^^ - >!> 3> ^^ THE LIBRARY OF THE UNIVERSITY OF CALIFORNIA RIVERSIDE c. K. OGDEN ; ^*Afy// *r Z r *> "X'*A***a> i - ^* ^ A '^ ' A A GEOLOGICAL STORIES: A SERIES OF AUTOBIOGRAPHIES IN CHRONOLOGICAL ORDER. BY J. E. TAYLOR, F.L.S., F.G.S, &c. J in AUTHOR OF ETC. F.TC THIRD EDITION. LONDON: HARDWICKE & BOGUE, 192 PICCADILLY, W. 1876. NOTE TO SECOND EDITION. IN introducing the Second Edition of " Geological Stories " to the public, the Author cannot but express his gratification at its general reception. .' ^ 'A. few errors which crept into the first have been \corrected in the present edition, which is now respectfully submitted to the public as a plain and simple introduction to the wonders of Geo- logical Science. . CONTENTS. CHAPTER I. THE STORT OF A PIECE OF GEANITE. PAGB Discussions on the origin of granite Plutonists and Nep- ttmists Victory of the former Eesult of carrying the victory too far Miueralogical composition of granite Quartz, its component parts Alkaline ingredients probably assisted in its fluxion Felspar, what it is composed of Its "rottenness" Origin of Kaolin, or "China-clay" Mica, description of Hornblende, its colours, chemical composition, &c. Mineralogical relations of granite Porphyry, origin of its name Relation of ditto to other igneous rocks Syenite Protogine Pegmatite Binary granites Ternary ditto Quaternary ditto Their classification The first formed crust of the globe Idea as to the origin of the metamorphic rocks Conditions under which granites were originally for- med Cavities in the quartz crystals of granite Heat and water concerned in origin of granite Pressure under which granite was formed Consequences of absence of pressure on igneous rocks The granites of the Highlands Pressure under whicli they were formed Ditto of the granites of Cornwall Difference of rock-pressure Great antiquity of the earth proved by above facts Granite probably formed of re-melted stratified rocks Deep-seated condition of latter Upheaval of granite nucleus of mountains How it is granite now occupies large areas The denudation of rocks formerly overlying granite outcrops Internal force of the earth as opposed to that of the sun Overlying rocks strip- ped off by atmospheric agencies Time occupied . . . 1 13 Vlll CONTENTS. CHAPTEE II. THE STORY OP A PIECE OF QTTAETZ. PACS Time as a factor in Geology Astronomical calculations Our notions of the earth's antiquity greatly expanded within last ten years The Cambrian period " Primary " rocks Pos- sibly older stratified rocks than any yet known Quartz rock, its external appearance Crystals of ditto Quartz and Quartzile Difference of ditto " Brazilian pebbles" The Laurentian period the oldest yet known Composition of Quartz How difference in colour was effected Amethyst Topaz Cairngorms Jasper Flint Chalcedony A gates The metamorphic rocks Former notion of ditto Absence of fossils in ditto Notion as to the Cambrian period Altered rocks Cause of ditto Poverty of species of organic forms in older rocks What quartz originally was How formed The Eozoon, or " Dawn-animalcule " Organiza- tion of ditto Its natural history habits Recollections of a Piece of Quartz Plumbago, or '' black-lead " How formed Lowly organization of earlier land plants The Laurentian limestones How they were probably formed Phosphates of lime Thickness of lower Laurentian rocks Changes during Laurentian period Elevation of marine deposits into dry land A period of submergence The upper Laurentian rocks How formed " Unconformability " illustrated In- ferences from such phenomena Changes through which Laurentian rocks have passed Denudations of ditto In- trusions of igneous rocks in ditto Metamorphism of sand- stones, limestones, &c. Contortion of rocks .... 14 23 CHAPTER HI. THE 8TOEY OF A PIECE OF SLATE. Locality of slate rocks Scenery of the Welsh mountains Original condition of latter Difference in mode of formation of sandstone and limestone rocks " Cleavage," what it is Probable cause of ditto "Joints " in slate rocks Contortions in Cambrian rocks Wear and tear of ditto Origin of the contortions, &c. Experiments on rock contortion The Pro- tozoic period, what it was thought to be Age of Cambrian CONTENTS. IX PAOK rocks Fossils of ditto Laws of the succession of life-forms Lowly organization of Cambrian fauna and flora Thick- ness of Cambrian rocks Composition of ditto Evidences of shallow sea deposition How such a thickness of rock ma- terial could thus be formed Arencolites, or fossil worm- borings Ripple-marks in Cambrian strata Rain-pittingg and sun-cracks in ditto The first crustaceans Zoophytes of the Cambrian seas The Lower Cambrian formation as a group of rocks Break in continuity of Cambrian rocks Absence of a great limestone deposit Where latter -will possibly be found The upper Cambrian rocks Lingula flags The brachiopodous mollusca Antiquity of certain forms of life Fossil shrimps Ancient sea-lilies Habits of ditto The Trilobites Pteropods Why Cambrian fossils are found as "casts" Influx of higher forms of life The Cephalopodous mollusca Orthoceratites 'Gasteropoda, or marine snails The Betterophon Paucity in specific types Progression of life system Inference from ditto . . 24 36 CHAPTEE IV. THE STORY OF A PIECE OF LIMESTONE. Limestones common to every geological formation Generally of vital origin Evidences of deep sea origin Characterized by abundance of marine organisms Sandstones contain more terrestrial ditto Silurian limestones in the "Black Country" The Wren's nest, Dudley Abundance of fossils Silurian limestones in America Origin of Petroleum, or " rock- oil" The Wenlock limestones Trilobites, abundance of species of Alternations iu stratification of Silurian rocks Shingle-beds Thickness of Silurian rocks Greater dis- tribution of sea areas Probable height of mountains The Lower Silurian rocks Evidences of volcanic disturbances Bala limestones Caradoc sandstones The Middle Si- lurian rocks May Hill sandstones Tarannon shales Tipper Silurian rocks Their thickness, &c. Woolhope beds Wenlock limestones and shale Ludlow beds Aymestry limestones Downton sandstones Marine ani- mals of the Silurian period Orthoceratites "Sea-pens" Graptolites Structure of the Trilobites Inferences of ditto X CONTENTS. PAGE Great change in physical geography during Middle Si- lurian period Thickness of volcanic lava and ash beds Abundance of marine life during Upper Silurian times Pectens Univalves Cystideans The " chain-coral " Ancient coral reefs in Shropshire, &c. Favosites polymorpha Brachiopodous mollusca of Silurians First appearance of Vertebrate animals as fishes Ancient feeding-grounds of ditto The Ludlow " Bone-bed " Recent bone-bed off the Irish coasts Presence of fossil spores of cryptogamous plants in Ludlow bone-bed Inferences from ditto Origin of metal lodes Usual preponderance of gold in Silurian rocks, &c. 37 57 CHAPTER V. THE STORY OF A PIECE OF SANDSTONE. Sandstone beds in every geological formation Psychometry How sandstone rocks were originally formed The physical changes that have taken place since Principal agents in formation of sandstones Origin of Old Red Sandstone Cementing agents in sandstone rocks Free-stones and flag- stones The Devonian period Rocks of ditto in America, South Africa, Russia, Asia-minor, and Australia Origin of the name Old Red Sandstone Thickness of ditto Divisions of ditto Varying thickness in different localities Error as to greater prevalence of Carbonic acid in atmosphere during Palxozoic epoch How the rocks were coloured red Ancient sea-weeds Huge Crustaceans Pterygotus "Age of fishes" Structure of first order that appeared, the Ganoids Rela- tion of ditto to existing species in America and elsewhere The Asterolepis Holoptychius PterichthysCephalaspisCoc- costeus, &c. External peculiarities of ganoid fishes The Placoid fishes Onchus Fossil fishes of Caithness, &c. Shoals of fossil fish How accumulated Reptilian characters of some Devonian fishes Corals, Trilobites, &c. Differences in physical condition of old sea-bottom Chief localities of Devonian fossiliferous strata Total number of species The " Pilton group " Brachiopodous shells Spirifer Clymenia " Sun-corals," &c. Coloured fossil corals of Torquay, &c. Peculiar Trilobites of Devonian rocks Devonian rocks in Ireland Evidences of fresh-water deposition The "Irish CONTENTS. XI PAGE primitive Fern" (PaUeopteris Hibernicus) Its structure Other Devonian plants Sagenaria Psilophyton Abund- ance of fossil fresh-water mussels (Anodonta) Kemains of Crustacea Resemblances of Devonian lakes to existing North American ditto ... 5878 CHAPTER VI. THE STOKY OF A PIECE OF COAL. The piece of coal commences its history How many periods elapsed since it was formed Their names Physical con- ditions of Carboniferous period Keptiles of ditto Ancient coral reefs Formation of " Mountain " or Carboniferous Limestone Its abundance of fossils The principal species Nautilus Goniatites Gyroceras Orthoceras, size and habits of Abundance of ditto Shoals of Spirifera Their structure Carboniferous Trilobites Their last appearance The Crinoids Derbyshire encrinital limestones Polyzoa of Carboniferous period Fishes of ditto Megalichihys Palxoniscus, &c. Forests of later Carboniferous period Their appearance Principal vegetable forms of ditto Lepi- dodendra Sigittarite, &c. Gigantic Club-mosses Cal- amites, or gigantic " Horse-tails " Coniferous trees Fossil ferns Accumulation of vegetable materials Chemical changes in ditto Gradual change to present state as coal Microscopical revelations of coal-ash Changes through which carbon has passed Gradual transition from wood to anthracite Correlation of physical forces Light and heat of the Carboniferous period " bottled-up " in coal Colours of original plants, &c. Economical advantages of coal to mankind 79113 CHAPTER Vn. THE STOKY OF A PIECE OF BOOK-SALT. Difference of story-teller from its fellows Natural origin of rock-salt Interval between Carboniferous and Triassic period occupied by the Permian Characters of latter Evidence of ancient Ice-action Permian " breccias " Be- Ill CONTENTS. PACK semblance of its fossils to Carboniferous forms Distribution of Rock-salt The New Red Sandstone, or "Trias" The brine-springs of Cheshire Divisions or Trias Bunter sand- stone Musckelkalk, or "shelly limestone" of Germany Keuper beds A tolerably deep sea in Germany "Lily" Encrinite Reptilian fishes " Breaks " in geological con- tinuity Hallstadt and St. Cassian beds "Unconform- ability" of members of the Trias Keuper beds those in which rock-salt found Cheshire strata Rock-salt and gypsum Thickness of strata Area of ditto Evidence of fish and reptile life No fossils in salt-beds An ancient "Dead Sea" Modern ditto The Keuper seas Pseu- domorphic crystals of salt Evidence of atmospherical and mechanical action Absence of vital ditto A " Dead Sea " in Cheshire and Worcestershire Origin of the Cheshire "meres" How Rock-salt was formed Dry-land appearance of Triassic age Great frog-like reptiles Ldbyrinthodon . Bhynchosaurus Feet-impressions on sandstone Extinct birds in America First appearance of mammalia Micro- lestes Its existing relations Rhsetic beds Ornithic affini- ties of reptiles South African Trias Its fossil reptiles Dicynodonts Flora of Triassic period Extinction of Palaeo- zoic forms . . 114127 CHAPTEE VIH. WHAT THE PIECE OF JET HAD TO SAY. Where jet occurs Lias beds Origin of jet Ditto of name "Lias" Stratigraphical appearance of Liassic sea The "struggle for life "Thickness of the Lias beds Division of ditto Lower Lias shales and limestones Dry land of the Liassic age Liassic flora Introduction of new forms The " Age of Reptiles " Ichthyosaurus Plesiosaurus Great land reptiles Flying Lizards Pterodactyles Physical geography of Lias sea Habits of marine lizards Fish of Liassic era Lepidotus Dapedius JZchmodus Hybodous Ancient sea-lilies Pentacrinus Description of ditto Sea-bed of Lias period Abundance of Cephalopods Ammo- nites Nautilus Belemnites, or " thunder-bolts " Nume- rical abundance of Ammonites Ditto of Belemnitea Census CONTENTS. Xlll PAGE of Liassic fossils Brachiopods Last appearance of Spiri- fera Numerical proportions of Conchifera Gryphxa Hippodium Avicula, c. Plants and insects of the Lias Continuity of the great Life-scheme The Plan of Creation 128 145 CHAPTER IX. WHAT A PIECE OF PUEBECK MABBLE HAD TO SAY. Use made of Purbeck marble Its ecclesiastical importance What formation it belongs to The Oolite period Sub- divisions of Oolite rocks Extinction and continuity of specific forms Description of members of Oolite series Physical geography resulting from their distribution Geo- graphical changes during Oolitic era Oolitic coal shales near Scarborough Physical conditions of the ancient sea- beds Destruction of ancient encrinites Dry land areas Ancient lakes Fossil fresh- water shells Planorbis Palu- dina, &c. Accumulation of shelly limestones Purbeck marble, how originally formed "Coral Rag" Ripple-marked flagstones Evidences of shallow water The great Oolite Thickness of entire series Fossils of the Oolite Their variety Description of Oolite seas Marine reptiles An- cient coral reefs Ancient ganoid fishes Mud-banks of Oolitic age The flying reptiles Terrestrial mammalia Their variety Flora of the Oolite Oolitic coal, how formed Oolitic iron-stone, how formed The Stonesfield slates Number of species of mammalia Marsupial animals Solen- hofen limestones Their richness in organic remains Cycads and Zamias Portland " Dirt-bed "How formed " Birds' nests " Great land reptiles Megalosaurus " Missing links " Bird-like affinities of Oolitic reptiles How many of them were two-legged Compsognathus Fossil reptilian eggs Gradual development of Reptilia The first Bird Arclixopteryx Its reptilian affinities Physical changes since the Oolitic period The Himalayahs All changes tending towards a higher condition of exis- tence , . . 146-166 Xiv CONTENTS. CHAPTER X. THE STOEY OF A PIECE OP CHALK. PACK The minerals diffused in sea- water Marine animalcules The composition of their shells Enormous power of multi- plication Chalk composed mainly of microscopic shells The Globigerinx Their antiquity How chalk was formed Coccoliths Atlantic mud Changes along Cretaceous sea-bed Silica, How flint was formed Flint-bands and nodules "Pot-stones" or Paramoudrx Cretaceous Echino- dernus Ananchytes, or "Fairy loaves" Micrasters Cidarids " Thunder-bolts," or Belemnites What they were Cretaceous Brachiopods Cretaceous fish Appearance of new orders A huge marine reptile Mososaurus or Leidodon The Wealden series, how formed Its thickness Fossil remains of ditto Great land lizards Subdivisions of chalk strata Characteristic fossils of ditto Beauty of certain fossils How they have been preserved Evidences of up- heaval of ancient sea-bottom Slowness of the process The forces of nature Ancient sea-birds How the newly-raised land was peopled Geographical changes subsequent to deposition of chalk 167192 CHAPTER XI. THE STOBY OF A LUMP OF CLAY. Commonness of clay How old clay strata have been altered The Eocene period Difference between the London clay and the Boulder clays Circumstances under which the London clay was formed A tropical climate in Britain The commencement of the Tertiary epoch Thickness of the Eocene strata Description of ditto Their fossils Geo- graphical distribution of animals and plants The flora of the Eocene period Fossil fruits Indian scenery in Britain Mammalia of the Eocene period Palfeotheria Ganoid fishes Boa-constrictors in England Water-snakes Ano- plotlieria Cheeropotamus, or ' ; river-hog " Dichobune Hyxnodon "Missing links" Mollusca of Eocene period Their sub-tropical character Sharks of the period Turtles CONTENTS. XV PAGE Duration of the Eocene period Elevation of mountain chains Physical geography of the Eocene period Decrease in climature The register of the earth's crust . . . 193204 CHAPTEE XII. THE STORY OF A PIECE OF LIGNITE. " Brown Coal," or Lignite, what it is Its appearance, &c. The Miocene period Great fresh-water lakes in Europe- Luxuriant flora of the Miocene period Extent of ditto No ice-cap at the North Pole Connection of the Old and New Worlds Number of flower-bearing plants found fossilized Temperature of Miocene period Its probable cause An- cestry of living animals and plants Lignite beds in Europe, Asia, &c. Preservation of vegetable remains Cosmopolitan character of the Miocene flora The great number of ever- green plants Distribution of Miocene species The American character of fossil flora Smilax Dryandroides Proteacea Fan-palms Tulip-trees Magnolias, &c. Beauty of the Miocene landscapes Lignite beds of Bovey Tracey Number of species of fossil plants denudation of the Dart- moor granite Miocene strata in Ireland and Scotland The last active volcanoes in the British Isles Lignite beds of Greenland, and what they teach Ditto of Iceland Ancient Miocene land Great fresh-water lakes in Switzerland Miocene strata of ditto Their fossils Fish, &c. Caddis- worms Indian butterflies Termites Various fossil insects Appearance of Quadrumana or monkeys in European woods The Dryopithecus Semnopithecus Pliopithecus Opossums in Europe Dinotheria Tapirs Mastodon Wart Hogs Hippopotami Wild Oxen Wild Deer The Hipparion, or three-toed horse Miocene deposits in India "Missing links" again The Sivatherium The great Indian tortoise Giraffe and camel in India Miocene horses in America Mastodons and elephants in ditto The long-armed monkey Volcanoes in Central France Up- heaval of sea-beds Formation of the Alps, Pyrenees, &c. Refrigeration of climature Formation of new sea- basins , 207221 XVI CONTENTS. CHAPTEE Xm. THE STORY OF THE " CEAGS." PAGE Meaning of the term " crag " Where these beds are found Their number The Pliocene period The Coralline, Eed, and Norwich Crags Suffolk the bed of a tolerably deep sea Fauna of the Coralline Crag sea Ancient sea-urchins Where now living Time since Coralline Crag was formed Abundance of mollusca in Coralline Crag sea The As- tartes Pectunculus Cyprina Number of species of mol- lusca An ancient sea-bed, and what it teaches No " dredging " required " Sea Mats " Fascicularia Ex- tremes in Coralline Crag sea Marine currents The oldest crag Physical conditions of Pliocene period Migration of mollusca southerly Coralline Crag shells in West Indies Ditto in Mediterranean Thickness of Coralline Crag How formed The Eed Crag Origin of name Denudations of Coralline Crag previous to it An ancient land surface in Suffolk and Norfolk How the "coprolite" beds were formed Mollusca of the Red Crag " Southern " forms "Northern" ditto Eefrigeration of climature Corals Cowrie shells False current bedding in Red Crag Physical geo- graphy of ditto The chalk of Norfolk A shallow estuary over site of Norwich Evidence of river communication The Norwich Crag Its fluvio-marine character Difference in fossils from previous crags Abundance of littoral shells Tettina Mactra Cerithium Fresh-water shells Pla~ norbis, Paludince Lymnea, &c. Land-snails Census of Norwich crag Ancient land-animals in Norfolk The Al- deby Crag Its fossils Increase of " Northerly " mollusca Evidence of rigorous climate The Upper Norwich Crag, and its lessons Pliocene and Pleistocene periods Analy- zation of shells of crags Number of extinct species in ditto The Belgium crags The " Box-stones" of Suffolk Their origin Evidence of a broken-up deposit Pliocene strata in Sicily English shells in ditto How they came there- Evidence of volcanic disturbance Formation of Mount Etna Height of Pliocene beds on its flanks Refrigeration of climate in northern hemisphere Preparation for the long Arctic winter The introduction of the Glacial epoch 222237 CONTENTS. XV11 CHAPTEK XIV. THE STOEY OF A BOTJLDEE. PAGE Its restless life The Glacial period Extent of Glacial de- posits "Noah's flood" The "Northern Drift" Connection of Tertiary life-forms with existing species Sand, gravel, and clay Evidence of extreme cold Recapitulation of slow refrigeration of climate during Tertiary epoch The Norfolk " Forest-bed " Its fauna and flora The bed of the German Ocean once a green wood Strange animals which lived in ditto An Arctic climate introduced into Britain England under a wintry sea Scotland and the north of England under an ice-sheet Greenlandic circumstances in Britain Description of Greenland glaciers Icebergs The Cromer cliffs Thickness of Lower Boulder Clay Iceberg action in drift The Atlantic sea-floor The Gulf stream Depth to which England was submerged How ascertained Moel Tryfaen An old sea-beach on ditto Re-emergence of the land Arctic mollusca in British seas Raised sea-beaches Stranding of ancient Icebergs Dropping of large boulders Migration of Arctic plants The " chalky " Boulder Clay The " Heavy Lands," how formed Denudation of mud sheet into valleys Post-glacial deposits Ice-grooves and scratches England still connected with the Continent No straits of Dover yet formed The Mammoth The Hairy Rhinoceros Land connection with Ireland and England The Irish Elk The Reindeer, Muskdeer Lemming, &c. Arctic plants living on British mountains How they got there, and when Glaciers in Scotland, Cumberland, Lan- cashire and Wales The Swiss glaciers The desert of Sahara once a sea English mollusca inhabiting it For- mation of the desert sands A warmer climate sets in Migration of existing fauna and flora Where from Separation of Ireland from England Of England from the Continent Bone caves Appearance of MAN Flint im- plements Migration and extinction of Mammoth, &c. Formation of rich subsoils Results of the glacial period . 238253 XVlli CONTENTS. CHAPTEE XV. THE 8TOEY OF A GRAVEL-PIT. PAGE The last of the race Incompleteness of the story Gravel- pits, and where Valley or river gravels How formed Eiver terraces Difference in age of gravels How detected Peculiar appearance of pebbles in valley gravels Heights of former river levels Evidences of rigorous climate Valleys scooped out Evidences of man's first appearance Flint implements in river or valley gravels Proofs of their human workmanship The antiquity of man Identity of pattern in flint implements Paleolithic types of ditto con- temporaries of primitive man The Mammoth Woolly-haired Bhinoceros, &c. Why human bones not found with flint implements Koman and Saxon cemeteries Percolation of running water Teeth and tusks most enduring Stalag- mite in limestones How it preserves fossils Human bones under ditto Kent's Cavern Evidence of human habitation of ditto The " Keindeer " period Bone caves in Southern France Artistic attempts The Neolithic period How distinguished Stone weap6ns Distribution of Neolithic and Palaeolithic implements The Lake Dwellings Ketrospect Evidence of Progression Development of cul- ture The Higher Life 254272 SUMMARY OF PBEYIOUS CHAPTERS . . 273 APPENDIX, giving Table of Eock Strata in British Islands Ex- planations and illustrations of geological terms, &c. Con- clusion . 284 INDEX . 293 GEOLOGICAL STORIES. CHAPTEE I. THE STORY OF A PIECE OF GRANITE. "We turned, we wound About the cliffs, the copses, out and in, Hammering and clinking, chattering stony names Of shale and hornblende, rag, and trap, and tuff, Amygdaloid and trachyte, till the sun Grew broader towards his death, and fell, and all The rosy heights came out above the lawns." TENNYSON'S Princess. fHEEE are few rock substances on the sur- face of the globe which have received more discussion and been more investi- gated than myself. I am somewhat proud of the attention I have received in this respect, for most of the leading geologists of every country, during the last century, have devoted themselves to the task of seeking out my antecedents. I am ac- quainted with a whole library of books, all most learnedly written, and various of them proving the reverse of the other, which have been penned on this inexhaustible subject. Even yet the question can hardly be regarded as finally settled. Every now B 2 THE STORY OF A PIECE OF GRANITE. and then some moot point or another crops up to engage the attention of philosophers, but, thanks to the progress of other sciences, the investigation of these is no longer confined to verbal expressions. It is not a little amusing to remember the hot discus- sions which were held over me at the beginning of the present century. Philosophers though they professed to be, the disputants resembled political squabblers more than anything else. One set de- clared I was born amid fire ; the other that I was of purely watery origin. Each party believed in their own ipse dixit, and, as nothing could be absolutely proved, backed their own opinions by personalities. Somehow or other the former sect, who were called Plutonists, got the better of the latter, who were termed Neptunists. (The origin of these phrases my listeners will not find it difficult to understand.) But my Plutonic commentators carried their victory too far. Not content with proving that I was not a mere aqueous rock, they proceeded to declare I was nothing more nor less than one which had cooled down from a fused condition, something like iron slag ; nay, it was even urged that I was older than any other rock, and the theorists mapped out an idea which existed for many years afterwards, chiefly owing to its remarkable novelty showing how the whole universe was formerly one great cosmical fog; that this diffused matter was con- densed into suns, planets, and satellites, each of which existed for ages in a molten condition, owing THE STOKY OF A PIECE OF GRANITE. 6 to the heat evolved during the process of condensa- tion ; that the exterior of each planet cooled during the time which followed, and that granite formed part, or whole of this cooled envelope! Such in brief was the orthodox notion of my birth, little more than a quarter of a century ago. Shall I enlighten my readers a little as to the nature of my mineralogical composition? I feel sure that most of them are acquainted with it already, but, if only for form's sake, I must go through with it again. My name is of Latin deri- vation, and was given me on account of the granular character presented by my different minerals. Gene- rally speaking, these are four in number Quartz. Felspar, Mica, and Hornblende. Very frequently there are also traces of other minerals; but these are the commonest, and in fact those which make up my bulk. The Quartz portion you may tell by its glassy appearance, and usually milk-white colour; whilst another good test is its superior hardness. This mineral is almost pure silica, and is one of the most refrangible of known substances. It can with difficulty be slightly dissolved in hot water, under great pressure ; whilst it requires a great deal of heat to melt it, and, generally speaking, some sort of flux to set it a-going. The next most abundant mineral in the constitution of myself and relatives (for our name is Legion) is that called Felspar. Your eye may detect it in my mass, by its pink or flesh-colour, whilst it is so soft that you may scratch 4 THE STORY OF A PIECE OF GRANITE. it with your finger nail. It is owing to the unusual abundance of this mineral that I am sometimes so friable or " rotten," as the felspar decomposes and then causes the other minerals to fall asunder, just as the bricks of a wall would if all the cementing mortar were to decompose away. In many districts, as in Cornwall, where granite comes to the surface and has been subjected to atmospherical wear-and- tear for ages, it is not uncommon to find the fine felspar wasted into a newer deposit. Such is the well-known " kaolin," or China clay of commerce. The chemical composition of felspar is more com- plex than that of quartz. For instance, although its commonest elements are silica and alumina, the former the base of common sand, and the latter of clay, there are also contained in it more or less of soda and potash, lime, magnesia, and iron. Mica, the next commonest mineral I possess, is so well known as hardly to need description. All my listeners are surely familiar with the small, thin, silvery-looking scales contained in almost every piece of granite. Its ingredients are much like those of felspar, only differently mixed. Frequently Hornblende is a mineral entering into my compo- sition, when you will readily recognise it from its black or dark olive-green colour. "When it is very abundant, it produces a rock varying from dark grey to black. A great number of what may be termed varieties of hornblende are known to mineralogists. Its chemical composition, generally speaking, is THE STORY OF A PIECE OF GEAN1TE. O about one-half silica, more than a quarter magnesia, and little more than half a quarter lime : besides these, there are usually traces of iron, alumina, and fluoric acid. I mentioned above that I had many relatives, who were more or less nearly connected (I cannot say by blood, but by mineralogical similarity of composi- tion). These take various names, on account of their leading peculiarities. Among them the com- monest is Porphyry, which takes its name from the purple variety used by the ancients in making vases, &c. This you may know from the large and distinct crystals, usually of felspar or quartz, which are imbedded in the granular matrix. Through porphyry granite passes into all sorts of allied igneous rocks, such as Claystone-Porphyry, Clinkstone-Porphyry, Felspar-Porphyry, and so on. When hornblende takes the place of mica in the composition of granite, the latter goes by the name of Syenite; when talc supplants mica, the result is called Protogine. A fine-grained compound of felspar and granite, with equally minute scales of mica, gives to you the varietal name of Pegmatite. According to the number of minerals entering into our composition, I and my relatives are roughly classed as Binary, Ternary, and Quaternary granites. All this detail of structure may sound very dry and tedious ; but it is absolutely necessary to go through with it, if my listeners wish to be more intimate with me. 6 THE STORY OF A PIECE OF GRANITE. Although I have not a distinct recollection of niy birth (as indeed, who has ?), yet I have more than a suspicion that such elements as soda, potash, lime, &c., greatly assisted as fluxes in bringing me into my original molten condition. I have mentioned the great number of relatives who claim near or distant kinship with me, and I have now only to remark that their affinity to myself has been deter- mined solely by the different circumstances attend- ing their origin. I distinctly and utterly refute the idea that the first-formed crust of the globe was a granitic one ! I am fully persuaded it could not possibly have been granite, and I will give you rny reasons by-and-by for this seemingly bold assertion. What that cooled crust was, I doubt if science will ever be able to discover. But the fact that it was not granite does not in the least invalidate the theory that every sun, planet, and satellite was con- densed from nebulous matter. This theory must rest on other grounds, and, singularly enough, ad- ditional facts are coming to its support every day. Men have not the slightest idea of what the primitive rock or crust of the globe was. The antiquated notion that it must have been granitic arose out of mistaken associations. It was found that, however old might be a stratified rock, whether containing fossils or not, some variety or another of granite was older still. Hence followed the hasty deduction, that originally one granitic crust encircled the fluid i ; :tter of the interior of the earth. It was thought THE STOBY OF A PIECE OF GRANITE. 7 that subsequent rocks were themselves formed out of the wear-and-tear of this granite, that the latter was in many places covered up by its own debris, and that the so-called metamorphic rocks were those first formed as stratified deposits, but altered to their present appearance through the intense heat of the newly-created seas, along whose bottoms they had been elaborated ! All this is wrong, and it behoves me now to descend from the region of pure hypothesis to that of fact. It is just possible, speaking generally of all the varieties of my family, that Protogine may be oldest. This, however, has never been thoroughly determined. One of my reasons for believing I could not have required any very great heat to reduce me to the molten condition, and that in this process the agency of water, as well as of heat, was necessary, is as follows : Many of the larger quartz crystals entering into my composition are hollow. Frequently these hollows are more or less filled with water. Now it is a known fact that molten matter at a white heat requires its tempe- rature to be considerably lowered before it can even evaporate the water mechanically mixed with it. It has been recently shown that crystallized matter which has undergone pure igneous fusion, has usually cavities in its crystals, not containing water, but either stony matter or a kind of glass, and, in many cases, even a perfect vacuum. Hence the conclusion is arrived at that in the case of coarse-grained 8 THE STORY OF A PIECE OF GRANITE. granite, containing much quartz, there is actually more proof of the action of water than of dry, igneous fusion. It is more than probable, therefore, that pressure, heat, and water combined, in the deeply-seated parts of the earth's crust, would cause the rocks to be reduced to a kind of paste, and that Fig. 1. Microscopic Section of Pitchstone, showing dendritic crystals. this paste, cooled under such circumstances, would be some variety of granite. I can hardly enter into the abstruse details of the deductions which have been made from the chemical and microscopical examinations of myself and relatives. Suffice it to say they result in proving that pressure, and this, THE STOKY OF A PIECE OF GEANITE. 'J generally speaking, of overlying rocks stratified or otherwise, is a preliminary and indispensable neces- sity to the formation of granite ; that, if pressure be absent or less than that required, notwithstand- ing all the other requirements may be present such as heat, similarity of mineral ingredients, &c. Fig. 2. Microscopic Section of artificial Porphyrine, showing ditto. such a resulting igneous rock would not be granite ! It might be a variety of porphyry, or basalt, or greenstone, or, if all pressure were re- moved, and the molten matter allowed to cool in the open air, simply ordinary Lava ! From a micro- scopical examination of various granites, it has been 10 THE STORY OF A PIECE OF GRANITE. shown that those of the Highlands of Scotland indicate their having been formed under no less a pressure than twenty-six thousand feet of overlying rocks more than were the granites of Cornwall. There is good reason for believing the latter to have required at least forty thousand feet of rock-pressure ; so, in that case, the granites of the Highlands must have been formed when sixty-six thousand feet of overlying rocks were piled above them ! One is naturally astounded by the magnitude of these operations, but I assure you there is little doubt as to the general correctness of the deductions. In this way the mineralogical construction of myself and others supplements the teaching of organic remains, as to the immense antiquity of the globe ! Nothing short of an eternity of time would have sufficed for all the changes which have been rung upon it. There is reason to believe that many of my granitic relations are nothing more or less than re-melted stratified rocks, with their enclosed fossils ! As these rocks have been slowly depressed or sub- merged, so as to bring the lowest-seated portions within the influence of the earth's internal heat, they have been first metamorphosed into a similar condition to gneiss and mica-schist, and, if the sinking went on, have passed through this stage into that pasty condition which deprived them of all stratified structure, and converted them into what I am myself ! Then succeeded a reversal of the move- ment ; so that this granite would be thrust slowly THE STORY OF A PIECE OF GEAN1TE. 11 upwards with all the overlying strata piled above it. The movement went on until these were tilted into a continuous mountain-chain, or high and extensive table-lands. Meantime the granite nucleus would form the heart of such mountains, the strata dipping away on each side, as in the Himalayas. I fancy I hear some of my listeners remarking " But if granite can only be formed under such immense pressure, how is it we find such large areas of country where nothing else is to be seen ? " In the answer to this we have the gist of the argument, and I would respectfully ask the special attention of my audience to it. Let them ask themselves where the materials came from to form the Laurentian, Cambrian, Silurian, Devonian, and, in short, all the other subsequent formations ? They could only have been formed out of the waste of still older and already solidified rocks. Each formation, therefore, represents the amount of wear-and-tear which went on during the period when it was deposited. If there had been no compensation against this levelling process, all the highest grounds would soon have been worn down to a common level, and the elabo- ration of more recent deposits been self-checked. But each succeeding formation shows that this was not the case, and indicates that the physical arrange- ments of our planet have been much the same through all time to what they are at present ; that atmospherical and marine wear-and-tear were coun- terbalanced by upheaval from beneath ; that the 12 THE STORY OP A PIECE OF GRANITE. external force emanating from the sun and resulting in all these atmospherical effects, was exactly ad- justed by the native force of the earth, exerted from the interior outwards. These two have exactly checked each other from the beginning, otherwise the great life-scheme of our globe would never have had time for its development ! I hope I have been successful in explaining a great Section showing Granite nucleus, with strata lying on its flanks, the overlapping and continuous portions of which have been denuded off. difficulty, and that my listeners now see the reason why I and my relatives come to the surface. It is because the rocks which overlay me at my birth have since been stripped off, and slowly removed l>y atmo- spheric and other agencies. All the formations which were then piled above me, are to be found in strati- fied rocks of later date ; therefore, the period of my birth is not limited to any particular geological THE STORY OF A PIECE OF GEANITE. 13 epoch. I am found at the surface, surrounded by rocks of every age, even including those of the Tertiary. Wherever the pent-up force of the earth's interior has thrust us up, there have we slowly elevated the rocks lying upon us. In many cases this elevation has been so slow that it has hardly exceeded the rapidity with which these overlying rocks have been gradually worn away! Think of the vast antiquity of the earth's crust, as indicated by these facts alone! Since the granites of the Highlands of Scotland were formed, twelve miles of overlying material must have been removed ! "Where has it all gone to? Ask the nineteen miles in thickness of the known stratified rocks, all of which have probably been formed since that granite itself. You scarcely need be afraid of Time, when you have Eternity to draw upon ! 14 THE STORY OF A PIECE OP QUARTZ. CHAPTEE II. THE STORY OF A PIECE OF QUARTZ. 'God worketh slowly; and a thousand years He takes to lift His hand off. Layer on layer He made earth, fashioned it and hardened it Into the great, bright, useful thing it is; Its seas, life-crowded, and soul-hallowed lands He girded with the girdle of the sun, That set its bosom glowing like love's own Breathless embrace, close-clinging as for life; Veined it with gold, and dusted it witli gems, Lined it with fire, and round its heart-fire bowed Rock-ribs unbreakable ; until at last Earth took her shining station as a star, In heaven's dark hall, high up the crowd of worlds." BAILEY'S Featus. ACT," they say, "is often stranger than fiction." I do not think you will find this old saw better illus- trated in the whole series of geological teachings than in my own history. That history is connected with one of the grandest discoveries of late years, inasmuch as it carries back the antiquity of the globe even beyond the mighty ages which had already been claimed for it. Indeed, the practical effect of this is to show the geologist that time, as a factor, has nothing to do with his investigations. That simple relation in the succession of events is all THE STORY OF A PIECE OF QUARTZ. 15 he can safely arrive at ; and that his finite mind can no more conceive of the myriads of years which are included in the world's biography, than it can sum up in human arithmetic the stars and systems which crowd the illimitable realms of space ! Within the last ten years a clearer geological knowledge of my origin has caused geologists almost to double the already known antiquity of the earth. At the time I mention, or thereabout, it was usually under- stood that the Cambrian period was the oldest and most primeval. The human mind is essentially conservative, and although geologists reasonably claim to be more catholic than most men, they are under the same influences. This is indicated by their unwillingness to make the world appear older than they possibly could help. Hence such terms as " Primary," " Primordial," &c. applied to the ancient strata which nevertheless are all much younger than myself are so many landmarks which have shown this tendency in the human mind. It may be, that although the geological formation to which I belong is undoubtedly the oldest known at present, in any country, subsequent research may eventually make known an older period still. The difficulty in doing so, however, will be consi- derably heightened by the fact of all these oldest rocks having passed through many changes, by heat and chemical action, so that nearly all traces of their former fossils are effaced, and thus they are reduced to a similarity of mineral condition all the world over. 16 THE STORY OF A PIECE OF QUA1JTZ. There are few of my readers who are not ac- quainted with my general appearance. They have gathered me as a milk-white pebble by the sea- beach, or have admired me as they climbed the Scotch mountains and saw me sticking out of the contorted rocks like a huge white rib. Or, they may have been more pleased still with the geometrical shapes which my substance is capable of assuming as a six-sided, pointed crystal. It is of my former state, rather than of my latter, that I intend now more particularly to speak. And yet it is necessary for me to say that there are two common conditions in which I am usually to be found. One is as Quartz, the other as Quarfaiie. These terms are merely significant of appearance, and include little or nothing of chemical difference. Quartz proper is usually found in veins, having been forced into fissures when it was in a soft, heated condition. Quartzite has not so completely lost all its original structure, and its particles or grains may often be seen retaining their original water-worn form. Again, Quartzite does not occur as an intrusive rock, but in huge stratified masses, hundreds of feet in thickness. And yet you may find transitions in these two extreme states of my family even from the transparent crystal condition of the " Brazilian pebbles " to the coarse-grained and resinous appear- ance of quartzite. Let me be thoroughly understood. Although I am representing that great, and at present oldest THE STORY OF A PIECE OF QUARTZ. 17 epoch in our planet's history the Laurentian I should not like you to fall into the mistake of sup- posing that I am limited to it alone. On the con- trary, formations of much more modern date than that to which I belong are rich in quartz veins and even beds. In short, any rock that has been ex- posed to the same influences as myself, if it con- tained the same chemical substances, would also become quartz as the result. They tell me that I am chemically composed of only one substance Silica. My normal condition is transparent and colourless, although I am rarely found like this except when in geometrically-shaped crystals. A milk-white colour is that which I commonly affect and this is due solely to the rate at which my parent mass cooled down. Hence it is that geologists can more or less tell from my appearance the circum- stances which attended my birth. From the pure, transparent condition I mentioned above, I pass through a great many modifications, and in each stage of these I am known by different names. But with the exception of very slight mixtures of other ingredients than this silica, I continue the same throughout ; thus, when I am of a violet tint I am called Amethyst; when of the colour of sherry, Topaz ; when of a smoke-brown hue, Cairn- gorm, &c. Mixed with other chemical substances I pass into jasper, flint, chalcedony, agates, &c., in all of which you will find that the largest portion of their whole bulk is silica. 18 THE STOKY OF A PIECE OF QUAETZ. Up to the time when the geological formation to which I belong had been discovered, as I before remarked, the Cambrian was looked upon as the oldest. But there were a series of schists, quartzose rocks, &c., which were still older than these, and which usually went by the name of Metamorphic, or " altered " rocks ; thus committing them to no par- ticular geological age. By many these rocks were regarded as transitional, that is, as passing from an igneous to a stratified condition. When it was imagined that all the granite rocks were formed as the outer crust of a once molten globe, then, it was also thought that the rocks which were formed along the bottoms of the hot seas must be of a very peculiar character. In short, these mica-schist, quartz, and gneissose strata were regarded as having been deposited and solidified under such circum- stances. Their absence of fossils, and proofs of having experienced great heat, were thought to bear out this view. I hardly need tell you how erroneous it was. The Cambrian period was believed to be that when Life first appeared on the Globe. Now this supposition is known to be as wrong as that which accounted for the mineralogical appearances of the metamorphic rocks. Although I am speaking only as a humble piece of quartz, you must remember that, when I am narrating the circumstances of my life, I am at the same time giving those of the mica-schist, gneiss, and altered limestones, which, equally with myself, THE STORY OF A PIECE OF QUABTZ. 19 belong to the Laurentian epoch. Indeed, the last- named rock, greatly altered though it is in appear- ance, so as to resemble loaf-sugar, could, perhaps, tell you more of the vital conditions of the ancient Laurentian seas than I can. First, let me impress you with the fact that when' we were formed, collectively, we did not differ in appearance from the sandstones, clays, and limestones of either the present or of any bygone geological era. All this wonderful alteration in our appearance and structure is due solely to the subsequent changes we under- went. Of these I shall speak presently. If you know anything of the great deductions of geology, you will be aware that the farther you go back in time, the fewer and simpler are the forms of life which, inhabited the earth. It was the general poverty of species, accompanied by their lowly organization, which caused the Cambrian epoch to be regarded as the first platform of Life. Now when you go farther back in time, to my own age you will find that the organisms are still lowlier. Indeed, of the objects that lived in the seas where I was originally deposited as a thick sheet of ordi- nary sand, all that I can remember is one abundant organism now known as Eozoon, or the " dawn- animalcule," in allusion t6 its primeval antiquity, It was lowly enough organized, being little above the natural history rank of the common sponge. This marine creature lived on the sea-bottom in vast quantities, and there grew by the addition of layer 20 THE STORY OP A PIECE OF QUARTZ. on layer of younger forms, just, as I am told, is the way in which coral reefs grow in modern seas ! Like the latter, it absorbed its carbonate of lime from the sea-water, and thus caused great masses slowly to accumulate. This was in the deeper parts of the sea, where the water was clear, and free from muddy sediment. But my recollection goes no far- ther to any animal type. No fishes swam in the blue water ; no crustacean crawled over where I lay ! Occasionally the rivers brought some lowly-organized vegetables in entangled masses, or sea-weeds drifted into my neighbourhood, and eventually became entombed in the sandy mud my then condition. An impure coal was thus formed, and when the rocks underwent their great transformation by the agency of heat, this vegetation somehow or another passed into . Plumbago, or " black-lead," as it is commonly and erroneously called. The great amount of carbon more than there is in many kinds of actual coal which makes up the composition of plumbago, had long indicated its vegetable origin. How lowly organized were the land plants of the Laurentian period you may guess at from the fact that many ages afterwards, during the Carboniferous epoch, they existed only as gigantic club-mosses ! What I have said about the vegetable origin of " black- lead" applies as logically to the origin of the Laurentian limestones. Some of the beds are as much as fifteen hundred feet in thickness, but altered throughout. As geologists are now aware, THE STORY OF A PIECE OF QUARTZ. 21 the limestones in every other formation are always of vital origin that is, they have been formed by the accumulation of coral reefs, shells, &c., cemented, perhaps, by a still greater bulk of microscopic organisms. The white chalk of Norfolk is nearly as thick as one of these beds of Laurentian lime- stones, and yet, to the naked eye, it offers no ex- planation of its origin. It is not until you have applied the microscope that you perceive it to be almost entirely built up of the shields of animalcula, some of them of the same species as are still living in the Atlantic ! If, therefore, the limestones of every known geological period have been formed by vital agency, one would imagine that those limestones, whose organic remains had been oblite- rated by the great heat to which they have been subjected, might be reasonably put down to the same origin. Again, the various phosphates, &c., found in these altered limestones, plainly tell of animal life having been employed in elaborating them. But, mighty though the transitions have been through which the whole of the Laurentian rocks have passed, all traces of fossils have not been lost. The limestones yet contain myriads of Eozoa, as plainly showing they were formed by its agency, as a coral reef tells you how its bulk grew to its present size. Twenty thousand feet of material had been strewa along the bottoms of the Laurentian seas in various places, the material varying according to its neigh- 22 THE STORY OF A PIECE OP QUARTZ. bourhood to the mouths of rivers, &c., whence it was brought. The solidification of this mass took place at the same time as its deposition. A great plutonic change then occurred, and what had been sea- bottom for ages, eventually became dry land. Then followed a period of submergence, when it was once more sea-bottom, and had piled over it ten thousand feet of extra material ! You ask how I know all this, and I reply by pointing to you how the upper ten thousand feet of rock lie unconformably on the lower masses. By " unconformability " I mean that the dip of their beds is not the same, the lower being different from the upper. This plainly shows that the lower beds were uptilted before the upper were formed, and that both series partook of the movement which finally elevated the upper Lauren- tian beds into dry land, in which state they remained during the subsequent Cambrian epoch. You can readily understand how the Laurentian rocks, being the first formed, must have undergone more changes than any other, inasmuch as they have had to partake of all that has gone on since they originated. It is a wonder that we now find any of them uncovered by rocks of subsequent date ; nor should we, had it not been for those great atmo- spherical denudations which have stripped off miles in thickness of overlying rocks, so as to expose those of an older date. The Laurentian strata have had, perhaps, miles in thickness of the rocks of other formations piled above them. They have had to THE STORY OF A PIECE OF QUARTZ. 23 undergo those great depressions which eventually brought them so much under the influence of the earth's internal heat. Masses of granite, trap, porphyry, &c., have been intruded through them, and thus they have been squeezed and contorted in the most fantastic manner. The sandstones, some of them five hundred feet in thickness, have been so affected by heat as to become quartz, or quartzite. Here, then, you have the secret of my origin the whole history of the changes which brought about my present appearance ! The limestones that were contemporaneous with myself were altered so as to resemble loaf-sugar, and had all, or nearly all, their organic remains obliterated. The shales and slates became transformed by heat, chemical change, and pressure, into mica-schists, gneiss, felstones, &c. So that the very peculiarity in dip, contortion, absence of fossils, and mineralogical changes, which mark all the rocks of the Laurentian age, tell of their vast antiquity; whilst the similarity in composition of these rocks in all parts of the world, in Ireland, Scotland, and North America, as well as the preva- lence of similar lowly-organized fossils in their lime- stones, indicate they have passed through the same transformations since they were contemporaneously deposited as limy muds, sands, and clays along the floors of the primeval seas ! 24 THE STORY OF A PIECE OF SLATE. CHAPTER III. THE STORY OF A PIECE OF SLATE. It is a lonely place, and at the side llises a mountain rock in rugged pride; And in that rock are shapes of shells, and forma Of creatures in old worlds, and nameless -worms Whole generations lived and died, ere man A worm of other class, to crawl began." CRABBE. always what you now see me. Far, far back in that almost infinite past, which geology claims before it can explain its phenomena, I was lying along the bottom of a tolerably shallow sea, as part of an extended sheet of fine mud. My birthplace is registered in the heart of the North Welsh mountains, and the for- mation to which I belong goes by the name of the Cambrian. Its rocks form some of the grandest scenery in he world. Steep precipices, on whicli grow rare ferns and wild plants, frequently too tempting to the botanical student, are the result of succeeding dislocations, jointings, and bedding. Mountain streams brawl over them ; and waterfalls, whose substance is evaporated into prismatic mists, pitch from the precipices of these Cambrian hills. Frp- THE STOF.Y OP A PIECE OF SLATE. 25 quently the rocks are so hard and bare, that even the lichen and moss fail to obtain foothold, and so the naked slate shines in the varying sunlight in coloured shades from pink to deep blue. Here, with the gathering cumuli, ring-like crowning their peaks, the Welsh hills stand forth in all their characteristic grandeur. No wonder that crowds of tourists should strive to forget the cares of business, and endeavour to get a mouthful of purer air, whilst climbing their steep sides ! It requires some faith in geology to carry the mind definitely backwards to the time when these rugged hills were extended sheets of marine mud ! But no mathematical deduction is more certain. You never find clay or sandstone rocks so full of fossils as limestones, for the simple reason that the former are of mechanical origin, and the occurrence of organic remains is therefore accidental. Whereas limestones are of vital origin, resulting from organic agencies almost entirely. You examine the slate rocks of which I am a humble representative. Their colour and general texture you easily recognize from the too familiar appearance of the London housetops. But, when in position, you are scarcely prepared to find that what you had imagined to be the result of bedding or lamination in the slates is actually due to what is termed cleavage. This is a peculiar feature about thin-bedded, argillaceous or clayey rocks, that they undergo, when subjected to pressure, and perhaps 26 THE STORY OF A PIECE OF SLATE. heat as well, a certain change, which is in reality a sort of rude, massive crystallization. By virtue of this process, the rock splits not so readily along the lines of stratification or bedding as along that of the cleavage, or planes of sub-crystallization. In addition to this structure, which is frequently diagonally across the line of stratification, these slate rocks are broken up into large cubic masses, caused by great joints traversing the rocks, irre- spective of any previous alterations. Fig. 4. Showing foldings in strata. The stratification itself is not horizontal, but frequently pitched up at a very steep angle, and commonly the rocks are contorted into a series of ribbon-like foldings. After all this cleavage, jointing, dislocation, and faulting, the solid rocks have been subjected to thousands of centuries of atmospheric and marine wear-and-tear ! Can it be wondered at, therefore, that there should result from all these combined agencies, continued through untold millenniums, all that wildness and grandeur of physical scenery which distinguish these old Cambrian rocks wherever they are met with ? THE STORY OF A PIECE OF SLATE. 27 The old rocks, especially those of an argillaceous character, are nearly always marked by contortions, to which those of a later date are strangers. It is from amidst them also that we have great bosses of granite coming to the surface, the contorted slate rocks surrounding them on every side. How is this ? I will endeavour to explain. My hot-tempered friend, the piece of granite, told you how it was absolutely necessary to his origin that the molten rock of which he was portion should be overtopped by a tremendous thickness of material when it was cooling. This my own experience will bear out. The contortions which characterize my family equally required an amount of overlying material to be piled upon them, or they could not have arrived at such singular ap- pearances. A mass of half-hardened rock, if displaced by a foreign body, such as a boss of granite being thrust up, would rise up as one great hill or mountain. But if there was sufficient pressure overlying the formation thus disturbed, then it would be thrown into a series of foldings, in order to make place for the laterally-intruded material. Of course the whole exterior surface would then be elevated ; but this -elevation would not be in a conical form, but along a large tract of country. In geological books you will find how, on a small scale, this experiment has been conducted. A series of layers of cloth has been formed ; pressure was THE STORY OF A PIECE OF SLATE. applied to the sides, when the surface naturally rose into a sort of mound; but the moment a heavy weight was laid on the top cloth (thus representing the overlying material of which I spoke), then the layers of cloth, when pressed at the sides, became folded up into a series of contortions. My hearers will now see why granite outcrops should frequently be the companions of slaty contortions ; for the agency of overlying rock-masses, which originated the former, by their pressing weight caused the latter, when disturbed, to assume the wrinkled, fan- tastic shapes they now present ! It is not long since the Cambrian formation was deemed the oldest in the world ; even its most learned and indefatigable observer called it the Protozoic, imagining its organic remains to be the " first life-forms." This provisional place of honour, however, has since been bestowed on a still older, and of course even a more contorted and meta- morphosed class of rocks, termed Laurentian. Whether this in its turn will have to give place to one older still I cannot tell; but this I know, that the more you study the rocks and their con- tained fossils in the field, the more will you be convinced of the enormous antiquity of the earth, and of the incalculable period during which life has been divinely manifested upon it! Human arith- metic will never be able to compute my own age, and therefore the very attempt would be futile. Seeing that we slate rocks are, as far as England is THE STOEY OF A PIECE OF SLATE. 20 concerned, the oldest known, who can wonder we should be found in such a dislocated and contorted condition ? Have we not had to bear the heat and burden of the day ? All the rocks of later date have been uplifted into dry land from the sea-bottoms on which they were formed; and seeing we were older, it was impossible to elevate them without also raising us at the same time ; so that the alter- nate elevations and depressions to which we have been subjected are innumerable. Meantime the overlying formations have been slowly eaten away, attacked either by atmospherical forces or by marine denudation. Far distant though the period of my birth may be, I have a lively recollection thereof. I am well provided with " hints to memory," in the shape of fossils impressed on, or included in, my parent bulk. I have only to turn to these, and immediately the old life-scene vividly recurs to me. What a strange time it was, and how different to anything I have since beheld! I can readily understand how the earlier geologists should reverently regard our fossils as the first created. In them Nature seems almost to have " tried her 'prentis han' ; " for these earlier organisms bear about them the impress of a lowlier fauna. Not that any are found which cannot be referred to existing natural-history orders, for Nature, like her Lord, knows " no variableness, or shadow of turning." Her plan has been to fill up the outline, and this has been slowly consummating 30 THE STORY OF A PIECE OF SLA.TE. during the unknown ages which have elapsed since the Cambrian period. Hence it is that the further you go back in time, the more simple is the fades, or general appearance, both of animals and plants. It is possible that, at the time I was born, the dry land was sparsely covered with a humble flora ; but it will be evident that as I am of purely marine origin, I cannot speak with certainty of what took place elsewhere. I have a dim recollection, how- ever, of certain obscure mosses, lichens, and perhaps reeds, but nothing more certain. That there was dry land, and that this dry land was watered by extensive rivers, I have not the slightest doubt. Otherwise, where would the materials have been derived which make up the bulk of my parent formation ? And, that this material -w&s-sloiuty, and not rapidly obtained, you yourselves may easily see from the fineness of the particles which enter into my composition. For the Cambrian forma- tion is no less than eighteen thousand feet in thick- ness ; and, with the exception of certain beds in the middle of this immense bulk (called by geologists respectively Harlech grits and Lingula flags) the rocks of this period are principally fine-grained slates. Even the grit-stones and flag-stones afore- mentioned which are not of a very coarse texture, bear witness to the slowness of their deposition. I believe the whole of this formation was deposited in tolerably shallow water, not near so deep as the present Atlantic, Perhaps you ask how it was, THE STORY OF A PIECE OF SLATE. 31 then, that the strata of a formation nearly three and a half miles in thickness could be deposited in only a tolerably shallow sea ? The question is natural enough, and I reply by stating that whilst these strata were slowly forming, the sea-bottom was as slowly subsiding. Hence it remained at almost the same depth during the long period when these fine muds were thrown down. You will find my statement verified by the fact that in the Lower Cambrian (in a group called the Longmynds) the tracks, holes, &c., of marine worms (termed Arenco- lites) are found distributed through a vertical thick- ness of over a mile of rock. Nor are these humble organic remains scarce; they occur in countless myriads. After the deposition of the Lower Cam- brian rocks, as far as I can recollect, the sea began to get deeper ; the deposits formed along its bottom did not quite equal the rate of depression, and so the depth of water increased; but before then I well remember how comparatively shallow the sea was. This is attested not only by the countless fossil worms which have won a geological immortality from the trails they left on these early sea-bottoms ; but also from the ripple-marks which equally characterize the same set of strata. Nay, we have even evidence of extensive mud-flats, for many of the beds are pitted with rain-drops, and marked with sun-cracks. Thus, far back as English geology can take you, you have evidence of exactly the same kind of meteorological agencies as those which now regu- "2 THE STOEY OF A PIECE OF SLATE. late the physical well-being of the external globe. Cloud and sunshine are testified to by these sun- cracks and ripple-marks. Vapours were raised by solar heat then as now, and the " bow was set in the cloud," although not as yet selected as a covenant to man ! In the same beds as these ripple-marks, sun- cracks, rain-pittings, and worm-tracks, we have innumerable remains of a small crustacean (Palteo- pyge), which used to flit through the shallow water in dense shoals. A pretty little zoophyte (Oldliamia) lived in quiet, sheltered spots, where it luxuriated abundantly, its little branched stems forming miniature forests along the old sea-bottom. These lowly creatures are almost all I remember of what is called the Lower Cambrian formation. The upper portion, however, is much richer in fossils ; and well do I remember when these now petrified organisms enjoyed the pleasures of animal life. Between the deposition of the strata of these upper and lower formations there was a break in the locality where I was born. Probably somewhere else in the globe there will be found a formation (possibly limestone) which was elaborated during this provisional rest. Of that, however, I can only conjecture. Concerning the animals which lived in the Upper Cambrian seas, I can speak more posi- tively. They were, first of all, far more abundant, both in species and individuals. Thus the basement rocks of this subdivision go by the name of Lingula THE STORY OF A PIECE OF SLATE. 33 flags, from the vast quantities of the fossil of that name occurring in them. The Lingula was a mol- lusk occupying the lowest class among shell-fish, that termed Bracliiopodous, or " arm-footed," from the peculiar arrangement of the breathing and loco- motive organs. Strange enough, this genus is still in existence, and you can hardly tell the difference between the horny shells of the living species and those which lived at this early epoch. Talk about genealogy ; no other family, except that of the marine worms, can claim an antiquity so vast. Not- withstanding all the mutations through which the surface of our old world has passed the upheaval of sea-bottoms into mountain-heights, the depression of mountains into sea-bottoms this one genus of shell-fish has triumphantly survived them all! It is now, I am told, fast passing into extinction, the final lot to which so many genera of subsequent date have succumbed. Among other animals which lived at the time was a species of shrimp (Hymenocaris), whose remains may be met with in the same rocks. Along this sea-bottom, in various places, lived colo- nies of a kind of sea-lily, or rather, of an animal halfway between them and the more recent sea- urchins : these now go by the name of Cystideans. Furnished with a short footstalk, which served to anchor them to their selected habitats, they flourished on the lower forms of life which swarmed in the waters of these primeval seas. Later on was introduced a crustacean afterwards THE STOBY OP A PIECE OF SLATE. to become famous, both for its abundance and the number of generic and specific forms it assumed. This was the well -known Flg ' 5 ' TriloUte. Several gen- era, and still more nu- merous species, were in existence, and so fast did the newly-introduced species breed, that they soon became the chief inhabitants of these early seas. Most of my listeners are acquainted with their tri-lobed forms (whence their name), and have admired the jointed coat of mail which protected them, and, at the same time, gave them all the necessary flexibility for movement. Out in the deeper water lived a peculiar kind of mollusk, whose type is still living. This is termed Tlwca, and its external protection consisted in a thin, almost glassy case ; not so fragile, however, but that it has been carefully fossilized. But in gritty sandstones, or coarse slates, it is rare you will find any remains Cambrian Trilobite (Paradoxides Bohemicus). THE STORY OF A PIECE OF SLATE. 35 of the old calcareous shell of the various creatures I have named. Subsequent changes, most of all the percolation of draining water, have removed the Hmy material, so that the fossils found are princi- pally as casts. Perhaps the lime thus removed has, in many cases, served as a natural cement to the sandy or clayey particles, so that much of the hard- ness which now characterizes these rocks may be originally due to the limy substance of the Cambrian inhabitants. Towards the close of this remarkable period, other forms of life appeared, the total number of genera and species considerably increasing. Shell-fish of a higher grade were introduced, until the highest type the Cephalopoda was brought on the stage of existence in the shape of Orthoceratites. These were allied to the living nautilus, only they had straight cham- bered shells, instead of coiled ones. Their arms, something like those of a cuttle-fish, extended out of the last, or body-chamber ; and on these, with their shell inverted like a spire, the creature would occa- sionally crawl over the muddy sea-bottom, where I was slowly forming. Belly-footed mollusca (Gas- teropoda), in the shape of a genus which has been extinct since the time of the coal formation, crawled about, their gracefully coiled shells being as beautiful as any of their recent representatives. Thus did the Cambrian period come to a final close. Of course my listeners cannot expect one poor 36 THE STORY OF A PIECE OF SLATE. memory accurately to remember all the types of life then existing ! Suffice it to say that, compared with those of subsequent periods, they were few and of a much lowlier kind : numerical abundance of individuals made up for poverty of genera and species. It was the dawn of life when organisms were in the cradle. Betwixt this and chaos was a great gulf fixed. The first outlines of that grand scheme which should ultimately link inorganic matter with spirit were then rudely sketched. Time was ordained for the sole purpose of filling them up, and, when the object is completed, time shall be no longer ! Even since this distant period, life has progressed until it has reached its physio- logical maximum in man. But in him, I am told, appear the germs of a new spiritual life, whose de- velopment shall extend into the future, just as organic life has been developed in the past ! Such are a few of the reminiscences of a piece of slate ! Of the agencies which uplifted me into a mountain- ridge, which consolidated the fine mud where I was born into hard slate, I cannot tell. These are all included in those chemical and geological changes which took place after my birth. But, whilst I have thus endeavoured to administer to the intel- lectual curiosity of man, I cannot forget that it is to these subsequent alterations that I am what I am, and that I now assist in roofing in and protect- ing the latest introduction of nature in the form of man ! iHE STORY OF A PIECE OP LIMESTONE. 37 CHAPTEE IV. THE STORY OF A PIECE OF LIMESTONE. : Millions on millions thus, from age to age, With simplest skill and toil unweariable, No moment and no movement unimproved, Laid line on line, on terrace terrace spread, To swell the heightening, brightening, gradual mound, By marvellous structure climbing toward the day. Each wrought alone, yet altogether wrought Unconscious, not unworthy instruments, By which a hand invisible was rearing A new creation in the secret deep. Omnipotence wrought in them, with them, by them; Hence what Omnipotence alone could do, Worms did. ***** Slime their material, but the slime was turned To adamant by their petrific touch; Frail were their frames, ephemeral their lives Their masonry imperishable. All Life's needful functions, food, exertion, rest, By nice economy of Providence Were ever ruled to carry on the work Which out of water brought forth solid rock." MONTGOMERY'S Pelican Island. AM elected as spokesman for a common and well-known mineral, which is abundant in every geological formation. Our age, there- fore, varies as greatly as it is possible for mundane time to allow. Chemically, our composi- 38 THE STOfiY OF A PIECE OF LIMESTONE. tion is always pretty much the same, being merely Carbonate of lime. In all the rock formations we are further dis- tinguished from the sandstones, shales, and con- glomerates, by our being almost wholly of vital origin, that is, formed through the agency of living beings; whereas the other rocks I have mentioned are the result of mechanical forces, wearing down and triturating pre-existing rocks, and then re- depositing the debris along old sea-bottoms. In consequence of this difference, the geologist finds in us by far the greater number of those organic remains, especially of marine animals, by whose aid he is enabled to sketch forth the development of the world's great life-plan. As a rule, all limestones have been deposited, as fine calcareous ooze, away out in deeper water ; consequently the circumstances have been doubly favourable for the preservation of any animals which might have died and become entombed in this limy mud. The more boisterous conditions which prevailed in the shallower waters, where coarse sands and con- glomerates were formed, prohibited such favourable preservation. At the same time, with the exception of what are known as freshwater limestones (which bear a very small per-centage to the other rocks of the earth's crust), I must acknowledge that the sandstones afford most valuable evidence of the terrestrial animals. This, as might be expected, is THE STOEY OF A PIECE OF LIMESTONE. 39 mainly owing to the fact that the latter were formed nearer to the shore so that carcasses of land animals accidently drowned or carried into the sea by rivers watering large islands or continents where they lived, would sink to the bottom, and be buried up in coast deposits ; whilst the sandstone and shala formations testify to the long-continued wear-and tear of the solid land by meteorological agencies. Therefore, the limestones bear out the idea of our planet's antiquity, by suggesting the immense lapse of time which must have occurred whilst simple and lowly animal functions were elaborating the greater proportion of all the limestone rocks. But I intend to let each of these speak for itself. They are of age, ask them ! Each contains its own suite of organic remains, the extinct creatures which lived and died whilst the limestone mass was slowly accumulating as calcareous ooze. They are tombs of the forgotten dead stony scrolls, written within and without. I myself belong to that most interesting geologi- cal formation known as the Silurian. Away in the heart of the " Black Country," where no less than thirty feet of solid coal abut against their flanks, you may see cropping up an irregular and continuous ridge of limestone hills. It is thence I am derived. You may gather some idea of the forces which slowly upheaved these strata by seeing the steep angle at which they lie : a little more and they would have been quite perpendicular. But this 40 THE STORY OP A PIECE OF LIMESTONE. upheaval was not violent or sudden ; on the con- trary, I distinctly remember its operating through long -continued ages subsequent to the Silurian period. The process was so slow as to be almost imperceptible, for Nature knows little or nothing THE STORY OF A PIECE OF LIMESTONE. 41 of those violent cataclysms which have been so foolishly ascribed to her ! Examine the steep flanks of the Wren's Nest, near Dudley. There is hardly a space of a pin's point which is not occupied by the remains of some creature in which the breath of life was enjoyed countless millions of years ago ! You strike the solid rock with your hammer, and immediately the percussion liberates a heavy sul- phuretted odour, which tells of the old animal oils in which the limestone is steeped. The very hardness of these rocks is more or less indebted to the same organic cause. I am told that when sculptors, now-a-days, wish to harden their plaster- of-Paris casts, they do so by boiling them in oil. The principle is the same with most limestone rocks of every age. They are steeped, saturated in animal oils ; nay, in many places across the Atlantic, where these old Silurian limestones and shales lie so deep down as to be within the action of the earth's internal heat, these oils have been distilled out of the rocks, and have followed the ordinary habits of fluids. It is by sinking through the over- lying masses that these oil-springs are reached, and the valued liquor comes bubbling to the surface. Well does it deserve its common name of Petroleum " rock-oil." But few people imagine, when its brilliant light is illuminating their comfortable homes, that they are indebted to distilled Trilobites for the luxury ! Here is another form of that grand law of correlation of 42 THE STORY OF A PIECE OF LBIESTOXE. physical force. The ancient Silurian sunlight fur- nished the means of vitality to the creatures which then enjoyed life. It was stored up in their tissues, and given forth in their buoyant gambols and locomo- tive powers. And when they died, what remained in their diminutive bodies decomposed, passed into other chemical forms, was preserved until our own day when men unlock this ancient sunlight from its oleaginous condition, and turn it to direct heat- ing and lighting account ! Fancy sunlight bottled up in the form of trilobites and mollusca ! No wonder these should present such stony and petrified appearances, w r hen all the animal oils have been so completely drained out of them. How long these Wenlock limestones (for that is the name by which this section of the Silurian for- mation is known), how long, I say, it is since these limestones were upheaved and exposed to the action of the weather, I cannot say. Their hardness, as I have already mentioned, is most intense; but the wear-and-tear of the atmosphere has been such as to cause the fossils to stand out in relief; and a strange sight, therefore, is the exposed surface of the limestone slabs. The eye is bewildered by the number and variety of organic remains, each stand- ing forth from the fine limy mud in which it was originally enclosed. Little or no vegetation grows on this bare limestone surface; the latter is too impenetrable to yield a foothold ; and so the geolo- gist has it all to himself. Heads and tails of Trilo- THE STORY OF A PIECE OF LIMESTONE. 43 bites, so plentifully dispersed that they immediately stamp the Silurian age of the rock, lie commingled with brachiopodous shells, worm-tubes, sea-mats, chain- corals, and encrinite stems. You require no prompter to remind you of the exuberance of animal marine life in this distant epoch, and yet the Silu- rian period immediately succeeds the Cambrian, about which my distant relative, the Piece of Slate, gave you an account some time ago. Whilst the limy mud which subsequently be- came hardened into solid rock, and then upheaved into its present condition was being slowly formed in deeper water, nearer to the shore there were deposits of a different nature going on : these con- sisted of muds poured into the sea by rivers, or wasted by tidal and current action from old coast- lines ; gradually, therefore, the limy deposits passed into the muddy ones, so that the line of junction was almost imperceptible. Occasionally the fine, mud was carried further seawards than usual, and. then a thin layer of argillaceous matter was thrown down over the limy material. This accounts for the frequent alternations of limestone bands and argil- laceous shales which you have doubtless seen in every section of Silurian strata. At various epochs during the immensely long period which elapsed whilst these beds were form- ing, alterations of the sea-bottom took place; the area where limy deposits had been forming became shallow, so that clay or mud began to accumulate 44 THE STORY OF A PIECE OF LIMESTONE. over the same spot ; or, the sea-bottom became deeper, and, in that case, calcareous or limy material slowly formed where mud had previously been accumulating. Occasionally, perhaps, the sea became so shallow that shingle-beds were strewn over the area where both lime and mud had been collecting. My hearers can readily understand operations like these ; they are still going on over various parts of the earth's surface ; but the time of observation has not been extensive enough to see what they can effect. Only that simple element of time is required and our planet is changed as by the will of some powerful magician ! And, for my own part, I do not see why the timid, unconceding spirits of modern times should begrude time to the geologist, any more than they do distance to the astronomer ! The various strata which vertically succeed each other in the Silurian formation plainly indicate the geographical changes which affected these ancient seas ; and, at the same time, imply the vast lapse of time during which they were brought about. Suffice it to say, this Silurian formation, with its enclosed strata, attains a total thickness of no less than twenty-six thousand feet ! Leaving my junior brethren to speak for them- selves when their turn comes, let me try and re- member some of the physical circumstances which marked the epoch of my own birth. First of all, what a different geography marked the surface of the globe then from what there is at present ! I THE STORY OF A PIECE OF LIMESTONE. 45 believe there was a much wider extension of sea than there is even now, when it extends over more than two-thirds of the earth's surface; and, owing to there having been fewer disturbances at that time, the sea was more equable in depth ; whilst, at the same time, the dry land was less distinguished by mountain-chains. In consequence of the equable depth (or nearly so) of the sea, and of the similar climature which the entire surface of the world seemed to have enjoyed alike, there was less differ- ence in the animals and plants of various geographical zones ; but this principle was in existence, although nothing like so broadly developed as at present. The Silurian limestones of America, Asia, and Europe differ very little in their general fades of organic remains. You have no difficulty in recognizing the old features which struck you when examining the Dudley strata; but when more minutely studied, the naturalist makes out certain "colo- nies," caused doubtless by difference of geographical circumstances. As Lingtll 7 ewi8ii> the time passed away during which the great sequence of beds belonging to the Silurian formation were being elaborated, other changes took place in organic life. The most marked feature was that of a progression from lower to higher types. Species multiplied, and the general total of life- forms became more varied and less cosmopolitan. 46 THE STOEY OF A PIECE OF LIMESTONE. The lowest beds of my parent formation go by the name of Llandeilo Flags, so named from the locality in North Wales where the typical section may be studied. They are, as their name implies, strata of flaggy sandstone, much worked for com- mercial purposes. There is a considerable quantity of limy matter in their composition, and this gives them a peculiar indurability. Interstratified with the beds of this deposit are immense layers of ancient volcanic matter, basalts or tuffs: these Fig. 8. Basaltic rock interstratLfied with aqueous rocks ; 6 Basaltic dyke. flowed over the old sea-bottoms, when ejected from submarine volcanoes, or volcanoes situated near to the coast, as we find they usually are now-a-days. The ashes or tuffs were carried by the winds, and the ancient seas had their surfaces thickly strewn with cinders for hundreds of miles; these sank to the bottom, and alternated with the regular shore deposits. Succeeding the Llandeilo Flags, we have another division, known as the Bala Lime- THE STORY OF A PIECE OF LIMESTONE. 47 stone, also named from a locality : it lias inter- stratified with it beds of sandstone, slates, and volcanic rocks again, which were doubtless strewn over the old sea-bottoms just like those already mentioned. The Caradoc Sandstones, named from their locality in Shropshire, containing also shelly sandstones, with soft shales and conglomerates, lie above the Bala Limestone, and complete what geolo- gists have termed the " Lower Silurian Kocks." They differ, as a whole, in Great Britain, from their comprising such a huge bulk of strata of igneous or volcanic origin. In some places these are actually thicker than the rocks of sedimentary origin. What a stormy, restless epoch was that ! The old sea- bottom was subjected to shocks and volcanic over- flow more intense than those in the neighbourhood of Iceland, where the Skaptar-jokul is quivering with suppressed rage and superfluous power ! Then, again, these Lower Silurian rocks have neither so abundant, nor so highly organized a fauna as the rocks of later date. Let me mention the next in order, before I give you my personal recollections of the extinct creatures you find imbedded in these rocks as fossils. The "Middle Silurian" strata commence with the Llan- dovery slates (another localism); after which you have the May Hill sandstones (about which not a few geo- logists quarrelled some years ago) and the Tarannon shales ; altogether, this series is about two thousand feet in thickness, the Lower Silurian beds I have 48 THE STORY OF A PIECE OF LIMESTONE. described being upwards of nineteen thousand feet thick. Next come the uppermost beds (to which I personally belong), known as the " Upper Silurians," and which attain a total vertical thickness of nearly five thousand feet. They include several deposits of minor importance; such as the Woolhope beds and the Wenlock limestones and shales, completing what is known as the "Wenlock Group." Then succeed the Ludlow beds, the Aymestry limestones, and the Downton sandstones, in the latter of which is found a bed composed of scarcely anything else than the bones, teeth, and scales of small fishes, belonging to the pkicoid and ganoid orders. It is in these soft shales you find the fossils so well pre- served. The shells, although they have been extinct for unknown millions of years, still retain their beautiful iridescent nacre, which, how- ever, soon decomposes by atmospherical influence. So much for the " strati- graphy " of this most inter- esting geological formation ! At the forms of life which swarmed the seas of this distant epoch I cannot do more than merely glance. I have mentioned that, gene- rally speaking, there was a progression. This 13 Fig. 9. Curved Orthoceras (Cyrtoceras Murchisont). THE STOEY OP A PIECE OP LIMESTONE. 49 Fig. 11. true only of the advance in the main, for, during the earlier portions of the Silurian period, huge Orthoceratites abounded, and these are F ^^' among the highest classes of the mollusca. Jflfe, The muddy sea-bottoms swarmed with 1|B " sea-pens," now known as Graptolites, allied to the little Corallines so plentiful in mo- dern seas. The chief difference between them being that the former were free and unat- tached, whereas the latter always adhere to some other body. But, of all forms of life, those of the Trilobite family were most abundant. Several hundred species are known to belong to the Silurian forma- tion alone. They were crusta- ceans, allied to the King Crab* of the Moluccas, and at that time represented the lobsters and crabs of the present day. This is a group which uraplome . Orthoceras, up- always been noted for its aber- per part ^ types. Like other Crustacea, the showing per- J * foratedcham- Trilobites underwent metamorphoses or ber - larval changes. So well do the old * The larva or young of the King Crab very much resembles some of the ancient Trilobites. 50 THE STOEY OF A PIECE OF LIMESTONE. rocks tell their story of ancient life, that the geologist has traced the metamorphoses of Trilobites through no less than twenty different stages, from the egg to the adult animal. In the last condition its body was enclosed in tri-lobed joints, which served as a defence, and at the same time were flexible enough to be adjusted to all the motions of their possessor. In fact, they served all the purposes Various species of Graptolitcs, from the Silurian rocks. of an ancient coat of mail. These various species of Trilobites literally swarmed in every sea of the Silurian period. There were species alike peculiar to deep water and to shallow, and the rocks formed under these different conditions (as I have above related) indicate which these species were. Well do I remember them crawling over the oozy sea- bottom, gorging the mud, as I am told earthworms THE STORY OF A PIECE OF LIMESTONE. 51 now do, for the sake of the animalculous matter dispersed through it. Not long ago, some of these fossils were found which were supposed to have the legs attached to the under side. As a rule, how- ever, the Trilobites are usually met with without these useful appendages, and no small discussion has arisen as to whether they had them or not a discussion which is now set at rest. When any danger approached, they coiled themselves up like modern woodlice, and, in this state, you may not unfrequently find them fossilized. When the adult animal moulted, he did so at the junction of the head and carapace; and this accounts for the myriads of detached heads and tails found in every piece Of Silurian limestone Spiny Trilobite (Atidaspis Dufre- or shale. The Trilobite had >yO- Silurian rocks of Bo -, -, hernia. compound eyes, arranged sessile, on half-round prominences, on which they were set like so many mounted jewels. Some species had not less than four hundred of these distinct eye- facets. Thus we find the structure of this little creature completely setting all those wild theories 52 THE STORY OF A PIECE OF LIMESTONE. at defiance in which some people have indulged. Their eyes indicate a similar constitution of the atmosphere then to what it is now, for the passage and refraction of the rays of light. And this fact is supplemented by the sun-cracks, rain-drops, &c., which pit the sandstones, telling of meteorological action identical in its operation with the present. Indeed, all the facts go to prove that even at this distant epoch of the world's history, the light of the sun and the atmo- sphere of the earth were exactly like what they are at the present time. During the period of the " Middle Silurian " there was a great change in physical geography. How long a time had elapsed since the Lower Si- lurian strata Lad been formed, with Trilobite from the theil 611ClOSed 8"** She6tS f VOlC&IliC Silurian rocks, lava and ash, may be guessed at from Pultowa, Russia the fact that the May Hill conglome- rates are com P sed of the waste frag- ments of the former ; they had there- fore been solidified into such rock as you now see them, and been uplifted from the sea-bottom into coast sections, and it was from their wear-and-tear, when in the latter condition, that the May Hill conglomerates were formed. Thus does the very structure of many of these deposits indicate the immense amount of time which elapsed during their elaboration. It was during the deposition of the THE STORY OF A PIECE OF LIMESTONE. 53 " Upper Silurian " beds, however, that life was most prolific was most varied. The sea was aglow with huge coral reefs, around which swarmed sea-lilies, star-fish, inollusca of innumerable species, nautili, orthocerata (of whimsical and various shapes), and trilobites. The scene was most busy and most animated ; the compound corals shone in various colours, and the adjacent sea-bottom was literally a submarine forest of crinoids, or sea-lilies. How abundant these lovely creatures were you may guess from the fact that you Ficr 15 can scarcely pick up a fragment of Upper Silu- rian limestone without perceiving some of their detached ossicles, or joint- ed plates. In and out of these waving forests, vrith the arms of the animals representing Pentamerus Knightii. branches, the innumerable species of trilobites swam, and crawled, and climbed. Every now and then some brightly-coloured -pecten flitted past like a butterfly. Univalves (Murchisonia and Euompha- lus) of delicate ornation and colour, slowly dragged their pretty shells about ; the Cystideans, with their dwarfed stalks, but highly-ornamented and sculp- tured heads, dotted the sea-bottom. Over all, the occasional long arms of star-fish wound and un- wound ; delicately beautiful nautili, of various species, 54 THE STORY OF A PIECE OF LIMESTONE. sometimes crawled, sometimes rilled their air-tubes, and mounted to the surface of the water. The whole of Wenlock Edge, in Shropshire, is nothing less than an ancient Silurian coral reef, around which, millions of years ago, all the vital circum- stances I have been attempting to describe took place ! Of all these beautiful coral forms none were so lovely as the " Chain-coral " (Hcdysites catenulatus). Well does it deserve its name, for even now it appears like some watch-chain of exquisite work- manship .inter folded in the solid rock! The largest of these corals was the Favosites poly- morpha. Amidst all should not be forgotten the nests, groups, or even banks of Terebratula, Atrypa, Rhynclionella, Spirifera, Producta, Stropliomena, and Pen- tamerus ; all of them belonging to the lowest class of Mollusca, then in luxuriant abundance, but now waning into extinetion. Towards the close of the Upper Silurian period, Vertebrata, in the form of fishes, made their appearance : at first they were few in number and small in size : but ere long they multiplied amazingly. They had their old feeding and breeding grounds, and along this part of the old sea-bottom their remains were of course most thickly accumulated. Such is the explanation of the THE STORY OP A PIECE OF LDIESTONE. 55 Fig. 17. BRACHIOPODS. 1. Lingula Lewisii (Silurian). 2. Obolus Apollinis (Silurian). 3. Leptaena transversalis (Silurian). 4. Orthis elegantula (Silurian). 5. Orthis striatula (Devonian). 6. Stropho- mena depressa (Silurian). 7. Atrypa reticularis (Silurian). 8. Pen- tamerus. 9. Spirifer striatus (Garb. Limestone). 10. Spirifer spe- ciosus CDevon). 11. Spirifer trigonalis (Carb. Limestone). THE STORY OF A PIECE OF LIMESTONE. 57 Ludlow bone-bed to which I have already alluded. I am told that off the western coast of Ireland, near Kockall, such a bone-bed is now actually in course of formation ; so that if it becomes covered over by succeeding deposits, it may one day present a similar appearance. Of the land plants of the Silurian period I cannot say much ; but that the dry land was more or less clad with green I have not the slightest doubt. What makes me feel so confident about this is that the small spores of club-mosses are to be found fossilized in the " bone-bed " I have mentioned. You can only see them with the microscope, but there is no doubt as to what they really are. These spores must have been carried by the land-breezes seawards, and strewn over the surface of the ocean until they sank, and were buried in the deposits accumulating along the bottom, where the bony- scaled and shagreen-skinned little fishes were living, breeding, and dying. My story is now finished, for the formation of cracks and fissures in our solid rocks belongs to a later time. Of the minerals and metals which were segregated along the walls of these fissures until the latter became " metal lodes," I cannot say ; but thus much that, apart from the numerous fossils contained in us, our rocks will always be esteemed interesting to man, seeing that it is in them that the over-valued metal gold is most abundant. 58 THE STORY OF A PIECE OF SANDSTONE. CHAPTEK V. THE STORY OF A PIECE OF SANDSTONE. " You may trace him oft By scars which his activity has left Besides our roads and path-ways (though, thank heaven, This covert nook reports not of his hand), He who with pocket-hammer smites the edge Of every luckless rock or stone that stands Before his sight by weather stains disguised, Or crusted o'er with vegetation thin, Nature's first growth, detaching by the stroke A chip or splinter to resolve his doubts; And with that ready answer satisfied, Doth to the substance give some barbarous name, Then hurries on ; or from the fragment, picks His specimen." WOEDSWORTH'S Excursion. IKE my mineralogical acquaintance, the piece of limestone, generally I am about to do duty for a group of individuals common to every geological formation. But each of us has a separate story to tell, and I shall find it quite sufficient to bring all the circum- stances of the epoch in which I lived sufficiently clear to my own recollection. It is said that a number of people who live in the present period (so far removed in time from mine) profess to be THE STORY OF A PIECE OF SANDSTONE. 59 able to interrogate a piece of limestone or sand- stone, by what they term Psychometry, and to get its story in some easier way than by the ordinary cross-questioning of science! All I can say is, I wish the events of my own life were so permeated in my substance. If this theory be true, the modern science of geology will have to give np induction, and fling itself into the arms of the spirit- rappers ! Every one of my listeners knows what a piece of sandstone is like. There is no heed for me to de- scribe my appearance, therefore, as novelists do their heroes. But how many thus familiar are aware that in ninety-nine cases out of a hundred every such piece of sandstone was originally formed along the floor of ancient oceans ? Those ocean bottoms are now represented by dry land surfaces, where the vegetation luxuriates on the mineral substances accu- mulated under such widely different circumstances. Even where no marine organic remains are present, as fossils, to prove the marine origin of the sand- stones, that origin is none the less certain. I can- not speak with certainty as to the nature and ex- tent of the dry lands and continents of the epoch in which I was born. Suffice it to say, they must have been great, for the rivers which watered them were large, and brought great quantities of mud and sand down to the sea. The ocean currents and tides also wore away the coast-line, and added to the quantity of loose sand and mud which accumulated THE STORY OF A PIECE OF SANDSTONE. Fig. 18. under the waves in consequence. Thus it was that I was born. My earliest remembrances are of my lying loose and unconsolidated on the ocean-floor, and of con- stant additions being made to the sheet of which I formed part. It was whilst I was lying in this state, as so much ordinary sand, that I received my impressions of what was going on around me. These consisted of a familiarity with the commoner animals which lived in the sea, or with occasional plants and vegetables which had been carried there by rivers, until they sank to rest in my bosom when they had arrived at a water-logged condition. Of these I will speak presently. Meantime let me make a few remarks as to the changes which transposed me from loose marine sand into hard sandstone ; and in doing so, it will be evident that the same explanations will answer for the similar alteration of sandstone rocks, both of earlier and later geological periods. The sand or mud brought down and laid on the sea-floor in the manner I have mentioned was not of an absolutely pure character as regards its mi- neral composition, that is to say, it was not all silica, or alumina, as the case might be. In most Calceola sandalina. THE STORY OF A PIECE OF SANDSTONE. 61 instances the material was mixed with more or less of iron rust, or of lime, and silica. The two latter acted as cementing pastes to those sandstone rocks which are now of a lightish colour ; whilst the iron was the compacting agent with such dark red rocks as that of which I form part. Indeed, in most cases, even when the sandstone is of a light yellow, a small percentage of iron has gone a great way towards binding the loose grains of sand together, and thus producing a hard rock. When this chemi- cal agent has been equally dispersed through the sandy mass, you have the thick-bedded sandstone, or " free stone." When it was intermittent in its action, or unduly mixed up, or occasionally alternated with something else, then the sandstone becomes " flag-stones " of greater or less thickness. Sometimes you will see a mass of red sandstone more or less mottled. This has been caused, in most instances, by patches of vegetable matter old world fucoids or something of that sort, which decomposed, and whose chemical changes combined with the iron, and locally prevented its colouring effect. Of course it will be evident that our hardness or softness greatly depends on the percentage of cementing material, or to the different circum- stances under which we were formed. I have no doubt that, when the chemical changes above men- tioned were going on through an immense thickness of accumulated sand, the hardening process was 62 THE STORY OF A PIECE OF SANDSTONE. greatly assisted by 'the pressure of the overlying volume of sea-water. The epoch to which I belong is sometimes called the " Old Red Sandstone," and, occasionally, the "Devonian." The former term is given to our formation to distinguish us from the " New Eed Sandstone," overlying the coal-measures ; whilst the latter name is of local origin, and indicates that the system is largely developed in the lovely county of Fig. 19. Clymenia. Devon. Indeed, that sunny land owes no little of its physical attractions to the various mineralogical structure of the rocks of our formation. Perhaps I can boast of the fact that there are few other formations which have such a world-wide extent as that to which I belong. In the United States it stretches over an area nearly as large as Europe, there being one continuous coral reef included in THE STOEY OF A PIECE OF SANDSTONE. 63 it which covers an area of nearly half a million of square miles. In Canada there is also a great ex- tension of this formation ; whilst in South Africa its area is greater still. In Kussia one sub-division is much greater than the whole of England, and there is a large extension of beds of similar age in Asia Minor, as well as in Australia. The original name of " Old Ked Sandstone," given to the formation of which I am a humble part, was conferred upon the thick beds found developed in Herefordshire, Worcestershire, Shrop- shire, and South "Wales, as well as others supposed to be of similar age in Scotland. In the former localities they attain their greatest thickness, which is between eight and ten thousand feet. There geologists have divided the series into four divisions, of which the lowest may be said to blend with the underlying Silurian formation, and the uppermost with the succeeding Carboniferous. In Scotland the beds are not so thick, their greatest vertical accumulation amounting to about four thousand feet. It would seem, therefore, as if the material which formed these rocks came from the south-west, thinning out in a north-easterly direction. In Devonshire, as well as in Ireland, there are two series of strata included in the same formation, which seem to have had quite a different origin. The former indicate a sea in which coral reefs abounded, and the latter tells us plainly of a large continent which existed towards the end of this 04 THE STOBY OF A PIECE OF SANDSTONE. epoch, on which there were freshwater lakes as ex- tensive as those of North America. Perhaps it was the same continent whose rivers contributed no little of the sand and mud which, when strewn on the sea- bottom, formed the sandstones of which I am part. I am told, however, that there are some geologists who imagine that all these red rocks were of fresh- water, and not marine, origin ; but I think that their immense area will convince you that this could not be the case. How shall I tell of the strange sights which I beheld when quietly lying on the ocean-floor ! The sea-water had the same specific gravity it has now, and the constitution of the atmosphere was similarly formed. It is an error to suppose, as some have done, that there was mixed a large percentage of carbonic acid in the air before the Carboniferous epoch, and that this was absorbed by the plants, and the atmosphere cleared and rendered fit for animal life ait the same time. The theory is ingenious, but there is not the slightest ground for believing it has any foundation in truth. Occasionally the sea-water became turbid and red, owing to larger quantities than usual of the refuse of igneous and metamor- phic rocks being carried down by the rivers. As is well known, these contain large quantities of iron, which are easily decomposed, and enter into new combinations as oxides ; whence my colour and also my cementing agent. The sea-bottom was covered with groves of fuci, or sea-weeds, in which a large THE STORY OF A PIECE OP SANDSTONE. 65 crustacean, bearing some resemblance in its huge claws to the modern lobster, lived and left its spawn. The latter is actually found fossilized in our sandstones, and bears some resemblance to a flattened blackberry. Among geologists, I am told, Fig. 20. Huge fossil Crustacean (^Ptcrygotua Anglicus). Old Red Sandstone, Forfarshire. it goes by the name of ParJcia, whilst the huge lobster which left it, and which was at least six or seven feet long, rejoices in the name of Pterygotus. Several species of this common form are met with in Scotland, as well as in England. Another large 66 THE STOEY OF A PIECE OF SANDSTONE. crustacean, which Appeared during later Silurian times, and was nearly related to the Ptenjgotus, now goes by the name of Eurypterus, on account of the breadth of its swim- 'a ming feet. | But by far the commonest creatures J which enjoyed life in the sea of my 5 birth were the fishes. Indeed, my % epoch has been justly called " the 2 age of fish." In many places they r? swarmed in shoals. Most of them ^ belonged to an order of which there ^ are very few now living, termed the J Ganoid, on account of their being | covered with a series of oval or o rhomboidal bony plates, instead of J scales. These bony plates had an ' exterior varnish ; whence their name. a At present, I am told, there are ^T several species living in the rivers of | North Africa, and others enjoying ^ life in the lakes and rivers of North t* America. But out of nine thousand species of fish known to naturalists ti the Ganoid species only number ^ about twenty-nine. Indeed, the wide geographical areas where the two *j, outliers of this once numerous and ^ world-wide family of fishes are now lingering, indicate their antiquity, and suggest how THE STORY OF A PIECE OF SANDSTONE. 67 many geological phenomena have taken place to bring about their present geographical isolation. By many it is supposed that the whole of this family would now have been extinct, had it not been for their withdrawing from the keen battle of life that subsequently went on in the seas by the introduc- tion of other species, and so confined themselves to fresh-water condition. Few of these peculiar species Fig. 22. Ptenchthys MUkri. have a bony skeleton properly hardened, as is the case with ordinary thin-scaled fishes. No doubt the strong, bony integument did duty instead. Indeed, among the fish which lived during my lifetime, scarcely any possessed a solid skeleton. The largest of these strange-looking fish is now called Asterolepis from the star-like markings on each of the scales. It reached the entire length of between twenty and 68 THE STOKY OF A PIECE OF SANDSTONE. thirty feet. Other common forms were the Holop- tycJiius, noted for its large oval scales being pecu- liarly wrinkled ; the Pterichthys, or " winged fish," so called on account of its two pectoral fins, which are very large and resemble paddles, being placed near the head, where they look like wing appendages. The plates which covered this fish were very large, and orna- mented by a series of granules. The former of these two species lived in what is now America, Eussia, and England, and Scot- land. Then came the Cephalaspis, or "buckler-headed" fish, so called because its queer-shaped head was encased in a shiny bony buckler, in form not un- like a cheesemonger's knife. Its trilobed body was covered with lozenge-shaped bony plates. The Osteolepis, or " bony-plated " fish, was the most abundant ; its name being PtencUUys cornutus. ' . derived from the minute rhom- boidal plates which covered its body, and protected it, like the links of an ancient coat-of-mail. Besides the fishes of this class, which, singularly enough, were further distinguished by their having the THE STOEY OP A PIECE OF SANDSTONE. 69 tail unequally lobed and not regularly cleft as in the common herring and other scaled fishes there "were associated with them others, having an affinity with species of the Shark family. These are called plaeoid fishes, on account of the skin being a kind of shagreen, dotted with minute plates or points of hard bony matter. They also have a cartilaginous skeleton, as, for instance, the common skate, sturgeon, &c. Well do I remember the above fish, ranging in size from the Asterolepis to the little Onchus and Osteolepis, of only a few inches in length! The quick, active movements of the latter fishes, as they roamed in and out of the thickets of seaweeds, caused the light to flash from their enamelled scales, and sometimes only too surely pointed out their playgrounds to their cestraciont enemies. They had their feeding and their spawning-grounds, and each of these places is now represented by the greater number of fish found fossilized in the flagstones, as in the Caithness flags, and the yellow sandstones of Dura Den. Sometimes, also, great numbers were killed by unusual quantities of mud being poured into the water and choking them, as a turbid river will, at the present time, suffocate the smaller of its tribes. How suddenly these died is indicated by the fact that thousands of fossil specimens are to be seen with their fins erect, like those of the perch when he is " struck by the angler." Others are contorted and bent, as if in pain ; their last dying struggles having 70 THE STOEY OF A PIECE OF SANDSTONE. thus been faithfully-, handed down by the stony records in which they were imbedded. Some few of the fossil fish of this period had reptilian characters in their teeth, &c., indicating and linking on, as it were, the next great family which should rule creation. Wherever the Old Bed Sandstone has been met with, some, if not all, of these peculiar ganoid fishes have been found fossilized. Therefore they are good indications of the geological age of any such formation. I will not trouble my listeners with the dry,, technical details of how the strata succeed each other in my parent formation. I want, if possible briefly but vigorously to sketch the life-character- istics of that distant epoch. I have thus far devoted myself to the fossil fishes because of their abundance, and also of their very striking peculiarities. I now come to other crea- tures, perhaps not less abundant, but not so at- tractive. I must premise, however, that such marine creatures as corals, mollusca, and trilobites were not very abundant over the area where I first saw the light. They delighted in clearer water, and so are to be found over the area where that existed. Indeed, generally speaking, those parts of the sea- bottom where most of the red muddy matter was poured in were shunned by all forms of life, not excluding the hardier fishes. Hence it is you rarely find, in the very red sandstones any organic re- mains or fossils beyond a few vegetable impressions. THE STORY OF A PIECE OF SANDSTONE. 71 Of course there were various parts of the same sea thus distinguished by different physical circum- stances, and life was developed, or located accord- ingly. Let me, therefore, give you some slight account of the area where " blue water " was most in force, and where, in consequence, there were the most numerous assemblages of Crustacea, shell-fish, and corals. The localities in Great Britain where these peculiar fossils are found in strata of the age I am describing, lie chiefly in South Devonshire, as well as along the North Devon coast. At the latter place you may see beds of sandstone, red and yellow, alternating with slates, limestone bands, &c., the last-mentioned being es- pecially full of organic re- mi, j. i i i Fossil Coral (Stanria astra;- mains. Ihe total number formis) of species of fossils of all kinds which have been found in Devon alone ig three hundred and eighty-three. The highest of the series go by the name of the "Pilton Group," and these are perhaps of the same geological a^9 as the Devonian strata in Ireland. Among the iv^s^il shells which lived during this epoch, and which occur at the above-mentioned places in the fossil state, the most numerous were those belonging to the Bracliiopoda. Indeed, these 72 THE STORY OF A PIECE OF SANDSTONE. shells far out-numbered the ordinary and more highly-organised conchifera, whereas at the present time the latter are by far in the majority. Among the commonest of the shells I remember were several species of Spirifer, Stringoceplialus, &c., and also of Clymenia, Megalodon, and others. The last was a lamelli-branchiate mollusc, allied to the oyster and mussel of the present day. Among the corals there abounded in Devonshire the Favosites polymorpha, or " many-shaped " coral, as well as Heliolites, or " sun-coral," Strombodes, &c. The latter my readers will readily recognise when I tell them it is the common pink or red variety usually bought at Torquay, and which, when polished in the mass for mantel- pieces, has such an attractive , T A . . , appearance. All of them are Zapnrentis cornicula. J - , ,.,,. , portions of reef-building corals, and well do I remember the animated appearance of the clear water when the " reefs " flourished in their bright colours, and trilobites, fish, and crustaceans swarmed around the busy pile. The Trilobites found in the Devonian limestones are of a peculiar type, equally distinct from those of the preceding Silurian period, or of the succeeding Carboniferous. Among the commonest of the genera were Brontes, noted for its fan-like tail, and Homdlonotus, equally distin- THE STORY OF A PIECE OF SANDSTONE. 73 guished by the double row of small spines running down the central lobe, and which give to it a more Fig. 26. Common Devonian Coral (Favosites polymorpha). Fig. 27. Cyathophyllum hexagonum. * trilobed " appearance than any other species in the 74 THE STOKY OF A PIECE OF SANDSTONE. whole family. But, clear though the sea-water generally was in which these Devonian beds were formed, every now and then shifting currents brought fine mud and other sediments. These were thrown down on the ocean-floor, where they alternated with the bands of limestone. Eventually, the sea again maintained its purity for a long period, during which the corals and other clear-water-loving animals resumed their avocations, and left behind them traces of their work. I have said that where Ireland now stands, was part of a great continent, or some other extension of dry land, towards the close of the age in which I was born. Of this I cannot speak with certainty; but the evidence is strongly in favour of the idea. In the country of Kilkenny are a series of fine- grained greenish sandstones, regularly bedded ; they are full of evidences of fresh-water deposition. Nowhere, in Europe at least, will you met with such well-preserved land-plants; all of which prove, by the perfect manner in which they have been pre- served, that they could not have been drifted from a distance, or been in the water long. Among the most attractive of these remains are those of a tree- fern, formerly called Cydopteris, or " Eound-leaved Fern," but now named Palssopteris Hibernicus, or the "Primitive Irish Fern." Nothing could be more exquisite than this beautiful fern, even in a fossil state, and you may therefore guess how attractive were its groves when it was the monarch THE STORY OF A PIECE OF SANDSTONE. 75 of the primeval forests, and its graceful fronds bent over the clear waters of a lake which equalled in picturesqueness those of the Emerald Island of these times. This fern is not unlike, in general appearance, the modern " Koyal Fern " (Osmunda regdlis), with the exception that it has no mid-rib its veins ramify- ing from the base towards the exterior of the leaf. Associated with this tree-fern were great and small club-mosses, which trailed over the ground, and formed a rich green carpet of various tints. Among the commoner of these extinct club-mosses were Sagenaria (of which the seed-vessels and catkins are well preserved); Psttopliyton, a simpler club- moss, and the larger and more tree-like Lepido- dendron, which afterwards became so abundant during the Carboniferous epoch. Besides these we have evidences of other kinds of vegetation, and there is no doubt that the higher grounds were more or less covered with more highly- developed and organized species. What is further corroborative of the fresh-water origin of the Irish sandstones is the immense number of bivalve shells, exactly resembling the large fresh-water mussels (Anodon) which abound in modern English rivers. Both in appearance and structure these fossil shells are evidently closely allied, and therefore they are called Anodonta. They abound by thousands in some parts of the sandstones, associated with plant- remains, and with those of crustaceans which seem 76 THE STORY OF A PIECE OF SANDSTONE. allied to the modern, crayfish. So long did these large Irish lakes exist, that mud was strewn along their bottoms which ultimately formed rock several hun- dred feet in thickness. I am told that similar de- posits of fine mud and shell marl are now going on along the floors of the forest-fringed lakes of North America. Change the character of the vegetation there, and you have no indistinct restoration of the Irish Devonian lakes. Many of the fish would do ; for the " bony pike," a ganoid fish, still lives there, associated with colonies of " swan mussels " (Anodon) clustering on the bottom. So much for the brief outlines of my story. Much more could be said upon this remarkable epoch ; but if I have given anything like an idea of my origin and of the character of the life-forms with which I was brought into contact, my business is done, and I accordingly retire for another geological speaker. THE STORY OF A PIECE OF COAL. 79 CHAPTEB VI. THE STOKY OF A PIECE OF COAL. ; A passion for plants had so grappled his soul, That an old Hortus siccus each spare moment stole ; For which he had ransacked the swamps and the meads, Till his Hortus was richest in grasses and reeds. But a strange antiquarian whim he displayed; From the simplest of plants his selection was made, And of structure primeval like none we descry 'Mid the bountiful gifts that the seasons supply; Nor confined he his search, for the earth widely knew, From the poles to the tropics the treasures he drew: Which long in his cabinet hoarded so slily, As an ancient Herbarium are prized very highly." King Cole's Levee. AN any of my listeners form any idea of what a million of years means ? It is very difficult, I grant, but I cannot give any more definite conception of my own great age than by saying I am many millions of years old. Before I attained my majority that is to say, before I became really and positively coal I had existed in manifold forms. You cannot hit upon a greater mistake than to suppose I was origi- nally made just what you now see me a jetty mass of mineral. The doctrine of metempsychosis, said to be held by the Hindoos, would apply almost 80 THE STORY OF A PIECE OF COAL. literally to my own biography. You may trace my career through a hundred different stages, each more widely various than the other. Nay, the process of elaboration through which I have passed is so complex that I may well be. forgiven if I have not a clear recollection of it myself. I am English born and bred, notwithstanding the seemingly tropical character of my antecedents. In some measure, it may be thought that I hardly partake of English characteristics as regards the climate which affected my earlier career ; but I can assure you I was never once removed from British ground. In the distant ages to which I have briefly referred, my recollections go back to waving forests of tree-ferns and gigantic club-mosses, as well as to a thick underwood of strange-looking plants. The name now given to this formation by geologists is termed the Carboniferous, and you may form some idea of the ages which have flowed away since then by the fact that no fewer than nine subsequent distinct formations and periods occurred. These are known as the Permian, Triassic, Liassic, Oolitic, Cretaceous (or chalk), Eocene, Miocene, Pliocene, and Pleistocene, to say nothing of the epoch com- prehending the human race. To make myself still more clearly understood, it is necessary to state that the formations newer than that to which I belong attain a vertical thickness of more than fifty thou- sand feet ! All this mass was slowly formed by gradual deposition along old sea-bottoms, &c., whilst THE STORY OF A PIECE OF COAL. 81 a more than equivalent period of time was taken up in the upheaving and other processes which have elevated these rocks into their present position ! Fig. 29. Vertical section of Calamite, cut through node. The climate and geography of Great Britain were 82 THE STOBY'*OF A PIECE OF COAL. very different from what they now are when I was born. You must imagine a soft balmy temperature, neither too hot nor too cold, and lacking those ex- tremes which at present characterize the seasons. There was no great necessity for extreme heat Branches, niid fruit (Lepidostrobus) of Lepidodendron. rather it was most important to the growth of a luxuriant vegetation to be free from cold. There were few ranges of hills or mountains, for these always cause a refrigeration of the atmosphere by condensing the clouds ; thus hanging the sky with THE STORY OF A PIECE OF COAL. 83 a curtain which shuts off a great deal of solar heafc. True, right across what is now central Englaa United excelled in grace and elegance that fo ^ s ' almo ^ which belonged to these lowly animated makes up the beings. In the solid masses of the Carboniferous limestone you may find them festooning shells and corals ; and few objects afford greater delight to the geologist when he comes across them. The single corals also that is bulk of the limestone. 96 THE STOBY OF A PIECE OF COAL. to say, those which did not grow in reefs, but lived solitary on the sea-bottom were not inferior in beauty to any now existing. Their fringe of gorgeously coloured tentacles made them appear like so many animated flowers ; and thus the dark caves of ocean then bore many a flower that was born to blush unseen. Slowly, through count- less myriads of years, the Carboniferous limestone increased to its present thickness, principally by the Fig. 38. d Pentremites, enlarged, e Showing the plates, &c., which make up the test. accumulation of dead shells. The sea-water con- tained more or less of carbonate of lime, which the shell-fish absorbed in order to build their dwellings, just as the trees did carbon that they might form wood. In this way the minute particles became ultimately condensed into rock masses. Meantime, the water was animated by little creatures that would have evaded human eyesight, although their THE STORY OP A PIECE OF COAL. 97 forms were not a whit less elegant and graceful than those of their larger neighbours. Their tiny shells fell to the sea-bottom, and there formed a limy mud, which acted as a fine cement for the bigger fossils. As time passed on, the sea actually became shallower, by reason of the vast numbers of or- ganisms lying on its floor. The weight of sea- water pressed them into a solid limestone rock, such as you now behold it. Can you wonder, after this, that such a deposit should take a high polish when worked, or that the marble thus produced should be speckled and marked by so many strange forms as you see it in your mantel-pieces or pillars ? In the shallower waters of the sea, and sometimes even in the marine lagoons where the trees grew, multitudes of strangely-clad fishes swarmed. The largest of these, the Megaliclitliys, or " great fish," possessed characters which linked it to the reptile family. Its teeth and jaws rendered it a formidable assailant, and its powerful build and rapidity in swimming made it the terror of its neighbours. In fact, the " great fish " occupied a place among the fishes of its time similar to that held in modern rivers by the pike ; its size, also, being about the same. Time, however, would fail me to enume- rate the various kinds of fish that lived in the same epoch that I did. From four or five feet in length, to thousands no bigger than the common stickleback, nearly all were covered with enamel plates instead of horny scales. Indeed, horny-scaled fishes did not 98 THE STORY OF A PIECE OF COAL. come into existence for ages afterwards. In many parts of Lancashire, in the shales which overlie the coal-seams, these shining enamelled plates may be turned up by the thousand. The smaller fishes haunted the shallower lagoons overhung by club- mosses and ferns, and the dim light that broke Fig. 39 Teeih and Scales of Carboniferous Fish. through these was often reflected from the sheeny mail of Palxonisci, as they wantoned and gambolled, unaware of " great-fish " lying near. "When the muddy bottoms of these reaches and lagoons became after- wards hardened into coal-shale, the dead fishes lying there, whose hard covering had protected them from decay, were entombed and passed into a fossil state. Fig. 40. a Lepidodendron (restored) ; 6 Sf c impressions on back ; d stem with leaves; e leaflet; / fruit of Lepidodendron, called Lepidostrdbus ; g showing spores in bracts of fruit. Fig. 41. : Siijilliiria (restored) ; b leaflet ; c $ d impressions on bark ; of stem ; / portion of cylinder, magnified. ms on bark ; e section THE STOKY OF A PIECE OF COAL. 103 Bat what tongue can describe the vegetable won- ders of the forests where I grew ? The woods were so thick, and the gloom so impenetrable in con- sequence, that it required a keen eye to make out individual peculiarities. Fancy Lepidodendra four or five feet in diameter, and as much as fifty or sixty feet high, and yet nothing but gigantic "club- mosses ! " Their long leafy ribbons waved like the leaves of the aspen, and, where these had fallen off, the bark was most Fig. 42. gracefully and geo- metrically patterned from their attach- ment. Thirty or forty different sorts of these immense club-mosses existed at the same time, each characterized by different leaves j -U i mi. Microscopical section of Fossil Wood, from and bark. The gigan- ^ iron . stone noduks . Oldham tic SigiUarise were nearly related to them, the main difference being their longer leaves, straighter stems, and the larger marks made on the bark. The roots, also, of this latter class of trees were very peculiar, and stretched through the mud on every side, seeking a firm foun- dation for the tree to which they belonged. Shooting many feet above these great club-mosses were huge " horse-tails," as easily distinguished from the rest as 104 THE STORY OF A PIECE OF COAL. the aspen-poplar nowadays is from oak and elm. These are called Calamites, and truly they were extra- ordinary objects. You have only to magnify the little Fig. 43. Vertical section of Fruit of Calamite, magnified. " horse-tails " now growing in ditches, until you see them fifty and sixty (or more) feet high, and you would have the best restoration of these Calamites THE STORY OF A PIECE OF COAL. 105 that could be imagined. There were many species, characterized by fluted joints, and by difference of foliage. Here and there, but more sparsely scattered, were graceful tree-ferns, whose former fronds had left great scars on each side the trunk. The higher grounds were occupied by peculiar species of pine, bearing great berries as big as crab-apples. The Fig. 44. Transverse section of Fruit of Calamite, magnified. humid morass was densely covered by a thick under- wood of smaller ferns, which grew there in rank abundance. The equable temperature, rich soil, and humid atmosphere were just the needful accessories to the growth of vegetation of the class I have men- tioned. It consequently flourished at a rate of which 100 THE STORY OF A PIECE OF COAL. Fig. 45. we can form but a poor idea from the present. The accumulated trees, ferns, &c., were very great, and these gathered in immense quantities over the entire area. I mentioned before that there was a slow sinking or sub- mergence going on. Well, oc- casionally, the tides brought up silt and strewed it over the de- composing vegetation. In fact, many of the forests were actually buried thus, and their trunks are frequently met with standing erect in solid sandstone rock. But though the covering-up of the vegetation prevented the liberated gases from escaping, it also obstructed for a time the growth of other trees. The latter could not well flourish on sand- banks, and so they were limited to conditions elsewhere similar to those I have mentioned. But as time elapsed, the old circum- stances returned. Another forest grew on the site of the older, to be buried up in its turn. During countless ages this alter- nate growth and covering-up went on, until in some places, as in the South Wales coal-field, there are no fewer than one hundred Fig. -iG. Calamites (a restored); 6 enlarged fig.; c, d, e, leaflets and branches; / catkin : . Fi-r. 14G. Fi away. Hence it is that, although the huge bones of elephants, &c., were un- doubtedly buried up in the same gravels, we find few or no traces of them. The commonest of their re- mains are teeth and tusks, whose dentine and ivory structure saved them from the gradual destruction to which the frailer members of the skeleton were liable. Fortunately, there were other agencies at work during the same period, which were conservative rather than destructive. Flint Arrow-head (Neolithic). J n fa e fi ssures O f li me . stone rocks, where water is percolating, the water is usually charged with carbonate of lime. Every drop of water that evaporates on the surface of the walls of a chasm or natural hollow leaves its con- tained particle of lime behind. This process is always going on, until there has been left on the THE STORY OP A GKAVEL-PIT. 265 Fig. 166. walls a great fold or layer of what is called stalactite. The water drips on the floor, and there a portion is evaporated, the lime being left behind. As you may guess, the process is marvellously slow, but the layer thus formed on the floor is called stalagmite. It is not difficult to see that anything lying on such a cavern-floor would be incrusted over, and eventually covered up. This is what I call a conservative process. Now at the time the valley-gravels were forming, savage man was glad to avail himself of any shelter, and the natural caves and hollows of the earth were anxiously sought after, as they are now by the lowest tribes of mankind else- where. To such places as Kent's Cavern, Brixham Cavern, &c., savages resorted, bringing with them the fruits of the chase. Here you may find the bones of animals which had been Palaeolithic split open in order to extract t n L, a- i the marrow, as well as the flint knives and implements of exactly the same kind as those/ound in a gravel-pit. Over these there has ac- cumulated a layer of stalagmite many feet in thickness ; thus carrying you back in time as far as does the Flint ments from Kent ' s C;l " vern, Torquay. 266 THE STORY OF A GRAVEL-PIT. knives deposition and origin of the valley-gravels themselves ! Yon see, therefore, that the two most accessible groups of facts both point to the same great fact of the antiquity of Man. Succeeding the Palasolithic age is that provisionally b * "Reindeer period," hare been chipped; on account of the large number Kent's Cavern. o f the remains of that northern animal which have been found in the bone-caves of the south of France. England and the Continent were then subjected to the periodical migrations of Arctic animals, among which were the Keindeer, Lemming, Glutton, Elk, &c. The flint implements found associated with the remains of these animals in the south of France exhibit a superior skill, indi- cating that man's nature was to progress, even at that early stage. Rude attempts at carving and drawing were also indulged in, as examples in your principal museums will attest. Then succeeded the next stage, known as Neolithic, or " Newer Stone age," which is dis- tinguished by the greater variety in shape of the flint implements, and, more particularly, by the fact that they are for the most part ground smooth and to a sharp knife-like cutting edge. These weapons, however, are usually found strewn on the surface, or imbedded only in peat-bogs and the most recent of river-deposits. Whereas the Palseolitliic types are THE STORY OF A GKAVEL-PIT. 267 Fig. 168. Fig. 169. Neolithic Implement, Mildenhall, Suffolk. Neolithic Implement, Mildenhall- more finished. Fig. 170. Ancient Neolithic Fliut Kuit'e. NEOLITHIC TVPES OF FLIXT INSTRUMENTS. THE STORY OF A GRAVEL-PIT. 269 limited to valley-gravels and tlie most ancient of bone-caves, the Neolithic show, by their universal distribution and superior workmanship, that they belong to an advanced period. All the savage races still using stone weapons are generally islanders, Fig. 171. Polished Stone Ceits (later date), from Cambridgeshire. cut off from the great centres, so that they are " outliers" of a system once universal. This later period is that of the " Lake Dwellings," which links on to -that known to antiquaries as the "Bronze period." To this succeeds the Iron age, and, if you 270 THE STOBT OF A GRAVEL-PIT. like, the present, or " Steel " age. The two former axe historical come within the range, not only of scientific deduction, but also of written history. I have simply mentioned them to show how, from the Fig. 172. Stone Celt (Neolithic), mounted in wooden haft, showing how these implements were used. The haft and weapon preserved in pea:. Cumberland. time when the most ancient and rude of the flint im- plements were deposited in the river-gravels, there is more or less of an unbroken sequence. THE STORY OP A GRAVEL-PIT. 271 Archaeology commences where geology leaves off - -the past and the present meet on common ground. Standing on this neutral area, you may gaze backward into the illimitable ages which have gone by, and see the gradual ascension in animal life which began in the dim and distant Laurentian epoch in the animalcule, and has terminated in Man. Looking forward from the same vantage-ground, you may hopefully note the development of society, the growth of civiliza- tion, and probability of the unfolding of the social and moral attributes of man as marvellously as the lower animal life has culminated in its existing apex ! Throughout, in the buried past, as well as in the yet unfolded future, you never lose sight of the operations of an Almighty Spirit ever working, never resting ! out of chaos bringing forth order out of simple protoplasmic material educing the animal and vegetable kingdoms, in all their multi- tudinous types and varieties, until a small area like the superficies of this planet has teemed with life sufficient to stock a million existing worlds ! One generation has passed away, but, in doing so, has furnished a new basis on which the new comer may ascend to a higher physiological platform. Every form, animal and vegetable, has been but the ex- pression of Divine Love, communicating to them the excess of its own joyous life ! Every species has been an outwardly crystallized Divine idea. Spirit has clothed -itself with matter, until in Man the past and the future have met : the ancient 272 THE STORY OF A GRAVEL-PIT. Greek fable has been more than realized, for it has been true spiritual fire from heaven given, not stolen which has been inspired into fleshly clay ! My story is now ended, and, with mine, the series, whose purpose has been to give as plain an outline of the biography of our old world as possible. It will have been seen that a story may be properly read off, even from so common and ordinary an object as a Gravel-pit. In geology, more than any other science, he that humbleth himself shall be exalted ! All its objects lie at your feet, and are of the lowliest kind. Not a pebble you accidentally kick before you, not a handful of dust blown by the wind into gutters, not a spadeful of soil turned over, but each is fraught with teaching of the utmost value and of the intensest interest. It is by recognising a Cause that you alone can unlock the secret, setting out with the full belief that every- thing exists by virtue of a right has resulted, not from accident, but law, until you arrive at the highest conception of which man is capable, that the total of these various laws meets and concen- trates into one focus, and finds its expression in a personal and Almighty God ! ( 273 ) RETROSPECT. the preceding pages we have endeavoured to limn, but in faint and sketchy outlines, the biography of our planet. We now propose still more briefly to connect the scattered ideas into a short summary. Perhaps the most difficult thing a person experiences when he comes into contact with geological teaching for the first time, is the great demand made upon his imagination for the article of Time, in which to account for geological phenomena. It bewilders one to contemplate such a practical eternity, and we ask " can all this be true ? " Many cannot accept the doctrine, but turn away sceptically discontented, thinking they are doing heaven service, by adhering to the older idea that the world is only some six thousand years old, as if the Deity were complimented by supposing His attributes were more honoured by limiting their display to six thousand years, than they are if extended into the past, and made eternal. The more we study the phenomena of geology, however, T 274 KETROSPECT. and the more knowledge of natural science we bring with us to the task, the more profoundly impressed do we become with the vast antiquity of our planet. Many men fall into the error of supposing that in discovering new laws in the universe, we are exiling the Deity, and giving to the operations of these laws the power that is really His. Even scientific men sometimes speak of the laws of nature as if they were entities, forgetting they use the term simply as a figure of speech. For, as Dugald Stewart has shown, the term "law" can only be applied in its correct sense to conscious agents, capable of under- standing the rule of conduct laid down, of obeying it or disobeying it. When we apply it to such a system as that which guides the planets, which arranges the animal and vegetable kingdoms, and which directs the operations of physical geography, we are speak- ing of unconscious objects, which cannot obey law, inasmuch as they are not conscious of it. To their relationships, therefore, the word " law " is used as a figure of speech, and limits itself to the mode by which an active Providence is operating on matter. Though it may seem strange indeed to hear that the world has been in elistence millions of years, and that its surface has been covered by numberless creations of animals and plants, yet the true natu- ralist sees in these extinct faunas and floras, conjoined with the present, only one great and harmonious scheme ! In the fossils of the rocks we have a gra- duated scale of animal and vegetable life, and we have RETROSPECT. 275 seen how, in spite of the imperfection of the geolo- gical record, it is possible to link object by object together, so that, when extended from the remote past to the present, they form a connected chain. Our planet's earliest existence seems to have been that of a cosmical mass a sort of world-fog or vapour something like those revealed by the tele- scope as being still in existence. Some of the best astronomers have shown that the probable origin of the entire Solar system has been a condensation of this cosmical vapour into planets, satellites, and plane- tary rings. Whether this was the case or not, it is certain that there is much in the shape and physical constitution of the planets to lend support to the idea. But, with the oblate shape of our globe, and its probable evolution from a cosmical mass, the geologist has little or nothing to do. But he knows, from the fact of igneous rocks having repeatedly been injected into the stratified rocks, so as to bind them together, as mortar does the bricks of a wall, that the interior of the globe still contains molten matter. The first time the geologist can lay his hand on a formation distinct in its character from the primitive igneous rocks, it is when he comes to the Laurentian system. They are thirty thousand feet in thickness, and so contorted and changed by the pressure, heat, and mechanical forces to which they have been subjected since the infancy of the world, that all original characters have been obliterated. But, by 276 RETROSPECT. the aid of the microscope, the explorer is yet able to discern that the ancient sea along whose floors these mica-schists, gneisses, and quartzites were deposited as muds and sands was not a lifeless area, but was tenanted by lowly creatures after their kind. The only solitary known fossil from the altered limestones of the Laurentian formation the Eozoon is suffi- cient to prove this. And from the occurrence of this lowly-organized creature up to the present, we never afterwards lose sight of the graduated life-scheme recorded in the rocks ! There is many a difficult chapter to spell out, many a leaf missing, but there is still sufficient left to interpret the stony scroll. Above the Laurentian system lies the Cambrian. But we should remember that this classification of the rocks into formations and systems is, at the best, but a harsh and forced one a remnant of the time, not long ago, when men believed there were distinct creations and destructions of separate faunas and floras. Geological and, in fact, all natural history classification is but an arbitrary arrangement to enable the human mind, in its faintness, to grasp and arrange the multitudinous facts presented to it. In reality there is no separation of geological systems, but more or less of a graduation of one into another. The world's biography is like a man's, not like a butterfly's, consisting of metamorphosed states, each unlike the other, and definitely separated from it. In the Cambrian formation, we find that life, which had begun, as it were, from a point, was radiating like EETKOSPECT. 277 the rays of light from a focus. Here we find the lowest order of shell-fish (brachiopods), worms, and, towards the later period, Crustacea. But it is in the Silurian system that we find the stream of life broadening out. The seas are full of coral-reefs, bivalve and univalve shells, huge Crustacea, tolerably highly-endowed Trilobites, &c. At the close of the formation, we came on placoid fishes, the first vertebral types. Thus we find a lateral development of species, in size, and a vertical one in organization. Then comes the Devonian, or Old Bed Sandstone epoch, whose seas abounded in strangely-clad and gigantic ganoid fishes, and whose deeper waters were busy with the manifold com- plexities of marine life. The dry land was scantily covered with a thin vegetation of a cryptogamous type, or of the lowliest of the exogens. Great fresh- water lakes existed, set in beautiful frameworks of tree-fern and huge club-moss. But it is when the Carboniferous era commences that we find abundant evidence of a dense flora, although one of a very lowly kind. Every foot of dry land, where the circumstances were favourable, seems to have been densely covered with forests, the trees of which now find their nearest allies in our " Horse-Tails " and club-mosses. Enormous Sigillaria, Lepidodendra, and tree-ferns constituted this vegetation, whilst there was no lack of species of Conifera. In the Carboniferous limestone period, which immediately preceded that of the coal measures, we have ample 278 RETROSPECT. evidence of seas in which life was very abundant, where floors were covered with thick submarine forests of sea-lilies, and which had numerous colonies of brachiopodous shells. Cephalopods, such as Ortlw- ceras, Nautilus, and Goniatites, abounded, and thus the huge thickness of limestone rocks grew out of their accumulated remains. The fishes were bony-plated, and, in the structure of their teeth, many of them showed decided reptilian affinities. It was in the waters of the Carboniferous seas that the first reptiles appeared, as the Archsegosaurus a creature belong- ing to the lowest order of reptiles, the amphibia. It exhibits decided affinities to the fish, as the ancient fish do to the reptiles. In the Permian epoch, geologically brief though it was, the physical geography seems to have been varied. Here we have evidence of a cold climate, and of glacial conditions, during which the "breccias" were formed. Eeptiles of a higher class abounded, and these are now known as Thecodonts. With the close of the Permian, we have the termination of the Primary, or Palaeozoic division of geological time. The Triassic epoch, or that of the New Bed Sand- stone, offers to us fresh scenes and new creature forms. Huge frog-like reptiles abounded, and left their numerous foot-prints on the soft muds. In the deeper seas, new species of sea-lilies grew, and new forms of cephalopods, such as Ammonites and Bdemnites, existed side by side with the old-world RETROSPECT. 279 forms, that were now rapidly dying out. Thus the Triassic limestones of Germany are as crowded with organic remains as the mountain limestone of Derby- shire. Elsewhere, the dry land was covered with saline lakes, or " Dead Seas," along whose floors Eock-salt was deposited. In America, the first birds appeared, whilst at the close of the Triassic era in Europe we have distinct and sure proof of the first introduced mammals. The latter belong to the group which all naturalists have by common consent placed at the bottom of the sub-kingdom mammalia. Thus it will be seen that the order in which the new groups of animals appeared on the stage of creation, is also that which we have ourselves arranged, more or less, as that of true succession. With the Lias, we have the commencement of that " Age of Eeptiles " which well deserves the name. New forms of cephalopods appeared, the Ammonites literally swarming in the seas, and actually forming limestones by their accumulated remains. New and complete species of sea-lilies grew on the ancient ocean-floors new plants, cycads and zamias, as well as complex- veined ferns, on the dry land. But the chief animal forms which strike the eye are the reptiles modified then to every condition of life, as we find the mammalia are now. As Ichthyosauri and Plesiosauri they were the tyrants of the deep ; and as Pterodactyles they winged the air like bats, their size being often bigger than that of any exist- ing bird. During the succeeding Oolitic period, 280 EETROSPECT. huge reptiles lived on land, such as the Megalosaurus, Hylteosaurus, and Iguanodon. Some of the reptiles walked on two legs, like the modern kangaroo, and were decidedly allied to birds. The first known European bird now put in an appearance, its feathers and bones having been found in the Solenhofen slates. It had a long vertebrated tail like that of a lizard, feathered down to its tip. In other respects also it possessed reptilian affinities. Mammalia abounded, but still as marsupials, although there had been a division into herbivorous and carnivorous species. We have evidence of great fresh-water lakes, along whose floors thick beds of limestone were formed by the slow accumulation of Paludina and other fresh-water shells. A great river watered a great continent, and at its mouth was formed a Delta, since known as the "Wealden formation. Out in the blue sea, coral reefs fringed the rocky coasts ; bony-plated fishes and sharks were in plenty, some of the former living on the mollusca. Then comes that period of great depression when the chalk strata were formed along the floor of a very deep sea, as its organisms plainly prove. For this white chalk is chiefly made up of shells so minute that the naked eye cannot perceive them. Many of the same types of marine creatures still lived, reptiles, brachiopods, and cephalopods. Echin- oderms were more abundant than ever, and their remains are to be found in every chalk quarry. A peculiar reptile, the Mososaurus, lived in the deep RETROSPECT. 281 sea, and was a most formidable animal. The sea-bed produced dense crops of sponges, great and small, some of them of as ornate a character as the recent " Venus' Flower-basket." On the dry land, towards the close of the period, there appear for the first known time trees of a higher order, such as the Oak, Walnut, and Elm. Thus came to a close the Secondary or Mesozoic division of geological time, during which we have seen animal and vegetable forms attaining higher and complexer organizations. The last, or Tertiary epoch, commences with the Eocene beds, in which warm-blooded animals appear so common, that the Tertiary has been not unfitly called " the Age of Mammals." Many of these mam- mals united characters which since then have been distributed among half-a-dozen later animals. In fact, nearly all the Eocene and Miocene mammals are veritable " Missing Links ! " We have, in the former period, evidence of at least a sub -tropical climate in Britain : palm-trees, tree-ferns, &c., grew abundantly. The seas had what we now regard as sub-tropical shells, Typhis, Volutes, Cones, &c., living in them, as well as turtles, sharks, sword-fish, &c. In the rivers, gavials and crocodiles wallowed. To- wards the close of the Eocene, monkeys made their appearance in English woods ; whilst in the Miocene period, they swarmed in several species all over Europe, one of them, singularly enough, being more anthropoid, or " man-like," than any now in existence. Extensive forests of warm temperate plants grew all 282 RETROSPECT. over the northern hemisphere during the Miocene age ; and there does not seem to have then been any ice-cap at the North Pole, for these virgin forests grew in Iceland, Greenland, and Spitzhergen. Ele- phants and mastodon, camels and giraffes, deer and oxen, now made their appearance. Great fresh-water lakes existed in Switzerland, along whose bottoms the decaying vegetation accumulated to form Lignite beds. In central France, Scotland, and Ireland, volcanoes were very active, as the lava sheets plainly prove. In studying the Miocene plants, shells, &c., we come across the same genera as are still in existence, so that the naturalist cannot turn away from the impression that many of our modern species are lineal descendants. In the " crags " of Norfolk and Suffolk, this impression rises to a certainty, for in them we actually do meet with hundreds of species of shells of exactly the same kind as those still in existence. These "crag" beds belong to the suc- ceeding Pliocene period, and they tell us very plainly of a refrigeration, or toning down, of the climature. This indication is fulfilled when we study the beds of the Northern Drift those accumulations of sand, gravel, and clay which occupy the area of the northern hemisphere. These were all formed under glacial conditions, and Europe lay for centuries beneath a thick swathing of land-ice. Arctic plants and Arctic mollusca lived in British latitudes. Our higher mountains sent forth streams of glaciers, KETKOSPECT. 283 which scratched and pounded the solid rocks over which they moved. In British seas icehergs were continually stranding and floating, dropping their burdens of sand and gravel, as well as the huge masses of rock which had been frozen into them. As boulders we frequently meet with these erratics, which had thus been carried miles from their native or parent bed. It was after the elevation of the glacial sea-bed into dry land, when the climate had toned down from its arctic vigour, although still much colder than it is now, that MAN first appeared on the scene. His rude flint implements have been found abundantly in the valley gravels of existing rivers, formed when those rivers had a greater volume of water than they have now. From that distant time to this, we never lose sight of him and his works, and there is exhibited in his history a similar development, or elevation, from a lower to a higher stage, to that which we have seen marking the lower animal and vegetable kingdoms in their appearance on the platform of existence. But it does not follow that because we can plainly trace the mode in which Deity has chosen to operate, that therefore He has been superseded by His own laws. Rather, it brings Him awfully near, for in the constant regulating and leading upwards of the organic world we never escape His presence ! ( 284 ) APPENDIX. In the foregoing pages frequent reference has been made to geological systems, formations, and divisions, besides the employment of other technical terms. We have therefore given, at the end, the following Table of the British Eocks, from the Catalogue of the School of Mines, Jermyn Street. THE following TABLE shows the Succession of the British Formations, beginning with the newest Strata. TABLE OF BRITISH FORMATIONS. f Brown Sand of various ages. I 'Alluvium I Peat |Raised Beaches Cave Deposits I Valley-, or Low-level Gravel. 1 1 Brick Earth High-level Gravel) and Glacial Drift > of various ages. (Till and Boulder Clay) (Cave Deposits. Norwich Crag. Red Crag. Coralline Crag. ( Leaf Bed of Mull. \ Lignite of Antrim. ( Bovey Beds. APPENDIX. 285 TABLE OF BRITISH FORMATIONS. | . CorbulaBeds ^ T I Hempstead pfj Upper Freshwater and Estuary Marls g r rJeas. Middle n 8 ' Lower S 1 p Bembridge Beds. t Bembridge Marls t Limestone .... Osborne ( St Helen's Sands ? < Beds i Nftttlfiatonft Grita i' 3- w I Headon Beds Upper Headon Beds r H W w Lower , OR TEB' 1 Bagshot Beds Upper Bagshot Sand. Mi,Mlp /Barton Clay. M!ddle JBracklesham Beds o Lower Sand and Pipeclay. o N; O S3 S (London Clay and Bognor Beds. , Woolwich and Beading Beds (Plastic ^ Q 8 1 Clay). 3 I I'-'W [ Thanet Sands. 5 f (Upper Chalk. . Lower ^ p Chalk Marl. Q. Chloritic Marl. g ' PH <^ P ! Upper Greensand. Q Gault. .. S ri o ( Folkestone Beds. 00 t Lower \ Sandgate Beds. Greensand. 1 Hythe Beds (Kentish Bag). (AtherfieldClay. 2 Q QJ N 1. Weald Clay. g 1 Upper Tunbridge Wells Sand. Grinstead Clay. ~ 1 1 j Hastings fe Sand. Lower Tuubridge Wells Sand. Wadhurst Clay, Ashdown Sands. ( \ ( \Ashburnham Beds. 286 APPENDIX. TABLE OF BRITISH FORMATIONS. . 1 Purbeck . Upper Purbeck Beds. Middle Lower I [ Portland Stone. Portland . \ Sand. [ Kimeridge Clay. f Coralline |o Oolite. Upper Calcareous Grit. Coral Rag. Lower Calcareous Grit. [2 -3 i * I fw*-j m / Oxford Clay and I 0xfordCla y \Kellaways Rock. j Forest Marble Cornbrash. Forest Marble and Bradford Clay. p d o 1 Great Oolite Great or Bath Oolite. Stonesfield and Collyweston Slate and Northampton Sands. MESOZOIC OR SE Lower Oolite. Fuller's Earth. Inferior Oolite. Upper Fuller's Earth. Fuller's Earth Rock. Lower Fuller's Earth. Ragstone and Clypeus Bed. Upper Freestone. Oolite Marl. Lower Freestone. Pea Grit. Upper Lias { L ^ s ^ Jnd Shale. J Middle Marlstone. Lower Lias Clay, Shale, and Limestone. . 1 Koessen Bed.^^* r We8tbury Beds - H 1 ( Red Marl and Upper Keuper Sandstone. Keuper . { Lower Keuper Sandstone and Marl ( (Waterstones APPENDIX. 287 TABLE OF BRITISH FORMATIONS. r r Bunter Muschelkalk, absent in Britain. St. Caseian Beds, Dolomitic Conglomerate (of Keuper or Bunter age, Somerset and Glou- cester). Upper Red and Mottled Sandstone. Pebble Beds. Lower Red and Mottled Sandstone. (Upper Red Marl. Upper Magnesian Limestone Lower Red Marl .... . Lower Magnesian Limestone | Red Marl, Sandstone, Breccia, and ( Conglomerate (Rothe-liegende). Zech- stein. Coal Carboniferous Limestone. SCOTLAND. ENGLAND. Upper Coal Measures. Middle Pennant Grit. Lower Coal Measures Gannister Beds. Millstone Grit ) MOOT Rock (Farewell Rock)./ ! k ck< Upper Limestone) Shale (Yoredale | Upper Limestones, Rocks). J-Edge Coals Series, Carboniferous I Lower Limestones. Limestone. ) T,owor slonel Sandstones, Shales, and urdie House Lime- Upper Devonian and Petherwin Lime- stone. Middle Devonian Limestone and Corn- stones. Lower Devonian. 288 APPENDIX. TABLE or BRITISH FOBMATIONS. Tilestone. Upper Ludlow. Ludlow . Aymestry Limestone. Lower Ludlow. jj IWenlock Limestone. I- Wenlock Shale, Sandstone, and Flags. Woolhope Limestone. Denbighshire Grits, Shales, Slates, and s Flags. *s ^ p 3 Tarannon Shale (Pale Sktes). 1 i .... Upper Llandovery Rock. (May Hill Sandstone). (Pentamerus Beds). g . Lower Llandovery Rock. PH I Caradoc or Bala Beds. g 1 Upper Llandeilo Flags and Limestone, O Llandeilo . &c. 1 i Tremadoc Slates. % * Lingula Beds. 3 Harlech Grits, &c. PH i Cambrian . Purple Slates and Grits (St. David's). Llanberis Grits and Slates. Longmynd Rocks. a Red Sandstone and Conglomerate (Scotland). Gneiss of the Lewis, &c. The above table, it will be seen, has reference to what are called " typical " sections of the different formations that is, to those exposures of rocks which have been most studied and are best known. Hence many of the names of the for- mations and groups are more or less local, as this was the APPENDIX. 289 only available manner of naming the sub-divisions when geology was a young science. It may seem absurd to speak Fig. 173. Illustrations of " Anticlinal " strata. of " Devonian " (or Devonshire) rocks in America, for instance, as we are forced to do by this method of nomenclature ; but, after all, it is not more singular than to call the language spoken in the United States English. The following terms are largely used in every work on geology, even the most elementary, and, as they cannot well be avoided, perhaps it will be desirable to give a short ex- planation of them. STRATUM (from the Latin word meaning Illustration of " Synclinal " strata. to strew or spread out) means a single bed of rock, sand, gravel, or clay. When rocks, therefore, lie in parallel layers, they are'said to be stratified; and when there is no appear- ance of such arrangement, they are termed unstratified STEATA is the plural of STRATUM. A geological FORMATION u 290 APPENDIX. means an assemblage of rocks which have some character in common, either of age, origin, or composition. Usually such rocks are grouped together into a system by having a great number of fossils common to them. Both in the use of this word, and SYSTEM, however, there is a great deal of looseness. The latter signifies groups of strata which have intimate relations to each other, generally in the order or sequence of their deposition. EPOCH is a word frequently used to express a particular division or period of geological time. It is, therefore, employed as being almost synonymous with " Age " or " Era." By the term CONFORMABLE, is meant that the strata lie in Fig. 175. Illustration of " Dip " of strata. parallel order, one above another. When this is not the case, but when one set of strata, for instance, lies on the upturned edges of the lower, the two are said to be UN- CONFORMABLE. Unconformability is generally regarded as a proof of a break in the order of deposition, and therefore of a period of time, sometimes very great, having elapsed in the interval of the formation of the two groups of rocks. By the DIP of a rock is meant the angle or inclination at which the strata slope. This is always measured from the level of the horizon. The opposite of DIP is EISE a word much in use among coal-miners. They both mean the same thing, only Dip has reference to the position of the observer standing at the surface, who sees the rock sloping away from APPENDIX. 291 him whereas when standing, say at the bottom of a coal- pit, and looking at the same bed, he sees it rising. Another frequent word, and one that often causes much trouble t the young geologist, is STRIKE. It means the direction, or line of outcrop, of any stratum. The STRIKE is said to be always at right angles to the dip. The best way of illus- trating the difference is by supposing the reader to be on the roofs of a row of cottages. Then the ridge running in their length would represent STRIKE, or extension, whilst the sloping of the tiles on either hand would illustrate the dip. We have already used the term OUTCROP, and the reader will have little difficulty in understanding what it means. It signifies that part of any inclined stratum of rock which comes to the surface of the ground. Sometimes, if the rock be hard, it thus forms more or less steep cliffs. Hence, whenever a rock thus comes to daylight, it is said to " crop out." it; With these few words of explanation for the benefit of the young and unsophisticated student, we bid him " God-speed" to a study which cannot fail to give him health and strength, both of body and mind ; or lead him to a wider and broader knowledge of our old world, and of the POWER whose wisdom and love have nursed it from the earliest times ! ( 293 ) INDEX. Acidaspis, 51. Acrodus, 138. Actlnocrinus, 93. Mchmodus, 138. Agates, 17. Age of Reptiles, 132. Aleutian islands, 209. Alum Shales, 128. Alumina, 5. American types, 212. American animals, 219. Amethyst, 17. Ammonites, 141, 142, 143, 144, 145, 157, 183, 187. Amphibia, 164. Amygdaloid, 1. Ananchytes, 183. Annularia, 111. Anodon, 75, 76. Anodonta, 75. Anonas, 198. Anoplotherium, 200. Anthracotherium, 201. Antrim beds, 214. Appearance of man, 252. Araucarian pines, 130, 161. Arch;v(]osaurus, 86, 87. Archseology, 271. Archxopteryx, 164, 165. Arctic flora, 249, 252. Arctic Ice-cap, 215, 221. Arctic mollusca, 244. Arencolites, 31. Argillaceous rocks, 25. Astartes, 225. Asterolepis, 67. Atlantic mud, 179. Atrypa, 54, 55. Ancyloceras, 187. Avicula, 145. Aymestry limestones, 48. Baculites, 188. Bala limestones, 46. SanJcsia, 213. Basaltic columns, 214. Basaltic rocks, 46. Basaltic dykes, 214. Bath Oolite, 150. Batrachians, 124. Beaked saurian, 124. Selemnites, 141, 145, 158, 184, 185. Sellerophon, 35. Birds' nests, 162. Black-lead, 20. Bovey Tracey lignite, 213. Boulder, 238. Boulder clay, 244, 255. Box-stones, 236. Brachiopods, 33, 71, 91, 144. 294 INDEX. Bracklesham sands, 195. Cleavage, 25. Breccias, 249. Clinkstone porphyry, 5. Brixham cavern, 265. Club-mosses, 57. Brontes, 72. Clymenia, 62, 72. Bronze period, 269. Coal, 79. , Brown coal, 207. Coccoliths, 179. Bryozoa, 225. Cockles, 185. Buccinum, 233. Comatula, 138. Bulimina, 170. Compsognathus, 163, Bunter sandstone, 116. Conclusion, 291. Cones, 202. Cairngorm, 17. Coniferous trees, 112. Calamites, 81, 83, 84, 104, 105, 107. Contorted rocks, 27. Calceola, 60. Coprolites, 229. Cambrian rocks, 24. Coralline crag, 223, 224, 226. 233. Camels, 219. Corallines, 49. Camphor-trees, 212. Coral Bag, 150. Caradoc sandstones, 46. Coral-reefs, 53. Carboniferous, 80. Cornbrash, 150. Carboniferous limestone, 90, 96. Cosmical hypothesis, 2. Carboniferous forests, 106. Crags, 222. Carcharodon, 202. Cretaceous formation, 80. Cardita, 224. Cretaceous sea, 169, 179. Cassidaria, 225. Crinoids, 92. Casts, 35. Cristellaria, 176, 178. Cave Tiger, 235. Crystals, 17. Cephalaspis, 68. Ctenoid fish, 185. Cephalopoda, 35. Cuttle-fish, 35. Geratites, 118. Cyathophyttum, 73. Chteropotamus, 201. Cycads, 161, 162. Chain-coral, 54. Cycloid fish, 185. Chalcedony, 17. ' Cyclopteris, 74. Chalk, 167, 181, 190. Cyprea Europea, 228. Chalk foraminifera, 167. Cyprina, 224. CJteirotherium, 124. Cyrtoceras Murchisoni, 48. Cheshire meres, 122. Cystideans, 33, 53. Chipped flints, 263. Cidaris, 152, 184. Dapediug, 138. Clay, 193. Dartmoor granite, 213. Claystone porphyry, 5. Dawn-animalcule, 18, INDEX. 295 Dead Sea, 120. Dead shells, 173, 174, 177. Deer, 218. Deinosauria, 162. Deinotheria, 218. Deltas, 216. Dendritic crystals, 8, 9. Dentalina, 167, 168. Denudation, 12. Devonian rocks, 62. Diclwlune, 201. Dicynodonts, 127. Diluvium, 238. Dirt-beds, 161. Downton sandstones, 48. Dryandroides, 213. Dryopitliecug, 218. Dudley strata, 45. Earthquakes, 189. Echinodermata, 183. Emarginula, 228. Encrinites, 117. England joined to continent, 249. English chalk, 168, 169. Elephants, 231, 235, 249. Eocene, 80, 194, 195, 202, 209. Eozoon, 18. Etna, 237. Eucalyptocrinus, 93, Euomplialus, 53. Eurypterus, 66. Evergreen plants, 212. Excess of salt, 121. Extracrinus, 138, 141. Fairy loaves, 183. Fan palms, 213. Fascicularia, 225. Faults, 113. Favosites, 54, 72, 73. Feather-star, 138, Felspar, 3. Felspar porphyry, 5. Fig-trees, 213. Flabellarias, 213. Flabellina, 111, 178. Flint, 17, 180, 18L Flint arrow-head, 264. Flint bands, 180. Flint cores, 266. Flint implements, 260, 261, 265, 267. Flint nodules, 180. Flying lizards, 161. Foldings of rocks, 26. Foot-print impressions, 119. Foot-prints of birds, 125. Foraminifera, 167, 168, 169, 170, 171, 172, 173, 174, 175, 176, 177, 178. Forest bed, 234, 235, 241. Forest marble, 150. Formation of lakes, 251. Fossil animalculse, 175. Fossil butterflies, 216. Fossil caddis worms, 216. Fossil corals, 71, 225. Fossil eggs, 163. Fossil feathers, 165. Fossil ferns, 106, 131. Fossil ferns, 211. Fossil flora, 211. Fossil flowers, 211. Fossil fruits, 197. Fossil insects, 216. Fossil Oolitic wood, 160. Fossil pitch, 129. Fossil tree fern, 109. Fossil turtles, 203. 296 INDEX. Four-homed deer, 219. France, Central, strata m, 216. Free-stone, 61. Fresh-water lakes, 215. Frondicularia, 168, 177. Fucoids, 61. Ganoid fishes, 66, 198. Gasteropoda, 35. Gaudryina, 169. Gault, 187. German Ocean, 233, 241. Giraffe, 219. Glacial beds, 232, 255. Glacial boulders, 239. Glacial period, 194, 239, 259. Glaciers, 242, 244, 245. GloMgerina, 173, 174, 176. Glutton, 249. Gneiss, 18. Gold, 57. Goniatites, 90. Granite, 4. Granite of Cornwall, 10. Granite of Scotland, 10. Granite nucleus, 12. Granite bosses, 27. Graptolites, 40, -49, 50. Gravel pit, 254, 272. Gravels, 259. Greek fable, 272. Greenland lignite beds, 214. Greenland ice, 243. Growth of civilisation, 271. Gryphea, 144, 153. Gulf-stream, 245. Gypsum, 119. Gyroceras, 90. Hafted stone celt, 270. Hairy rhinoceros, 249. Hamites, 188. Halysites, 54. Harlech grits, 30. Headon series, 195. Hearts, 183. Heliolites, 72. Hipparion, 219. Hippodium, 145. Hippopotamus, 218. Homanolotus, 72. HoloptycMus, 68. Hornblende, 3. Horse-tails, 103, 104. Hybodus, 138. Hysenodon, 201. Hyl&osaurus, 187. Hymenocaris, 33. Ice action, 249. Icebergs, 243. Iceland lignite beds, 214. Iceland, fossil plants in, 214. Ice-sheet, 250. Ichthyosaurus, 132, 133. 134. Ichthyocrinus, 93. Ideal landscape of Triassic period, 114. Ideal landscape of Oolitic epoch, 147. Ideal landscape of Oolitic epoch, 206. Ideal landscape of Quaternary period, 254. Iguanodon, 187. Illxnm, 52. Inferior Oolite, 150. Influence of earth's heat, 23* Irish elk, 250, 251. Iron age, 269. INDEX. 297 Iron-stone, 156. Japanese Islands, 209. Jasper, 17. Jet, 128, 149. Joints, 26. Jordan river, 121. Jura Alps, 165. KAOLIN, 4. Kelloway rock, 150. Kent's cavern, 265. Keuper beds, 116, 119. Keuper sea, 121. Kilkenny sandstones, 74. Kimmeridge clay, 150. King-crab, 49. Labyrinthodonts, 86, 124, 125. Lake Dwellings, 269. Lamp-shells, 144. Land ice, 242. Landscape of Carboniferous period, 78. Last active volcanoes, 214. Laurentian, 17. Lava, 9. Leiodon, 185. Lemming, 249. Lepidodendron, 75, 82, 84, 85, 99, 103. Lepidosteus osseus, 66. Lepidostrobus, 82, 99. Lcpidotus, 138. Leptsrna, 55. Liassic formation, 80, 128. Lignite beds, 201, 207, 211. LHy encriflite, 117. Limpet shells, 229. Limestone, 37. Lingula, 33. Lingula flags, 30, 33. Lingula Lewisii, 45, 55. Lituola, 177. Llandeilo flags, 46. London clay, 194, 229. Long-armed monkey, 220. Longinynd rocks, 31. Lower Cambrian, 31, 32. Lower Cretaceous, 188. Lower green sand, 187. Lower Oolite, 150. Lower Silurian, 47. Ludlow beds, 48. Ludlow bone-bed, 57. Lump of clay, 193, 196, 197, 198. Machairodus, 218. Mactra, 230. Magnesian limestone, 115. Magnolias, 213. Mammoth, 248, 263. Man's appearance, 252, 259. Mastodon, 217, 218. Marginulina, 168. Marsupials, 126, 131. May Hill sandstones, 47, 52. Mechanical origin of rocks, 25, 38. Megalichthys, 97. Megalodan, 72. Megalosaurus, 163, 187. Metal lodes, 57. Metamorphic rocks, 18. Meteorological agencies, 38. Mesozoic epoch, 117. Mica, 3. Mica schist, 10. Micraster, 183. Microlestes, 126, 127. Microscopic section, 180, 181. 298 Microscopic structure of fossil Norwich Crag, 223, 230, 234, 241. wood, 112. Nummulites, 195, 196. of coal, 112. Middle drift, 255. Obolus, 55. Middle Silurian, 47, 52. Older Pliocene, 223. Middle Oolite, 150. Oldhamia, 32. Minute fossils, 177. Old Red Sandstone, 62, 70. Miocene, 80, 206, 208, 210. Onehus, 69. Miocene forests, 210. Oolitic animals, 166. Miocene plants, 211. Oolitic period, 80, 149. Missing links, 163, 165, 201, 219. Oolitic strata, 160. Mitres, 202. Ophioderpeton, 86. Moel Tryfaen, 245. Opossum, 218. Molasse, 209. Orthis, 55. Monkeys, fossil, 217. Orthoceratites, 35, 49, 90. Mososaurus, 185, 186. Osmunda, 75. Mountain-chains, 11. Osteolepis, 68, 69. Murchisonia, 52. Oxford clay, 150. Muschelkalk, 116, 118. Oysters, 236. Muskdeer, 249. Mussels, 236. Paleolithic flint implements, 266. Mya, 231, 232. Palaeolithic period, 263. Mylodon, 222. Pateoniscus, 98. Pateopterls, 74. Natica, 228. Palxopyge, 32. Nautilus, 53, 141, 143, 202. Palxotheria, 198, 199. Neocomian beds, 187. Palaeozoic brachiopods, 55. Neolithic implements, 264, 267. Palaeozoic Encrinites, 93. Neptunian controversy, 2. Paludina, 153, 155. Neuropteris, 106. Paradoxides, 34. Newer Stone age, 266. Paramoudra, 182. New Bed Sandstone, 116, Parlda, 65. Nipadites, 197. Pebbles, 256. Nodosaria, 167. Pecopleris, 109. Norfolk cliffs, 244. Pecten, 53. Norfolk forest-bed, 234. Pectunculus, 224, 22$. North Atlantic, 145. Pegmatite, 5. Northern drift, 239. Pentacrinus, 139. Northern shells, 231. Pentamerus, 53, 54, 55. Norway spruce pine, 234, 242. Pentremites, 95. INDEX. 299 Percolation, 35. Permian breccias, 115. Permian formation, 115. Petroleum, 41. Phillipsia, 92. Phlebopteris, 156. Phosphates, 21. Phosphate of lime, 188. Phosphatic nodules, 229. Phragmacones, 184. Piece of chalk, 167. Pilton group, 71. Pitchstone, 8. Placoid fishes, 69. Plagiostoma, 145. Planorbis, 153, 230. Platijcrinus, 83. Pleistocene, 231. Plesiosaurus, 132, 135. Pliocene, 80, 215, 223, 226, 236, 237. Pliopithecus, 218. Plumbago, 20. Plutonic controversy, 2. Polished Celts, 269. Polypothecia, 180, 181. Porphyrine (artificial), 9. Porphyry, 5. Portland Stone, 150. Pot-stones, 182. Primary rocks, 15. Primitive rocks, 6. Producta, 54, 115. Proteacea, 213. Protogine, 5. Protozoic rocks, 28. Psilophyton, 75. Psychometry, 59. Pterichthys, 67, 68. Pterodactyl**, 132, 136, 137, 155. Pterophyttum, 131. Pterygotus, 65. Purbeck marble, 146, 153, 159. Purbeck series, 150. Pyrula, 225. Pyrulina, 168. Quartz, 3, 14. Quartz crystals, 7. Quartzite, 16. Quaternary, 80. Bain-drop pittings, 119. Eed Crag, 223, 229, 230, 241. Eed Crag, shells of, 229. Reindeer, 249, 266. Reindeer period, 266. Reptile-like birds, 164. Restored Belemnite, 185. Restored Calamites, 107. Restored Lepidodendron, 99. Rhsetic formation, 126. Rhinoceros, 234, 236, 249. Rhodocrinus, 93. Bhynchonella, 54, 145, 184. Mhynchosaurus, 124. Ripple-marks, 31, 32, 89, 119, 154. River-gravels, 255. EosteUaria, 202. Rock-oil, 41. Rock-salt, 115. Posalina, 172. Rotalina, 173, 175, 177. Sagenaria, 75. Sagrina, 174. Sahara sea, 251. Salisburia, 215. Sandstone, 58. Scales of Carboniferous fish, 98 300 ScapMtes, 188. Sea-urchins, 183. Section of fossil wood, 103. Segregation of metals, 57. of minerals, 57. Semnopithecus, 218. Sequoias, 213. Sewalik hills, deposit of, 219. Sharks, 185, 203. Sicilian beds, 236. Sigillaria, 84, 85, 102, 103. Silica, 3, 17, 179, 181. Silurian rocks, 39. limestones, 41, 45. Single corals, 95. Siphuncle, 143. Sivatherium,219. Slate rocks, 24. Smilax, 212. Spiculse, 182. Spin/era, 54, 55, 72, 91, 144. Spirorbis, 84. Spondylus, 185. Stalactite, 265. Stalagmite, 265, Star-fish, 53. Stauria, 71. Stone Celt, 270. . Stonesfield slate, 150, 163. Stringocephalus, 72. Stromatopara, 72. Strophomena, 54, 55. Structure of Pentremites, 96. Sub-tropical climate, 190. Suffolk strata, 223. Sun-cracks, 32, 89, 119, 120. Sun-corals, 72. Tapiroid animals, 199. Tapirs, 218. Tarannon shales, 47. Taxocrinus, 93. Teeth of Carboniferous fish, 9S. TeUina Balthica, 244. Tellina crassa, 228. Temne-chinus, 224. Temperature of Miocene Period, 209. Terebella, 202. Terelratula, 54, 145, 151, 184. Ten-aces, 255. Terraced hills, 256, 257. Tertiary epoch, 191, 194. Textularia, 169. Thtca, 34. Thickness of lias, 130. Thunder-bolts, 144, 145, 158, 184. Topaz, 17. Tortoise, huge, 219. Transition rocks, 18. Transverse section of calamite, 83. Transverse section of fruit of ca- lamite, 105. Tree-apes, 218. Tree-ferns, 105. Trias, 116. Triassic Period, 114. Trigonia, 154. Trilobites, 34, 40, 41, 49, 51, 72. Trogontherium, 235. Truncdtulina, 171. Turrilites, 188. Turritella, 195. Turtles, 203. TypUs, 202. Unconformable rocks, 22, 119. Upper Crag, 233. Upper Eocene, 204. Upper green sand, 188. INDEX. 301 Upper Oolite, 150. Upper Silurian, 48, 53, 54. Valley-gravels, 255, 263. Vancouver's Island, 209. Yerneuilina, 170. Vertebrata, 54. Vertical section of calamite, 81. Vertical section of fruit of calamite, 104. Volutes, 202, 226. Wart-hogs, 218. Wealden strata, 186, 187, Wenlock group, 48. Wenlock limestones, 42, 48. Wentle-traps, 230. White whelk, 233. Woolhope beds, 48. Woolly-haired elephant, 263. Woolly-haired rhinoceros, 263. Worm-tracks, 32. Zamias, 161. Zaphrentis, 72. THE END. c--~ ."-A/Wv UTHERN REGIONAL LIBRARY FAC 000 639 766 5 SX^AWWWM &$to^%M ^X,..*^i*^**&0 $JW 0?