, e; great-eared ; great ear. 
 melacactoldes; melocactus-like ; resembling the melocactus. 
 mel&nia; black (a genus of shells). 
 melanoldes; like the shell melania ; black-like. 
 Melitensis, is, e; of or belonging to the island of Malta. 
 membrandceus, a, um; membrane-like ; formed of membrane. 
 menisco'ideus, a, um; meniscoid ; concavo-convex. 
 mespili/6rmis, is, e; medlar-shaped. 
 micans; shining ; glistening with enamel. 
 micdstron; little star. 
 micracdnthus, a, um; small-spined. 
 microctphalus, a, um; small-headed. 
 microdus; small tooth ; minute tooth. 
 microlepid6tus, a, um; small-scaled. 
 microphyllus, a, um; small-leaved. 
 micropleurus, a, um; small-sided. 
 micropdrus, a, um; small-pored. 
 Milleri; after Mr Hugh Miller, geologist. 
 minimus, a, um; the least ; very small. 
 minor, or, us; the less, less. 
 minutulus, a, um; very minute ; minutely small. 
 minutus, a, um; minute, small. 
 
 mioccenus, a, um; found in the Miocene or Middle Tertiaries. 
 mirdbilis, is, e; wonderful ; admirable. 
 mitrceformis, is, e; mitre-shaped ; mitriform. 
 mitrdtus, a, um; mitre-like; in the form of a mitre. 
 modiola, modiolus; a bushel-measure (a genus of shells). 
 modioldris, is, e; bushel-shaped. 
 molendindceus, a, um; mill-sail-shaped. 
 MonGnsis, is, e; belonging to the Isle of Man (Mona). 
 monile; a necklace ; bead-string-like. 
 monileformis, is, e; necklace-shaped; bead-like. 
 moniletectus, a, um; necklace-covered. 
 moniliferus, a, um; beaded ; necklace-like. 
 mon6ceros; one-horned ; the narwhal. 
 
 monticuldtus, a, um; having many small projections ; covered with conical 
 points. 
 
 492 
 
MOO NIT 
 
 Mooreii; after Mr C. Moore of Bath, geologist. 
 
 MmYuii; after Professor Morris of London, geologist. 
 
 mosdicus, a, um; tessellated like mosaic work ; patterned. 
 
 mucrondtus, a, um; sharp-pointed ; dagger-like. 
 
 multicarindtus, a, um; having many keels or ridges. 
 
 multiceps; many-headed. 
 
 multidigitdtus, a, um; many-fingered. 
 
 multifidus, a, um; many-cleft ; having many segments. 
 
 multigrdnuldtus, a, um; many-grained ; dotted with numerous grains. 
 
 multilorqiiatus, a, um; many times twisted ; often twisted. 
 
 multinervdtus, a, um; many-nerved. 
 
 multinddus; many-knotted. 
 
 multiradidtus, a, um; many-rayed. 
 
 multisulcdtus, a, um; many-furrowed. 
 
 Munsteridnus, a, um; after Count Munster, geologist. 
 
 MurchisCni; after Sir Roderick Murchison, the geologist. 
 
 muricdtus, a, um; like the shell murex. 
 
 Murraydnus, a, um; after Dr Murray of Yorkshire. 
 
 muscarifdrmis, is, e; brush-shaped. 
 
 musculus; a little mouse ; mouse-like. 
 
 mutdbilis, is, e; mutable ; changeable. 
 
 muticus, a, um; without a beard ; beardless. 
 
 m$a; gaper (a genus of shells). 
 
 mysticetus, a, um; sperm-whale-like. 
 
 myliloldes; like the mytilus, or mussel-shell. 
 
 N 
 
 ndnus, a, um; dwarfish. 
 
 napifdrmis, is, e; turnip-shaped. 
 
 nasutus, a, um; having a prominent nose. 
 
 nautiloldea; resembling the shell nautilus. 
 
 nautilus; a little sailor (a genus of chambered shells). 
 
 navicula; a little ship ; boat-shaped. 
 
 naviculdris, is, e; ship-like. 
 
 ndvis; a ship. 
 
 negUctus, a, um; neglected ; overlooked. 
 
 nemordlis, is, e; frequenting woods ; of the grove. 
 
 Neocomiensis, is, e; of or belonging to the Neocomian or Lower Greensand 
 
 formation. 
 
 nephrocdrpus, a, um; kidney-fruited ; fruit kidney-shaped. 
 nervdsus, a, um; full of nerves. 
 nexilis, is, e; entwined ; interlaced. 
 Niagarensis; of or belonging to the Niagara district. 
 Nicoli; after Professor Nicol of Aberdeen, geologist. 
 nitens; bright ; shining. 
 nitidulus, a, um; rather neat. 
 nitidus, a, um; neat ; pretty. 
 
 493 
 
NIV ORB 
 
 niveus, a, um; snowy ; white as snow. 
 
 ndctulus, a, um; belonging to the twilight ; of twilight habits. 
 
 nod6sus, a, um; knotty ; knobbed. 
 
 noduldsus, a, um; in small knots. 
 
 NVgger&thii; after Dr Noggerath, German fossil botanist. 
 
 normdlis, is, e; normal ; according to rule ; following the usual structure. 
 
 Nwn&gicus, a, um; of or belonging to Norway. 
 
 notdtus, a, um; marked ; stamped with a mark. 
 
 nucleus; a kernel ; kernel-like. 
 
 nucula; a little nut (a genus of bivalve shells). 
 
 nudus, a, um; naked ; uncovered. 
 
 numismdlis, is, e; coin-like (round-lenticular). 
 
 nummdrius, a, um; coin-like ; coin-shaped. 
 
 nummi/6rmis, is, e; coin-shaped ; in the form of small coins. 
 
 nummuldrius, a, um; nummulus-like in form. 
 
 ntimmulus, or little coin (a genus of foraminiferous shells, so called from 
 
 their form). 
 nutans; nodding ; bent downwards. 
 
 obcdnicus, a, um; rather conical ; slightly conical. 
 obesus, a, um; fat ; plump in form. 
 
 obldtus, a, um; oblate ; broader than long ; broadly-round. 
 obliqudtus, a, um; oblique ; slanting. 
 obliquus, a, um; oblique ; leaning to one side. 
 oblongus, a, um; oblong ; rather long ; longer than broad. 
 obovdtus, a, um; egg-shaped ; with the broad end uppermost. 
 obsoUtus, a, um; obsolete ; scarcely distinguishable at the margin. 
 obtusilobus, a, um; obtuse-lobed ; having blunt lobes. 
 obvolutus, a, um; folded ; tied about. 
 ocelldtus, a, um; furnished with little eyes, or eye-specks. 
 ochrdceus, a, um; ochrey ; having the colour of ochre. 
 octoplicdtus, a, um; eight-folded. 
 oculdtus, a, um; full of eyes, or eye-like dots. 
 oculinus, a, um; eye-like ; spotted with eyes. 
 Oldhami; after Professor Oldham of Dublin. 
 olivdceus, a, um; olive-like ; olive-coloured. 
 6lla; a pot ; pot-shaped. 
 onl/chius, a, um; shaped like a little claw. 
 oocephalus, a, um; egg-headed ; broad end up. 
 Ooliticus, a, um; of or belonging to the Oolite. 
 opalinus, a, um; opal-like ; having the lustre of opal. 
 operculdris, is, e; furnished with an opercular bone ; opercular. 
 oppdsitus, a, um; opposite ; placed on opposite sides. 
 orbicula; rounded ; little orb (a genus of shells). 
 orbiculdris, is, e; orbicular; orb-shaped. 
 Orbignyi; after D'Orbigny, the celebrated French savan. 
 
 494 
 
ORD PAT 
 
 ordiiiarius, a, um; ordinary ; common ; frequent. 
 
 6rganum; an organ ; arranged like the pipes of an organ. 
 
 omatissimus, a, um; most ornamented ; highly ornamented. 
 
 orndtus, a, um; ornamented ; adorned. 
 
 ornithocephalus, a, um; bird-headed ; like a bird's head. 
 
 oryza; a grain of rice ; like a rice-grain. 
 
 dsculifer, a, um; having a little mouth. 
 
 6sseus, a, um; bony ; composed of, or armed with, bone. 
 
 ostreceformis, is, e; oyster-shaped. 
 
 ovdlis, is, e; oval ; in the form of an egg. 
 
 ovdtm, a, um; ovate ; egg-shaped. 
 
 ovif6rmis, is, e; egg-shaped ; ovate. 
 
 ovoldea; egg- like ; in the form of an egg. 
 
 ovula; a little egg (a genus of shells). 
 
 O'weni; after Professor Owen, the celebrated naturalist. 
 
 packyderma; thick-skinned; thick-barked. 
 
 pachygndthus; thick -jawed ; strong-jawed. 
 
 pach$omus; thick shoulder-blade ; thick-shouldered. 
 
 pachydpterus, a, um; thick-finned ; thick- winged. 
 
 paledtus, a, um; chaffy. 
 
 pdllidus, a, um; pale-coloured. 
 
 palmdtus, a, um; palmate ; having five lobes like the fingers of the human 
 
 hand. 
 
 palpebr6sus, a, um; having large eyelids ; deeply fringed. 
 pandurdtus, a, um; fiddle-shaped. 
 pdndus, a, um; bent downwards. 
 
 paniceus, a, um; bread-like ; in the form of a cake of bread. 
 papaverdceus, a, um; poppy-like. 
 papiliondtus, a, um; butterfly-shaped. 
 papilldtus, a, um; nipple-like ; covered with papilli. 
 papillosus, a, um; covered with numerous tubercles. 
 paraddxicus, a, um; paradoxical ; puzzling ; questionable. 
 paraddxus, a, um; questionable ; extraordinary. 
 parasiticus, a, um; parasitic ; living on or attached to another. 
 pardoldes; panther-like ; allied to the panther. 
 Parisiensis, is, e; belonging to Paris ; found near Paris. 
 Parlcinsonis, is, e; after Parkinson the palaeontologist. 
 pdrvidens; small-toothed. 
 pdrvulus, a, um; very small ; diminutive. 
 parvus, a, um; small. 
 
 patella; a small plate ; the knee-pan ; the limpet-shell. 
 patelldris, is, e; limpet-shaped. 
 patttliformis, is, e; patella or limpet-shaped. 
 patens; spreading; exposed. 
 patu'dsus, a, um; broad; expanding. 
 
 495 
 
PAT PHR 
 
 p&tulus, a, urn; broad ; spread out. 
 pducidens; few-toothed ; having few teeth. 
 paucifolius, a, um; few-leafed ; having few leaves. 
 paucisulcdtus, a, um; having few furrows or depressions. 
 pauperdtus, a, um; impoverished ; meagre. 
 paxillosus, a, um; resembling a little stake. 
 Peachii; after Mr Charles Peach, collector and discoverer. 
 pecten; a comb (the scallop-shell) ; comb-like. 
 pectindtus, a, um; pectinated ; toothed like a comb. 
 pectinifer, a, um; comb-bearing. 
 pectinoldes; comb-like. 
 pectunculus; little comb (a genus of shells). 
 pectestris, is, e; furnished with feet ; footed. 
 pgdum; a shepherd's crook. 
 
 pedunculdtus, a, um; furnished with a footstalk or peduncle. 
 peldgicus, a, um; belonging to the deep sea. 
 pSllis serpgntis; serpent's skin. 
 pellucidus, a, um; quite transparent ; pellucid. 
 peltdtus, a, um; buckler or half-moon shaped. 
 peltiformis, is, e; in the form of a half-moon buckler. 
 pen&llus; a brush or pencil. 
 
 PengHlyi; after M. Pengelly of Torquay, geologist. 
 penncefdrmis, is, e; feather-like ; feather-shaped. 
 pennic6stis, is, e; feather- ribbed. 
 pentdgonuj, a, um; five-cornered ; pentagonal. 
 pentremataides; like or resembling the pentremite. 
 perdmplus, a, um; very large ; unusually large. 
 perarmdtus, a, um; completely armed. 
 perattenuatus, a, um; much attenuated ; very slender. 
 peregrinus, a, um; foreign ; wandering. 
 perfortttus, a, um; perforated ; full of holes or pores. 
 perldtus, a, um; very broad ; very wide ; unusually wide. 
 Permidnus, a, um; of or belonging to the Permian system. 
 perorndtus, a, um; highly ornamented ; unusually ornamented. 
 perovdlis, is, e; very oval ; almost round. 
 perreticuldtus, a, um; highly reticulated ; reticulated all over. 
 perrugdtiis, a, um; very full of wrinkles ; extremely wrinkled. 
 person&tus, a, um; personate ; mask-like. 
 pertusus, a, um; pierced ; struck through. 
 pes-diiseris; goose-foot ; shaped like a goose's foot. 
 pes-rdnce; frog-foot ; shaped like a frog's foot. 
 petaliferus, a, um; bearing petal-like appendages. 
 petallifdrmis, is, e; shaped like the petals of a flower. 
 petioldtus, a, um; furnished with a petiole or leaf-stalk. 
 petricolus, a, um; stone- dwelling ; living in stone. 
 2)haseolmus, a, um; kidney-bean-shaped. 
 phaseolus; in the form of a kidney-bean. 
 Pkillipsii; after Professor Phillips of Oxford, geologist. 
 phrtigmiger, a, um; separated by thin partitions ; partitioned. 
 
 496 
 
PIC POL 
 
 pictus, a, urn; painted. 
 
 piledris, is, e; in the form of a peaked hat or cap. 
 
 pileopsis; like a peaked hat (a genus of limpet-like shells). 
 
 piliferus, a, um; hair-bearing; hair-pointed. 
 
 pillula; a little ball or pill. 
 
 pinaster; like the pine-tree, pinaster. 
 
 piniformis, is, e; pine-shaped ; pine-tree-like. 
 
 pinna; a fin ; the bivalve shell pinna. 
 
 piriformis, is, e; pear-shaped, pyriform. 
 
 piscatdrius, a, um; fishing ; fish- catching. 
 
 piscatorum; of fishermen ; used by fishers. 
 
 pisiformis, is, e; pea-shaped. 
 
 pistiUiformis, is, e; pestle-shaped ; in form of a pestle. 
 
 pisum; a pea ; like a pea ; pea-shaped. 
 
 placentiformis, is, e; placenta- or cake- shaped. 
 
 plandlns, a, um; smoothed ; plain. 
 
 pldniceps; smooth-headed; flat-headed. 
 
 planicostdtus, a, um; smooth-ribbed. 
 
 planorbis; even-whorled ; having the spires lying in the same plane (a 
 
 genus of spiral- circular shells). 
 planuldtus, a, um; rather smooth ; somewhat flat. 
 platycephalus, a, um; broad-headed. 
 pldtyceps; broad head ; broad-headed. 
 platyn6tus; broad back. 
 platljodon; broad-toothed. 
 
 platyphljllus, a, um; broad-leafed ; expanded like a leaf. 
 platljpterus, a, um; broad-finned. 
 platypus, a, um; broad-footed. 
 platyrachis; having a broad rachis or stalk. 
 pleiodon; pleiodus; the larger- toothed. 
 plica; a fold or plait. 
 plicat&lla; a little fold or plait. 
 plicdtilis, is, e; slightly folded, in small folds. 
 plicdtus, a, um; folded, plaited. 
 plic6mphalus, a, um; folded in the middle or navel. 
 plioccenus, a, um; found in the Pliocene or Upper Tertiaries. 
 pluma; a feather or plume. 
 plumdrius, a, um; plume-like ; feathery. 
 plumfisus, a, um; feathery. 
 
 pluriradidlis, is, e; many-rayed, as in certain corals. 
 poculiformis, is, e; cup- or goblet- shaped. 
 poculum; a cup or goblet ; cup- shaped. 
 podocarpo'ides; like the podocarpus, one of the yews. 
 politus, a, um; polished ; smoothed ; not figured. 
 Pollexfeni; after the Rev. Mr Pollexfen, naturalist. 
 polydactylus, a, um; many-fingered. 
 polygon&tus, a, um; many-angled ; many-cornered. 
 polljgyrus, a, um; many-twisted ; many-circled. 
 polymdrphus, a, um; many-shaped ; of many forms. 
 
 497 2 1 
 
POL PUR 
 
 poll/odus, a, um; many-toothed. 
 polydmmata; many-eyed. 
 polyphyilus, a, um; many-leaved. 
 polypodivides; like the fern polypodium or polypody. 
 polyspotidyluS) a, um; having many vertebrae. 
 polystdchya; many-spiked ; many-eared. 
 poltftoma; cut into many parts. 
 ponder6sus, a, um,; heavy ; bulky. 
 porosus, a, um; full of pores ; porous. 
 porrectus, a, um; stretched out. 
 Portlockii; after Major-General Portlock, geologist. 
 posterogenius, a, um; later-born ; not the first of its kind. 
 prceacutus, a, um; very acute ; thin and sharp. 
 prcem6rsus, a, um; jagged as if bitten off. 
 prat&nsis, is, e; inhabiting meadow or river-land. 
 Prestvici; after Mr Prestwich of London, geologist. 
 Prevostii; after M. Constance Prevost, French geologist. 
 primcevus, a, um; primeval ; very ancient. 
 primigenius, a, um; original ; first-born. 
 primordidlis, is, e; primordial ; first in order. 
 priscus, a, um; ancient. 
 
 pristoddntus, a, um; saw-toothed ; jagged like a saw. 
 Pritchardi; after Mr Pritchard, the microscopist. 
 proitvus, a, um; ancient ; belonging to the first ages. 
 problemdticus, a, um; problematical ; doubtful. 
 proboscoideus, a, um; proboscis-like. 
 proliferus, a, um; putting forth a new shoot. 
 propinquus, a, um; neighbouring ; related to. 
 propter$gius, a, um; fore-finned. 
 
 prostrdtus, a, um; prostrate ; creeping on the ground. 
 protensus, a, um; stretched forth ; stretched out. 
 prunifdrmis, is, e; prune-shaped. 
 psilopora; having smooth pores ; smooth-pored. 
 psittaceus, a, um; parrot-like ; hooked like a parrot's bill. 
 psittadnus, a, um; parrot-like ; bent like a parrot's bill. 
 pterdcera; winged-horn ; a genus of univalves ; like the shell pterocera. 
 pteroldes; wing-like ; fern-like. 
 ptycho'ides; wrinkle-like. 
 puUscens; downy ; covered with fine hairs. 
 pucillus, a, um; very small. 
 pulcMllus, a, um; lovely ; minutely pretty. 
 pulcher, a, um; beautiful. 
 pulcherrimus, a, um; fairest ; very beautiful. 
 pulverulentus, a, um; covered as with small dust ; powdery. 
 pulvindrium; a cushion ; cushion-shaped. 
 pulvindtus, a, um; cushioned. 
 pumXlus; a dwarf or pigmy. 
 
 punctdtus, a, um; punctured ; marked with dots ; dotted. 
 pupa; a swathe or bandage ; a genus of univalves. 
 Purbeclcensis, is, e; from the isle of Purbeck in Dorsetshire. 
 
 498 
 
PUS RET 
 
 pvsillus, a, um; very small ; diminutive. 
 pustuldtus, a, um; pustuled ; covered with pustules. 
 pustuliferus, a, um; bearing pustules ; marked with pustules. 
 pustuldsus, a, um; full of or all over with pustules. 
 pygmceus, a, um; diminutive in size ; pigmy-like. 
 pyramiddlis, is, e; pointed like a pyramid. 
 pyriformis, is, e; pyriform ; pear-shaped. t 
 
 quadratiguldris, is, e; quadrangular ; four-sided. 
 quadrdtus, a, um; square-shaped. 
 quadricostdtus, a, um; four-ribbed. 
 quadrifidus, a, um; cleft or split into four. 
 quadrigeminus, a, um; four times doubled. 
 quadriplicdtus, a, um; four- folded. 
 quadrisulcdtus, a, um; four-furrowed. 
 quadrivittdtus, a, um; having four chaplets. 
 quinquecostdtus, a, um; five-ribbed. 
 quinqueddctylus, a, um; five-fingered. 
 
 R 
 
 racf,m6sus, a, um; full of bunches, bunchy. 
 racemus; a bunch or cluster of florets. 
 radidtus, a, um; radiating from a point ; ray-like. 
 rddicans; rooting ; branching out like roots. 
 radicif6rmis, is, e; root-shaped ; root-like. 
 
 radio-punctdtus, a, um; marked with radiating or star-like punctures. 
 ramdsus, a, um; branching ; having many branches. 
 Ramsayii; after Professor Ramsay of the Geological Survey. 
 ramulosus, a, um; branchy ; full of little branches ; slightly branching. 
 Eankinti,; after Dr Rankine of Carluke, in Lanarkshire. 
 raphiodon; needle-toothed; prickle-tooth. 
 raricostdtus, a, um; having few rib-like processes. 
 rarispinus, a, um; having few spines. 
 rarist&lla; having few star-like pores. 
 rastellum; a little rake ; rake-like. 
 r&ctus, a, um; straight ; without bend. 
 recurvirdstra; bent beak or jaw. 
 recurvus, a, um; bent back. 
 remif6rmis, is, e; oar-shaped. 
 reniformis, is, e; kidney-shaped. 
 
 repdndus, a, um; repand ; slightly waved at the margin. 
 replicdtus, a, um; folded back upon itself. 
 resupindtus, a, um; upside down. 
 retidrius, a, um; netted ; meshed like a net. 
 reticuldius, a, um; reticulate ; like network. 
 
 499 
 
EET SCO 
 
 retrdrsus, a, um; turned backwards ; bent back. 
 
 retrusus, a, um; thrust back ; -hidden ; concealed. 
 
 retusus, a, um; blunt. 
 
 reversus, a, um; reversed ; turned or bent back. 
 
 revolutus, a, um; turned back ; curled back. 
 
 rhapkiodon; club-tooth ; shaped like a club. 
 
 rhdmbus; a rhomb or lounge ; lozenge-like. 
 
 rhombo'ides; like a lozenge ; diamond-shaped. 
 
 Richardsoni; after Mr Richardson of London, geologist. 
 
 rigidulus, a, um; somewhat stiff ; stiffish. 
 
 rigidus, a, um; rigid; stiff; not flexible. 
 
 rimdsus, a, um; full of chinks. 
 
 ringens; gaping ; having an open orifice. 
 
 Robertsoni; after Mr Robertson of Edinburgh, geologist. 
 
 rostralinus, a, um; having a little beak. 
 
 rostrdtus, a, um; beaked. 
 
 rostro-minor, or, us; minor-beaked ; lesser-snouted. 
 
 r6ldtus, a, um; wheel-shaped ; wheel-like. 
 
 Rothomagensis, is, e; from or belonging to Rouen. 
 
 rdtifer, a, um; wheel-bearing. 
 
 rdtulus, a, um; slightly rounded. 
 
 rotunddtus, a, um; rotund ; rounded. 
 
 rudis, is, e; not worked or fashioned ; rude. 
 
 wiffdtus, a, um; wrinkled. 
 
 rugdsus, a, um; full of wrinkles. 
 
 rugulosus, a, um; somewhat wrinkled ; minutely wrinkled. 
 
 runcindius, a, um; hook-backed. 
 
 s 
 
 sagittdtus, a, um; arrow-shaped ; barbed like an arrow. 
 sagittida; a little arrow ; like a little arrow. 
 salmdneus, a, um; salmon-like ; pertaining to the salmon. 
 sarcinuldtus, a, um; having a wallet or pouch. 
 sauropUsius, a, um; most closely allied to the lizard family. 
 saxdtilis, is, e; stony. 
 saxeus, a, um; stony ; stony in texture. 
 scaber, a, um; rough ; rough-surfaced. 
 scabriculus, a, um; rough. 
 
 scabriusculus, a, um; somewhat rough ; roughish. 
 scaldrif6rmis, is, e; ladder-shaped. 
 scarabceus; a beetle ; beetle-shaped ; beetle-like. 
 scaraboides; beetle-like ; like the scarabaeus. 
 scaridsus, a, um; scarious ; having a dry shrivelled appearance. 
 schizurus, a, um; split-tail ; rent-tail. 
 scissus, a, um; split ; marked by a line of division. 
 scobriculdtus, a, um; pitted. 
 scopiformis, is, e; tufted ; tuft-shaped. 
 Scolticus, a, um; Scottish ; found in Scotland. 
 
 500 
 
SCO SOW 
 
 Scouleri; after Dr Scouler of Glasgow, naturalist. 
 scrofa; a sow ; sow-like. 
 scrolifdrmis, is, e; pouch-shaped. 
 scutdtus, a, urn; shield-like ; buckler-shaped. 
 scutelUformis, is, e; buckler-formed. 
 scutifdrmis, is, e; scute- or shield-shaped. 
 sectus, a, urn; cut or cleft. 
 
 secunddrius, a, urn; secondary; second in order ; inferior. 
 securif6rmis, is, e; hatchet- shaped. 
 
 Sedgvnckii; after Professor Sedgwick of Cambridge, geologist. 
 selaginoides; selago-like ; leafed like the plant selago. 
 Selwyni; after Mr Selwyn of the Geological Survey. 
 semiflaMlliffirmis, is, e; half fan-shaped. 
 semigl6bus; half-globe; hemispherical. 
 
 seminiferus, a, um; seed-bearing ; marked with small seed-like granules. 
 semiorndtus, a, um; half -ornamented. 
 semipldnus, a, um; half-smooth. 
 semiplicdtus, a, um; half-folded. 
 semiserrdtus, a, um; half-serrated. 
 semistridtus, a, um; half-striated. 
 semisulcdtus, a, um; half-furrowed. 
 semiteres; half-taper. 
 semiverruc6sus, a, um; half -warty. 
 senticdsus, a, um; covered with prickles ; prickly. 
 septdtm, a, um; divided by septa or partitions. 
 septemplicdtus, a, um; seven-folded. 
 septdsus, a, um; full of septa or partitions. 
 seridiis, is, e; in rows or series. 
 serxceus, a, um; silky. 
 serpentinus, a, um; serpentine ; winding. 
 serpuldrius, a, um; serpula-like ; worm-like. 
 serpulus, a, um; creeping ; worm-formed. 
 serra; a saw; saw-like. 
 
 serratissimus, a, um; highly serrated ; excessively serrated. 
 serrdtus, a, um; saw-edged ; serrated. 
 sernfet'us, a, um; bearing serrations. 
 serruldtus, a, um; minutely serrated. 
 sertus, a, um; bound ; joined together. 
 sigmouleus, a, um; sigma- shaped ; like the letter S. 
 siliqudria; pod-like. 
 
 Sillimani; after Professor Silliman, American geologist. 
 Siluriensis, is, e; belonging to the Silurian system. 
 simillimus, a, um; most like ; most closely allied to. 
 simplex; simple ; undivided ; not branching. 
 siuistrCrsus, a, um; left-handed ; turned to the left. 
 sinudtus, a, um; marked with depressions ; wavy. 
 socidlif, is, e; living in groups ; social. 
 soldrium; sun-dial ; like the flattened univalve solarium, 
 solenoldes; like the razor-shell, solen. 
 Sotoerbyi; after Mr Sowerby of London, conchologist. 
 
 501 
 
SPA SUB 
 
 spatuldtiis, a, um; spatula- shaped ; spatulate ; blade-shaped. 
 specidsus, a, ^lm; beautiful. 
 spectdbilis, is, e; notable ; worth seeing. 
 spelceus, a, um; belonging to a cave ; cave-dwelling. 
 speluncdrius, a, um; cavernous. 
 sphwicus, a, um; spherical ; round-bodied. 
 sphcero'idelis, is, e; spherical. 
 
 spictdtus, a, um; spiked ; in spikes like an ear of corn. 
 spiniger, a, um; spiny ; bearing spines. 
 spinipes; spine-footed ; having the feet armed with spines. 
 spindsus, a, um; spiny ; covered with many spines. 
 spinuldsus, a, um; full of little spines. 
 spirdtus, a, um; having spires ; spiral. " 
 spirorbis; spiral- whorl (shell of an annelid). 
 squamdtus, a, um; scaly ; furnished with scales. 
 squdmiger, a, um; carrying scales ; faintly scaled. 
 squamdsus, a, um; scaly ; covered with scales. 
 stelldris, is, e; starred ; rayed like a star. 
 stelldtus, a, um; starred ; covered with star-like dots. 
 Sternbergii; after Count Sternberg, fossil botanist. 
 stramineus, a, um; as if covered with straw. 
 striatellus, a, um; minutely striated ; slightly striated. 
 stridto-punctdtus, a, um; spotted in striae or parallel lines. 
 stridtulus, a, um; somewhat striated. 
 stridtus, a, um; striated ; minutely fluted. 
 StricTclandii; after Mr Hugh Strickland, English geologist. 
 slrioldtus, a, um; very minutely striated. 
 strombo'ides; resembling the shell strombos. 
 Stutchburii; after Mr Stutchbury, geologist. 
 styttphora; mark-bearing ; impressed with a mark. 
 subanguldtus, a, um; somewhat cornered. 
 subardtus, a, um; somewhat defaced (literally, ploughed up). 
 subarcudtus, a, um; slightly bow-shaped or bent. 
 subarmdtus, a, um; somewhat armed. 
 
 subcarindtus, a, um; somewhat keeled ; furnished with slight ridges ; in- 
 distinctly ridged. 
 
 subconv$xus, a, um; somewhat convex. 
 siibcristdtus, a, um; rather crested. 
 subdeprssus, a, um; somewhat depressed. 
 subfimbriatus, a, um; slightly fimbriated. 
 subfusifdrmis, is, e; somewhat spindle-shaped. 
 
 subnoddsiis, a, um; somewhat knotted ; marked witL slight projections. 
 subnudus, a, um; somewhat naked. 
 subreticuldius, a, um; somewhat reticulated. 
 sitbrotundus, a, um; sub-rotund ; somewhat round ; roundish. 
 subserrdtus, a, um; slightly serrated. 
 subteres; somewhat tapering. 
 subtfigonus, a, um; somewhat three-cornered. 
 subturbiiidtus, a, um; somewhat top -shaped. 
 subuldtus, a, um; awl-shaped ; subulate. 
 
 502 
 
SUB TOL 
 
 svbulidens; awl-toothed ; having awl-shaped teeth. 
 
 succulens; succulent ; soft and not woody. 
 
 succulosus, a, urn; very soft and succulent. 
 
 SitffolciGwu, is, e; of or belonging to Suffolk. 
 
 sidcdtus, a, um; furrowed. 
 
 sulcifer, a, um; bearing furrows ; marked with furows. 
 
 sulcostdmus, a, um; having a mouth deeply furrowed. 
 
 supSrbus, a, um; superb ; magnificent. 
 
 Sussexiensis, is, e; found in or belonging to Sussex. 
 
 sylvestris, is, e; belonging to the woods ; inhabiting the woods. 
 
 tabvMtus, a, um; boarded ; planked. 
 
 tceni&nus, a, um; tape-worm-shaped. 
 
 tardndus; the reindeer ; reindeer-like. 
 
 taxinus, a, um; belonging to the yew-tree ; yew-like. 
 
 tdxus; the badger ; badger-like. 
 
 tentllus, a, um; very tender ; delicate. 
 
 Tennanti; after Professor Tennant of London, mineralogist. 
 
 tenuwaulis, is, e; slender-stemmed or stalked. 
 
 tenuiceps; slender head ; slender-headed. 
 
 Unuidens; slender tooth ; slender-toothed. 
 
 tenuifascidtus, a, um; slender-banded. 
 
 tenuifdlim, a, um; slender-leaved. 
 
 tenuilamelldsus, a, um; having slender lamellae, or thin plates. 
 
 tenuirdstris, is, e; slender-beaked ; slender-snouted. 
 
 tenuis, is, e; slight; slender. 
 
 tenuiseptus, a, um; slightly divided ; slender-partitioned. 
 
 tenuispinus, a, um; slender- spined. 
 
 tenuistridtus, a, um; finely striated ; slightly striated. 
 
 terebra; a borer or auger. 
 
 terebrdlus, a, um; bored ; perforated. 
 
 tZres; rubbed to a point ; tapering. 
 
 teretiusculus, a, um; slightly tapering ; somewhat taper. 
 
 tesselldtus, a, um; tessellated, like the squares of a dice-board. 
 
 tesseracontadactylus, a, um; forty-fingered. 
 
 testacella; little shell. 
 
 testudinifdrmis, is, e; turtle- or tortoise-shaped. 
 
 tetrdgonus, a, um; four-cornered. 
 
 telrdsticha; in four rows. 
 
 texftlis, is, e; woven ; like a web. 
 
 thujoldes; like the thuja, or arbor-vitae, one of the coniferse. 
 
 ihymifdlius, a, um; thyme-leaved ; leaves like the thyme. 
 
 thyreosp6ndylus; having perforated vertebrae. 
 
 tichorhinus, a, um; partition-wall-nosed ; applied to a fossil rhinoceros, in 
 
 allusion to the structure of the nose- or snout- bones. 
 tintinndbulum; a little bell ; like a little bell. 
 tolidpicus, a, um; pestle-like ; from the Isle of Sheppey. 
 
 503 
 
TOM UMB 
 
 tomentdsus, a, um; thickly covered with short stiff hairs. 
 
 Tommasinii; in honour of Tommasini, the podesta of Trieste. 
 
 torqudtus, a, um; twisted round. 
 
 tortudsus, a, tim; tortuous ; twisted. 
 
 Trailli; after Dr Traill of Edinburgh, naturalist. 
 
 transversus, a, um; transverse ; cross-wise. 
 
 trapeziformis, is, e; four-sided ; trapezium-like. 
 
 triacontaddctyhis, a, um; thirty-fingered. 
 
 triangularis, is, e; triangular- shaped ; three-cornered. 
 
 tricMtomus, a, um; divided into three. 
 
 triddclylites; three-fingered ; three-fingered -like. 
 
 trifidus, a, um; cleft or divided into three. 
 
 trifolidtus, a, um; three-leafed. 
 
 trifurcdtus, a, um; three-forked. 
 
 trigontllaris, is, e; triangular ; three-cornered. 
 
 trig6niceps ; triangular-headed. 
 
 trigonoc&nthus, a, um; three-cornered spine. 
 
 trigondcenis, a, um; three-cornered or triangular horn. 
 
 trigonopsis; three-cornered-like. 
 
 trigonus, a, um; three-cornered. 
 
 trilobdtus, a, um; three-lobed ; in three main parts. 
 
 triiiervis, is, e; three-nerved ; having three veins. 
 
 trinodus, a, um; three-knotted ; consisting of three knots or knobs. 
 
 trochiformis, is, e; trochiform ; like the trochus or wheel-shell. 
 
 trockledris, is, e; pulley-shaped. 
 
 trocholdes; like the trochus or wheel-shell. 
 
 tropceus, a, um; twisted or turned round. 
 
 truncdtus, a, um; truncated ; cut short. 
 
 tubceformis, is, e; trumpet-shaped. 
 
 tuberculdtus, a, um; covered with tubercles ; warty. 
 
 tuberdsus, a, um; tuberose ; composed of tuber-like parts. 
 
 tubipdra; organ- piped ; tubular-pored. 
 
 tubuldris, is, e; hollow like a pipe ; tubular. 
 
 tubuldtus, a, um; furnished with pipe-like pores or passages. 
 
 tubuUsus, a, um; abounding in tubes ; made up of tubes. 
 
 tumldulus, a, um; slightly swollen. 
 
 tumidus, a, um; tumid ; swollen out. 
 
 TunstalUnsis, is, e; after Tunstall Hill in Durham. 
 
 turbindtus, a, um; top-shaped. 
 
 turbinttlus, a, um; little top-shaped. 
 
 turbinoides; shaped like a top. 
 
 turgidus, a, tim; turgid ; swollen out. 
 
 turris; a tower ; tower-shaped. 
 
 U 
 
 umbella; an umbrella ; umbrella-like. 
 umbilicdtus, a, um; navel-shaped ; umbilicated. 
 umbondtus, a, um; bossed ; protuberant. 
 umbraculif6rmis, is, e; umbrella-shaped. 
 
 504 
 
UMB VES 
 
 umbrdsus, a, urn; shadowed. 
 
 uncdtus, a, urn; hooked ; hook-shaped. 
 
 uncifolius, a, urn; hook-leafed ; hook-like leaf. 
 
 uncindtus, a, urn; hooked ; furnished with hooks. 
 
 undans; waving ; in waving lines. 
 
 unddtus, a, um; wavy. 
 
 undosus, a, um; wavy ; full of heights and hollows. 
 
 unduldtus, a, um; undulating ; in wavy lines. 
 
 unguiculatus, a, um; claw-like ; furnished with claw-like processes. 
 
 unguifdrmis, is, e; claw-shaped, 
 
 unicarindtus, a, um; having one ridge or keel. 
 
 unicdlor; one-coloured ; of uniform colour. 
 
 unilinedtus, a, um; one-lined ; marked with one line. 
 
 uniplicdtus, a, um; once folded. 
 
 urceoldtus, a, um; pitcher-shaped ; pitcher-like. 
 
 Urii; after the Rev. Dr Ure of Rutherglen. 
 
 urophyllus, a, um; tail-leafed ; tapering like a tail. 
 
 utriculfiris, is, e; bag-like. 
 
 v&gans; wandering. 
 vagina; a sheath. 
 
 Valdensis, is, e; belonging to the Wealden formation. 
 vdlidus, a, um; strong ; stoutly built. 
 Vanuxemi; after Vanuxem, American geologist. 
 varidbilis, is, e; variable ; not always the same. 
 varians; variable ; changing. 
 varicdsus, a, um; varicose ; having swollen veins. 
 variocostdtus, a, um; differently ribbed ; having ribs of different sizes. 
 varioldris, is, e; spotted with pimples. 
 vasculdris, is, e; vascular ; having little vessels. 
 Vecliensis, is, e; of or belonging to the Isle of Wight. 
 veldmen; a covering or veil. 
 vtticans; sail-like ; with sail-like fins. 
 velox; swift ; fitted for rapid motion. 
 velutinus, a, um; velvety; soft. 
 ven6sus, a, um; full of veins. 
 ventricdsus, a, um; bulging out ; bellying. 
 ventropldnus, a, um; smooth-bellied. 
 venustus, a, um; fair ; elegant. 
 vermiculdris, is, e; worm-shaped ; vermicular. 
 vermiculo'ides; worm-like; vermicular. 
 Verneuilidnus, a, um; after M. Verneuil, geologist. 
 verructisus, a, um; warty ; covered with wart-like projections. 
 vertebr&lis, is, e; vertebra-like. 
 verticill&tus, a, um; whorled ; verticillate. 
 verus, a, um; true ; genuine. 
 vesiculdris, is, e; vesicular; bladder-like. 
 vesiculdsus, a, um; full of vesicles ; bladdery. 
 
 505 
 
VET ZIN 
 
 vetustus, a, um; ancient. 
 
 villdsus, a, um; villous ; covered with soft short hairs. 
 
 vimineus, a, um; osier-like ; withy. 
 
 violdceus, a, um; approaching to a violet hue. 
 
 virgdtus, a, um; twig-shaped ; rod-like. 
 
 virgula; a rod or twig. 
 
 mrgul&tus, a, um; rod-shaped ; like a bundle of rods. 
 
 vitreus, a, um; glassy ; like glass in lustre. 
 
 vittdtus, a, um; banded or bound with a fillet. 
 
 vdmer; a ploughshare ; ploughshare-like. 
 
 vulgdris, is, e; vulgar ; very common. 
 
 vulgdtus, a, um; common. 
 
 vulpiceps; fox-headed ; having a head like a fox. 
 
 mdturensis, is, e; vulture-like ; belonging to the vultures. 
 
 w 
 
 WaterJiousii; after Mr Waterhouse of London, zoologist. 
 Wetherelli; after Mr Wetherell, botanist and geologist. 
 Whitbignsis, is, e; from Whitby on the Lias in Yorkshire. 
 Williamsonis; after Dr Williamson of Scarborough, botanist. 
 Withami; after Dr Witham of Edinburgh, palaeontologist. 
 Woodii; after Mr Searles Wood of London, geologist. 
 Woodwardii; after Mr Woodward, conchologist. 
 Wrightii; after Dr T. Wright of Cheltenham, palaeontologist. 
 Wymani; after Professor Wyman of Canada. 
 
 X 
 
 xiphodon; sword-tooth ; having a sword-like tooth. 
 
 zamiotdes; zamia-like ; resembling the plant zamia. 
 zebra; the zebra ; striped or banded like the zebra. 
 zic-zac, zig-zag; slanting in straight lines from side to side. 
 zingiberiformis, is, e; ginger-root-shaped. 
 
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WILLIAM BLACKWOOD AND SONS. 7 
 
 CHRONICLES OF CARLINGFORD : SALEM CHAPEL. 
 
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 VOL. I. The Glenmutchkin Railway. Vanderdfecken's Message Home. The 
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 VOL. II. Lazaro's Legacy. A Story without a Tail. Faustus and Queen Eliza- 
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 College Theatricals. 
 
 VOL. III. A Reading Party in the Long Vacation. Father Tom and the Pope. 
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 VOL. IV. How I stood for the Dreepdaily Burghs. First and Last. The Duke's 
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 VOL. VII. My English Acquaintance. The Murderer's Last Night. Narration 
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 VOL. XI. The Natolian Story-Teller. The First and Last Crime. John Rintoul. 
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 1 VOL. XII. Tickler among the Thieves ! The Bridegroom of Barna. The Invol- 
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 ( ' i 
 
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