IN MEMORIAM 
 George Davidson 
 1825-1911 
 
 
 Professor of Geography 
 University of California 
 
ELEMENTS OF GEOLOGY, 
 
 FOR THE 
 
 USE OF SCHOOLS AND ACADEMIES. 
 
 BY PROF. WM. W. MATHER, GEOLOGIST. 
 
 FOURTH EDITION, 
 
 NEW YORK: 
 
 CLEMENT & PACKARD, 
 
 180 PEARL STREET. 
 
 And sold by the principal Booksellers in the 
 
 United States. 
 
 1841. 
 
/ ' ** I 
 
 Entered according to Act of Congress, in the year one 
 thousand eight hundred and thirty-eight, by WILLIAM W. 
 MATHER, in the Clerk's Office of the District Court of the 
 United States, for the Southern District of New York. 
 
 Stereotyped by Smith & Wright, 
 216 William-st., New-York. 
 
rj 
 PREFACE TO THE FIRST EDITION. 
 
 THE object of the following pages, is, to exhibit a concise sketch of 
 Geology for the use of Academies and the higher classes in primary 
 schools. It is desirable that the community should be familiar with 
 the leading facts of this science, that they may be enabled to apply 
 them to the various economical purposes of life. Every science is 
 valuable to the community, in proportion as the knowledge of its 
 facts and applications, is disseminated among the mass of the people. 
 As the number of observers increases, more facts will be accumula- 
 ted, and the resources of the country developed. 
 
 Young men preparing for college should acquire a knowledge of the 
 elementary principles of geology ; and in their collegiate course, the 
 study might then be carried much farther than it is at present. Inde- 
 pendent of the practical utility of this science, it furnishes a constant 
 source of amusement, or pleasant occupation, in journeying over 
 tracts of country that would otherwise be perfectly uninteresting. It 
 even offers an inducement for the exercise of walking and travelling 
 to those who would otherwise be too sedentary in their habits. 
 
 In the arrangement of the subjects, Bakewell's Geology has been 
 followed with few exceptions. The works employed in the compila- 
 tion of this work were Bakewell's Geology, edited by Professor Siili- 
 man ; Conybeare & Phillips' Geology ; De La Beche's Geology ; Ea- 
 ton's Geological Text Book ; Cleaveland's Geology ; Greenough's 
 Geology ; Silliman's Journal ; Journal of the Academy of Nat. Sciences 
 of Philadelphia ; Annals of the Lyceum of Nat. History of New- 
 York ; Maclure's Geology ; American Philosophical Transactions ; 
 Philosophical Transactions of the Royal Society of London ; Jour- 
 nal of the Royal Institution of Great Britain, and Edinburgh 
 Journal of Science. When quotations are made without refer- 
 ence, they are from the American edition of Bakewell's Geology, edi 
 ted by Professor Silliman, and containing a sketch of his course of 
 Lectures in Yale College. The author has introduced some things, 
 for which he alone is responsible, and derived from his own observa- 
 tion. The organic contents of the " superior rocks" have befin but 
 casually touched upon, as a more extended course is required, to en- 
 able one to distinguish strata by their organic remains. 
 
 This little work is a sketch of the author's public course of instruc- 
 tion in geology ; during the progress of which, its principles are illus- 
 trated by references to American localities, and by visiting those lo- 
 calities when practicable. 
 
PREFACE TO THE SECOND EDITION. 
 
 Since the publication of the first edition of this little work, a multi- 
 tude of facts has been collected by the various persons engaged in 
 geological investigations in Europe, the United States, and other parts 
 of the world ; but none, it is believed, tend to modify, in any material 
 degree, the elementary principles of geology. Some new theoretica* 
 views have been brought forward in the geological reports of the 
 several States, more or less strongly supported by facts, and many new 
 facts have been observed in the United States connected with econo- 
 mical as well as scientific geology ; but these are not introduced, as 
 this little book is intended only to give a sketch of the elements of 
 geology, and a few facts as illustrations of the principles of that 
 science. 
 
 Many works on geology, or containing geological memoirs, have 
 been used in the compilation of this work, in addition to those men- 
 tioned in the preface to the first Edition ; but it is believed that credit 
 has been given to the authors, by reference when their names were 
 known. 
 
 For the last six years the author has been occupied during a large 
 portion of the time, in making geological explorations in the employ- 
 ment of the U. S., of several of the States, and of individuals. 
 
 The people are now beginning to realize the economical value of a 
 knowledge of the materials that form the surface or the substrata of 
 their lands, as is evident from the geological surveys that are now in 
 progress in more than one half the States of the Union. These sur- 
 veys are of great practical utility to the people as a mass, and to 
 many individuals in particular. But if a knowledge of the elementa- 
 
 S principles of geology, and of the more common and useful miner- 
 s and rocks were diffused in the community, it is believed that many 
 valuable discoveries would be made. Every man would know what 
 materials were accessible on his land, and to what uses they could be 
 applied. The general diffusion of this kind of knowledge, would al- 
 so tend to destroy the illusions and charlatanism so extensively prac- 
 tised in this country by the designing, and by the Professors of the 
 mineral and divining rods. It is not intended to convey the idea that 
 all who use the mineral rod are impostors ; but that those who are 
 not imposters are their own dupes. 
 
 The geologists of the Several States cannot, in consequence of the 
 great areas, to be examined, and the limited time for examinations, do 
 more than explore particular points, and unravel the general geologi- 
 cal structure of the country. The developement of the minute local 
 geology of each farm, must depend on the individuals owning the pro- 
 perty ; and with the hope that this little volume may aid in diffusing a 
 knowledge so useful to the community, it is now sent on its errand, 
 end may God grant that it may do as much good as its author wishes. 
 
CONTENTS. 
 
 INTRODUCTION. 
 
 Geography and its branches. Physical geography in- 
 eludes geology. Geology definition of. Earth of what 
 composed. Objects of geology. Minerals definition of. 
 Geological alphabet. Veins definition of. Associations of 
 minerals. Rocks, and mineralogical structure of rocks. 
 Granular, crystalline and compact rocks. Mean density of 
 the earth. Indications of high temperature and fluidity of 
 the interior of the earth more caloric radiated than re- 
 ceived mean temperature not changed in 2,000 years. 
 Tropical animals and plants remains of in cold climates. 
 Supposed change of the earth's axis. Impossibility demon- 
 strated rapidity of undulations during earthquakes occa- 
 sional simultaneous action of valcanos increase of tern, 
 perature on descending into the earth. Explanation of the 
 interior high temperature of the earth offered by an Ameri- 
 can writer. Crust of the globe only exposed to observation. 
 Relative thickness actually exposed to observation. . .13 
 
 CHAPTER I. 
 
 
 
 Foundation of geology laid by Lehman, Primitive and 
 secondary rocks. Organic remains, fossils, and petrifactions. 
 Ocean has not always been confined to its present limits. 
 Evidences of this. Conclusions from these facts. Eleva- 
 tion of continents, and evidences. Disruption, contortion, 
 overturned and highly inclined strata. Ancient beaches, 
 
 i* 
 
VI CONTENTS. 
 
 valleys of excavation, and evidences of denuding causes. 
 Remains of animals and plants imbedded in rocks how en. 
 tombed there different from existing species. Strata depo- 
 sited in succession. Period of time to produce the fossilif- 
 erous rocks. Explanation of the term day. Interpretation. 
 Bakewell's views. Geological discoveries consistent with 
 the Bible. Extracts from Buckland's Geology Mantell's - 
 Chalmer's Evidences of the Christian Revelation Sedg- 
 wick's discourse. 25 
 
 CHAPTER II. 
 
 Elementary bodies forming the mass of the globe. Prin- 
 cipal elementary bodies and relative proportions. Slight 
 discussion of these and their compounds. Oxygen, chlo. 
 rine, quantity of salt, and mean depth of the ocean. Hy- 
 drogen, and its uses silicon, sand, glass, carbon, charcoal, 
 mineral coal, and diamond sulphur and its compounds- 
 iron and its combinations oxides, earths, and alkaline 
 earths minerals formed of the above substances 45 other 
 simple bodies known slight description of each. . . 48 
 
 CHAPTER III. 
 
 Geological alphabet, viz. quartz, properties, crystals, 
 quantities, feldspar, constituent of rocks, mica, and uses, 
 hornblende, augite, chlorite, talc, gypsum, limestone, serpen. 
 tine, slate and clay 62 
 
 CHAPTER IV. 
 
 ON STRATIFICATION. 
 
 Rocks regularly arranged. Practical utility of a know, 
 ledge of this arrangement. Dip of strata. Utility of the 
 dip to man. Uniformity of scenery along the line of bear, 
 ing. Change of scenery along the line of dip. Importance 
 of determining the order of superposition. Practical dim". 
 culties. Not generally necessary to bore to determine the 
 
CONTENTS. Vii 
 
 order of superposition. Bearing is known by ascertaining 
 the dip. Outcrop of strata. Thickness of strata how es. 
 timated. Conformable and uncomformable strata. Strati, 
 ficattun of slate and slaty layers. Difficulty in determining 
 the strata planes of slate rocks how obviated. Clays also 
 divided .by parallel seams dependent on some law of nature. 
 Thickness of strata. Bent and contorted strata. Liability 
 to mistake the dip and position of strata. Dip how deter 
 mined. Sources of error in determining the superposition. 
 Seams sometimes mistaken for strata planes. Anticlinal 
 axis, (d.) Strata intersected by valleys. Faults and dykes, 
 and sources of error 72 
 
 CHAPTER V. 
 
 FORMATIONS AND PRIMITIVE ROCKS. 
 
 Definitions of formations. Independent formations. Geo- 
 logical equivalents, and parallel formations. Some rocks 
 not stratified. Rocks traversed by veins. Metallic ores 
 found mostly in veins. Origin of veins. Walls, floor, and 
 roof of veins. Systems of veins. Ages of veins how de- 
 termined. Grouping of rocks into primitive, secondary, &c. 
 Tertiary, diluvion, alluvion, &c. Substitution of other 
 names. Conybeare and Phillips's arrangement. De La 
 Beche's classification. Primary or primitive rocks. Granite 
 porphyritic stratification of other rocks near division 
 seams of. Eurite. Graphic granite. Oxide of tin in gra- 
 nite. Granite as a building material. Gneiss and mica 
 slate. Stratification, and slaty structure of gneiss. Pas- 
 sage of gneiss and mica slate into each other. Talcose and 
 chloritic slate. Hornblende rock, gneissoid hornblende. 
 Augite rocks, and trap rocks. Serpentine rocks, and verd 
 antique. Crystalline limestone. Marbles. Great extent 
 of this rock in the United States. Quartz rock. . ". 84 
 
Vlil CONTENTS. 
 
 CHAPTER VI. 
 
 TRANSITION ROCKS. 
 
 Situation of transition rocks. Organic remains are an- 
 cient records. Ores in transition rocks. Line of demarka- 
 tion between primitive and transition rocks. Slate the 
 lowest of transition rocks. Names of the principal transi- 
 tion rocks. Synonims and varieties of slate. Graywacke 
 and graywacke slate. Red sandstone, new and old. Red 
 sandstone of Connecticut and New Jersey, and its extent. 
 Fossil remains and ores found in this stone. Transition or 
 mountain limestone. Organic remains found in it. Encri- 
 nites. Lead ore in this mountain limestone. Caverns in 
 mountain limestone, and sink holes. Rivers engulphed. 
 Large springs. Hornstone and chert. . . .97 
 
 CHAPTER VII. 
 
 SECONDARY ROCKS. 
 
 Secondary rocks divided into upper and lower secondary. 
 Coal and salt formations most important. Coal measures, 
 and description of the members coal, sandstone, shale, iron 
 ore, and limestone of. Distinction between the transition 
 and lower secondary drawn from the fossil remains. Plants 
 of coal formation analogous to those of the tropics. De- 
 duction from an extensive series of these facts. Coal mea. 
 sures frequently not conformable to lower strata. Coal 
 formation somewhat variable in position. Some coal rocks 
 indicate a mechanical origin others a chemical. Derange- 
 ments of the strata. Some strata rapidly deposited. Many 
 strata of coal in one deposite. Coal fields, origin and shape. 
 Alternations of strata. Origin of coal. Fossil remains of 
 plants in shale. Outcrop of coal beds. Methods of search, 
 ing for coal. Coal of the United States and Europe. Va- 
 rieties of coal. Geological position of bituminous coal and 
 anthracite. Wood coal, lignite, jet. Amber with imbedded 
 insects 104 
 
CONTENTS. IX 
 
 CHAPTER VIII. 
 
 UPPER SECONDARY ROCKS. 
 
 Division of the upper secondary rocks. Synonims, and 
 important minerals of the red sandstone. Magnesian lime- 
 stone. Effect of magnesia on soils. Distinction between 
 the sandstone of the coal measures, and of the red sandstone. 
 Organic remains of the red sandstone. Saurians. Minerals 
 of red sandstone. Rock salt. Gypsum. Saltmines of Europe 
 and America. Deposition of salt in Africa. Salt springs. 
 Salt licks of the United States. Fossil bones at the licks 
 Mastodon and Elephant. Origin of salt deposits and salt 
 springs. Distribution of salt. Lias limestone and clay. 
 Lithographic stone, and its necessary qualities. Saurians 
 of great magnitude in lias. Lias clay used to make hydrau- 
 lic cement. Lias clay used to make alum. Oolite and or- 
 ganic remains of oolite. Oolitic limestone in the United 
 States. Organic remains and uses of oolite. Coral ragg. 
 Wealdon rocks. Gigantic saurian animals. Chalk forma- 
 tion. Flint. Chalk formation of the United States. 114 
 
 CHAPTER IX. 
 
 TERTIARY ROCKS. 
 
 Tertiary rocks described. Minerals of the tertiary. Ter- 
 tiary often confounded with alluvial and diluvial. Stratifi- 
 cation of the tertiary. Fossils of the tertiary. Mammifers 
 of the tertiary and insecta. Testacea. Basins of Paris and 
 London. Artesian wells. Fossil fishes of Europe and the 
 United States 128 
 
 CHAPTER X. 
 
 DILUVIAL DEPOSITS. 
 
 Distinction between alluvial and diluvial deposits. Dis. 
 cription of diluvion. Erratic blocks. Explanation of the 
 transport of those blocks. Theories explanatory of the 
 
X CONTENTS. 
 
 same. Bore or Pororoca. Examples of the effects of the 
 tide. Examples of the effects of the waves. Examples of 
 the effects of the lakes bursting their boundaries. Minerals 
 and ores of the diluvial deposits. Metals of the diluvial de- 
 posits. Bone caves. Bone breccias. Bone breccias con- 
 taining also land and fresh water shells. Bones of various 
 animals in caves. Human bones in diluvial gravel, Human 
 bones in recent rocks. 136 
 
 CHAPTER XI. 
 
 ALLUVIAL DEPOSITS. 
 
 Description of alluvial deposits. Animal and vegetable 
 remains imbedded. Causes of alluvial action. Fall of the 
 Dent du Midi. Landslip of Champlain. Glaciers, and their 
 uses. Transport of rocks by ice. Delta of the Po. Rivers 
 raise their beds in some parts of their course, arid excavate 
 in others. Dykes on the Mississippi. Transport by tides 
 and oceanic currents. Illustration of the power of water 
 in transporting rocks. Effects of wind in transporting ma- 
 terials. Encroachments of sands on cultivated lands. Sands 
 of Egypt. Petrified forest. Shoals from drifted sands. Coral 
 reefs of Pacific and Indian Ocean. Silicious and calcareous 
 deposits from springs. Peaty alluvions and description of. 149 
 
 CHAPTER XII. 
 
 TRAP ROCKS. 
 
 Trap and volcanic rocks have no regular geological posi- 
 tion. Composition of trap rocks. Trap rocks occur in dykes, 
 beds, columnar and globular masses. Derivation of the term 
 trap. Greenstone composition and discription of. Exam- 
 ples of trap in the United States. Greenstone. Sienitic. 
 Clinkstone. Wacke. Amygdaloid. Basalt. Dykes. Faults. 
 Natural walls of North Carolina. Effects of balsatic dykes 
 on the rocks traversed. Experiments on trap and limestone. 
 Globular and columnar form of basalt. Organic remains in 
 basalt. . . 162 
 
CONTENTS. XI 
 
 CHAPTER XIII. 
 
 EARTHQUAKES, VOLCANIC PHENOMENA, AND VOLCANIC ROCKS. 
 
 Earthquakes and volcanic phenomena frequently accom- 
 pany eaeh other. Phenomena attending and preceding earth- 
 quakes. Extent of the effects. Elevation of Jorullo. Cause 
 of earthquakes. Explosion of coal mines. Safety lamp. 
 Heaving of the ground during earthquakes. Volcanos, defi- 
 nition of. Crater. Materials ejected. Moya. Mud. Fishes. 
 Lava. Gases. Hot springs. Indication of a volcanic erup- 
 tion. Time of eruptions and quantities of erupted matter. 
 Eruptions of .^Etna. Eruptions of Skapta Jokul, in 1783. 
 Eruptions of Sumbawa. Eruptions of Vesuvius. Columnar 
 lava of Vesuvius. Long repose of volcanos, and examples. 
 Submarine volcanos. Volcanic islands rise from the sea, and 
 some sink again. Volcanos in groups. Volcanic mountain 
 engulphed. Composition of volcanic rocks. Sulphur. Pum- 
 ice. Trachyte. Lava, &c 172 
 
 CHAPTER XIV. 
 
 RECAPITULATION OF THE PRINCIPAL FACTS OF GEOLOGY. 
 
 j Slight discussion of some theories. Geology has no ne- 
 cessary connection with theory. Uses of theories. Werne- 
 rian and Huttonian theories excited much discussion. Nei- 
 ther of them fully sustained by facts. Wernerian theory. 
 Huttonian theory. Remarks upon these theories. Professor 
 Silliman's views on this subject. .... 194 
 
 USEFUL APPLICATIONS OF GEOLOGY. 
 
 I. AGRICULTURE. 
 
 Soil dependent on composition and substratum. Light 
 and heavy soils. Soils, how formed. Soils of different geo- 
 logical formations. Variations in productiveness of soils. 
 Texture of soils, discussion of. Composition of soils, dis- 
 cussion of, Effect of iron on vegetation. Permanency of 
 
Xll CONTENTS. 
 
 soils. Effects of springs and substrata. Effects of tilling 
 land and washing. Alluvions of Hudson. Food of plants. 
 Connection of geology and agriculture. Effect of imper- 
 vious and pervious rocks on the soil. Effect of loose stones 
 in the soil. Drainage by means of pervious strata. Drain, 
 age by means of faults. Mixtures of mineral substances to 
 improve soils. Importance of lime in soils. Importance 
 of particular substances in soils for particular kinds of 
 tillage 213 
 
 II. ROADS, 
 
 Materials for construction. Location in regard to strati, 
 fied rocks 230 
 
 III. CANALS. 236. 
 
 rv. WELLS. 236. 
 
 V. MINING. 
 
 Geological knowledge necessary to the preliminary ex* 
 plorations, and to the working of mines. . . 238 
 
 VI. BUILDINGS. 
 
 Importance of a judicious selection of materials. 240 
 
 SKETCH OF THE HISTORY OF GEOLOGIC 
 
 Concluding remarks. 244 
 
INTRODUCTION. 
 
 GEOGRAPHY is a description of the Earth, or it 
 is a science that teaches the positions of all the re- 
 gions of the earth, with regard to each other, and 
 describes the principal objects they contain. Many 
 of the sciences group themselves around Geography, 
 and yield to it, and to each other, a mutual support. 
 
 Geography is now considered in a more enlarged 
 sense than it was originally. It now comprehends 
 four great divisions, viz : 
 
 1. Mathematical geography occupies itself in 
 measurements of the earth's surface, and in ascer- 
 taining the location of places, with reference to cer- 
 tain fixed lines, or lines of latitude and longitude. 
 
 2. Historical geography consists in noting the 
 times of particular events, and the places and cir- 
 cumstances of their occurrence. 
 
 3. Political geography describes the earth in its 
 relations with men. 
 
 QUESTIONS ON THE INTRODUCTION TO GEOLOGY. 
 
 What is geography ? What does geography now compre- 
 hend ? What is mathematical geography ? What is histo- 
 rical geography ? What is political geography ? 
 2 
 
14 INTRODUCTION. 
 
 4. Physical geography is a branch of geography 
 which is freed from the limitation of kingdoms and 
 empires, and all artificial divisions. It embraces 
 the natural history of the earth, all objects that 
 can be represented by geographical maps, and every 
 thing, depending on causes, which may have con- 
 curred, at different times, in the actual constitution 
 of the earth. Physical geography includes GEO- 
 LOGY. 
 
 GEOLOGY is a science that has for its object the 
 examination of the structure of the earth, the man- 
 ner in which all the materials forming it are ar- 
 ranged with regard to each other, and the action 
 of frosts, rains, floods, tides, winds, earthquakes and 
 volcanoes, in effecting changes upon its surface. 
 The study of geology leads us to examine and re- 
 flect upon the works of nature that we see every 
 where scattered around us. It reveals to us the his- 
 tory of the great convulsions and revolutions that 
 the earth has experienced at remote periods of time. 
 The question, " to the scholar" says the Reviewer of 
 Silliman's Chemistry in the Christian Spectator, 
 vol. ii. p. 135, " personally the relations of a particu- 
 lar branch of knowledge to the economical pur- 
 poses of life, is of secondary importance. There- 
 fore he enquires, not whether a science will furnish 
 pecuniary profit or promote bodily comfort and en- 
 joyment, but rather if its investigations lead to phy- 
 sical and moral truth; whether the objects with 
 
 What is physical geography ? or what does it embrace ? 
 What is geology? What does geology lead us to examine? 
 What does it reveal to us ? What should the scholar enquire ? 
 
INTRODUCTION. 15 
 
 which it is conversant, are of sufficient interest to 
 excite curiosity and bring into exercise the higher 
 powers of the mind." 
 
 " What is the earth made of?" 
 
 has probably presented itself to every mind, and this 
 question, under certain limitations, includes most of 
 the objects of geology, viz : 
 
 " What are the substances of which the earth is 
 composed ? 
 
 What is the order in which they are arranged ? 
 
 What are the changes which they appear to have 
 undergone ?" 
 
 " The true object of Geology is to describe the 
 earth as it is at present, so far as it is exposed to our 
 observation ; and thus far, this science is susceptible 
 of as much certainty as any of the physical sciences." 
 [Humboldt on rocks.] 
 
 Geology being a science that has for its object a 
 knowledge of the earth's structure, as far as it lies 
 open to our observation, the fundamental point on 
 which it rests, is, to ascertain the order in which 
 the materials constituting its surface are super- 
 posed on each other. It is necessary to say its 
 surface, far below this, comparatively, we cannot 
 penetrate. 
 
 If at any point of the earth's surface we examine 
 the substances composing it, we find that they'are 
 either clay, sand, gravel, rock, or various mixtures 
 
 What are the principal subjects of geological enquiry? 
 What is the true object of geology? What is it designed to 
 ascertain? Of what materials do we find the earth com- 
 posed ? 
 
16 INTRODUCTION. 
 
 of these, and that if rock be not found at the sur- 
 face, it may be by digging to some depth below, and 
 that below this, the solid rock continues as far as the 
 power of man has hitherto enabled him to penetrate. 
 When we slightly examine the surface of the 
 earth, every thing seems without regularity ; but 
 by close observation, we see that the rocky, as well 
 as the earthy materials exposed to our view, are not 
 all alike, but differ much in their appearance, pro- 
 perties and composition, and that these rocks are 
 arranged in a regular order one over the other. 
 The rocks and other earthy bodies are composed of 
 minerals. Sometimes a single kind of mineral 
 forms the masses of sand, clay or rock ; but more 
 often, two or more mineral substances are aggre- 
 gated to form those bodies. 
 
 Minerals, are those bodies found in or upon the 
 earth, that are not animal or vegetable productions. 
 There are only ten that occur in such abundance 
 as to form the proper constituent parts of the rocks, 
 and these are by Professor Eaton called the geolo- 
 gical alphabet. 
 They are 
 
 QUARTZ ; CHLORITE ; 
 
 FELDSPAR ; TALC ; 
 
 MICA ; GYPSUM ; 
 
 HORNBLENDE ; LIMESTONE ; 
 
 AUGITE ; SERPENTINE. 
 
 Does the solid rock always occur within a moderate depth 
 from the surface ? and how far does it continue ? Of what 
 are the rocks composed ? What are minerals ? How many 
 and what minerals form the rocks ? Where do the other mi 
 nerals occur? 
 
INTRODUCTION. 17 
 
 The other minerals are found in veins, which ap- 
 pear to have been once open fissures in the rock, 
 and since filled with mineral matter ; or in beds 
 which are isolated masses of mineral, imbedded in 
 other rocks ; or else they are disseminated, or scat- 
 tered irregularly in the rocks in small grains and 
 masses. 
 
 Certain mineral substances are found almost con- 
 stantly associated with certain others, so that if one 
 be found in any particular situation, the others may 
 be expected to be found by searching for them. 
 Salt, and salt water, for instance, are almost always 
 found in connection with clay and gypsum. Lead 
 ores with those of zinc. Tin ores with those of tung- 
 sten and with topaz. This fact is observed not 
 only among the ores and the common minerals and 
 gems, but those minerals which by their aggrega- 
 tion constitute rocks, form masses so very similar 
 that specimens from far distant countries can 
 scarcely be distinguished from each other eves by 
 a practised eye. 
 
 Rocks are the aggregates of grains or pieces of 
 one or more minerals, adhering to each other so as 
 to form masses. 
 
 The grains of minerals are so small in some rocks, 
 as not to be distinguished from each other, and then 
 these rocks are said to be compact. When the 
 
 What are veins ? and what beds ? When are minerals dis- 
 seminated ? Do particular minerals almost constantly accom- 
 pany each other ? What minerals accompany salt and salt 
 water ? What ores are associated with the lead ores ? What 
 ores and mineral with tin ores ? What of those minerals that 
 constitute rocks ? What are rocks ? When are they compact ? 
 2* 
 
18 INTRODUCTION. 
 
 grains are distinguishable from their magnitude, 
 the rock is said to be granular in its structure. 
 When the parts composing the rocks show plane 
 and brilliant surfaces on being broken, they are said 
 to be crystalline. The close grained limestones are 
 generally instances of the compact structure. Com- 
 mon sandstone shows the granular. The white 
 marbles and granite, the crystalline structure. 
 Rocks are said to be slaty, or to have a slaty struc- 
 ture, when they split out in thin layers like common 
 slate, or roofing, or drawing slate. 
 
 The mean density* of the earth is about five times 
 greater than water. And as the mean density or 
 specific gravity of the mass of materials at, and 
 near the surface of the earth is only two and a 
 half, it follows, that the mean density at some dis- 
 tance below, is greater than at, and near its surface. 
 
 There are certain phenomena, which seem to in- 
 dicate, that the mass of the earth at some distance 
 below the surface, must be in a liquid or melted 
 state. 
 
 1. The earth has the exact form that a fluid body 
 would assume, moving as the earth does. 
 
 When granular ? and when crystalline ? What rocks are 
 instances of the compact, granular, and crystalline struc- 
 tures ? What is the slaty structure ? What is the mean den- 
 sity of the earth ? What is the mean density of the bodies 
 near the surface ,,of the earth ? What results from this diffe. 
 rence ? What form has the earth ? 
 
 * The density and specific gravity are synonymous, and both mean 
 the relative weight of a body, when compared with an equal bulk of 
 water. 
 
INTRODUCTION. 19 
 
 2. The earth loses more caloric* than it receives 
 in the course of a year, and sufficient to melt seve- 
 ral feet in depth of snow over its whole surface. 
 This would indicate, that it is a gradually cooling 
 mass. " The mean temperature of the earth has not 
 varied for the last 2000 years, as the length of the 
 day is the same now as then. A change of the mean 
 temperature would cause a change of the velocity 
 of rotation, and consequently of the length of the day. 
 
 The occurrence of animals and plants imhedded 
 in such vast numbers in the rocks in high lati- 
 tudes, whose analogues are found only in tropical 
 climates, seem to indicate that the mean tempera- 
 ture of the globe has been at some former period 
 much superior to what it is at present. It has been 
 attempted to account for these tropical fossils oc- 
 curring in high latitudes, by supposing that the axis 
 of the earth formerly had a different position from 
 the present one, and that the polar regions had once 
 been where the equator is now, but astronomical 
 observations show that this cannot have been the 
 case. 
 
 " The most conclusive argument against the fact 
 of any disturbance having in remote antiquity, 
 
 What indicates that the earth is a gradually cooling mass ? 
 How long has the temperature of the earth not varied? 
 What would a change of temperature cause ? Where are 
 animals and- plants imbedded? What do they indicate? 
 How is it accounted for ? 
 
 t Caloric is that which enters into a body when heating, and passes 
 off when cooling. Heat is a term applied to the sensation we per- 
 ceive in touching a hot body. 
 
20 INTRODUCTION. 
 
 taken place in the axis of the earth's rotation is to 
 be found in the lunar irregularities, which depend 
 on the earth's spheroidal figure." However insuffi- 
 cient the mere transfer of the mass of the ocean, 
 from the old to the new equator, might be to insure 
 the permanence of the new axis, the enormous abra- 
 sion of the solid materials of such immensely pro- 
 tuberant continents as would on that supposition 
 be left by the violent and constant fluctuation of an 
 unequilibrated ocean, would according to an ingeni- 
 ous remark of Prof. Playfair, no doubt in lapse of 
 some ages remodel the surface to the spheroidal 
 form ; but the lunar theory teaches us that the inter- 
 nal strata as well as the external outline of the globe 
 are elliptical, their centres being coincident and 
 their axes identical with those of the surface, a 
 state of things incompatible with a subsequent ac- 
 commodation of the surface to a new and different 
 state of rotation from that which determined the 
 original distribution of the component matter." 
 [Rep. Brit. Assoc. i. p. 407.] 
 
 The Baron Fourrier has computed that the ex- 
 cess of radiant heat of the earth, over that absorbed 
 by the sun, does not cause a difference in mean 
 temperature, of ^ of a degree of the centigrade ther- 
 mometer, and the cooling of the earth may now be 
 considered as having reached an asymptotic condi- 
 tion. [Rep. Brit. Assoc. i. p. 221.] 
 
 3. The rapidity with which motion is communi- 
 cated over extensive portions of the earth during 
 
 What is said of the axis of the earth's rotation? What 
 does the lunar theory teach us ? What is said of the radiant 
 heat of the earth '( 
 
INTRODUCTION. 21 
 
 earthquakes, is somewhat like the ground swell, felt 
 on the ocean, and on floating icefields, hours before 
 any motion of the air is perceived. 
 
 4. The occasional simultaneous action of vol- 
 canos, far distant from each other. 
 
 5. After going 50 or 60 feet below the surface of 
 the earth, the heat increases according to the depth, 
 from one to two degrees of Farenheit's thermometer 
 for every 100 feet. The warmth of the earth below 
 the surface is variable from 30 to 60 feet, in conse- 
 quence of the variation of the seasons, and the filter- 
 ing of rain and spring water through the ground ; 
 but below that, the temperature is uniform from 
 season to season, and warmer as you descend far- 
 ther. In the caves under the city of Paris, the 
 thermometer does not show a variation of one-tenth 
 of a degree of Farenheit's thermometer from one 
 year's end to another. 
 
 If the temperature increases with the same rapi- 
 dity to the centre of the earth, as it does for 2000 
 feet from the surface, the heat, from 30 to 60 miles 
 below, would be sufficient to melt the most refrac- 
 tory rocks. 
 
 An explanation of the temperature of the interior 
 of the earth, is offered by a writer in the American 
 
 What resembles the ground swell ? How far below the 
 surface is the temperature variable from the effects of the 
 seasons, springs &c. ? Below that depth does the tempera, 
 ture vary at any particular place ? As you descend deeper 
 does the temperature diminish or increase ? What do the 
 foregoing phenomena seem to indicate ? Should the temper- 
 ature increase at the rate observed, at what depth would the 
 heat be sufficient to melt the rocks ? 
 
22 INTRODUCTION. 
 
 Quarterly Review, vol. xvi. p. 433. He remarks, 
 " If solids were capable of indefinite compression, 
 steel would be compressed into ^, and stone into -i 
 of its bulk at the centre of the earth ; but long be- 
 fore such a degree of condensation could be marked, 
 the temperature would be so far increased as to 
 cause the bodies to enter into igneous fusion ; and 
 it has been calculated, that at the depth of 30 miles, 
 every solid substance known to exist at the earth's 
 surface, would be melted by the heat caused by the 
 pressure of the superincumbent mass." 
 
 It is only the crust of the globe that comes under 
 our direct observation, and it is to this, that geology 
 more particularly confines itself. 
 
 In speaking of the crust of the globe, it is not 
 meant to convey an idea that the earth is hollow, or 
 in a fluid state, but that the part coming under our 
 observation is analogous to a thin crust or rind, in 
 comparison with the mass of the earth. The greatest 
 depth to which man has penetrated is less than 3000 
 feet, and the highest mountains, the Himalaya, are 
 less than 27,000, so that not more than 30,000 feet 
 from the surface towards the centre, is exposed to 
 our observation. 30,000 feet is about one-seven 
 hundredth part of the distance from the surface to 
 the centre. 
 
 If solids were capable of compression what would that of 
 steel be ? Of stone ? What would be the result of such com- 
 pression ? What part of the Earth comes under our obser- 
 vation? What is meant in speaking of the crust of the 
 globe ? To what depth has man penetrated into the Earth ? 
 How high are the highest mountains on the globe ? 
 
INTRODUCTION. 23 
 
 This portion of the earth exposed to our observa- 
 tion, bears no more proportion to the magnitude of 
 the globe, than does the thin coat of varnish on an 
 artificial globe to its mass. The most elevated 
 mountains, may be compared to the dust collected 
 on a school globe ; and the great mountain chains, 
 to fibres of silk stretched across its surface. 
 
 Such views show the insignificance of man when 
 compared with the stupendous works of our Creator , 
 and we may well exclaim with the Psalmist : " What 
 is man that thou art mindful of him." Ps. viii. 4. 
 
 How does the whole thickness that we can examine, com- 
 pare with the whole Earth ? To what may the mountains 
 and mountain chains be compared ? 
 
ELEMENTS OF GEOLOGY. 
 
 CHAPTER I. 
 
 THE proper foundation of Geology, as a science, 
 was laid by a German, of the name of Lehman. He 
 observed that although there were many kinds of 
 rock, they could all be referred to two general 
 classes. He likewise observed that the lowest rocks 
 exposed to our observation were more or less crys- 
 talline in their structure, and contained no traces 
 of the remains of plants or animals. That the rocks 
 lying over the latter were generally compact, slaty, 
 or granular ; and abounded in the remains of marine 
 animals, such as various shells and bones, or with 
 plants, as the ferns and reeds. From the circum- 
 stances of their different structure, and from one 
 containing organic remains, or remains of animals 
 and plants, he inferred, that the lower rocks con. 
 ________ 
 
 By whom was the foundation of Geology laid ? What did 
 he observe as to the kinds of rock ? What was the structure 
 of the lower rocks ? What was the structure of the upper 
 rocks ? What were found in the upper that were not in the 
 lower rocks ? From the organic remains found in the upper 
 rocks, what conclusion was drawn as to the relative ages of 
 the upper and lower rocks ? 
 
 3 
 
20 ELEMENTS OF GEOLOGY. 
 
 taining no organic remains, were formed first, from 
 which circumstance he called them primary or 
 primitive rocks ; and the others lying upon the pri- 
 mary, and containing organic remains, he called 
 secondary rocks. The remains of animals and 
 plants, naturally enclosed in the rocks, clays, &c. 
 are called organic remains, because they are the 
 remains of organic bodies ; they are also called fos- 
 sils ; and when the organic substance is changed 
 into stony matter, they are called petrifactions. 
 
 The ocean has not always been confined to its 
 present bed, for, rocks composed mostly of the re- 
 mains of various marine animals, are found in almost 
 every country. The rocks containing these remains 
 are not confined to detached masses, but often form 
 extensive layers, or strata, as they are called, of 
 many miles, and often, many hundreds of miles in 
 extent. They not only occur in valleys, but they 
 cap the highest mountains, and their thickness 
 varies from a few inches to several hundred feet. 
 Nearly all the organic remains, being those of ani- 
 mals calculated only for living in water, the sea 
 must, at some time, have covered all the land for a 
 considerable period. We see then, that the relative 
 levels of the continents and ocean must have 
 
 What were the upper or fossiliferous rocks called ? What 
 are organic remains or fossils? What are petrifactions? 
 Has the ocean been always confined to its present bed ? And 
 what evidence is there that it has covered all the land ? Do 
 the rocks containing organic remains occur abundantly in 
 f almost every country ? And do they occur of any great ex- 
 tent and thickness ? Were the animals, whose remains are 
 found, adapted for living in water or on land ? 
 
ELEMENTS OF GEOLOGY. 27 
 
 changed ; and one of two conclusions follows, viz : 
 that the ocean has fallen below its former level and 
 exposed the dry land, or, that the continents have 
 been raised and made to emerge from the ocean. 
 
 If continents have been violently elevated, traces 
 must have been left where the changes of level have 
 been greatest, viz. in the vicinity of the highest 
 mountains ; such as contortion, disruption, over- 
 turned and highly inclined strata. Such is the case ; 
 vertical beds of limestone containing encrinites, 
 have been found lying parallel and in contact with 
 coalshale, containing canes and fern leaves. 
 
 As respects the vertical and highly inclined posi- 
 tion of recomposed beds, it is admitted that they 
 cannot have been thus deposited ; but must have 
 been since changed in position ; for it is physically 
 impossible to support an aggregation of loose gravel 
 in vertical or highly inclined planes. [Boston Jour- 
 nal, vol. 1. p. 243/j 
 
 Biggsby in speaking of the geology of Lake 
 Huron, says ; ancient beaches are not uncommon, 
 at some distance from the water, as on the Lesser 
 Manitou. It is 'likewise evinced by the belts of 
 rolled masses which gird every slope, and even mark 
 the successive retreats of the Lake. [Sil. Journal, 
 vol. 3. p. 257.] 
 
 " The numerous valleys which furrow the earth's 
 surface are highly interesting." The observer 
 
 From observing that rocks filled with the marine animals 
 . are abundant over a large portion of the earth, what conclu- 
 sion follows ? What is the case respecting the violent eleva- 
 tion of continents ? What is admitted of recomposed beds ? 
 What is said of valleys ? 
 
28 ELEMENTS OF GEOLOGY. 
 
 will remark their beautifully regular configuration, 
 where they serve as channels to drain the countries 
 they traverse, conveying the waters to " their final 
 receptacle, and at the same time their principal 
 source the ocean." " Numerous branches ramify- 
 ing over extensive tracts of country are collected 
 into a principal trunk opening into some estuary, 
 and a regular and continuous descent is preserved 
 throughout the whole course, calculated to facilitate 
 the passage of the waters through the whole system." 
 
 "Now this configuration is exactly that which 
 would be produced by the action of the waters 
 scooping out channels for their passage in draining 
 themselves off from the face of a country. We 
 may daily see the same operation repeated in min- 
 iature, by the drainage of the retiring tide on mud- 
 dy shores, especially in confined estuaries, where 
 the fall is considerable and rapid." [Conybeare 
 and Phillip 's Geology.] 
 
 The proof of some valleys having been formed by 
 denuding causes, are ; 
 
 1. The strata in the same planes on the opposite 
 sides of such valleys. 
 
 2. The occurrence of broken fragments of the 
 materials which once filled up these intervals scat- 
 tered over the surface. 
 
 " Not only do we observe these natural breaches 
 bearing every mark of the violence which has pro- 
 duced them, but we find the ruins themselves strewn 
 
 What of their configuration ? What proof have we that 
 some valleys have been formed by denudation ? That the 
 superior strata has been swept off by the same cause ? 
 
ELEMENTS OF GEOLOGY. 29 
 
 around; immense accumulations of debris, torn 
 from the adjacent rocks, and generally more or less 
 rounded, (as if by attrition against each other while 
 rolled along by the action of strong currents,) very 
 generally cover the bottom of the valleys which tra- 
 verse, and the plains which stretch beyond the base 
 of the elevated chains. [Boston Journal, i. p. 245.] 
 
 " The same agency that has excavated valleys, 
 appears also to have swept off the superior strata 
 from extensive tracts which they once covered ; 
 the proofs of this are to be found in the insulated 
 hills, or outlines of those strata placed at conside- 
 rable distances from their continuous range with 
 which they have every appearance of having been 
 once connected ; in the abrupt escarpments which 
 form the usual terminations of strata ; and in the 
 very great quantity of their debris, scattered fre- 
 quently over tracts far distant from those where they 
 still exist in situ. This stripping off of the superstrata 
 is appropriately termed denudation. [Conybeare 
 and Phillip's Geology. Boston Journal, i. p. 246.] 
 
 We find the remains of animals and plants im- 
 bedded in the rocks, not only near the surface of the 
 earth, but at the depth of hundreds and even thou- 
 sands of feet. Another point deserves attention, 
 viz : that these organic remains are not of every 
 kind jumbled together, but that particular species 
 belong tA particular strata, where in general, they 
 appear to>-have grown, died, and been imbedded. 
 
 Are the organic remains imbedded in the rocks near the 
 surface only ? Are they of every kind, jumbled indiscrimi- 
 nately together ? And how are they arranged ? 
 3* 
 
30 ELEMENTS OF GEOLOGY. 
 
 Many of the rocks are several hundred feet in thick- 
 ness, and the strata of each exhibit distinct species 
 and genera of animals. 
 
 The animals cannot have penetrated through the 
 vast masses under which they are entombed, and 
 the succession of different animals shows, that the 
 strata must have been formed in succession, and 
 each, must at some time have been the uppermost 
 stratum, in, and upon which the animals were depos- 
 ited, and afterwards covered by succeeding strata. 
 
 In the lower secondary rocks, the organic remains 
 are almost entirely different from the existing ge- 
 nera and species of animals and plants ; and in pro- 
 portion as the rocks are of more recent origin, lying 
 successively upon the lower ones, the fossils ap- 
 proach more and more nearly to the animals and 
 plants in existence. 
 
 The fossil remains of animals, not now in exis- 
 tence, entombed in the solid rocks, present us with 
 durable monuments of the great revolutions which 
 the earth has undergone at remote periods of time, 
 and open to us a new page for our study and inves- 
 tigation in the great book of nature. 
 
 The period of time required to produce the effects 
 observed in the fossiliferous rocks must have been 
 
 Do the animals appear to have penetrated through the 
 masses under which they are found ? And what does the 
 succession of different animals in the different strata show ? 
 Are the animals in the lower secondary rocks, similiar to 
 those now existing ? In the most recent rocks do the organic 
 remains approach more nearly to the animals and plants now 
 existing ? What do the fossiJ remains show us ? Does any 
 great period of time appear to have been required to produce 
 the observed results ? 
 
ELEMENTS OF GEOLOGY. 31 
 
 very great. Clearly, that was not a temporary in- 
 undation like the deluge, the evidences of which we 
 see every where on the surface of the earth ; but, it 
 would seem, must have continued for almost count- 
 less ages. 
 
 This may at first seem to clash with the Mosaic 
 account of the creation of the world ; but instead 
 of that, geology offers incontestable evidence of the 
 truth of the Mosaic account. The order which this 
 account assigns to the different epochs of creation, is 
 precisely the same as that, which has been deduced 
 from geological considerations. 
 
 Geology is a science which has been thought by 
 many persons to draw conclusions at variance with 
 the Book of Genesis ; but, " when at last more ma- 
 tured by a series of careful observations and legiti- 
 mate induction, it teaches us precisely what Moses 
 had taught more than three thousand years ago." 
 [SiHimcLfl? s Journal^ 
 
 In construing day, in the Mosaic account of the 
 creation, periods of time of indefinite duration must 
 be substituted. The reader who may have any 
 doubts upon this interpretation of the term day, is 
 referred to the American Journal of Science, Vol. 
 XXV. pages 30 41, where a full exposition of the 
 terms employed in 1st. of Genesis is given, indepen- 
 dent of geological considerations. 
 
 All geologists, or at least the largest portion ^of 
 
 Do we see evidences of the deluge, as well as of other con- 
 vulsions and inundations ? From geological phenomena how 
 is the term day explained, as used in the Mosaic account of 
 the creation of the world ? Does geology serve to prove any 
 part of the sacred writings ? 
 
32 ELEMENTS OF GEOLOGY. 
 
 them admit, that the discoveries of geology are con- 
 sistent with the Mosaic History. The following 
 extract from Bakewell's Geology bears in some de- 
 gree upon the same point. 
 
 " The six days in which Creative Energy reno- 
 vated the globe, and called into existence different 
 classes of animals, will imply six successive epochs, 
 of indefinite duration. The absence of human bones 
 in stratified rocks, or in undisturbed beds of gravel 
 or clay, indicates that man, the most perfect of ter- 
 restrial beings, was not created till after those great 
 revolutions, which buried different classes and en- 
 tire genera of animals, deep under the present sur- 
 face of the earth. 
 
 That man is the latest tenant of the globe, is con- 
 firmed by the oldest records or traditions that exist 
 of the origin of the human race. 
 
 The great convulsions which have changed the 
 ancient surface of the globe, and reduced it to its 
 present habitable state, were not, it is reasonable to 
 believe, effected by the blind fury of tumultuous and 
 conflicting elements, but were the result of deter- 
 mined laws, directed by the same wisdom which reg- 
 ulates every part of the external universe. 
 
 Compared with the ephemeral existence of mac 
 on the earth, the epochs of these changes may ap- 
 pear of almost inconceivable duration ; but we are 
 expressly told, that with the Creator " a thousand 
 years are as one day, and one day as a thousand." 
 
 What geological phenomenon shows that man is the ani 
 mal last formed upon the earth ? Do the oldest records anc 
 traditions prove the same thing ? 
 
ELEMENTS OF GEOLOGY. 33 
 
 Geological Discoveries Consistent with the Bible. 
 
 " It may seem just matter of surprise, that many 
 learned and religious men, should regard with jeal- 
 ousy and suspicion, the study of any natural phenom- 
 ena which abound with proofs of some of the 
 highest attributes of the Deity ; and should receive 
 with distrust, or total incredulity, the announce- 
 ment of conclusions which the geologist deduces 
 from a careful and patient investigation of facts 
 which it is his province to explore. 
 
 These doubts and difficulties, result from the dis- 
 closures made by geology respecting the lapse of 
 very long periods of time before the creation of man. 
 Minds which have long been accustomed to date the 
 origin of the universe, as well as that of the human 
 race, from an era of about six thousand years ago, 
 receive with reluctance any information, which if 
 true, demands some new modification of their pres- 
 ent ideas of cosmogony ; and, as in this respect, geol- 
 ogy has shared the fate of other infant sciences, in 
 being for a while considered hostile to revf ,Jed reli- 
 gion ; so like them, when fully understood, it will be 
 found a potent and consistent auxiliary to it, exalt- 
 ing our conviction of the power and wisdom and 
 goodness of the Creator. 
 
 No reasonable man can doubt that all the pheno- 
 mena of the natural world derive their origin from 
 God ; and no one who believes the bible to be the 
 
 What do the doubts respecting geology result from ? 
 what will geology when understood be found auxiliary ? 
 
34 ELEMENTS OF GEOLOGY. 
 
 word of God, has cause to fear any discrepancy be- 
 tween his word and the results of any new discov- 
 eries respecting the nature of his works ; but the 
 early and deliberative stages of scientific discovery 
 are always those of perplexity and alarm, and during 
 these stages the human mind is naturally circum- 
 spect, and slow to admit any new conclusions in 
 any department of knowledge. 
 
 The prejudiced persecutors of Galileo apprehend- 
 ed danger to religion, from the discoveries of a 
 science, in which a Kepler, and a Newton found de- 
 monstration of the most sublime and glorious attri- 
 butes of the Creator. 
 
 A Herschel has pronounced that Geology in the 
 magnitude and sublimity of the objects of which it 
 treats, undoubtedly ranks in the scale of sciences 
 next to astronomy ; and the history of the structure 
 of our planet, when it shall be fully understood, must 
 lead to the same great moral results that have fol- 
 lowed the study of the mechanism of the heaven?, 
 
 Geology has already proved by physical evidence, 
 that the surface of the globe has not existed in its 
 actual state from eternity, but has advanced through 
 a series of creative operations succeeding each other 
 at long and indefinite intervals of time ; that a*ll the 
 actual combinations of matter have had a prior exis- 
 tence in some other state ; and that the ultimate 
 atoms of the material elements through whatever 
 changes they may have passed, are, and ever have 
 
 What science does geology rank next to ? What has it 
 already proved ? What do these results accord with ? 
 
ELEMENTS OF GEOLOGY. 35 
 
 been, governed by laws as regular and uniform, as 
 those which hold the planets in their course. 
 
 All these results entirely accord with the best feel- 
 ings of our nature arid with our rational conviction 
 of the greatness and goodness of the Creator of the 
 universe. The reluctance with which evidences 
 of such high importance to natural theology, have 
 been admitted by many persons who are sincerely 
 zealous for the interests of religion, can only be ex- 
 plained by their want of accurate information in 
 physical science ; and by their ungrounded fears, 
 lest natural phenomena should prove inconsistent 
 with the account of Creation in the book of Ge- 
 nesis. 
 
 It was assuredly prudent in the infancy of Geo- 
 logy, and during the immature state of those phys- 
 ical sciences which form its only sure foundation, 
 not to enter upon any comparison of the Mosaic 
 account of the Creation, with the structure of the 
 earth, then almost entirely unknown ; the time was 
 not then come when the knowledge of natural phe- 
 nomena was sufficiently advanced to admit of anjr 
 profitable investigation of this question ; but the 
 discoveries of the last half century have been so ex- 
 tensive in this department of natural knowledge, 
 that, whether we will or not, the subject is now 
 forced upon our consideration, and can no longer 
 escape discussion. , 
 
 The truth is, that all observers, however various 
 
 When was it prudent to refrain from a comparison of geo- 
 logical deductions with the Mosaic account of the earth ? 
 Why is the question now forced upon us ? What is admitted 
 by all observers ? 
 
36 ELEMENTS OF GEOLOGY. 
 
 may be their speculations, respecting the secondary 
 causes by which geological phenomena have been 
 brought about, are now agreed in admitting the lapse 
 of very long periods of time to have been an essen- 
 tial condition to the production of these phenomena. 
 
 The disappointment of those who look for a de- 
 tailed account of geological phenomena in the bible, 
 rests on the gratuitous expectation of finding there- 
 in historical information, respecting all the opera- 
 tions of the Creator in times and places with which 
 the human race has no concern ; as reasonably 
 might we object that the Mosaic history is imper- 
 fect, because it makes no specific mention of the 
 satellites of Jupiter, or the rings of Saturn, as feel 
 disappointment at not finding in it the history of 
 geological phenomena, the details of which may be 
 fit matter for a scientific encyclopedia, but are 
 foreign to the objects of a volume intended only to 
 be a guide of religious belief and moral conduct. 
 
 We may fairly ask of those persons who consid- 
 er physical science a fit subject for revelation, what 
 point they can imagine short of a communication 
 of Omniscience at which such a revelation might 
 have stopped without imperfections of omission less 
 in degree, but similar in kind, to that which they 
 impute to Moses ? 
 
 A revelation of so much only of astronomy as was 
 known to Copernicus, would have seemed imperfect 
 after the discoveries of Newton ; and a revelation of 
 
 What is said of those who look for a detailed account of 
 geological phenomena in the bible ? What question may we 
 fuirly ask such persons ? What is said of the astronomy of 
 Copernicus? and of that of Newton? 
 
ELEMENTS OF GEOLOGY. 37 
 
 the science of Newton would have appeared defec- 
 tive to La Place ; a revelation of all the chemical 
 knowledge of the 18th century would have been as 
 deficient in comparison with the information of the 
 present day, as what is now known in this science 
 will probably appear before the termination of an- 
 other age. 
 
 In the whole circle of sciences there is not one to 
 which this argument may not be extended, until we 
 should require from revelation a full developement 
 of all the mysterious agencies that uphold the me- 
 chanism of the material world. Such a revelation 
 might indeed be suited to beings of a more exalted 
 order than mankind, but unless human nature had 
 been constituted otherwise than it is, the above 
 supposed communication of Omniscience would 
 have been imparted to creatures utterly incapable of 
 receiving it, under the present moral or physical 
 condition of the human race ; and would have been 
 also at variance with the design of all God's other 
 disclosures of himself, the end of which has uniformly 
 been, not to impart intellectual but moral know- 
 ledge." [Buckland's Geology, vol. i.] 
 
 " Sound philosophy and revealed religion are na- 
 turally connected with each other. However widely 
 they may differ as to the manner in which they 
 severally proceed, they are both tending towards one 
 
 What of the chemical knowledge of the 18th century? 
 How far may this argument be extended? To whom 
 would such a revelation be suited ? What appears to be the 
 end of God's disclosures of himself? To what do sound phi- 
 losophy and revealed religion tend ? 
 4 
 
38 ELEMENTS OF GEOLOGY. 
 
 common object, the establishment of truth. Philos- 
 ophy sets out in its pursuit of this object from the 
 lowest point Religion from the highest : the for- 
 mer begins with the last effect, the latter commences 
 with the first cause. 
 
 Geology and religion are inevitably brought in 
 contact on the great point of the creation of the 
 world, and it appears highly desirable to ascertain 
 if the facts of geology and the Mosaic account of 
 the creation are not reconcilable with each other. 
 
 The commonly received opinions of the Mosaic 
 account, are at variance with the inferences deduced 
 from the researches of geology. 
 
 It will probably occur to most Christians that 
 they can recollect the time when they supposed that 
 every night and day mentioned in the first chapter 
 of Genesis, must be understood to mean periods of 
 twenty-four hours, though there can be no doubt 
 that Moses did not intend such restriction. Critics 
 also inform us that his words ought not to have 
 been thus translated. 
 
 We are told that the word day does in fact signify 
 an indefinite period of time, and common sense 
 ought to bring us to the same conclusion in regard 
 to the three first days, for the text says, that the sun, 
 moon, and stars, were placed in the firmament to 
 divide the day from the night. 
 
 Moses is generally supposed to give a particular 
 description of the creation of the world out of no- 
 
 How does philosophy set out ? From what point does re- 
 ligion start ? What is highly desirable to ascertain ? What 
 is said of the first chapter of Genesis ? What is Moses gene- 
 rally supposed to give ? 
 
ELEMENTS OF GEOLOGY. 39 
 
 thing, and to fix the date of the creation at a period, 
 either immediately previous to, or contemporary 
 with, the three first days afterwards mentioned. 
 
 These suppositions are gratuitous. All that 
 Moses says of the creation is : 
 
 1. That it was created by God, and: 
 
 2. That this creation took place in the beginning. 
 
 Nothing can be more positive than the first decla- 
 ration, or more indefinite that the second." [Man- 
 telPs Geology of Sussex, p. 1 to 3.] 
 
 " Does Moses ever say, that when God created the 
 the heavens and the earth he did more at the time 
 alluded to than transform them out of pre-existing 
 materials ? or that there was not an interval of many 
 ages between the first act of creation at the begin- 
 ning, and those more detailed operations, the account 
 of which commences at the second verse, and which 
 are described to us as having been performed in so 
 many days ? 
 
 Or finally, does he ever make us to understand 
 that the genealogies of man went any farther than 
 to fix the antiquity of the human species, and of con- 
 sequence that they left the antiquity of the globe a 
 free subject for the speculation of philosophers." 
 [Chalmer's Evidence of the Christian Revelation.'] 
 
 "It has long been matter of discussion among 
 learned theologians whether the first verse of Gen- 
 esis should be considered prospectively, as contain- 
 ing a summary announcement of that new creation, 
 
 Are those suppositions correct ? What questions are those 
 respecting Moses ? What has long been a point of discus- 
 sion among learned theologians ? 
 
40 ELEMENTS OF GEOLOGY. 
 
 the details of which follow in the record of the ope- 
 rations of the six successive days ; or as an abstract 
 statement, that the heaven and the earth were made 
 by God, without limiting the period when the crea- 
 tive agency was exerted. The latter of these opin- 
 ions is in perfect harmony with the discoveries of 
 geology. 
 
 The Mosaic narrative commences with a decla- 
 ration, that ' In the beginning God created the hea- 
 ven and earth.' 
 
 These few first words of Genesis may be fairly 
 appealed to by the geologist as containing a brief 
 statement of the creation of the material elements, 
 at a time distinctly preceding the operations of the 
 first day ; it is nowhere affirmed that God created 
 the heaven and the earth in the first day, but in the 
 beginning ; this beginning may have been an epoch 
 at an unmeasured distance, followed by periods of 
 undefined duration, during which all the physical 
 operations disclosed by geology were going on. 
 
 The first verse of Genesis, therefore, seems ex- 
 plicitly to assert the creation of the Universe ; * the 
 heaven,' including the siderial systems, and <the 
 earth' more especially specifying our planet, on the 
 subsequent scene of the operations of the six days 
 about to be described : no information is given as 
 to the events \vhich may have occurred upon this 
 earth, unconnected with the history of man between 
 
 What opinion is in harmony with the discoveries of geol. 
 ogy ? What may be appealed to by geologists ? What may 
 the beginning have been ? What does the first verse of Ge. 
 nesis assert ? 
 
ELEMENTS OF GEOLOGY. 41 
 
 the creation of its component matter, recorded in the 
 first verse, and the era at which its history is re* 
 sumed in the second verse ; nor is any limit fixed 
 to the time during which these intermediate events 
 may have been going on. 
 
 Millions of millions of years may have occupied 
 the indefinite period between the beginning in which 
 God created the heaven and the earth, and the even- 
 ing or commencement of the first day of the Mosaic 
 narrative. 
 
 The second verse may describe the condition of 
 the earth on the evening of this first day, (for in 
 the Jewish mode of computation used by Moses, 
 each day is reckoned from the beginning of one 
 evening to the beginning of another evening.) 
 
 This first evening may be considered as the ter- 
 mination of the indefinite time which followed the 
 primeval creation, announced in the first verse, as 
 the commencement of the first six succeeding days, 
 in which the earth was to be fitted up and peopled 
 in a manner fit for the reception of mankind. 
 
 We have in this second verse a distinct mention 
 of earth and waters, as already existing and involved 
 in darkness ; their condition also is described as a 
 state of confusion and erupting, (tohu bohu) words 
 which are usually interpreted by the vague and in- 
 definite Greek term * chaos,' and which may be 
 
 What time may have elapsed between the periods spoken 
 
 of in the first verse, and that in the second ? What may 
 
 the second verse describe ? What may the first evening be 
 
 considered ? What peculiar words occur in the second verse 7 
 
 4* 
 
42 ELEMENTS OF GEOLOGY. 
 
 geologically considered as designating the wreck 
 and ruins of a former world. 
 
 At this intermediate point of time, the preceding 
 undefined geological periods had terminated, a new 
 series of events commenced, and the work of the 
 first morning of this new creation was the calling 
 forth of light from this temporary darkness, which 
 had overspread the ruins of the ancient earth. 
 
 Prof. Pussey remarks that the words 'let there be 
 light' by no means imply that light had not before 
 existed. 
 
 We have mention of the ancient earth and ancient 
 sea in the ninth verse, in which the waters are com- 
 manded to be gathered together into one place, and 
 the dry land to appear ; this dry land being the same 
 earth whose material creation had been announced 
 in the first verse, and whose temporary submersion, 
 and temporary darkness, are described in the second 
 verse ; the appearance of the land and the gather- 
 ing together of the waters are the only facts affirm- 
 ed respecting them in the ninth verse, but neither 
 land nor waters are said to have been created on the 
 third day. 
 
 A similar interpretation may be given of the four- 
 teenth and four following verses. What is herein 
 stated of the celestial luminaries seems to be spoken 
 solely with reference to our planet, and more espe- 
 cially to the human race then about to be placed 
 upon it. 
 
 How may they be geologically designated ? What is said 
 of the words let there be light ?' What is mentioned in the 
 ninth verse ? 
 
ELEMENTS OF GEOLOGY. 43 
 
 We are not told that the substance of the sun and 
 moon were first called into existence on the fourth 
 day. The text may equally imply that these bodies 
 were then prepared and appointed to certain offices 
 of high importance to mankind ; to give light upon 
 the earth and to rule over the day and over the night ; 
 * to be for signs and for seasons and for days and for 
 years.' The fact of their creation had before been 
 stated in the first verse. 
 
 'The stars also' are mentioned (Gen. i. 16.) in 
 three words only, almost parenthetically ; as if for 
 the sole purpose of announcing that they also were 
 made by the same Power as those luminaries which 
 are more important to us, the sun and the moon. 
 
 This very slight notice of the countless host of 
 celestial bodies, all of which are probably suns, the 
 centres of other planetary systems whilst our little 
 satillite, the moon, is mentioned as next in impor- 
 tance to the sun, shows clearly that -astronomical 
 phenomena are here spoken of only according to 
 their relative importance to our earth and to man- 
 kind, and without any regard to their real impor- 
 tance in the boundless universe. 
 
 It seems impossible to include the fixed stars 
 among those bodies which are said (Gen. i. 17.) to 
 have been set in the firmament of the heaven to give 
 light upon the earth ; since without the aid of teles- 
 copes, by far the greater number of them are invis- 
 ible. The same principle seems to pervade the 
 
 What is said of the sun, moon, and stars ? What shows 
 that these are mentioned only according to their relative im- 
 portance to the earth? What is said of the fixed stars? 
 What difficulties are solved by this interpretation ? 
 
44 ELEMENTS OF GEOLOGY. 
 
 description of creation which concerns our planet ; 
 the creation of its component matter having been 
 announced in the first verse, the phenomena of geo- 
 logy like those of astronomy, are passed over in 
 silence, and the narrative proceeds at once to de- 
 tails of the actual creation which have more im- 
 mediate reference to man. 
 
 The interpretation here proposed, seems more- 
 over, to solve the difficulty which would otherwise 
 attend the statement of the appearance of light on 
 the first day, while the sun and moon and stars were 
 not made to appear until the fourth day. 
 
 If we suppose all the heavenly bodies and the earth 
 to have been created at the indefinitely distant time 
 designated by the word beginning, and that the dark- 
 ness described on the evening of the first day, was 
 a temporary darkness, produced by an accumula- 
 tion of dense vapours ' upon the face of the deep,' an 
 incipient dispersion of these vapours may have re- 
 admitted light to the earth upon the first day, whilst 
 the exciting cause of light was still obscured, and 
 the farther purification of the atmosphere upon the 
 fourth day, may have caused the sun, moon, and stars, 
 to re-appear in the firmament of heaven, to assume 
 their new relations to the newly modified earth, and 
 to the human race. 
 
 We have evidence of the presence of light during 
 long and distant periods of time, in which the many 
 
 What is the supposition respecting the heavenly bodies and 
 the earth? What is said of the first day? What of the 
 fourth day ? What is evidence of the presence of light dur- 
 ing long and distant periods of time ? 
 
ELEMENTS OF GEOLOGY 45 
 
 extinct fossil forms of life succeeded one another 
 upon the early surface of the globe. This evidence 
 consists in the petrified remains of the eyes of ani- 
 mals found in geological formations of various ages. 
 
 The eyes of the Trilobites are beautifully preserved 
 in the transition rocks, and were constructed so as 
 to bear a remarkably close resemblance to those of 
 existing crustaceous animals. 
 
 The eyes of the Ichthyosaurus of the Lias con- 
 tained an apparatus so similar to that of many birds, 
 as to leave no doubt that they were optical instru- 
 ments, and calculated to receive impressions and 
 convey sensations of sight to living animals. This 
 conclusion is farther strengthened by the general 
 fact, that the heads of all fossil fishes and reptiles, in 
 every geological formation, are furnished with cavi- 
 ties for the reception of eyes, and with perforations 
 for the passage of optic nerves, although the in- 
 stances are rare in which any part of the eye itself 
 has been preserved. 
 
 The influence of light is also so necessary to the 
 growth of existing vegetables that we, cannot but in- 
 fer, that it was equally essential to the developement 
 of the numerous fossil species of the vegetable king- 
 dom which are co-extensive and co-eval with the re- 
 mains of fossil animals. 
 
 In conclusion it should be recollected that the 
 
 What are preserved in the transition rocks? What do 
 they resemble ? What contained an apparatus ? To what 
 were they similar ? For what are they calculated ? What gene- 
 ral fact is spoken of? What conclusion is strengthened by 
 this general fact ? What would you infer from the influence 
 of light? 
 
46 ELEMENTS OF GEOLOGY. 
 
 question is not respecting the correctness of the 
 Mosaic narrative, but of our interpretation of it ; and 
 still further, it should be borne in mind that the ob- 
 ject of this account was, not to state in what man- 
 ner, but by whom, the world was made. 
 
 As the prevailing tendency of men in those early 
 days was to worship the most glorious objects of 
 nature, viz. the sun, moon and stars ; it should seenj 
 to have been one important point in the Mosaic ae* 
 count of creation, to guard the Israelites against the 
 Polytheism and idolatry of the nations around them ; 
 by announcing that all these magnificent celestial 
 bodies were no gods, but the works of one Almighty 
 Creator to whom alone the worship of mankind is 
 due. [BucklancFs Geology.] 
 
 Professor Sedgwick, in his eloquent and admirable 
 discourse on the studies of the University of Cam- 
 bridge in 1833, in which he ably points out the rela- 
 tions which geology bears to natural religion, thus 
 sums up his valuable opinion as to the kind of in- 
 formation we ought to look for in the bible : 
 
 " The Bible instructs us that man, and other living 
 things have been placed but a few years upon the 
 earth ; and the physical monuments of the world 
 bear witness to the same truth : if the astronomer 
 tells us of myriads of worlds not spoken of in the 
 Sacred records ; the geologist, in like manner proves 
 (not by arguments from analogy, but by the incon- 
 trovertible evidence of physical phenomena,) that 
 
 Respecting what should the question be ? What is the ob- 
 ject of this account ? What seems to be an important point 
 in the Mosiac account of creation ? In what does the Bible 
 instruct us ? In what does geology ? 
 
ELEMENTS OF GEOLOGY. 47 
 
 there were former conditions of our planet, separated 
 from each other by vast intervals of time, during 
 which man, and the other creatures of his own date, 
 had not been called into being. 
 
 Periods such as these belong not, therefore, to the 
 moral history of our race, and come neither within 
 the letter, nor the spirit of revelation. Between the 
 first creation of the earth, and the day in which it 
 pleased God to place man upon it, who shall dare 
 to define the interval ? 
 
 On this question scripture is silent, but that silence 
 destroys not the meaning of those physical monu- 
 ments of his power that God has put before our eyes, 
 giving us at the same time faculties whereby we 
 may interpret them, and comprehend their meaning." 
 [BucHand's Geology, i. p. 34.] 
 
 CHAPTER II. 
 
 Every one must have observed that the mineral 
 substances upon the surface of the Earth, differ 
 much in their hardness, weight, colour, and other 
 qualities. 
 
 The different minerals appear at first so nume- 1 * 
 rous as to make it difficult to become familiar with 
 them, but on examination it is found, that the num- 
 
 On what question is scripture silent? Do the mineral 
 bodies differ much in their qualities ? Do they appear very 
 numerous ? and are they as numerous as they appear to be ? 
 
48 ELEMENTS OF GEOLOGY. 
 
 her of minerals is not very great, and the elemen- 
 tary substances composing them still less. 
 
 The bodies called elementary or simple bodies, 
 are those that have never as yet been decomposed 
 into two or more other bodies, as for instance, gold, 
 silver, tin, copper, lead, sulphur, &c. 
 
 The whole number of the elementary substances 
 forming all the minerals, rocks, plants, animals, and 
 every thing we can see upon or in the earth, is only 
 about fifty-four. 
 
 The elementary substances entering into combi- 
 nation* with each other to form the principal part of 
 the mass of the globe, are, 
 
 OXYGEN; SILICON; ALUMINUM; POTASSIUM; 
 CHLORINE; CARBON; CALCIUM; SODIUM; 
 HYDROGEN; SULPHUR; MAGNESIUM; IRON. 
 
 Oxygen is the most common substance existing 
 in combination with other bodies, and is supposed 
 to constitute about one half of the whole weight of 
 the materials on the surface of the globe. By its 
 combination with silicon it forms silex, which enters 
 
 What are elementary or simple bodies ? What is about 
 the number of simple bodies ? Are all substances formed of 
 those few simple bodies? What are the elementary sub. 
 stances that form almost all the mass of the globe as far as 
 we know ? Which of these is most common in combination 
 with other bodies ? About what proportion of the weight of 
 the bodies of the Earth, is oxygen supposed to constitute ? 
 What does it form by combining with silicon ? 
 
 * Substances are said to combine, when they unite with each other 
 so as to change their properties. Thus potassa or soda, by union with 
 oil or grease, form soap, a substance totally different from the bodies 
 of which it is formed. 
 
ELEMENTS OF GEOLOGY. 49 
 
 into most of the minerals and rocks in large pro- 
 portion. 
 
 Oxygen combined with hydrogen forms water. 
 With carbon, it forms invisible elastic bodies like 
 air, but which if breathed destroy life. With sul- 
 phur it forms acids,* one of which is used in bleach- 
 ing straw, and which you always smell when sul- 
 phur is burnt in the air ; another of these acids is 
 called sulphuric acid, and oil of vitriol. 
 
 Oxygen unites with aluminum, calcium, magne- 
 sium, potassium, and sodium, which are metals, and 
 forms with the first alumina, which exists abun- 
 dantly in the clays and slates ; with calcium it forms 
 lime, with magnesium magnesia, with potassium 
 potash, and with sodium soda, and with iron it forms 
 the common ores of iron. 
 
 Oxygen is contained in large proportion in the 
 air, and it is that which supports life by our breath- 
 ing. It is for want of oxygen that persons die soon 
 
 What does it form by uniting with hydrogen ? What does 
 It form when combined with carbon ? What effect is pro. 
 duced by breathing those compounds ? When oxygen unites 
 with sulphur what are formed ? For what is one of these 
 acids used and what is its odour ? What is the other acid 
 called ? When oxygen unites with aluminum, what is formed, 
 and in what does alumina exist abundantly? What are 
 formed by the union of oxygen with calcium, magnesium, 
 potassium, sodium, and with iron ? In what is oxygen found 
 in large proportion ? What must be in the air, to support 
 life when we breath it ? Why is it that persons drown under 
 water ? 
 
 t Acids are generally sour to the taste, and by their combination 
 with other bodies, they form substances differing both from the acidL 
 and the other body. 
 
 5 
 
50 ELEMENTS OF GEOLOGY. 
 
 when under water. Most bodies when uniting with 
 oxygen, burn, or give out light and heat. 
 
 It is owing to the combination of oxygen with 
 other substances, that oil, tallow, and wood burn. 
 
 Oxygen, when free, is a gaseous body ; that is, an 
 elastic,* transparent body like air. 
 
 When oil, tallow, charcoal or wood are burning, 
 carbonic acid or fixed air is formed, by the combi- 
 nation of carbon and oxygen. Carbonic acid is the 
 gas that causes so many accidents in caves, wells, 
 &c. by people descending into them without prop- 
 er caution. Being heavier than air, it occupies 
 the lower portion of the well or cave, and as soon as 
 a person is immersed in it, life is destroyed. As a 
 candle or lamp will not burn in it, its presence can 
 be ascertained by lowering a candle into the well, 
 cave or mine. Should the candle not burn freely, 
 it is not safe to enter. 
 
 Chlorine and hydrogen are also gaseous bodies, 
 but will not support life. 
 
 When bodies unite with oxygen, what generally happens ? 
 Why is it that oil, tallow, wood, &c. burn when heated in 
 the open air ? What is oxygen ? What is a gas, or gaseous 
 body ? What gas is formed during the burning of wood, oil, 
 tallow, or charcoal ? Is this gas heavier than air ? Does it 
 ever cause accidents, and of what kind ? Will a candle burn 
 in it, and how can you ascertain if this gas exists in any 
 situation, and when is it safe to enter a well, cave, &c. 1 Is 
 chlorine a gas, and will it support life ? 
 
 * Bodies are said to be elastic when they can be compressed into 
 a smaller space, and when the pressure is removed, they restore them- 
 selves to their original form and bulk. Bodies that are solid may be 
 bent, if longer than broad and thick. If they restore themselves to 
 toeir first shape they are also said to be elastic. 
 
ELEMENTS OF GEOLOGY. 51 
 
 Chlorine is of a yellowish green colour, and of a 
 peculiar odour. It exists abundantly in combina- 
 tion with sodium to form common salt. Salt is 
 contained in the waters of the ocean, and in such 
 quantity, that if separated, it would cover all the land 
 on the globe to the depth of 1800 feet. 
 
 La Place estimated the mean depth of the ocean 
 at 10 miles, and from this and the known quantity 
 of salt in the water, the above estimate is made.* 
 
 Hydrogen gas is the lightest of all known bodies. 
 It has no colour, burns with a hardly visible flame, 
 but gives a great deal of heat, and when this gas is 
 mixed with air or oxygen, and a flame applied, it ex- 
 plodes with great violence, and water is formed. 
 
 It is used for filling balloons by which men are en- 
 abled to ascend many thousands of feet in the air. 
 If a piece of cork be put under water, it rises to the 
 surface, because it is lighter than the water. In the 
 same way, as hydrogen is so much lighter than air, a 
 large bag filled with it, is lighter than the air, and if 
 left to itself, rises to a certain height in the atmos- 
 
 What is its colour, and has it any odour ? With what does 
 it exist in combination abundantly 7 To what depth would 
 the salt of the ocean cover all the land on the globe ? Of 
 what is salt composed, besides chlorine ? What is the esti- 
 mated mean depth of the ocean ? What is the lightest of all, 
 known bodies? Has hydrogen any colour, and does it give 
 any light or heat during its burning ? When mixed with 
 air or oxygen and inflamed, what effect is produced, and what 
 formed ? For what is hydrogen used ? 
 
 * This estimate has been reduced to 3 miles, by more recent inves- 
 tigations. 
 
52 ELEMENTS OF GEOLOGY. 
 
 phere. A balloon is a ball-shaped bag filled with 
 hydrogen, or with rarified air. 
 
 Silicon is a dark coloured substance, burns under 
 certain circumstances, and by its union with oxygen 
 forms silex, which is a white coloured powder. 
 Silex exists pure in rock crystal, and nearly pure 
 in many minerals, as flint, agate, cornelian, jasper, 
 quartz, &c. 
 
 Sand is almost entirely composed of silex, and 
 silex forms probably nearly one half of the materials 
 of the crust of the globe. 
 
 Silex, when melted with potassa or soda, forms 
 glass, and this is one of its most important uses. 
 
 Carbon is the principal substance in all the kinds 
 of mineral coal, and charcoal, and it exists in large 
 proportion in wood, oil, tallow, and all vegetable and 
 animal substances. 
 
 The diamond is pure carbon. Carbon is black, 
 except when crystallized as in the diamond. 
 
 Carbon is naturally combined with hydrogen, as 
 in bitumens, oils, &c., with oxygen forming carbonic 
 acid, and with iron forming plumbago, or black lead, 
 steel and cast iron. Carbon, and the substances 
 
 Why is it that, a balloon filled with hydrogen will rise ? 
 What is the appearance of silicon, and by its union with 
 oxygen, what is formed ? In what does silex exist pure, and 
 in what nearly pure ? Of what is sand mostly composed ? 
 What proportion of the crust of the Earth is silex? What 
 is silex mostly used for, and how is glass made ? In what 
 is carbon the principal substance, and in what does it exist in 
 large proportions? What substance is pure carbon? In 
 what is carbon naturally combined with hydrogen ? What 
 are formed by the union of carbon and iron ? 
 
ELEMENTS OP GEOLOGY. 53 
 
 containing it in large proportion, are mostly used 
 for obtaining light and heat, and for reducing the 
 ores of the metals. 
 
 Sulphur is a simple body of yellow colour, brittle, 
 without taste, burns easily in the open air, ancT gives 
 a peculiar pungent odour. It rarely occurs uncom- 
 bined with other bodies, except in volcanic coun- 
 tries. It is found united to many of the metals form- 
 ing ores, which are called sulphurets. It is used 
 mostly for the manufacture of gunpowder, and sul- 
 phuric acid, or oil of vitriol. 
 
 Iron, combined with oxygen, forms most of the 
 useful ores of iron, but there are few places compar- 
 atively, where these ores are found in such quan- 
 tity as to be valuable. 
 
 This combination is more uniformly distributed 
 through the mineral kingdom than any other sub- 
 stance, and it colours almost all minerals. Hardly 
 a fragment of mineral or rock can be selected, that 
 does not contain traces of iron, but generally it is 
 in small quantity. 
 
 Oxides are combinations of oxygen with other 
 bodies. The oxides, silex, alumina, lime, and mag- 
 nesia, are called earths, and the two last, alkaline 
 
 For what are carbon, and substances containing it in large 
 proportions, employed ? What are some of the properties of 
 sulphur ? Does it occur uncombined with other bodies, anfl 
 where ? When united with the metals, what are formed, 
 and what are they called ? For what is sulphur mostly em. 
 ployed ? Of what are most of the useful ores of iron com. 
 posed ? Are these found in quantity every where ? Is iron 
 almost universally distributed in the mineral kingdom? 
 Does it generally colour minerals ? What are oxides ? What 
 are the most abundant earthy oxides ? 
 5* 
 
54 ELEMENTS OF GEOLOGY. 
 
 earths. These earths are most abundant in the 
 same order in which they are mentioned, and they 
 constitute at least three fourths of the solid mate- 
 rials upon the surface of the globe. 
 
 These substances, by their various combinations 
 with each other, and with other bodies, form a great 
 variety of minerals, and it is not a little remarkable, 
 that those minerals and substances most useful to 
 man, are most abundant and most uniformly dis- 
 tributed. 
 
 There are about forty-five simple bodies known, 
 in addition to those already described ; and although 
 they form a small portion of the mass of the globe, 
 in comparison with those previously noticed, some 
 of them are highly useful, and almost indispensable, 
 to man in his civilized state. 
 
 They are : 
 
 BROMINE ; CHROMIUM ; 
 
 IODINE ; URANIUM ; 
 
 FLUORINE ; VANADIUM ; 
 
 NITROGEN ; MOLYBDENUM ; 
 
 BORON ; TUNGSTEN ; 
 
 PHOSPHORUS ; TITANIUM ; 
 
 SELENIUM ; COLUMBIUM 
 
 ARSENIC ; LITHIUM ; 
 
 ANTIMONY ; MAGNESIUM ; 
 
 TELLURIUM ; STRONTIUM ; 
 
 Which is most abundant ? What proportion of the solid 
 materials of the globe do they form ? When these substances 
 combine with each other and other bodies, do they form many 
 minerals ? Are the most useful minerals the most abundant 
 and widely distributed ? How many simple bodies known in 
 addition to those already given ? Name them ? 
 
ELEMENTS OF GEOLOGY. 55 
 
 BARIUM ; TIN ; 
 
 GLUCINIUM ; BISMUTH ; 
 
 YTTRIUM ; COPPER ; 
 
 ZIRCONIUM ; MERCURY ; 
 
 THORIUM ; SILVER ; 
 
 MANGANESE ; GOLD ; 
 
 NICKEL ; PLATINUM ; 
 
 COBALT ; PALLADIUM ; 
 
 CERIUM ; RHODIUM ; 
 
 ZINC ; IRIDIUM 
 
 CADMIUM ; OSMIUM. 
 
 LEAD ; 
 
 " Bromine and Iodine are both found in combi- 
 nation with other bodies, most frequently in sea 
 water, and in small quantities. 
 
 " Iodine is the most important of the two. It 
 forms several compounds, and is useful in medicine 
 and the arts. 
 
 " Fluorine is a principle found to exist in the min- 
 eral called fluorspar. It has not yet been obtained 
 in a perfectly pure state. The fluoric acid gaslnto 
 the composition of which the fluorine enters, is re- 
 markable for its property of corroding glass. 
 
 "Nitrogen constitutes four-fifths of atmospheric 
 air, and is an ingredient of animal substances. 
 This element is remarkable for its negative quali- 
 ties; it is neither combustible nor a supporter ^of 
 combustion ; neither acid nor alkaline. No ahi- 
 mal can exist in it ; not because it has any injuri- 
 
 What of the two first ? Which is the most useful ? What 
 of Fluori MC ? What corrodes glass ? What portion of atmos- 
 pheric air does Nitrogen constitute ? fume the qualities for 
 which it i remarkable 1 
 
56 ELEMENTS OF GEOLOGY. 
 
 ous effect upon the lungs, but solely from the ab- 
 sence of oxygen. 
 
 " Nitrogen, however, when it combines with other 
 substances, forms compounds which are not distin- 
 guished by negative qualities, but are highly impor- 
 tant in the arts and medicine. 
 
 " Boron is a dark olive-coloured powder, and is 
 the base of borax, a substance found in the East In- 
 dies and in the lakes of Thibet and China. It has 
 no taste and is insoluble in water. 
 
 "Phosphorus is never found in nature uncom- 
 bined. Nor can it exist in this state, for it is ex- 
 ceedingly combustible ; and (according to Dr. Hig- 
 gins,) burns at a temperature of 60 Fahrenheit, in 
 atmospheric air. It combines with nearly all the 
 metals, the earths, and the principles already de- 
 scribed. 
 
 " Selenium was discovered by Berselius, but its 
 quantity in nature is so small, that it is difficult to 
 say what purpose it can have to accomplish. It is 
 usually combined with sulphur. 
 
 " Selenium forms two acids with oxygen. It also 
 forms a deleterious gaseous compound, hydroselenic 
 acid with hydrogen. 
 
 "Arsenic sometimes occurs native, but it is usually 
 in combination with cobalt or iron. The white 
 arsenic of commerce is not the pure metal, but con- 
 tains oxygen, and is the arsenious acid. This and 
 
 When combined with other substances what does it form ? 
 What of Boron ? How is Phosphorus always found ? Why ? 
 Who discovered Selenium ? What does it form with Oxy- 
 gen ? What with Hydrogen ? In what state is Arsenic 
 found ? What of the white Arsenic of commerce ? 
 
ELEMENTS OF GEOLOGY. 57 
 
 arsenic acid, are known for their extremely poison- 
 ous qualities. 
 
 " Pure metallic arsenic has a bright bluish-white 
 colour, a crystalline texture, and is very brittle. 
 When cold, it has no smell ; but its vapour has the 
 odour of garlic, by which the metal may be always 
 distinguished. 
 
 "Antimony was discovered by Basil Valentine 
 in the fifteenth century, and is said to have received 
 its name from the circumstance that several monks 
 were killed by taking it as a medicine. It is some- 
 times found native, but more frequently as a sul- 
 phuret. The metal has a bluish-white colour, con- 
 siderable brillancy and is very brittle. The oxides 
 of antimony are used in medicine. 
 
 "Tellurium, Chromium, Uranium, Vanadium, 
 Molybdenum, Tungsten, Titanium, and Columbium, 
 are not abundant in nature ; and excepting chro- 
 mium, which is sometimes used in the preparation 
 of colours, are useless in the arts. The mere men- 
 tion of their names will therefore be sufficient. 
 
 " Lithium is the metallic base of Lithia, a sub- 
 stance found in a mineral called petalite by M. 
 Arfwedsen, and since found in spodumere, lepidolite. 
 
 " Lithium is a white-coloured metal, and has a 
 great affinity for oxygen. 
 
 " We are indebted to Davy for the knowledge of 
 lithium, potassium, and sodium, all of which were 
 
 What distinguishes the pure metallic Arsenic ? By whom 
 was Antimony discovered ? By what circumstance did it 
 receive its name ? Name those bodies that are useless in the 
 arts? Who discovered Lithium? To whom are we in- 
 debted for the knowledge of it ? 
 
58 ELEMENTS OF GEOLOGY. 
 
 detecte by the application of voltaic electricity to 
 their several oxides. 
 
 " Strontium the base of strontian, is a heavy me- 
 tal ; and not abundant in nature. 
 
 " Barium is a dark gray-coloured metal that has 
 a strong attraction for oxygen, and is the base of 
 barytes. 
 
 " Glucinium, Yttrium, Zirconium, and Thorium, 
 are metallic principles discovered by the analysis of 
 some rare minerals. They appear to exist in very 
 small quantities ; and it is therefore only necessary 
 that their names should be mentioned. 
 
 " Manganese is never found in a metallic state ; 
 for it has so great an affinity for oxygen, that it is 
 oxydised by mere exposure to the air. It was first 
 procured in a metallic form by Gahn in the year 
 1775. Manganese is a bright metal, of a darkish- 
 white colour, brittle, but hard. 
 
 " Nickel is a white ductile malleable metal. Its 
 principal ore is a copper-coloured mineral, called 
 Kupfer, or copper nickel, which is an arseniuret. 
 It is not abundant as a mineral, but is found in 
 nearly all meteoric stones. 
 
 " Cobalt is a grayish-coloured metal, brittle, and 
 difficult of fusion. Both cobalt and nickel obey the 
 magnetic force. The ores of cobalt are procured from 
 Sweden, Saxony, and from some parts of England. 
 
 How was it detected ? What of Strontium ? What of 
 Barium ? What bodies were discovered by the analysis of 
 some rare metals ? Why is Manganese not found in a me- 
 tallic state ? By whom was it first procured ? What of 
 Nickel ? Where are the ores of Cobalt procured ? What 
 attractive force do Cobalt and Nickel obey ? 
 
ELEMENTS OF GEOLOGY. 59 
 
 " Cerium was discovered in the year 1804, but its 
 properties are not known ; and it has been obtained 
 only in very small quantities. 
 
 " Zinc is one of the most combustible of all the 
 metals, has a bluish-white colour, laminated texture, 
 and great fusibility. Calamine, a native carbonate ; 
 and Blende, a native sulphuret ; are its most im- 
 portant ores. 
 
 " Cadmium is a soft, ductile metal, usually found 
 in combination with zinc. It was discovered in an 
 oxide of zinc, in the year 1817, by Strome,yer. 
 
 " Lead is chiefly obtained from a mineral called 
 galena^ which consists of lead and sulphur. The 
 ores of this well known metal are very abundant, 
 and the metal itself is extensively employed in the 
 arts. 
 
 " Tin was known to the ancients. Cornwall has 
 been long celebrated for its production. It chiefly 
 occurs as an oxide among the primitive rocks. Tin 
 is a white, malleable metal, and is extensively used 
 in the arts, and in the manufacture of metallic goods. 
 
 " Bismuth is a reddish-white laminated metal, and 
 is found native, as well as in combination with other 
 substances. 
 
 " Copper is one of the most abundant of the me- 
 tals, and is chiefly obtained from the native sul- 
 phuret though it is also found in its metallic state. 
 
 When was Cerium discovered ? What peculiar property 
 distinguishes Zinc? What are its most important ores? 
 When and by whom was Cadmium discovered ? From what 
 is Lead chiefly obtained ? Where does Tin mostly occur as 
 an oxide ? For what has Cornwall been long celebrated ? 
 What of Bismuth ? What distinguishes Copper ? 
 
60 ELEMENTS OF GEOLOGY. 
 
 It may be distinguished from all other metals, ex- 
 cept titanium by its red colour.* 
 
 " Mercury, or quicksilver, is the only metal that 
 is fluid at common temperatures. It is found in 
 various states, both native and in combination, 
 chiefly with sulphur. 
 
 " Mercury freezes at thirty-nine degrees below 
 zero of Fahrenheit's scale, and in Hudson's Bay it 
 was not only solidified, but beaten into sheets as 
 thin as writing paper. The mercury of commerce 
 is chiefly obtained from Spain and Peru. 
 
 " Silver is found native, and in combination with 
 sulphur and several of the metals. Although the 
 metal has a great commercial value, yet as an in- 
 gredient in the composition of the earth's crust, it 
 is very unimportant. 
 
 " Silver has however many properties such as 
 malleability, ductility, and tenacity, which would 
 make it valuable in the arts, if it could be obtained 
 for such purposes. 
 
 " Gold has always been found in a metallic state, 
 either pure or in combination with some other me- 
 tal. Gold is chiefly obtained from Africa and South 
 America, but in so small quantities, that it must be 
 considered as an unimportant mineral principle, f 
 
 How is Mercury usually found ? At what degree does it 
 freeze ? What is said of it in Hudson's Bay ? What is said 
 of Silver ? What properties has Silver ? In what state has 
 Gold been always found ? 
 
 * Copper may be distinguished from Titanium by its softness. 
 
 t It is found in the United States in larger masses and more exten- 
 sively diffused than in any other Country. Masses of more than 
 201b. weight hare been found in North Carolina. 
 
ELEMENTS OF GEOLOGY. 61 
 
 "Platinum is the heaviest of all metals, has a 
 brilliant white colour and is very ductile. It is 
 found in many parts of South America, and usually 
 in grains. The largest mass ever found, now in the 
 Royal Museum at Madrid, does not weigh more 
 than a pound and three quarters. 
 
 " Palladium, Rhodium, Iridium, and Osmium, are 
 also obtained in very small quantities, and together 
 form so inconsiderable a portion of the earth's crust, 
 that we need not take any farther notice of them. 
 
 " In the vast laboratory of the earth, these prin- 
 ciples have been at various times so submitted to 
 each other, as to produce the compounds which are 
 now found in large masses, constituting rocks, and 
 in smaller portions as mineral specimens. 
 
 " But all these compounds have been formed in 
 obedience to the same general laws as now influence 
 the union of particles and masses, and it is upon our 
 knowledge of these laws, that we must depend for 
 an explanation of the many difficulties that are felt 
 in accounting for the present state of mineral com- 
 pounds."* 
 
 What qualities has Platinium ? What is the weight of the 
 largest mass of it ever found ? Name those bodies that form 
 so inconsiderable a portion of the earth's crust ? On what 
 are we to depend for our knowledge of general laws ? 
 
 * Higgins on the earth, pp 371. 377. , 
 
 6 
 
62 QUARTZ. 
 
 CHAPTER III. 
 
 It has been remarked that notwithstanding the 
 variety of minerals, those forming the mass of the 
 globe, as far as exposed to our observation, are few 
 in number, viz : 
 
 1 QUARTZ ; 6 CHLORITE ; 
 
 2 FELDSPAR ; 7 TALC ; 
 
 3 MICA ; 8 GYPSUM ; 
 
 4 HORNBLENDE ; 9 LIMESTONE ; 
 
 5 AUGITE ; 10 SERPENTINE. 
 
 Slate and clay might be added, but they are rather 
 aggregated minerals, in a minute state of division, 
 than distinct minerals. 
 
 QUARTZ. 
 
 Quartz consists entirely of silex. Rock crystal, 
 which is clear transparent quartz, is pure silex. 
 Quartz varies much in its colour, but is most gene- 
 rally white or light coloured. It is hard scratches 
 glass cannot be cut with a knife strikes fire with 
 steel cannot be easily melted alone and when two 
 pieces are rubbed together in the dark they give out 
 light, or phosphoresce, as it is termed, and a pecu- 
 liar odour is emitted. Quartz, when broken, has a 
 
 What are the minerals of the geological alphabet ? What 
 substances might be added ? Of what is quartz composed ? 
 ; What mineral is pure silex? What are the properties of 
 ; quartz? 
 
FELDSPAR. 63 
 
 lustre upon the surface like broken glass, but when 
 the quartz is not clear or transparent, the lustre is 
 greasy or looks like a bright surface over which oil 
 had been rubbed. 
 
 Quartz is generally in rough, shapeless masses ; 
 but sometimes is in beautifully regular forms, more 
 brilliant, and perfect in form, than the Lapidary 
 could make them. 
 
 These regularly formed bodies, whether they 
 be quartz, or any other mineral, or any sub- 
 | stance whatever, are called crystals. The 
 usual form under which quartz crystallizes, 
 is a six-sided prism terminated by six-sided 
 pyramids, as seen in the margin. 
 
 Quartz occurs compact or solid, when it is said 
 to be massive ; and granular, when , composed of 
 grains like some of the sandstones. When quartz 
 is very porous it is said to be spongiform ; when in 
 pendulous masses like a stalactite or icicle, it is 
 stalactical quartz. 
 
 Quartz sometimes forms whole mountains, but 
 more often it is in aggregated masses with other 
 minerals, to form rocks. Quartz occurs abundantly 
 on the sea shore, and in the interior of almost every 
 country, in the form of sand. The white pebbles 
 
 In what form is quartz generally observed ? What are 
 crystals ? and what is the form in which quartz crystallizes ? 
 What is massive quartz ? What granular quartz ? What 
 spongiform quartz ? and stalactic quartz ?. Does quartz ever 
 form mountain masses ? In what situation is it more fre- 
 quently found ? What is sand ? What are the white peb- 
 bles in gravel"? 
 
64 MICA. 
 
 in gravel are quartz, as are most of the hard stones 
 that we see about the country. 
 
 FELDSPAR. 
 
 There are several varieties of Feldspar, but they 
 agree in some of their more important characters. 
 They are composed of the same ingredients, viz : 
 silica, alumina, and potassa. They are all hard 
 enough to scratch glass, but are less hard than 
 quartz. Feldspar is laminar, or composed of plates, 
 and it has a shining lustre. Its colour is variable, 
 but is generally white or reddish. It can be melted 
 without difficulty. 
 
 It is sometimes crystallized, and almost always 
 crystalline ; and the brilliant surfaces 
 when it is broken, are in the direc- 
 tions of the faces of the figure in the 
 margin, the faces P and M being per- 
 pendicular to each other, the others 
 oblique. 
 
 Feldspar is sometimes compact, and sometimes 
 forms mountain masses, but more frequently it forms 
 a constituent part of other rocks, as granite, sienite, 
 &c. Feldspar is used in the manufacture of por- 
 celain or china ware as it is called. 
 
 MICA. 
 
 Mica is composed of the same substances essen- 
 
 Of what is feldspar composed ? What are the properties 
 of feldspar ? Is feldspar always crystalline ? Does it ever 
 form mountains, and where is it more commonly found, and 
 in what rocks ? For what is feldspar employed ? Of what 
 is mica composed ? 
 
HORNBLENDE. 65 
 
 tially as Feldspar, but in different proportions. 
 Mica, or isinglass as it is sometimes called, is found 
 imbedded in rocks either in small scales, or some- 
 times in masses of some magnitude. It very easily 
 splits into thin layers or leaves, which are transpa- 
 rent, flexible and elastic. Mica is sometimes called 
 Muscovy glass, because in Russia it is often used 
 instead of glass for windows. It occurs of all shades 
 of colour^from white to black. The surface of the 
 plates of mica has a strong shining lustre ; and it 
 in fact derives its name from the Latin, micans, 
 signifying glittering. It melts without difficulty. 
 It is found in greater or less quantity in a large 
 proportion of the rocks. Its elasticity, and the 
 strength of its thin plates, renders it superior to 
 glass for many uses. It can be scratched by a 
 knife, but is scarcely hard enough to scratch glass. 
 
 HORNBLENDE. 
 
 Hornblende is composed of silex, alumina, lime, 
 magnesia, and oxide of iron. It is generally of a 
 dark green colour, and between that and black. It 
 is heavier than quartz or feldspar, but not so hard, 
 and is much more difficultly broken. It derives a 
 part of its name from its being tough, and difficult 
 to break, like horn. It can be scratched witli a 
 knife, and its powder is of a light green colour. 
 
 What is a common name for mica, and where is it found ? 
 
 What are the properties of mica? For what is mica 
 sometimes used, and why ? Is mica found in many of the 
 rocks ? Of what is hornblende composed ? What are its 
 properties ? From what does it derive its name ? 
 6* 
 
66 HORNBLENDE AUGITE. 
 
 When breathed upon it gives an odour like that of 
 moist clay, which is called the argillaceous odour. 
 It melts easily, and boils up or intumesces when 
 melted. It often occurs crys- 
 tallized, as seen in the margin, 
 but is far more common in rude, 
 shapeless masses. IF however 
 these masses be examined closely, minute crystals, 
 having the first of these forms, may be observed. 
 
 Hornblende is sometimes in granular masses, or 
 else composed of long needle-shaped, or acicular 
 crystals, and sometimes these long crystals diverge 
 from a centre, and are stellar or star-shaped, or ra- 
 diated like the spokes of a wheel, and the lustre is 
 either shining, or silky. Common hornblende some- 
 times forms entire mountains by itself, but it is more 
 frequently aggregated with other minerals to form 
 rocks, as sienite, greenstone, &c. 
 
 AUGITE. 
 
 Augite is composed principally of silica, lime and 
 magnesia. It is generally black or green, but some- 
 times light coloured. It often resembles 
 hornblende, but it is much harder, arid will 
 strike fire with steel ; and it does not melt 
 so easily. It is often crystallized in 4 or 
 8 sided prisms. Augite is found abun- 
 
 Does it occur crystallized ? Under what other forms does 
 it occur? Does hornblende ever form extensive masses? 
 In what rocks is it contained as a part of the rock ? Of 
 what is augite composed ? What are its properties ? Does 
 it ever occur crystallized ? In what rocks is it found ? 
 
CHLORITE TALC. 67 
 
 dantly in rocks of volcanic origin, and in some of 
 the rooks called trap-rocks, and which are by many 
 thought to be of volcanic origin. It is also found 
 in primitive rocks. It occurs massive, or without 
 any regular form ; and granular, and then it is called 
 coccolite. 
 
 CHLORITE. 
 
 Chlorite is composed principally of silica, alumina, 
 magnesia, and oxide of iron. It is of a green colour, 
 usually a dark green, and derives its name from a 
 Greek word signifying green. It is in general an 
 aggregation of small green scales ; is so soft that it 
 can be scratched by the finger nail, and feels soft 
 and smooth, or unctuous when rubbed between the 
 fingers. It is much softer than mica, and the lat- 
 ter does not feel greasy or soapy between the fingers. 
 
 TALC. 
 
 Talc is composed principally of silex and mag- 
 nesia. It has many of the properties of chlorite, 
 but it has various colours, and is rarely of a dark 
 green like chlorite. It feels more unctuous and 
 soapy between the fingers than chlorite. Talc \s 
 distinguished from mica, by its plates being flexible, 
 
 When it is granular, what is it called ? Of what is chlo- 
 rite composed ? What are its characters ? How is it dis- 
 tinguished from mica ? Of what is talc composed ? How 
 does it differ from chlorite ? How do talc and chlorite feel 
 between the fingers ? Which is. most unctuous ? How is 
 talc distinguished from mica ? 
 
68 GYPSUM. 
 
 but not elastic like mica. Talc is generally softer 
 than chlorite, and is easily scratched with the finger 
 nail. It does not easily melt, but chlorite does. 
 Both talc and chlorite enter into the composition of 
 rocks, and the rocks are said to be talcous or chlo- 
 ritic. 
 
 GYPSUM. 
 
 Gypsum is composed of sulphuric acid or oil of 
 vitriol, united with lime. The common gypsurn 
 also contains water united to the above mentioned 
 substances. Gypsum is generally white, but some- 
 times gray, red, and of various colours. It is often 
 compact, but sometimes granular and crystallized. 
 When crystallized, it is frequently in 
 transparent plates, having 4 sides, and 
 can be separated into thin plates like 
 mica and talc. If heated, it does not 
 melt easily, but loses about one-fifth of its weight, 
 and if transparent, it becomes white and opake.* 
 It is used for a great variety of purposes, the most 
 important of which, are, for a manure, for cements, 
 and for castings. It sometimes forms hills, but 
 more often it forms layers or beds in other rocks, 
 and is generally connected with salt springs or rock 
 salt. 
 
 Of what is gypsum composed ? What does gypsum con- 
 tain besides sulphuric acid and lime ? What are the proper* 
 ties of gypsum ? When gypsum is heated, what are the 
 effects ? For what is gypsum used ? With what is gypsum 
 generally connected ? 
 
 * A body is opake when the light cannot be seen through it. 
 
LIMESTONE. 69 
 
 LIMESTONE. 
 
 Limestone is composed of carbonic acid united 
 or combined with lime, and is called carbonate of 
 lime ; gypsum is called sulphate of lime. Lime- 
 stone or carbonate of lime varies more in its ap- 
 pearance than any other mineral. It occurs of all 
 colours, and varies from a coarse grained, to the 
 most compact marbles ; from a rough un- 
 seemly stone, to a fine earthy powder ; 
 and not unfrequently it is found in the 
 most beautiful crystals. The crystals 
 occur under more than seven hundred different 
 forms, but by splitting them, the same form, or primi- 
 tive form, is obtained from all of them. The primi- 
 tive form is a rhomboid, a solid, having all its faces 
 equal to each other, but the angles not right angles. 
 The crystallized transparent carbonate of lime is 
 called calcareous spar, and has some remarkable 
 qualities. If a rhombic crystal of calcareous spar 
 be placed on a piece of paper, with a fine line of ink 
 drawn upon it that may be distinctly seen through 
 the crystal, the line appears double, or there appear 
 to be two lines near together. If the crystal be 
 turned around gradually, the lines approach each 
 other until only one is visible, and by turning it still 
 
 Of what is Jimestone composed ? By what other names 
 are limestone and gypsum called? Does limestone vary 
 much in its appearance ? What are some of the various 
 appearances and textures it presents? Does carbonate of 
 lime occur crystallized? Has it many crystalline forms? 
 Can they all be reduced to one? What is the primitive 
 *brm ? What remarkable properties are observed in calca- 
 xms spar ? 
 
70 LIMESTONE. 
 
 farther they again appear, and recede from each 
 other until you have turned it half round, after which 
 they again approach until only one line appears. 
 This is called double refraction.* Calcareous spar 
 becomes electrified")* by rubbing it, and even by pres- 
 sing it between the fingers, and retains its elec- 
 tricity for some time. 
 
 Notwithstanding the great variety of appear- 
 ranees presented by carbonate of lime, it may be 
 easily recognized by the following characters. Car. 
 bonate of lime can be scratched with a knife acids 
 when poured on it boil up or effervesce violently 
 and when heated highly, it becomes quicklime, in 
 which state it is easily recognized by the taste, and 
 by its burning the tongue. If a large fragment of 
 it have water thrown upon it, it becomes hot and 
 crambles to a white powder. 
 
 Limestone occurs abundantly in every country ; 
 it forms mountains, and even ranges of mountains. 
 The strong granular and compact limestones are used 
 as marbles ; many of them make good building 
 stones, and lime ; chalk is used for marking, and mak- 
 ing lime and whiting, and marl is used as a manure. 
 
 How may carbonate of lime be recognized ? Does lime- 
 stone occur abundantly ? For what are the various kinds ot 
 carbonate of lime employed ? 
 
 * Light is said to be refracted when, in passing through a transparent 
 body, it is bent out of its course. A stick, when put into water, ap- 
 pears bent, and to have a different direction in the water from what it 
 has out. This is owing to refraction. 
 
 t Electrified bodies attract light substances : and if the electrified 
 surface be of any considerable magnitude, on approaching it to any 
 part of the body, a small spark is seen, and a snapping noise heard. 
 The spark is similar to lightning, and the noise to thunder, only infi- 
 nitely smaller. 
 
SERPENTINE SLATE AND CLAY. 71 
 
 SERPENTINE. 
 
 Serpentine is composed of silica, magnesia, and 
 water, but sometimes contains a small proportion 
 of other substances, as alumina, oxide of iron, dec. 
 Its colour is generally some tint of green, but often 
 variegated. Serpentine derives its name from the 
 colours being variegated somewhat like the skin of a 
 serpent. It is generally compact rarely granular 
 or crystalline yields to the knife is somewhat 
 unctuous to the touch and is capable of receiving 
 a high polish. It is sometimes used as a marble, and 
 limestone sometimes contains serpentine dissemi- 
 nated through it in grains, and is then called verd 
 antique marble. Serpentine forms considerable 
 masses in many parts of the world, and it seems to 
 be the repository of the chrome iron, used so exten- 
 sively to obtain chromate of lead or chrome yellow. 
 
 SLATE AND CLAY. 
 
 s 
 
 These substances are mostly composed of silica 
 and alumina, and sometimes a little carbon or oxide 
 of iron. Most of the slates can be scratched easily 
 by the knife, and the clays by the finger nail. The 
 slates generally split out into thin layers, and some 
 of the clays do the same. When broken, they both 
 show a fine grained fracture, and the clay, parti* 
 
 Of what is serpentine composed ? What is its colour ? 
 What are its properties ? For what is it employed ? What 
 is verd antique marble ? Does serpentine form large masses ? 
 What mineral is found in serpentine, and for what is it em- 
 ployed ? Of what are slates and clays composed ? What 
 are their characters ? 
 
72 STRATIFICATION. 
 
 cularly, shows what is called the earthy fracture. 
 Both slates and clays give the argillaceous odour 
 when breathed upon. 
 
 Slate is used for drawing slates and for pencils, 
 for roofing buildings, &c., and the clays are em- 
 ployed for making bricks, and various kinds of pot- 
 tery. 
 
 Slate often forms extensive masses, and clay ge- 
 nerally occurs in detached beds, often of consider- 
 able extent. 
 
 CHAPTER IV. 
 STRATIFICATION. 
 
 Knowing the elementary and mineral bodies of 
 which the globe is composed, we find, by observa- 
 tion, that the aggregated masses of these substances, 
 or rocks, are arranged in a regular order of super- 
 position with regard to each other. For instance, 
 rocks, containing coal, in one country, lie below 
 those containing salt. In other countries, the same 
 rocks may be expected to occur in the same rela. 
 tive positions. 
 
 For what is slate used ? For what are clays employed ? 
 Is there any regular order of arrangement of the rocks over 
 each other ? What is the position of coal, compared with 
 that of rocks containing salt? Do rocks have the same 
 relative positions in all countries ? 
 
STRATIFICATION. 73 
 
 This is a fact of much practical utility ; and by 
 it, in connection with some others, a man is enabled 
 to say whether any particular rock or mineral may 
 probably be found in any district of country, by 
 knowing the rocks exposed there to observation. 
 We frequently see but one kind of rock in a dis- 
 tance of several miles, but more frequently there are 
 two or more. 
 
 Few rocks have their layers, or strata, in a hori- 
 zontal position, but they generally slope, or dip 
 downwards, and sometimes they stand vertically 
 upon their edges. This inclination or dip of the 
 rocks, is of great importance, as rocks are thus 
 brought to our view that would otherwise be buried 
 deep in the earth. When 
 strata of different rocks, in- 
 cline, they emerge in succes- 
 sion upon the surface of the 
 earth, thus, so that in travelling in the direction of 
 the dip you may, in a few hours, pass over many 
 different kinds of rock. The line of dip is the direc- 
 tion towards which the rock slopes. The line of 
 bearing is the direction along which the rock emer- 
 ges, or more strictly, it is the line of intersection 
 of the plane of the stratum with the horizontal plane. 
 
 "In travelling over an extent of country, the 
 direction of the strata is characterized by sameness 
 and uniformity. There is little variety in the pro- 
 
 What is the utility of a knowledge of this ? Are rocks 
 generally in a horizontal position? In what position are 
 they observed ? Of what importance is this inclination of 
 rocks ? In travelling across the strata what is observed ? 
 What is the line of dip ? What is the line of bearing ? 
 7 
 
74 STRATIFICATION. 
 
 ductions of the land, or the condition and employ, 
 ment of the inhabitants. On the contrary, in travel- 
 ling along the line of dip, our eyes are continually 
 regaled with a change of scenery. Every hill has 
 a character of its own ; a steep ascent on one side 
 is met by a gentle declivity on the other. A poor 
 soil is succeeded by one of remarkable fertility." 
 [Greenough } s Geology.] 
 
 The developement of the order of superposition 
 of rocks, is one of the most important connected 
 with geological science, both m an economical and 
 scientific point of view. 
 
 Many practical difficulties obstruct its perfect 
 accomplishment, such as the difficulty of finding 
 the junction of rocks, their imperfect stratification, 
 bent and contorted strata, faults, &c. "but these 
 difficulties disappear when several formations of 
 great extent are compared together, and the order 
 of superposition, and the relative ages of the rocks 
 are as determinate as any mathematical problem. 1 ' 
 [Humboldt on Rocks.] 
 
 A knowledge of the principles and phenomena of 
 stratification is of much practical importance, not 
 only to the geologist, but the community generally 
 and may lead to the discovery of many useful rock* 
 and minerals. It is not generally necessary to bora 
 through rocks to ascertain what lie below them. 
 
 What is most important in an economical and scientific 
 point of view ? When do these difficulties disappear ? Of 
 what use is a knowledge of stratification ? Is it necessary 
 to bore, to ascertain the rocks below or above any particulai 
 one? 
 
STRATIFICATION. 75 
 
 There is a regular order in which the rocks lie 
 over each other : knowing this arrangement, and 
 the direction in which the rocks dip, we know that 
 
 B they must 
 emerge in 
 succession. 
 
 Instead of 
 
 digging or boring through the strata at A, they may 
 be examined by travelling towards B, in a direction 
 opposite to the direction of the dip. The bottoms 
 and sides of water courses, and the cliffs in the hills 
 and mountains, are the situations where the rocks 
 can be examined to the greatest advantage. 
 
 In this way, as the different strata emerge in suc- 
 cession, they can be examined with any required 
 degree of attention, and better than by boring, as 
 then but a very small portion of the rock can be ex- 
 posed to observation. If the line of dip be known, 
 the line of bearing is also known, for it is at right 
 angles to it. If the line of bearing be known, the 
 direction of the dip does not follow, for it may dip 
 in two directions from that line, thus, 
 as the sides of a roof from the ridge. 
 When rocks dip, their inclination is 
 expressed in degrees of the quadrant.* 
 
 How would you ascertain their positions ? What situations 
 are most favourable for examination ? If the line of dip be 
 known, is the position of the line of bearing known ? and the 
 reverse ? 
 
 * The quadrant is one quarter of a circle. A circle is divided into 
 360 degrees, and of course, the quadrant contains 90 degrees, or equal 
 parts. 
 
76 STRATIFICATION. 
 
 Whatever the angle or degree of inclination may 
 be, the thickness of the stratum is measured by a 
 line perpendicular to the plane of the stra- 
 tum, (as seen in the margin.) When the 
 edges of the strata project from, or show 
 themselves on the surface of the earth, they 
 are said to out crop, and the projection is termed the 
 crop out of the strata. 
 
 Strata generally lie upon each other like the 
 leaves of a book, and then they are said to be con- 
 formable strata. Sometimes other sets of strata lie 
 upon the last, which are conformable among them- 
 selves, but not 
 to the first, 
 thus, and they 
 are then said 
 to be unconformable. 
 
 It is necessary to distinguish strata, from the 
 thin slaty layers into which some rocks divide. 
 When rocks are divided into regular layers of con- 
 siderable extent, they are said to be stratified. 
 
 The planes of stratification, and those in which 
 the rocks most readily split, are not always the 
 same; arid this is remarkably the case in slate. 
 The strata and thin layers into 
 which this rock splits, are ar- 
 ranged thus, the coarse lines 
 representing the strata seams, and the fine ones the 
 thin layers of slate. 
 
 How is the thickness of a stratum measured ? What is 
 the outcrop of strata ? What are conformable, and uncon- 
 formable strata ? What is the distinction between layers and 
 strata 1 
 
STRATIFICATION. 
 
 77 
 
 There is frequently some difficulty in determin. 
 ing the true planes of stratification in slaty rocks ; 
 but if one fact be kept in mind, the difficulty 
 vanishes. This fact is, that the strata vary in their 
 texture ; some are very fine grained, some are coarse 
 as a sandstone and the planes of these beds of diffe- 
 rent materials, or of various textures, indicate the 
 direction of the planes of stratification. 
 
 Clays are also often divided by parallel seams, 
 making an angle with the strata seams, too regular 
 to be the effect of chance, they must be regulated 
 by some law of nature. 
 
 Some clays break into regular rhombic figures, 
 as regular in their forms as crystals. 
 
 Strata vary from a few inches to several feet in 
 thickness. 
 
 Strata are not always plane surfaces, . 
 but are often curved, or bent, thus. 
 
 Sometimes the 
 layers are much 
 bent in various directions, (as 
 seen in the margin,) and the 
 rocks are then said to be con- 
 torted.* 
 
 What fact if observed dispels the difficulties found in de- 
 termining the true planes of stratification ? What inference 
 must be drawn from clays being often divided by parallel 
 seams ? Into what figures do some clays break ? Do the 
 layers of slate correspond with the strata ? Are strata always 
 in plane layers ? What are contorted strata ? 
 
 * M. Ramond, in speaking of the compact and argillaceous lime- 
 stones and slates of Estaube, and the sandy limestone, breccias, and 
 grits of Mont Perdu, says: "They seem to have been driven 
 against one another by opposite forces, which, at the point of contact, 
 
 7* 
 
78 STRATIFICATION. 
 
 Unless care be taken to ascertain the direction 
 of the dip, the apparent dip is very apt to be mis- 
 taken for the real one. If the edges of the rock be 
 examined in the direction of the line of bearing, the 
 strata appear to be horizontal, when by examina- 
 tion in other directions, they would be found con- 
 siderably inclined. 
 
 The following figure will perhaps serve to illus- 
 trate. The end of the 
 figure represents the 
 inclination, and the top 
 and long side show the 
 strata edges in the direction of the line of bearing. 
 A person should never judge of the dip of strata, 
 from seeing a section in only one direction, but should 
 always seek to see sections in at least two directions, 
 from which he can obtain data for calculating the 
 true dip. 
 
 In most instances, a practiced eye would be able 
 to judge of the direction and amount of the dip j 
 
 Is there any liability to mistake the direction or quantity 
 of dip ? What precaution should be taken in judging of the 
 dip of strata ? Where the direction and amount of the dip, 
 and the direction of the line of bearing of the strata is of par- 
 ticular practical utility, what should be done ? 
 
 have shivered them into short, irregular, tortuous veins, tne entangle- 
 ment of which forms the intervening masses. Figure to yourself," 
 says he, " a number of viscid liquors, differently coloured, spreading 
 themselves in whirling laminae in the vessel in which they are poured, 
 watch a thick column of smoke floating in the air, you will have be- 
 fore you an image of the confusion which prevails in these rocks. The 
 struggle of two conflicting masses, the repeated assaults of the one, 
 the perservering resistance of the other, this is the idea naturally sug- 
 gested on contemplating the contorted veins in these rocks. 'Tis a 
 sea consolidated in a storm, the violence of which may still be seen in 
 the petrified waves." GreenougWs Geology. 
 
STRATIFICATION. 79 
 
 but where the determination of these, and the direc- 
 tion of the line of bearing of the strata is of any 
 particular practical utility, as in opening mines, 
 quarries, &c., the direction by compass of a small 
 vertical plane, on each of the two sections, and the 
 angular dip of the lines of stratification on those 
 vertical sections, should *be measured. Data are 
 thus afforded for trigonometrical calculation of the 
 direction of the line of bearing, and of the dip with 
 its exact angle. 
 
 There is another error that may be committed by 
 a person not attending closely to the dip and direc- 
 tion of the strata. " Suppose a hill to be covered 
 with vegetable soil, and a quarry or pit, was made 
 in it near the bottom, as at A, the stone was disco- 
 vered to be sandstone ; suppose another pit had been 
 B sunk near 
 
 the sum- 
 mit, at B, 
 which cut 
 
 into limestone. It might be supposed that the lime- 
 stone lay over the sandstone stratum, when it is in 
 reality below it." In this particular instance two 
 strata intervene in the figure. 
 
 In limestone mountains, the fissures are apt 
 to be mistaken for strata seams. These partings 
 and seams are sometimes nearly vertical, when the 
 starta are horizontal. These sometimes enlarge 
 
 
 What is the result ? Is there any liability to mistake the 
 positions of rocks on hills ? What causes the difficulty of 
 ascertaining the stratification of limestone in some cases ? 
 Do these strata ever appear vertical, when they are in realitv 
 horizontal ? 
 
80 
 
 STRATIFICATION. 
 
 so as to be more conspicuous than the strata seams. 
 " To add to the difficulty it very frequently hap- 
 pens, that a calcareous deposition, like a coat of 
 plaster, covers the face of a rock ; this has been 
 formed by water running over the surface and de- 
 positing calcareous particles upon it. 
 
 " This deposition sometimes conceals the strati- 
 fication seams, as completely as a coat of plaster 
 covers the rows of brick in a building. The ver- 
 tical seams or partings, are sometimes open, and 
 sometimes have formed parallel ridges which efface 
 the appearance of the strata seams in one part of 
 the rock, but not in the other ; and in such instances, 
 we have apparently a mountain mass, in which the 
 strata are partly horizontal and partly vertical." 
 [BdkeweWs Geology.] 
 
 In the accom- 
 panying figure, a, a, 
 are the apparently 
 vertical strata and 
 b, b, the horizontal 
 and proper strata. 
 Strata generally appear to terminate at their out 
 crop. When the strata are bent, the same strata 
 may often be found again not far from their appa- 
 rent termination, as may be observed in the figure. 
 The strata that appear to terminate near A, are 
 35 C found again 
 
 on the other 
 side of A; the 
 curvature or 
 
 Do strata always terminate at their outcrop ? 
 
STRATIFICATION. 81 
 
 dip varying, they approach and then recede from 
 the surface, dipping in opposite directions at A, B 
 andC. 
 
 A stratification analogous to this, is often ob- 
 served adjacent to some of the mountain ranges, 
 where the strata appear to rest against the sides of 
 the mountain masses ; d 
 being the mountain, and 
 a a, b b, c c, similar strata 
 of rocks. 
 
 There is another in- 
 stance in which the strata may not terminate at 
 their outcrop, but appear again in the opposite hill, 
 as a a, but b 6, by its prolongation, would pass over 
 the hill C. 
 
 C Where the strata 
 
 are nearly horizon- 
 tal similar strata are 
 almost always found 
 
 on the opposite sides 
 
 a of a valley, as if they 
 
 had been formerly continuous, and the valley since 
 formed by some powerful cause. 
 
 There is another point in relation to stratification, 
 (and it is also applicable to veins, in rocks that are^ 
 not stratified,) that, from its practical importance 
 in mining, should be well understood. The bed of 
 coal, or vein of ore, appears suddenly to terminate. 
 
 Do strata rest or lean against mountains ? Does the same 
 stratum ever appear on the opposite sides of valleys ? When 
 beds of coal terminate suddenly, can they be regained ? and 
 how? 
 
82 
 
 STRATIFICATION. 
 
 a When this occurs, 
 b the bed may be found 
 again, either above or 
 below its original level. 
 At its apparent termi- 
 nation, a fissure, or else 
 a different kind of rock, occurs, generally in the 
 form of a vein, as c c. 
 
 Repeated observation has shown, that if, at the 
 apparent termination, the rock cutting it off inclines 
 towards you, so as to project over your head, the bed 
 of coal, or other mineral, lies at a lower level on the 
 other side of c c, as though the mass of strata on 
 one side of the vein had slid down to a lower level. 
 In the figure, a a and b b represent beds of coal cut 
 off by the vein or dyke, c c. In proceeding from 
 a to a, the reverse of the above would take place. 
 
 Analogous appearances are sometimes presented 
 upon the surface of the earth, where there are high 
 precipices of rock in successive ranges of hills, as 
 a & a in the figure. 
 
 The same strata 
 o -- apparently occur 
 in each succes- 
 sive ridge, and the strata all dip in the direction a b, 
 and the masses, forming the ranges of hills appear 
 to have cracked off, and each succeeding mass to 
 have slid down over the cliff of the preceding. 
 
 "What has been observed of the positions of the beds of coal, 
 in reference to the sloping of the vein or dyke ? What appears 
 to have caused the present position of the beds ? Is there 
 any analogous appearance in the hills on the surface of the 
 earth ? and what is the appearance presented by such hills ? 
 
STRATIFICATION. 83 
 
 " In the coal formation at Newcastle in England, 
 the strata, at distances of 2 or 3 miles, are shattered 
 by fissures which extend many leagues. Where 
 these fissures occur, the strata have been dislocated, 
 and the subsidence amounts in some instances to 
 1000 feet ; yet, the surface of the earth is uniform 
 and level, which shows the immense mass of mate- 
 rials that must have been removed and deposited to 
 conceal thus these subterranean mountains." [Rep. 
 Brit. Association, i. 381. 
 
 The various phenomena of stratification indicate, 
 that powerful forces have been put in action, thus 
 to bend and break up the solid strata of the globe. 
 In some parts of the world, the stratified masses of 
 great extent are thrown into every variety of posi- 
 tion, and as much confusion prevails in their ar- 
 rangement, as in the masses of ice that we see in 
 our rivers, where the currents or tides have brought 
 large fields of it crushing against others, breaking 
 them into large fragments, thrusting and overwhelm- 
 ing them in every direction, and the frost cementing 
 them thus together. 
 
 What is observed of the coal formation at Newcastle? 
 What does it show ? What do the phenomena of stratifica. 
 , tion indicate ? What is said of confused stratification ? To 
 what is it compared ? 
 
84 FORMATIONS. 
 
 CHAPTER V. 
 FORMATIONS. 
 
 When a series of strata of a similar rock, are ar- 
 ranged with occasional strata of other rocks inter- 
 vening, which recur in different parts of the series, 
 they are regarded as having been formed during the 
 same epoch, and under similar circumstances ; and 
 such series are called, by geologists, Formations. 
 Thus the strata of sandstone, slate, limestone, &c. 
 accompanying coal, are altogether, called the cool 
 formation. 
 
 Humboldt's definition of a formation is, " an as- 
 semblage of mineral masses so intimately connected, 
 that it is supposed they were formed at the same 
 period, and that they present in the most distant 
 parts of the earth, the same general relations both 
 of composition and relation to each other." [Hum- 
 boldt on Rocks, p. 1.] 
 
 Some formations are called independent forma- 
 tions, and that which is considered a proof of the 
 " independence of a formation is its immediate super- 
 position on rocks of a different nature which ought, 
 consequently to be considered as more ancient." 
 Trap and volcanic rocks are an exception to this 
 rule. [Humboldt on Rocks, p. 6.] 
 
 What are formations ? What is Humboldt's definition of 
 a formation ? What is the proof of independant formations ? 
 What are exceptions to this rule ? 
 
FORMATIONS. 85 
 
 Some formations are called geological equiva- 
 lents because, although they may differ in their ex- 
 ternal appearance, and in mineralogical and chemi- 
 cal composition, they contain similiar assemblages 
 of organic remains ; and have the same geological 
 position. 
 
 Humboldt's parallel formations are equivalents 
 that replace or represent each other. 
 
 Among the various proofs of equivalent forma- 
 tions in the most distant parts of the earth, is the 
 identity of the organic bodies buried in beds having 
 a similar geological position. \Humboldt on Rocks, 
 p. 44.] 
 
 When formations succeed each other, it is usually 
 the case that strata and beds of the one, begin at 
 first to alternate with the other ; until after these 
 preludes to a change, a new formation appears with- 
 out any subordinate beds. [Humboldt on Rocks 
 p. 14. Relation Historique, ii. p. 140.] 
 
 The idea may have been derived from what pre- 
 cedes, that all rocks are stratified, but it is not so. 
 Many show no traces of stratification, but are in 
 large shapeless, mountain masses, as granite, sienite, 
 porphyry, &c. 
 
 All rocks, whether stratified or not, are traversed 
 by veins of various mineral substances. Most of* 
 the metallic ores are found in veins. Veins appear 
 to have been once open fissures, formed by the 
 
 What are geological equivalents ? and what proof is given 
 of them ? When formations succeed each other what is 
 usually the case ? Are all rocks stratified ? What are all 
 rocks traversed by ? Where are most of the ores found ? 
 What are veins ? 
 
 8 
 
86 FORMATIONS. 
 
 cracking of the strata, and since filled with the sub- 
 stances now occupying them. 
 
 The walls of a vein are the rocks contiguous to 
 it. The upper side of the vein, when inclined, is 
 called the roof, and the lower the floor. In the 
 same rock, there are frequently several systems of 
 veins, formed at different times, and then we can tell 
 the relatives ages of each, for the oldest is inter- 
 sected by all, and the newest is not crossed by any 
 of the others. Veins vary from a few lines to many 
 feet in breadth. They are sometimes of the same 
 materials as the rock traversed by them, but gene- 
 rally different. 
 
 It has been observed, that all the rocks might be 
 referred to two general classes, which were called 
 the primitive and secondary rocks. Geologists have 
 since arranged rocks into a greater number of 
 groups. 
 
 A class of rocks was observed that had some of 
 the crystalline structure, like primitive rocks, and 
 the} 7 also contained the remains of animals imbedded 
 in their mass. From these rocks showing charac- 
 ters intermediate between the primitive and secon- 
 dary rocks, they were called transition rocks. There 
 is another class constituting the more recent rocks, 
 called tertiary rocks. 
 
 How do they appear to have been formed ? What are the 
 walls of a vein ? What its roof? What its floor ? Is there 
 often more than one system of veins ? How can the relative 
 ages of the veins be determined ? Are veins ever of the 
 same material as the rock ? Into what two classes can rocks 
 be divided ? What are transition rocks ? What secondary ? 
 What are tertiary rocks ? 
 
FORMATIONS. 87 
 
 More recent still, in point of time, are the depos- 
 ites of sand, clay and gravel, that we see almost 
 every where, and which cannot have been placed in 
 their present position hy the action of water, run- 
 ning as it does in the present water-courses. This 
 is called dihrnion, or a diluvial deposit, from its hav- 
 ing been deposited, apparently, during the deluge. 
 
 Most recent of all is the alluvion, or alluvial de- 
 posit, which is now forming by the action of water 
 and winds. The mud and sand brought down by 
 rivers and torrents, and deposited in a different situa- 
 tion from what it had before, is alluvion. 
 
 These classes of rocks and deposites, arranged in 
 the order in which they occur naturally, are ; 
 
 1 ALLUVIAL deposites ; 4 SECONDARY rocks ; 
 
 2 DILUVIAL 5 TRANSITION " 
 
 3 TERTIARY rocks ; 6 PRIMITIVE " 
 
 Within a few years, it has been proposed to sub- 
 stitute other names, upon the ground that these in- 
 ;roduce theoretical considerations, as to the time, or 
 mode, of formation of the rocks. If such names be 
 substituted as may suggest the idea of relative posi- 
 tions only, observers will be less apt to be influenced 
 by particular theories, when they come to the ob- 
 servation of facts. 
 
 What are alluvial deposits ? What diluvial ? What is the 
 jrder in which these classes of rocks and deposits are arranged ? 
 For what reason has it been proposed to substitute other 
 iam.es for those just mentioned ? 
 
88 FORMATIONS. 
 
 In conformity with this plan, Conybeare and 
 Phillips have arranged rocks in five classes, viz : 
 
 1 SUPERIOR; 3 MEDIAL ; 5 INFERIOR. 
 
 2 SUPERMEDIAL ; 4 SuBMEDIAL ; 
 
 In this classification, the coal formation, in the 
 lower part of the secondary of the other arrange- 
 ment, is taken as the medial class ; the submedial 
 corresponding with the transition, and the inferior 
 to the primitive rocks. The supermedial embraces 
 the upper part of the secondary class, and the supe- 
 rior, the tertiary rocks and the diluvial and alluvial 
 deposites. 
 
 De La Beche has also given a classification of 
 rocks that is very good. He makes two general 
 classes, like Lehman, calling them Superior and In. 
 ferior rocks ; the first comprehending all the rocks 
 containing fossils, and the latter corresponds with 
 the primitive rocks. 
 
 The first, or superior rocks, are divided into 
 groups, according to the arrangement of the organic 
 remains contained in them. The inferior, are di- 
 vided into stratified and unstratified rocks, and they : 
 are described in the usual manner. 
 
 The arrangement which has been generally em- ; 
 ployed in describing the rocks, will be adhered to 
 in this treatise, as more convenient, and more easily 
 
 What is Conybeare and Phillips' arrangement? Wha 
 formation is assumed as the medial ? To what do the infe 
 nor, submedial, supermedial and superior correspond in th 
 former classification ? What is De La Beche's arrangement " 
 
FORMATIONS. 89 
 
 applied by those who have made no great progress 
 in a knowledge of fossils. 
 
 The rocks will be described in the order of their 
 position, beginning with the lowest. 
 
 " If any rocks can with propriety be denominated 
 primary, or primitive, they are those which are 
 most widely spread over the globe, in the lowest re- 
 lative situation, and which contain no remains of 
 organic existence. Primary rocks are .supposed, 
 by geologists, to constitute the foundation on which 
 rocks of all the other classes are laid ; and if we take 
 an enlarged view of the structure of the globe, we 
 may admit this to be the fact, but the admission 
 requires certain limitations." 
 
 The same causes that have produced certain rocks 
 in masses of great extent below all the other rocks, 
 have, in certain situations, reproduced them in 
 smaller masses, covering the transition and secon- 
 dary rocks. 
 
 " The structure of primary rocks is crystalline ; 
 they form the central parts of the most elevated 
 mountain chains, and they occur at the lowest depths 
 that have been yet explored, and are hence believed 
 to be the most ancient of the rock formations." 
 
 The principal rocks called primitive, are 
 
 1 GRANITE ; 3 MICA SLATE. 
 
 2 GNEISS, or SLATY GRANITE ; 
 
 There are some other primary rocks that occur 
 
 What are primitive rocks, and what are they supposed to 
 constitute the foundation of? What is the structure of prim- 
 itive rocks ? What are the principal primative rocks ?^ 
 / 8* 
 
90 GRANITE. 
 
 imbedei in, and interstratified with, the principal 
 primitive rocks. They are called subordinate rocks. 
 They are 
 
 HORNFL^NDE ROCK ; CRYSTALLINE LIMESTONE ; 
 
 SERPENTINE " QUARTZ ROCK. 
 
 " The three principal rocks of the primary class, 
 granite, gneiss and mica slate, might with propriety 
 be regarded as belonging to one formation. They 
 are con-posed essentially of the same minerals, vary- 
 ing in rifferent proportions, and are rather modes of 
 the same rock, than different species. They pass 
 by gradation into each other, as one or other of their 
 constituent minerals becomes more or less abun- 
 dant ; they alternate with each other in various 
 situations, and may be regarded as cotemporaneous. 
 It may, however, for convenience of description, be 
 proper to treat of each separately." 
 
 GRANITE. 
 
 Granite is an aggregation of grains, or masses of 
 quartz, feldspar, and mica, adhering to each other 
 without any cement. The feldspar and mica are 
 generally crystalline, but the quartz rarely shows 
 this structure. 
 
 What are the subordinate primitive rocks ? Do granite, 
 gneiss and mica slate belong to one formation ? Do they 
 bear any analogy with each other ? Do they alternate with 
 each other ? Of what minerals is granite composed ? Are 
 the minerals crystalline 1 
 
GRANITE. 91 
 
 The minerals of which granite is composed are 
 aggregated differently in different granitic rocks, 
 and often, even in the same rock, the grains and 
 crystals in one part of the rock are coarse, in the 
 other fine ; and perhaps one of the minerals may 
 predominate in one part, and be in small quantities 
 in another. 
 
 When granite or any other rock is fine grained, 
 with lar^e crystals of feldspar imbedded, it is said to 
 be porphyritic. 
 
 Feldspar, in general, constitutes by far the largest 
 part of granite, and its colours are various, but gen- 
 erally white or red. The mica is variable also, in 
 colour, but is generally black or white. 
 
 Sometimes other minerals replace the mica en- 
 tirely, or in part, in granite, without altering its gen- 
 eral character. When hornblende -supplies the 
 place of mica, the rock is called sienite, and when 
 talc, or chlorite enters into the composition, it is 
 called talcose, or chloritic granite, and sometimes 
 protogine. 
 
 " Granite is considered as the foundation rock on 
 which slate and all secondary rocks are laid." When 
 
 granite rises above 
 the surface, the beds 
 
 ^ tner rocks > V 1 
 
 _ the same district, 
 rise toward, and lie against it, thus ; but there are 
 
 Are the minerals aggregated in different proportions in 
 granite ro^ks ? When are rocks porphyritic ? Which min- 
 eral predominates in granite ? What is sienite ? and what 
 is protogine ? How do rocks lie in the vicinity of granite 
 mountains ? Do they ever pitch or dip under granite ? 
 
92 GRANITE. 
 
 instances where they appear to pitch under the gra. 
 nite, as seen in the figure. 
 
 The aspect of granite 
 mountains is extremely vari- 
 ous. When the beds are 
 horizontal, or when the rock is soft and disintegrat- 
 ing, the summits are rounded and unpicteresque.. 
 When hard and soft granite occur in the same mass, 
 the soft decomposes, and leaves the hard in large, 
 loose masses upon the soil, or if they lie in alternate 
 >^1 f~\ f*\ A a Eighty inclined beds, the 
 [ y Lj I/ V^v hard granite forms high and 
 
 v * *** almost inaccessible peaks, as 
 
 seen in the figure. 
 
 Masses of granite are commonly divided by fis- 
 sures into large blocks, which often ap- 
 proach to a rhomboidal form, thus, and 
 sometimes a columnar structure may be 
 observed. Granite is rarely found at any 
 great elevation in the United States. It is not often 
 observed, except in beds or veins, or interstratified 
 with other rocks in New England. 
 
 Granite often forms veins, traversing the super- 
 incumbent rocks. This is a fact of some impor- 
 tance in a geological point of view. 
 
 There is a variety of granite very finely granular, 
 or almost compact, called by the English geologists 
 
 Does the aspect of granite mountains vary ? When hard 
 and soft granite alternate in beds, what is the appearance of 
 the mountains ? Into what shaped masses is granite often 
 divided ? Does granite often form veins ? 
 
GRANITE. 93 
 
 compact feldspar; and by the French, described 
 under the name of Eurite. 
 
 Another variety of granite is called graphic gran- 
 ite. In this variety, the feldspar greatly predomi- 
 nates, and the quartz is arranged in it somewhat in 
 the form of Chinese letters,thus 
 This variety of granite decom- 
 poses readily, and, during its de- 
 composition, the potassa, or soda, 
 contained in the feldspar is removed by the rain, or 
 by water percolating through it, and leaves a clay 
 used in the manufacture of porcelain, and called 
 kaolin and porcelain clay. 
 
 Oxide of tin sometimes replaces the mica in gran- 
 ite and then it takes the name of stanniferous gran- 
 ite. Stanniferous granite is usually much disinte- 
 grated, the feldspar passing into kaolin. 
 
 Granite supplies a durable material for architec- 
 ture, but as some of the varieties crumble by the 
 action of the weather, care is required in its selec- 
 tion. In selecting proper building materials, ob- 
 serve whether the rock, in its natural situation, and 
 where exposed to the weather, shows any appearance 
 of having crumbled. If the rock is firm, and not 
 easily crumbled, where it has been long exposed na- 
 turally, it will stand well if put into buildings. " 
 
 What is eurite ? What is graphic granite ? What clay is 
 formed by the decomposition of this granite ? When oxide 
 of tin replaces the mica in granite what name does it take ? 
 For what is granite used ? What is necessary in selecting 
 granite for building 1 
 
94 GNEISS, AND MICA SLATE. 
 
 GNEISS, AND MICA SLATE. 
 
 Gneiss and mica slate are often interstratified 
 with each other and with granite, and are generally 
 considered as cotemporaneous, or formed at the 
 same time. 
 
 Gneiss is composed of the same minerals as gran- 
 ite ; viz : quartz, feldspar, and mica, and is a slaty 
 granite. Granite and gneiss pass into each other 
 by almost insensible gradation. If in granite the 
 feldspar be diminished in quantity, and the mica in- 
 creased and arranged in layers, the granite loses its 
 massive structure, and becomes slaty, and then we 
 have a true gneiss. 
 
 Bakewell, an English geologist, who has been a 
 close observer of facts, thinks that the stratification 
 of gneiss has been confounded with its slaty struc- 
 ture, and this structure, he thinks, is the effect of 
 crystallization. Gneiss is employed for ma ny pur- 
 poses, among which are : for building and flagging, 
 and some varieties are good stones for standing fire 
 in furnaces, fireplaces, &c. 
 
 Mica slate, or micaceous schistus, as it is some- 
 times called, is composed essentially of qu-u-tz and 
 mica. Feldspar is not uncommon in this rock, but 
 is not esteemed an essential constituent. Mica 
 slate passes by slight gradations into granite and 
 gneiss. 
 
 Are gneiss, granite and mica slate interstratified? Ot 
 what is gneiss composed? How does granite pass into 
 gneiss ? For what is gneiss employed ? Of what is mica 
 slate composed ? 
 
HORNBLENDE ROCK. 95 
 
 This rock is very fissile, or easily split in one di- 
 rection ; its colour is generally gray, or inclining 
 to green or yellow, and it has generally a pearly or 
 shining lustre. Mica slate and gneiss are often 
 bent and contorted. Crystals of garnet and of 
 staurolide are the most common minerals imbedded 
 in mica slate. 
 
 Mica is sometimes either entirely or in part re- 
 placed by talc or chlorite, and then the rock is 
 called taJcose and cliloritic slate. Gneiss and mica 
 slate are nearly similar in their constituents, and 
 geological positions ; and most of the metalic ores 
 and minerals that occur in one, occur also in the 
 other. Crystalline limestone, hornblende and ser- 
 pentine, more frequently occur in mica slate, than 
 in gneiss. 
 
 HORNBLENDE ROCK. 
 
 Rocks in which hornblende predominates, are not 
 uncommon in beds in primitive rocks. When the 
 rock is slaty, it is called hornblende slate and gneis- 
 soid hornblende. Augite rocks are also not uncom- 
 mon. Hornblende and feldspar, and augite and 
 feldspar, under certain circumstances, form partic- 
 ular rocks, which will be discussed under the terfn 
 of trap rock. 
 
 Is it fissile ? What is its appearance ? Is it ever con- 
 torted? What are the minerals imbedded in it? When 
 talc or chlorite replaces the mica, what is the rock called ? 
 What subordinate rocks occur most frequently in mica slate ? 
 When hornblende rock is slaty, what is is called ? Are augite 
 rocks found in primitive rocks ? 
 
96 CRYSTALLINE LIMESTONE. 
 
 SERPENTINE ROCKS. 
 
 Serpentine rocks are mostly composed of serpen- 
 tine, with small quantities of minerals imbedded. 
 Most of these minerals contain magnesia as a con- 
 stituent. 
 
 Serpentine rock sometimes forms mountain 
 masses, and is sometimes magnetic. Serpentine is 
 frequently mixed with primitive limestone, and then 
 forms a beautifully variegated marble of various 
 shades of green, yellow, black and white, like that 
 near New Haven, and called verd antique marble. 
 
 CRYSTALLINE LIMESTONE. 
 
 Crystalline limestone, of which statuary marble 
 is a variety, occurs forming immense beds in gneiss 
 and mica slate. The common grave-stones of white 
 marble, are of this limestone. A bed of this rock 
 extends, with few interruptions, 700 miles in length ; 
 beginning in Canada, passing through Vermont, the 
 western parts of Massachusetts and Connecticut 
 thence through New York, New Jersey, &c. to Vir- 
 ginia, and is extensively quarried in a great many 
 places, and supplies most of the marbles used in this 
 country. Limestones that take a good polish, are 
 called marbles. 
 
 Of what are serpentine rocks composed ? What substance 
 do most of the minerals that occur with serpentine contain 1 
 Does serpentine ever form large masses ? When mixed with 
 limestone, what does it form ? In what rocks is crystalline 
 limestone found ? Does it form extensive masses ? Is any 
 instance given in this country ? 
 
TRANSITION ROCKS. 97 
 
 QUARTZ ROCK. 
 
 This rock is composed of grains of quartz, aggre- 
 gated without cement. It is usually white or stained, 
 or shaded with gray, red and yellow. Its structure 
 is slaty, but in its small masses, it is nearly com- 
 pact. It is used as a flagging stone, and fire stone. 
 
 CHAPTER VI. 
 TRANSITION ROCKS. 
 
 Transition rocks lie immediately over the pri- 
 mary ones when both occur together, and are dis- 
 tinguished from the lower, or primitive rocks, by 
 their containing some of the remains of plants and 
 animals. The transition rocks therefore " may be 
 regarded as the most ancient records of our globe, 
 imprinted with the natural history of its earliest in- 
 habitants." "Transition rocks are the principal 
 repositories of metallic ores, which occur both in 
 beds and veins more abundantly in many of the rocjje 
 of this class, than in primary rocks." 
 
 Of what is quartz rock composed ? What is its appear- 
 ance ? What its structure ? and what its uses ? How are 
 the transition rocks situated with relation to the primitive ? 
 How distinguished from them ? In what class of rocks are 
 metallic ores abundant ? 
 
 9 
 
98 TRANSITION ROCKS. 
 
 Geologists have often been perplexed in their at- 
 tempts to draw a well-marked line of distinction be- 
 tween primary and transition rocks ; the difficulty 
 has arisen chiefly from their arranging slate with 
 the primary class. 
 
 " So long as it may be proper to class rocks con. 
 taining organic remains, with the transition rocks, 
 we must place slate among them. Nor can this be 
 invalidated by the fact, that in some slate rocks, no 
 vestiges of animal or vegetable remains occur ; for, 
 among the secondary strata abounding in such re- 
 mains, we often meet with alternating beds, in which 
 they are never found ; but we do not, on that ac- 
 count, class them with primary rocks." The fol- 
 lowing are the principal transition rocks, slate lying 
 next the primitive rocks : 
 
 1. TRANSITION, or mountain limestone ; 
 
 2. GRAYWACKE, and graywacke slate, passing 
 into old red sandstone ; 
 
 3. SLATE, and its varieties. 
 
 SLATE. Roof-slate, and the slate of which school - 
 slates are made, are well known varieties of this 
 rock. It is sometimes called clay slate, argillaceous 
 slate, and argillaceous scJiistus-. There is a soft kind 
 of slate occurring with coal, and called slate clay 
 and shale ; this must not be confounded with clay 
 slate. The colours of slate are, gray of various 
 shades, blue, green, purple and red. 
 
 " Slate rocks are commonly divided into beds of 
 
 What rock is lowest in the transition rocks? What are 
 the principal transition rocks ? What are the other names 
 for slate ? What mu&t slate not be confounded with ? 
 
TRANSITION ROCKS. 99 
 
 various degrees of thickness, which, generally, are 
 much elevated, and, from the natural divisions of 
 the rocks, they often form peaked and serrated 
 mountains." " Slate has been described by former 
 geologists, as distinctly stratified, because it splits 
 easily into thin laminae, and the direction of the 
 laminae is asserted to be in the direction of the beds : 
 but in opposition to the authority of many eminent 
 geologists, I maintain that slate, unless it be of a 
 soft or coarse kind, approaching to shale or to gray, 
 wacke, invariably splits in a transverse direction 
 to that of the beds, making with that direction an 
 angle of about 60 degrees." Succeeding observa- 
 tions have confirmed the above statement. 
 
 Slate rocks vary much in quality in the same 
 mountains. When magnesia enters into the com- 
 position of slates, they are distinguished by their 
 green colour, and pass into chloritic and talcose 
 slates. Whetstone slate, and hone, are varieties of 
 talcose slate, containing imperceptible particles of 
 quartz. 
 
 Roof slate is generally imbedded in a coarse slate. 
 The varieties of this slate are preferred that split 
 into thin even layers, with a smooth, plane surface. 
 Slate is regarded as one of the rocks in which ore^ 
 abound more than in any other. 
 
 Graywacke and graywacke slate, in their most 
 common forms, may be described " as a coarse slate, 
 
 Is slate distinctly stratified ? When magnesia enters into 
 the composition of slate, how is it distinguished ? What 
 are whetstone, slate and hone ? What varieties of slate are 
 preferred for roofing ? Is slate a metalliferous rock ? De- 
 scribe graywacke ? 
 
100 TRANSITION ROCKS. 
 
 containing particles or fragments of other rocks or 
 minerals, varying in size from two or more inches, 
 to the smallest grain that can be perceived by the 
 eye. " When the imbedded particles become ex- 
 tremely minute, gray wacke passes into slate. When 
 the fragments and particles are numerous, and the 
 slate in which they are cemented can scarcely be 
 perceived, graywacke becomes coarse sandstone or 
 gritstone." When the fragments are larger, and 
 angular in their forms, the rock forms what is called 
 a breccia. When the rock contains rounded frag- 
 ments and pebbles, it is called pudding stone. 
 
 The fragments of graywacke, including the brec- 
 cias and pudding stone, are always of the lower 
 rocks, and never of the upper strata. 
 
 The red sandstone, called old red sandstone, is a 
 graywacke, coloured red by the oxide of iron. There 
 is another red sandstone, called new red sandstone, 
 occupying a much higher situation in the geological 
 series, and it is sometimes difficult to distinguish 
 them. The red sandstone, quarried so largely for 
 building, near Middletown, Conn, and in New Jer- 
 sey, is by some thought to belong to one of these 
 sandstones, and by some to the other. 
 
 Red sandstone is a rock of considerable impor- 
 tance as a building material. Wlien beds of clay, 
 or argillaceous beds, alternate with this rock, the 
 soil is generally very fertile ; but where the sand* 
 
 When does it become gritstone ? When breccia ? When 
 pudding stone ? What is old red sandstone ? Is it ever dif- 
 ficult to distinguish between the old and new red sandstone ? 
 For what is red sandstone employed ? What are the agri- 
 cultural characters of red sandstone ? 
 
TRANSITION ROCKS. 101 
 
 stone alone prevails, the land is mostly a sterile 
 waste. A deposit of red sandstone extends with 
 few interruptions, from Vermont, through Massa- 
 chusetts and Connecticut, down Connecticut river 
 to Middletown, thence to New Haven, thence to the 
 Rappahannock, in Virginia, a distance of seven 
 hundred miles. 
 
 Charred wood, fossil bones and impressions of 
 plants and fish, have been found in it, and in the 
 argillaceous rocks imbedded in it. Copper and lead 
 ores are found in it in some places, as at Simsbury, 
 Ct. ; Belleville, Somerville, &c. New Jersey ; and 
 Perkiomen, Pennsylvania ; and these ores some- 
 times contain silver and gold in small quantities. 
 
 Transition, or mountain limestone, is one of the 
 most important of the transition rocks. Its mineral 
 characters vary considerably. Its usual colour is 
 gray, but is often reddish, brown, or black. It is 
 often much variegated, veined, and spotted. 
 
 This limestone is rarely as crystalline as primi- 
 tive ; or so compact and earthy in its texture as 
 secondary limestone. It often alternates with slate 
 and graywacke slate, and the strata are sometimes 
 remarkably contorted. It is the mountain lime- 
 stone, upon which, as a basis, the coal formation is 
 generally found resting. . 
 
 This rock contains a great variety of organic 
 
 Where is there an extensive deposite of this rock ? What 
 fossils have been found in it ? What ores, and where ? Is 
 transition limestone a rock of any importance ? Describe it ? 
 What does it alternate with ? Are the strata ever contorted ? 
 Upon what does the coal formation generally rest ? Does 
 transition limestone contain many organic remains ? 
 9* 
 
102 TRANSITION ROCKS. 
 
 remains, and the individual fossils are, in some 
 places, exceedingly numerous ; the rock in fact ap. 
 pearing to be formed of the aggregated remains of 
 coralline animals, and of those having a shelly cov- 
 ering, called testaceous animals. 
 
 Mountain limestone is also called metalliferous 
 limestone, from its containing large quantities of 
 metallic ores. The ores found in this rock are 
 mostly lead ores, which often contain a considerable 
 portion of silver. The lead and silver obtained in 
 Derbyshire England, and in the Hartz mountains 
 in Germany, are from this rock ; and the mines of 
 lead in Missouri and Illinois are in this, and the 
 associated rocks, and in the soil produced by their 
 decomposition. 
 
 This limestone is also called encrinal limestone, 
 from the great numbers of fossil encrinites imbedded 
 in it. The encrinites are sometimes called 
 screw-stones, from their bearing some re- 
 semblance in form to a screw, thus. 
 
 They are also called, in common Ian- ' 
 guage, wheel-whirls, because the parts seen in the 
 sketch separate into thin circular plates 
 like a wheel, and generally appears thus. 
 
 The heads of the encrinite are often found 
 in the limestone, and are mentioned by 
 people unacquainted with fossils, as petrified wal- 
 nuts, petrified acorns, &c. 
 
 And of what classes of animals ? What are other names 
 for mountain limestone ? What ores are most abundant in 
 this rock ? From what does this rock derive the name en- 
 crinal limestone ? What are the encrinites sometimes called ? 
 What have the heads of the encrinite been called ? 
 
TRANSITION ROCKS. 103 
 
 It is almost invariably the case, that mountain 
 limestone is found abounding in fissures and caverns. 
 Most of the caverns in England, Germany and the 
 United States, are in this rock. Rivers that flow 
 in it are often suddenly engulphed, and pursue, for 
 a considerable distance, a subterranean course. 
 Large springs and streams burst suddenly out from 
 the hills. 
 
 Where this rock approaches the surface of the 
 earth, in many parts of England and of the United 
 States, it shows a great number of deep, funnel- 
 shaped cavities, some of them 100 or more yards 
 across, and 100 or 200 feet deep, and some only a 
 few yards in width and depth. In England they 
 are called swallow holes, because they swallow up 
 the streams of water that sometimes run into them. 
 In the United States they go by the name of sink 
 holes, because the earth is sometimes observed to 
 sink and form them. 
 
 There is generally a cavity in the bottom, through 
 which the water is conveyed into the caverns and 
 Assures underneath. They appear to have been 
 formed by the water running in the fissures of the 
 rock, and gradually dissolving it. This appears to 
 have continued until the spaces became so large, 
 that the rock was not strong enough to support the 
 superincumbent weight, and by falling in, caused 
 the earth above to sink, and form large cavities 
 upon the surface. The edges of these cavities con- 
 
 What does this limestone abound in ? What is said of 
 livers and springs ? Where the rock approaches the sur- 
 face, what are observed ? Describe the sink or swallow 
 holes ? How do they appear to have been formed ? 
 
104 SECONDARY ROCKS. 
 
 tinually crumble away, until the cavity has a fun- 
 nel shape, sloping steeply down on all sides to the 
 centre. 
 
 These sink holes may be observed in great num- 
 bers a few miles south of St. Louis Missouri ; also 
 in some parts of Kentucky, Tennessee, Illinois, &c. 
 The great caverns in some of those states, com- 
 municate with numbers of these cavities, and in 
 some places, the light may be seen through the hot- 
 torn of the sink holes, by the observer, when stand- 
 ing in the caverns below. 
 
 Nodules of hornstone sometimes resembling flint, 
 are seen in this limestone in many parts of the 
 country. 
 
 Mountain or transition limestone is generally 
 sufficiently firm to take a good polish, and from its 
 being often beautifully variegated, it is used as a 
 marble. It also makes good lime when burnt. 
 
 CHAPTER VII. 
 SECONDARY ROCKS* 
 
 Geologists now divide the secondaiy rocks, into 
 upper secondary, and lower secondary. The most 
 
 Where may these holes be observed ? Do they ever com- 
 municate with caverns ? What mineral occurs imbedded in 
 the form of nodules ? Does transition limestone take a good 
 polish ? For what is it employed ? What two great divis- 
 ions are made of the secondary rocks ? 
 
SECONDARY ROCKS. 105 
 
 ,mportant rock formations, in an economical point 
 of view, are 
 
 The coal formation in the lower secondary series, 
 and the rock salt or saliferous formation in the upper 
 secondary. 
 
 The rocks associated with coal, are called coal 
 measures. The coal measures consist of a series of 
 alternating layers of coal, slate, sandstone, arid some- 
 times limestone, the alternations being frequently 
 and indefinitely repeated. 
 
 The sandstones of the coal formation are quite 
 tender and micaceous. Some of them afford good 
 free stones, for building, whet-stones, grind-stones, 
 flagging-stones, dec. The shale, or slate clay, differs 
 from clay-slate, in being more tender, and often con- 
 taining the impressions of vegetables. 
 
 An ore of iron, called clay iron stone, is almost 
 constantly found in the shale of the coal measures, 
 either in distinct layers, or in courses of nodules. 
 The occurrence of this, the most useful of the metals, 
 directly associated with the combustible and flux 
 necessary to reduce it, is an instance of arrange- 
 ment happily adapted to the purposes of human in- 
 dustry, and is one of the proofs that the distribution 
 of the rude materials of the earth, was determined 
 with a view to the convenience of its inhabitants. * 
 
 No well marked line of distinction can be drawn, 
 
 What are the most important rock formations in these di- 
 visions ? What are the coal measures ? For what are some 
 of the sandstones of the coal measures used ? How does 
 shale, or slate clay, differ from clay slate ? What ore of iron 
 occurs in the coal measures ? What difference is there in 
 the fossils of the lower secondary, and the transition rocks ? 
 
106 SECONDARY ROCKS. 
 
 in the appearance of the rocks between the lower 
 secondary and transition, but there is a remarkable 
 difference in the nature of the fossil remains, that 
 serves as a distinction. In the transition, it was 
 remarked that the fossils were mostly the remains 
 of animals, either coralline or testaceous. In the 
 lower secondary, the remains of plants are most 
 numerous, and they are analagous to those growing 
 in tropical climates. 
 
 The coal fossils of Newcastle Liege, Melville's 
 Island, and Pennsylvania, are identical, as are the 
 trilobites of Dudley, and of Trenton Falls ; the shells 
 of the coral ragg of England, are those of animals 
 still living but confined to tropical seas ; all seems 
 to indicate that the climate of the earth was at some 
 remote period uniform throughout its whole extent, 
 more heated than the most torrid regions are at pre- 
 sent, and utterly unfit for the habitation of any exist- 
 ing varieties of the human race. [Am. Quarterly 
 Review, Vol. vi. p. 446.] 
 
 The strata of the coal formation often rest uncon- 
 formably on the more inclined strata below them. 
 
 The coal formation is somewhat variable in posi- 
 tion but within limits which are easily assigned. 
 [Brongniart's Remains.'] 
 
 The rocks forming the coal measures, by their 
 appearance indicate an origin almost entirely me- 
 chanical. The coal alone by its nature, its homo- 
 geneousness, ij:s breaking into rhombic masses, and 
 
 In what places are the fossils identical ? What does this 
 seem to indicate ? 
 
SECONDARY ROCKS. 107 
 
 the presence of some crystalline metallic minerals, 
 indicate the influence of chemical action. 
 
 The strata of the coal formation are numerous, 
 extensive, and parallel ; but they are often bent, in- 
 dulating, curved, broken, and contorted in various 
 ways. The coal formation is often intersected by 
 dykes, and faults, which have separated the beds of 
 coal, or broken the strata and deranged the position 
 to such a degree, as to render it difficult to find it 
 again on the other side of the fault or dyke. [ Brong- 
 mart's Remains.] 
 
 The strata connected with the coal, bear evidences 
 in some instances of having been rapidly deposited ; 
 thus, the vertical stems of plants standing in their 
 natural position, in many coal mines, and the rocks 
 deposited around them in horizontal or slightly in- 
 clined strata. The stems of arborescent plants, 2 
 or 3 feet in diameter, are thus found piercing through 
 the strata many feet. 
 
 The sand and mud must have been deposited 
 within a comparatively short time around them, else 
 in a climate such as that in which these plants grew, 
 they would have decayed and left no indications of 
 their existence. [Vido Am. des Mines, 1821.] 
 
 " About 2 miles above Galliopolis, and half a mile . 
 from the Ohio river is a location of several petrified 
 trees." 
 . They are imbedded in a coarse sandstone belong. 
 
 What facts respecting coal indicate, the influence of chemi- 
 cal action ? What of the strata of the coal formation ? What 
 are the evidences that the strata connected with the coal in 
 some instances have been rapidly deposited ? Where have 
 fossil trees been discovered ? What is said of them ? 
 
108 SECONDAKY ROCKS. 
 
 ing to the coal formation, near the foot of a mural 
 precipice of 50 to 70 feet in height, a few feet above 
 the foot of the cliff. The trees observed were 7 in 
 number, and are scattered through a space quarter 
 of a mile in length. " Some appear to have fallen, or 
 been deposited with their tops or branches towards 
 the river ; and others in the opposite direction. 
 Some project from the rock obliquely, and others at 
 right angles ; they vary from 8 to 18 inches in 
 diameter." "They are readily distinguished from 
 the rock in which they are imbedded by their differ- 
 ent colour and composition." 
 
 ** The interstices between the lamina? are in some 
 places filled with small crystals of quartz ; and in 
 others with thin layers of stone coal." "The cor- 
 tical part seems to have been more difficult to pe- 
 trify than the ligneous portions." The bark of the 
 tree easily separates from the trunk, and is in some 
 cases coloured with oxide of iron, and in others is 
 black and fragile easily crumbling to pieces. [Hil- 
 dreth Am. Journal, xii. p. 205.] 
 
 Coal occurs in regular strata, which vary in thick- 
 ness from a few inches to several feet or even yards. 
 In the same coal formation, many strata of coal 
 occur under each other, separated by strata of shale, 
 sandstone, &c. 
 
 The series of strata which occur together, is 
 called a coal field. " Coal fields are of limited ex- 
 tent, and the strata often dip to a common centres, 
 being often arranged in basin shaped cavities, which 
 appear to have been originally detached lakes that 
 
 Bo many strata of coal occur in the same coal field, amd 
 how are they arranged ? 
 
SECONDARY ROCKS. 109 
 
 were gradually filled by repeated depositions of car- 
 bonaceous and mineral Sandstone. Bv^pT^^ 
 matter.' 5 Slate. 
 
 The different strata Co ^ 
 over and under the beds Slate. 
 of coal are frequently Sandstone. : 'jjj$. 
 
 similar, and the same se- gi a t e . 
 ries of strata is repeated ^ oal 
 for each successive stra- Slate &c 
 turn of coal, thus IPHplB^^ 
 
 Sometimes the strata *&#&88$$$$i 
 
 between the succeeding beds of coal, are, in the ag- 
 gregate, of several hundred feet in thickness, but 
 often, they are not many feet thick, and sometimes 
 only a few inches. In the latter case, the adjacent 
 beds are considered as one, and wrought as one bed. 
 The stratum over the bed of coal is called the roof, 
 and that under it, the floor. Sometimes there are 
 as many as forty distinct beds of coal below each 
 other in the same coal field, but in general, only a 
 few are of sufficient thickness, or of a proper quality, 
 to afford profit in working. 
 
 The facility of getting coal depends very much 
 upon the strength of the roof, and the impermeabil- 
 ity of the rock to water. At Newcastle, in Eng- 
 land, coal is wrought at the depth of fifteen hundred 
 feet, and has been found there by boring, at the 
 depth of three thousand feet. 
 
 There has been some disagreement as to the 
 origin of coal, upon the ground that if we admit its 
 
 Upon what does the facility of working coal depend ? 
 10 
 
110 SECONDARY ROCKS. 
 
 vegetable origin, we are bound by similar reasoning 
 to admit that the limestones containing organic re- 
 mains are animal deposites, arising from the suc- 
 cessive growth and death of myriads of animated 
 beings, and few are willing to admit that the enor- 
 mous masses of rock, often some hundreds of miles 
 in length and breadth, and many hundreds of feet 
 in thickness, can have arisen from such a source, 
 notwithstanding the evidence afforded by their nu- 
 merous remains. 
 
 Such need only glance at the effects of the com- 
 bined labours of successive races of millions of mil- 
 lions of polypi, in the formation of the extensive reefs 
 of coral, which obstruct the navigation of many parts 
 of the Pacific and Indian oceans. 
 
 The abundance of vegetable remains usually found 
 in connection with coal, and the vegetable structure 
 that the coal itself sometimes exhibits, will hardly 
 allow a doubt as to its origin. 
 
 At most coal mines even the thinnest layers of 
 slate, when split off, show the impressions of the 
 leaves and flat stems of the various grasses, reeds 
 and ferns, in all their most delicate parts. The im- 
 pressions between the layers of slate often give as 
 perfect a representation of the plant, as if the plant 
 had been pressed and dried in a book, and the leaves 
 then opened to display it. 
 
 " Whatever may have been the origin of coal, we 
 cannot hesitate in admitting that vegetable life on a 
 great scale, attended the formation of coal, and both 
 preceded, accompanied, and followed, that event ; 
 
 What is supoosed to be the origin of coal ? 
 
SECONDARY HOCKS. Ill 
 
 and that the causes which established its existence, 
 were repeated many times," at considerable inter- 
 vals of time, and continued to operate during the de- 
 position of the successive strata : that a sedimentary 
 rock in a loose and impressible form, (the shale,) 
 was deposited with the vegetables, and enveloped, 
 covered, and preserved them ; that a fragmentary 
 rock succeeded, composed of pebbles, rounded or an- 
 gular fragments, or of cemented sand, which were the 
 ruins of pre-existing formations. [Silliman's Jour- 
 nal, xviii. p. 321.] 
 
 Coal and the accompanying strata usually lie 
 parallel to each other, like the leaves of a book, and 
 incline under a small angle to the horizon, so that 
 the strata would emerge on the ffT/7j/7i 
 surface, thus. It is rare that the ///////// 
 coal, or shale, crop out on the sur- \f*-i<ff*Jf 
 face, because a diluvial or alluvial covering usually 
 conceals the outcrop, except in the sides of ravines, 
 the banks of streams, or the faces of cliffs. " The 
 rock strata are in geology, what the bones are in 
 anatomy, when the covering is once removed, the 
 absolute structure is at once seen." \Eatotfs 
 Geology. ,] 
 
 In searching for coal, observe the kinds of rock, 
 loose stones, and pebbles, examine the springs and 
 beds of streams for sooty matter, and trace it as near 
 as possible to whence it issued ; ascertain the direc- 
 tion of the dip, then bore in a proper situation, and 
 
 Do the coal strata generally crop out on the surface ? In 
 searching for coal, how would you proceed ? 
 
112 SECONDARY ROCKS. 
 
 ' ascertain the quality and thickness of the bed, and 
 whether there be more than one bed. 
 
 Coal exists very abundantly in the United States, 
 and it is in general very conveniently situated for 
 working to advantage. The coal mines of Virginia 
 and Pennsylvania are more extensively wrought 
 than any others in the United States, and the quan- 
 tity seems perfectly inexhaustible. 
 
 In Europe, where the people are mostly dependent 
 upon the produce of their coal mines for fuel, the 
 coal mines are extensively wrought, and under cir- 
 cumstances that require all the aid that the sciences 
 yield. There are more hazards to encounter, and 
 difficulties to overcome, in working coal mines than 
 any other. 
 
 The coal formation which has been described, is 
 the great or independent coal formation, and is sup- 
 posed to be the principal repository of carbonaceous 
 matter applicable to use. This coal is the bitumi- 
 nous coal, called also sea-coal, black-coal, caking- 
 coal, &e. It gives much smoke when burning. 
 
 It has generally been thought that the anthracite 
 coal 9 of Pennsylvania, belonged to the transition 
 rocks ; but Prof. Eaton thinks he has traced its con- 
 nection with the Tioga bituminous coal, and the or- 
 ganic remains are many of them similar to those of 
 the great coal formation. It would seem, then, that 
 
 Is coal abundant in the United States ? and where are the 
 mines wrought most extensively ? Are there many difficul- 
 ties in working coal mines ? What coal formation is that 
 which has been described, and what are the names of the 
 coal ? Does the anthracite of Pennsylvania seem to have 
 the same geological position as the great coal formation ? 
 
SECONDARY ROCKS. 113 
 
 the anthracite of Pennsylvania belongs to the great 
 coal formation. 
 
 There is another species of coal, occurring in a 
 different geological position from either of the others, 
 and is called wood coal and lignite, from its showing 
 distinctly that it has been formed from wood. It is 
 often found in the form of trees, branches and fruits, 
 and still retaining the appearance of the wood, ex- 
 cept the colour. " Wood coal is found in low situa- 
 tions, and appears to have been formed of heaps of 
 trees, buried by inundations under beds of clay, sand 
 or gravel." "In wood coal we may almost seize 
 nature in the act of making coal, before the process 
 is completed. These formations of coal are of far 
 more recent date than that of common coal, though 
 their origin must be referred to a former condition 
 of the globe, when the vegetable productions of tro- 
 pical climates flourished in northern latitudes." 
 
 Jet, which is used as an ornament, is a variety of 
 lignite which has lost its ligneous structure. Am- 
 ber is generally found with lignite, and appears to 
 have been a resinous substance that exuded from 
 the wood, and has become changed by being so long 
 imbedded in the earth. Amber often contains fn- 
 sects imbedded, which shows that it must have been ^ 
 in a soft state, and on the earth's surface, and in * 
 
 Is there any other kind of coal, and having a different 
 geological position ? What is it called ? and from what cir- 
 cumstance? Which coal is of the most recent origin? 
 What kind of plants flourished when this coal was deposited ? 
 What is jet ? In what situation is amber found ? What 
 appears to have been its origin ? What does amber often 
 contain ? 
 
 10* 
 
114 UPPER SECONDARY ROCKS. 
 
 which they became entangled, as they do now in 
 the gums and resins that exude from certain trees. 
 They may be often observed in gum copal beauti- 
 fully preserved. 
 
 Lignite occurs in large quantities in New Jersey, 
 along Raritan Bay, in the cliffs, and in various other 
 parts of the country. The large bodies of the plants 
 
 <^ *a are generally flattened, (as seen in the 
 
 margin,) as though the weight of the su- 
 perincumbent earth had pressed the sides together. 
 
 CHAPTER VIII. 
 UPPER SECONDARY ROCKS. 
 
 The upper secondary rocks comprise all the dif- 
 ferent formations above the great coal formation, to 
 the upper limit of the chalk series. These rocks 
 are divided into 3 formations, viz : 
 
 1. CHALK, or cretaceous rocks, including the fer- 
 ruginous and green sand ; 
 
 2. OOLITIC ROCKS, lias limestone and lias clay ; 
 
 What does this show? In what may insects be observed 
 beautifully preserved? Does lignite occur in the United 
 States? How do the bodies of the large plants appear? 
 What seems to have caused this flattening ? What are the 
 limits of the upper secondary rocks ? Into what formations 
 are they divided ? 
 
UPPER SECONDARY ROCKS. 115 
 
 3. RED SANDSTONE, including magnesian lime- 
 stone. 
 
 The red sandstone goes also by the names of va- 
 riegated sandstone, new red sandstone, and red marl ; 
 and is most important as being the principal reposi- 
 tory of rock salt. The magnesian limestone is the 
 lowest part of this rock formation,* This limestone 
 dissolves more slowly than other limestone, and is 
 generally of a buff colour, and sandy in its texture. 
 Some of these limestones form an excellent building 
 material, and yield a fetid smell when hammered. 
 They make a good lime for cements, but it will not 
 answer for liming land, as it injures the fertility of 
 the soil. Magnesia is found to be uniformly injuri- 
 ous to vegetation, and magnesian soils are barren. 
 The fossils in this limestone are not numerous. 
 
 The texture of the rocks of the red sandstone for- 
 mation is very various. It appears sometimes as a 
 reddish marl or clay, sometimes as a sandstone, and 
 sometimes these are interstratified, or pass into each 
 other, and it is sometimes associated with beds of a 
 conglomerate rock, which is composed of pebbles 
 and fragments of other rocks cemented together. 
 
 The soil where this formation occurs is reddish, 
 and sheep living on it have their wool tinged with 
 red. 
 
 There is often a strong similarity between the 
 sandstone of the coal measures, and that of this for- 
 
 For what is the red sandstone most important ? What 
 are the characters of magnesian limestone ? What are the 
 characters of the red sandstone formation ? What is the 
 colour of the soil of this formation ? 
 
116 UPPER SECONDARY ROCKS. 
 
 mation, but they may be distinguished by the latter 
 containing gypsum. 
 
 The red sandstone formation is characterized by 
 the first appearance of any abundance of the remains 
 of the saurian, or lizard-shaped animals. The re- 
 mains of a number of species have been found, dif- 
 fering in their appearance from the crocodile and 
 alligator, and some of them must have been from 60 
 to 120 feet in length. 
 
 These animals appear to have lived in salt water, 
 unlike any of this class with which we are acquaint- 
 ed at the present (jay, all of which belong either to 
 the land, or to fresh water. They had neither feet 
 nor fins, but paddles, like the sea-turtle, and their 
 tails were long, of the form of an oar, and fitted to 
 propel them in the most agitated waters,* 
 
 The most valuable minerals found in the red sand- 
 stone are, gypsum and rock salt. The gypsum is 
 fibrous, massive, and crystallized. Many reposito- 
 ries of rock salt are situated near the foot of moun- 
 tain ranges, and although salt is more frequently 
 found at a comparatively low level, it has also been 
 
 How are the sandstones of this and the coal formation dis- 
 tinguished ? By what organic remains is the red sandstone 
 characterized ? What appears to have been the size of those 
 animals ? Where do they appear to have lived ? Had they 
 feet, or fins ? Were they calculated for moving on land, or 
 in the water ? What are the most valuable minerals found 
 in the red sandstone ? How is rock salt situated ? Does it 
 ever form extensive masses ? 
 
 * Fish are common in a bi turn in on s marly state belonging to this 
 formation in Europe, and also in the U. S., as Sunderland Mass., Mid- 
 dletown, and Durliam, Conn. 
 
UPPER SECONDARY ROCKS. 117 
 
 found high above the level of the sea, as in the Alps, 
 and on the Andes. 
 
 The great salt mines of Cheshire, in England, of 
 Wielictska, in Poland, and those in Germany, Spain, 
 Russia and Turkey, are in the red sandstone forma- 
 tion. The salt of Cardona, in Spain, appears to 
 have been an enormous mass, in which the water 
 has formed vallies, " leaving several detached moun- 
 tains." [S. J. xv. p. 1, 2.] 
 
 *' Nothing can compare with the magnificence of 
 the spectacle which the mountain of Cardona ex- 
 hibits at sunrise. Besides the beautiful forms which 
 it presents, it appears to rise above the river like a 
 mountain of precious gems, displaying the various 
 colours produced by the refraction of the solar rays 
 through a prism." [Bakewell, p. 187.] 
 
 Hungary and Poland afford the most numerous 
 and extensive repositories of rock salt in Europe. 
 
 There is a formation of rock salt on each side of the 
 Carpathian mountains, six hundred miles in length. 
 
 " The salt mines of Welielska, near Cracow, have 
 been long celebrated, and frequently described : 
 they are worked at the depth of 750 feet." "At 
 Paraid, in Transylvania, there is a valley, the bot- 
 tom and sides of which are pure rock salt. The 
 mine of E per is is about 990 feet deep. Water is 
 sometimes enclosed in blocks of salt." [Brongniart, 
 Miner alogie.~\ 
 
 On the northern shore of Africa, not far from Al- 
 giers and Tunis, are salt lakes, communicating with 
 
 In what parts of Europe is rock salt found abundantly ? 
 How is rock salt found in lakes in Africa ? 
 
118 UPPER SECONDARY ROCKS. 
 
 the Mediterranean Sea by small openings, through 
 which, during the warm season, there is a continual 
 influx of the salt water, and from the deposit of salt, 
 consequent upon the evaporation of the water, some 
 of them have become shallow, and their bottoms 
 covered to an unknown depth with rock salt. Some 
 of the salt lakes of Africa dry up entirely in the 
 summer, and leave a bed of pure rock salt. 
 
 The salt lakes of Africa, on the borders of Caf- 
 fraria, east of the Cape of Good Hope, contain beds 
 of rock salt variously coloured. There is a re- 
 markable formation of salt at Posa, in Castile, 
 placed in the immense crater of an extinct volcano. 
 
 The salt of Northwich (Cheshire Co. England) 
 alternates with clay, and marl containing gypsum. 
 The upper bed of salt is from 60 to 90 feet thick, 
 and below this, separated by a bed of clay, is ano- 
 ther which has been penetrated 108 feet without 
 finding its bottom. This mine yields 156,000 tons 
 of salt per annum. The mines and springs of salt 
 in Europe yield 15,000,000 tons of salt per annum. 
 
 Rock salt has not been found in the United States, 
 except far to the west of the Mississippi. " The salt 
 mountain is situated at the head of one of the western 
 branches of the Arkansas." [StoddarcPs Sketches, 
 p. 403.] 
 
 Salt springs are very numerous in many parts of 
 the United States. The water sometimes flows na- 
 
 Has rock salt been found in the United States ? Are salt 
 springs numerous in the United States ? How is the salt wa- 
 ter more frequently obtained than from the natural springs 
 upon the surface ? 
 
UPPER SECONDARY ROCKS. 119 
 
 turally, but more frequently it is obtained by boring 
 through the strata where salt water is known to 
 exist, in the vicinity of salt licks.* These licks 
 were the places of resort for wild animals before the 
 settlement of the country. They were easily found 
 when the country was newly settled, by the paths 
 which converged from various directions to the licks, 
 where the animals repaired to lick the clay impreg- 
 nated with salt. 
 
 Some of these licks are remarkable for the quan- 
 tities of fossil bones found adjacent to them. The 
 bones of the Mastodon, the Elephant, &c., are most 
 abundant, and the lick called Big Bone Lick, in 
 Kentucky, is the one at which these remains have 
 been found in the greatest abundance. 
 
 The Mastodon was the largest land animal that is 
 known to have existed. This animal, which is not 
 in existence at present, was formed much like the 
 elephant, except in the teeth ; but the elephant must 
 have seemed a pigmy by his side. The teeth of the 
 great Mastodon often weigh from six to seven pounds 
 each, and one of the tusks is as much as a strong 
 man can lift. 
 
 As to the origin of salt deposits, and salt springs, 
 many opinions have been advanced. Rock salt is 
 ________ * 
 
 What are salt licks ? For what are some of these remark- 
 able ? Which of these licks has the greatest number of those 
 fossil bones? Of what animals are the remains most com- 
 mon ? What is said of this animal ? Upon what are all 
 agreed in the deposition of rock salt ? 
 
 * It is necessary to drill, or bore through rocks, often several hun- 
 dred feet, before the salt water is reached,, and then the water rises, 
 and overflows at the surface. 
 
120 UPPER SECONDARY ROCKS. 
 
 usually of a crystalline texture, and is associated 
 with materials that have evidently been subjected to 
 the action of water, as clays and sands, and con- 
 glomerates of sand, gravel, pebbles, &c., and these 
 often contain shells, and the teeth and bones of ma- 
 rine animals. 
 
 All agree, that the salt deposits bear conclusive 
 evidence of having been deposited from water. 
 
 Salt springs, in Europe, are most abundant where 
 rock salt abounds, and from flowing over its beds, 
 the water is doubtless impregnated. This explana- 
 tion will not hold for our salt springs, for, rock salt, 
 although it has been diligently sought for in the 
 vicinity of salt springs in this country, has not been 
 found. 
 
 Prof. Eaton has published a fact that goes far to 
 prove its origin. He mentions, that fragments of 
 the hydraulic limestone, found a few miles west of 
 the Onondaga salt springs, when examined exter- 
 nally, or pulverized, presents nothing to the senses 
 resembling common salt, but when kept a few days 
 in a moist cellar they became incrusted with com- 
 mon salt.- [S. J. vi. p. 242.] 
 
 He has also found in some of the rocks, cubic 
 cavities, and cavities like the hopper-shaped crystals 
 of common salt. Although several minerals crystal- 
 lize in the cubic form, none but salt are known to 
 have the hopper-shaped form. 
 
 These facts constitute a train of evidence, which 
 
 Will the same explanation hold for our salt springs, as for 
 those of Europe ? From what is it probable that the salt of 
 our salt springs is derived ? 
 
LIAS. 121 
 
 renders it probable, that the salt of the salt springs, 
 is derived either from salt, or its elements, contained 
 in the rocks overlying that, on which, as a floor, all 
 the salt springs are found. 
 
 It is a fact worthy of remark, that salt, a min- 
 eral so necessary to supply the wants of man, is 
 found abundantly in almost every country, either in 
 its solid state, or dissolved in the water of springs. 
 Denmark, Sweden, and the eastern part of the United 
 States, are exceptions, but they are placed in such a 
 situation that they can easily draw their supplies 
 from the great reservoir of this mineral, the ocean. 
 
 LIAS. 
 
 The lias limestone and clay, when fully developed, 
 form a mass of several hundred feet in thickness, 
 lying upon the red sandstone formation. 
 
 The limestone is of a bluish or light buff colour, 
 and very compact. It often contains bitumen, alu- 
 mina, and oxide of iron. The finer kinds of lias 
 limestones receive a polish, and are used for lithog- 
 raphy. The lithographic stone to be well adapted 
 for this use should be very compact ; have a very 
 fine grained uneven conchoidal fracture ; should 
 contain some earthy matter insoluble in nitric acid? 
 and if the stone is light coloured it is better, as the 
 
 Is salt found abundantly in every country ? Whence do 
 people draw their supplies of salt, when they have neither 
 rock salt nor salt springs ? Upon what does the lias lie ? 
 What are the characters of the lias limestone ? For what is 
 it employed ? What qualities should the lithographic stone 
 
 11 
 
122 LIAS. 
 
 drawings can be done more accurately than on a 
 darker ground. 
 
 The quarries of Pappenheim, and Solenhofen, 
 near Eichstaedt in Bavaria, supply almost all the 
 stone used for lithography. The quarries above 
 mentioned supply the cabinets of geology with many 
 beautiful specimens of fossil fish imbedded in the 
 limestone. This limestone is also employed for 
 making hydraulic cement. 
 
 The lias is beautifully stratified in regular layers 
 which, in most places where it has been observed, 
 are horizontal. It derives its name from a provin- 
 cial pronunciation of the word layers. It is charac- 
 terized by its numerous and finely preserved fossils. 
 The most remarkable of the fossils are fishes, and 
 the large saurian animals called the ichthyosaurus, 
 and plesiosaurus. 
 
 Some idea of the magnitude of some of these ani- 
 mals may be formed from the fact, that the orbits 
 for the eyes of some of these animals are 9 and 10 
 inches in diameter. The lias clay occupies the 
 upper, and the limestone the lower parts of the for- 
 mation. Bones and other organic matter can be 
 rapidly petrified in the pyritous lias clay. 
 
 The lias clay often occurs in the form of a soft 
 clay or shale, impregnated with pyrites and bitumen. 
 When made red hot, if more be piled on the first, 
 
 Where is it chiefly obtained ? From what does lias de- 
 rive its name ? What are the most remarkable of the fossils 
 of the lias ? What position does the lias clay occupy in the 
 formation ? What the limestone ? How does the lias clay 
 appear ? Can it be made to burn ? 
 
OOLITE. 123 
 
 it also ignites, and continues to burn gradually for 
 some time. In this way, immense heaps of this ma- 
 terial, called alurn slate, are roasted, and prepared 
 for making alum.* 
 
 OOLITE. 
 
 The oolitic rocks are composed o various strata 
 of limestone, clay, sand and sandstone. Oolite de- 
 rives its name from the small globules that are im- 
 bedded in the rock, and some of the masses appear 
 composed of little rounded globules like the roes of 
 fish, from which it is also called roe stone. 
 
 Limestone rocks having an oolitic structure have 
 been found in many places in the United States ; 
 but they have not been shown as equivalents to the 
 European oolite, either by there position or organic 
 remains. 
 
 r Warwick, N. Y. 
 J Saratoga, " 
 Localities. < Schoharrie, " 
 
 Easton, Pa. 
 I Franklin, N. J. 
 
 What is made from it after it has been burnt ? How is 
 alum m ade ? Of what are the oolitic rocks composed ? From 
 what does oolite derive its name ? In what places in th 
 United States has limestone rock of oolitic structure been 
 found? 
 
 * Alum is composed of sulphuric acid, alumina, and potassa. The 
 sulphur of the pyrites in the clay, forms a sulphuric acid during the 
 burning, which unites with the alumina and potossa in the clay, and 
 forms alurn. By leaching water through the burnt clay, and evapo- 
 rating the water, alum is obtained. Sometimes the clay does not 
 contain potassa, and then that is supplied by mixing common wood 
 ashes with the burnt clay, and leaching and evaporating the water as 
 before. 
 
124 OOLITE. 
 
 This limestone is sometimes employed as a build- 
 ing stone, but it is not durable. The oolitic rocks 
 are remarkable for the great variety of organic re- 
 mains contained in them. " The vertebrated ani- 
 mals, whose remains are found in oolite, are some of 
 them of the same genera as those discovered in lias ; 
 but others belojyg to the crocodile genus, and had 
 feet, like the living species of crocodile, and were 
 probably amphibious :* hence we may infer, that 
 that there were rivers and dry land in the vicinity." 
 
 "It may well excite surprise, that calcareous 
 strata should so rarely be found which present dis- 
 tinct indications of having been formed exclusively 
 by coralline polypi, particularly as coral rocks and 
 reefs of great extent are so rapidly forming in our 
 present seas. There are, however, among the strata 
 of oolite, some which are almost entirely composed 
 of madreporites, and have received the name of coral 
 ragg. There are other strata which abound in the 
 remains of fossil sponges, alcyonia, and with con- 
 geries of minute millepores and madrepores." 
 [BakeweWs Geology, p. 201.] 
 
 Between the oolite and chalk, a formation of limit- 
 ed extent has been found in England, called the 
 Wealden rocks. The different strata are called 
 
 For what are these rocks remarkable ? Are there any 
 rocks formed by the coralline polypi among the oolitic strata ? 
 What are they called ? Are any filled with fossil sponges ? 
 What are the different strata of the wealden rocks called ? 
 
 * These were the ichthyosauri. The plesiosauri had long arched 
 necks longer than the body, which were adapted like that of the tes- 
 tndo ferox for darting forward to seize its prey. 
 
OOLITE. 125 
 
 purbeck beds, iron sand, weald clay, and green 
 sand. 
 
 The animal remains are those belonging to the 
 land, and to fresh water. The teeth and bones of 
 fish and reptiles are abundant, and intermixed with 
 fresh water shells. The reptiles are mostly saurian 
 animals, and turtles. The plesiosaurus, megalosau- 
 rus, and iguanodon are among them ; and some of 
 them must have been 70 feet in length, and of the 
 height of an elephant. The iguanodon resembled 
 the iguana of the West Indies in some of its charac- 
 ters, but its teeth are similar to those of herbiferous 
 mammalia, which grind their food between them, 
 like the horse and ox. Its length was between 60 
 and 70 feet, and it had a horn in size and form re- 
 sembling that of the rhinoceros. It seems to have 
 been fitted for subsisting on the hard coarse plants 
 which prevailed at this period. 
 
 The vegetable fossils in these rocks consist of the 
 trunks of palms, arborescent ferns, and gigantic 
 reeds, and similar ones now grow only in tropical 
 climates. 
 
 In one of the rocks belonging to the oolite, viz : 
 the stonesfield slate, the earliest remains of mammif- 
 erous animals were observed. They are stated by 
 Cuvier to belong to an extinct species of the opos- 
 sum. Animals belonging to this order, are now 
 found only in America, and New Holland. 
 
 What are the different animal remains found in them ? 
 What of the Iguanodon ? What are the vegetable fossils of 
 these rocks ? In what have the earliest remains of Mammif . 
 erous animals been found ? 
 
 11* 
 
126 CHALK. 
 
 CHALK. 
 
 The cretaceous rocks or those belonging to the 
 chalk formation, are mostly calcareous. The car- 
 bonate of lime is sometimes very pure as in white 
 chalk, sometimes mixed with clay and sand to form 
 marl of various colours, as white, gray, blue, green, 
 yellow, and black. Sometimes it is consolidated 
 into a limestone, and is used for building and mak- 
 ing lime. Some of the beds of the chalk formation 
 are sandy. 
 
 The chalk formation is entirely sedimentary, ap- 
 pearing to have separated from suspension in wa- 
 ter ; and it shows no traces of crystallization, ex- 
 cept where organic remains have been replaced by 
 carbonate of lime. 
 
 The stratification is often indistinct, and it then 
 ^'presents itself as a thick mass intersected by numer- 
 ous fissures, which divide the mass into enormous 
 irregular masses. If the seams of stratification did 
 not indicate clearly a successive deposit of the dif- 
 ferent parts of the formation, the flint nodules which 
 occur in regular parallel beds in the chalk, would 
 leave no doubt on this point. 
 
 The chalk formation in Europe, presents itself 
 under the form of extensive plains with steep escar- 
 pments on the sides, or round backed hills of little 
 
 What of cretaceous rocks ? What of carbonate of lime ? 
 What distinguishes the chalk formation ? What appearance 
 does its stratification present ? What is the proof of succes- 
 sive deposit of this formation ? How does the chalk forma- 
 tion in Europe present itself ? 
 
CHALK. 127 
 
 height but with steep declivities. It often covers 
 a great extent of country, and generally contains 
 neither caverns nor currents of water, but large open 
 fiss- :es are numerous. 
 
 The chalk formation has not been recognized in 
 the United States until within a few years. Dr. 
 S. G. Morton of Philadelphia has demonstrated that 
 a chalk formation of great extent, exists in the 
 United States ; although proper mineralogical chalk 
 has not been found. 
 
 The chalk formation is characterized by particu- 
 lar fossils. The fossils of the chalk are very nu- 
 merous both in individuals and in genera and species, 
 but they are very unequally distributed. In some 
 districts they are rare, and again in particular lo- 
 calities they are found in great numbers. 
 
 Mr. Mantell concludes his " Illustrations of the 
 geology of Sussex" with the following remarks : 
 " The gigantic Megalosaurus, and yet more gigantic 
 Iguanodon, to whom the groves of palms and arbores- 
 cent ferns would be mere beds of reeds, must have 
 been of such prodigious magnitude, that the existing 
 animal creation presents us with no fit objects of 
 comparison. Imagine an animal of the lizard tribe 
 three or four times as large as the largest crocodile, 
 having jaws, with teeth equal in size to the incisors 
 of the rhinoceros, and crested with horns ; such a 
 creature must have been the Iguanodon ! Nor were 
 the inhabitants of the waters much less wonderful , 
 
 Who has demonstrated the existence of the chalk forma- 
 tion in the United States ? 
 
128 TERTIARY ROCKS. 
 
 witness the plesiosaurus, which only required wings 
 to be a flying dragon : the fishes resembling Siluri, 
 Balistse, &c." 
 
 CHAPTER IX. 
 TERTIARY ROCKS. 
 
 The tertiary rocks comprise all the regular beds 
 of limestone, clay, marl, sandstone, or sand, which 
 were deposited since chalk. 
 
 The tertiary deposits contain no beds of minerals 
 capable of exploration except lignite and jet, which 
 are used for fuel and ornament, clay for pottery, sand 
 for the manufacture of glass, pyrites for the manufac- 
 ture of coperass and alum, and hydrate of iron, 
 which is a valuable iron ore. The pyrites are found 
 only in detached nodules and small interrupted beds. 
 
 No veins either strong or metallic are found in 
 the tertiary. 
 
 There are sometimes fissures, sinuous passages, 
 vertical pits, and some caverns in the tertiary, but 
 they are rare. 
 
 The predominating minerals of the tertiary are 
 sand, clay, and marl. Sandstone, gypsum, lime- 
 stone, and buhrstone are sometimes found. Most 
 
 What do the tertiary rocks comprise? What minerals 
 capable of exploration are contained in the tertiary deposits ? 
 What are the predominating minerals of the tertiary ? 
 
TERTIARY ROCKS. 129 
 
 of the buildings of Paris are built of the three first 
 of these rocks, which are largely quarried under the 
 city. 
 
 Tertiary rocks were, until within a few years, 
 confounded with alluvial and diluvial deposits, and 
 were but little noticed. It is now ascertained, that 
 the tertiary formations are widely spread over our 
 islands and continents, and that some of them are 
 of considerable thickness. 
 
 The mode of formation of the tertiary deposits is 
 almost entirely mechanical, and often the sediment 
 was coarse. There are some rocks in these deposits 
 formed by means of solution, as travertine, gypsum, 
 buhrstone, and some other siliceous rocks. 
 
 The organic remains which these deposits con- 
 tain, and particularly the absence hitherto without 
 exception, of many genera, and a great number of 
 species of animals, characterize particularly this 
 geological epoch. 
 
 The stratification of the tertiary formations is 
 generally distinct, the layers being parallel, and in 
 most instances nearly horizontal. It forms hills of 
 moderate elevation, and plains. The hills are round- 
 ed and with slight declivities, except on the coast, 
 or streams, where they are worn away, and then they 
 sometimes present escarpments, displaying a fiife 
 section of the strata. 
 
 With what were they formerly confounded ? What rocks 
 in these deposits are formed by means of solution ? What 
 characterizes this geological epoch ? How is the stratifica- 
 tion of the tertiary generally found ? 
 
130 TERTIARY ROCKS. 
 
 " The most remarkable discovery that has been 
 made respecting the tertiary deposits, is, that many 
 of them contain the bones of mammiferous quadru- 
 peds, as perfect in their organization, as any of the 
 existing species of land animals ; but most of them 
 belong to genera or species that are extinct. The 
 tertiary strata are further remarkable, for presenting 
 the frequent alternation of beds containing the re- 
 mains of marine animals, with other beds, that con- 
 tain the bones of land animals, or fresh water shells. 
 It appears that the tertiary strata were chiefly form- 
 ed in detached inland seas, or lakes : hence, there 
 is a considerable diversity in the thickness, number, 
 and quality, of the beds, in different districts or 
 countries." 
 
 It may be well here to remark, that the remains 
 of mammiferous animals, or those that suckle their 
 young, are not found below the tertiary deposits.* 
 
 The principal mammalia belong to the pachy- 
 dermata, carnivora, and cetacea. Birds are not 
 very rare. Reptiles of all the orders occur, but tur- 
 tles are most abundant. Fishes are abundant in 
 some localities. Crustacea, and some insects occur. 
 
 The testaceous molusca are very abundant, and 
 
 What remarkable discovery has been made respecting the 
 tertiary deposits ? What is remarkable in the fossils of the 
 alternating beds ? Where do these strata seem to have been 
 formed ? Are the remains of mammiferous animals found 
 below the tertiary strata ? 
 
 * There are a few exceptions to this rule, but they are in what have 
 been termed anomalous deposits, and are by some thought to be only 
 apparent, but not real exceptions. 
 
TERTIARY ROCKS. 131 
 
 those most numerous are what are called littoral 
 shells. More than 1200 species have been deter- 
 mined. The most characteristic are the cerite, 
 fusus, cytherea area, and nummulite. The trilobite, 
 productus, spirifer, orthoceratite, inoceramus, catil- 
 lus, ammonite, and belemnite are never found in the 
 tertiary in such a state as to indicate their having 
 lived there. 
 
 The vegetable characters are no less important 
 than the preceding. 
 
 The phyllites, or leaves of the dicotyledons, the 
 stems of palms, the fruits of the different genera of 
 this family, are common ; and many of them are 
 peculiar to these formations. The true fern is ex- 
 ceedingly rare in the tertiary, and no stem of the 
 calamite, licopodites, or cycadies, has ever been 
 found in it. [Brongniart, Ter de Vceonce du Gl. 
 p. 128.] 
 
 " During the deposition and consolidation of the 
 upper secondary strata, the crust of the globe ap- 
 pears to have remained in a quiescent state, and to 
 have experienced few violent concussions and de- 
 rangements, from internal causes." 
 
 We find the upper secondary and tertiary strata 
 arranged horizontally, or nearly so, over the inclin- 
 ed lower secondary, transition, and primitive rocks.* 
 
 How many species have been determined as existing in 
 the tertiary ? Which are the most characteristic ? What 
 are the vegetable remains ? Do the upper secondary rocks 
 seem to have been deranged in their positions during their de. 
 position ? Are the upper secondary and tertiary strata ar 
 ranged conformably over the lower rocks ? 
 
132 TERTIARY ROCKS. 
 
 The faults and dykes, so common in the lower stra- 
 ta, and in the vicinity of which the rocks are so 
 much bent, contorted, and deranged in position, 
 rarely extend into the upper secondary and tertiary 
 strata. Where these latter rocks " have experienc- 
 ed any considerable disturbing force, it appears to 
 have operated at a comparatively recent period, 
 after the deposition of the tertiary strata," for they 
 appear to have been raised, or depressed together. 
 The cities of London and Paris are both situated 
 on a tertiary deposit, which rests upon chalk, and 
 from the basin-shape, they are termed the London 
 and Paris chalk basins. 
 
 " The country in which the capital of France is 
 situated, is perhaps the most remarkable that has yet 
 been observed, both from the succession of different 
 soils of which it is formed, and from the extraordi- 
 nary organic remains which it contains. Millions 
 of marine shells, which alternate regularly with fresh 
 water shells, compose the principle mass. Bones of 
 land animals, of which the genera are entirely un- 
 known, are found in certain parts ; other bones, re- 
 markable for their vast size, and of which some of 
 similar genera exist only in distant countries, are 
 found scattered in the upper beds. A marked char- 
 
 Do faults and dykes often extend into the upper secondary 
 and tertiary strata ? Where the upper secondary and ter- 
 tiary rocks have been deranged in their position, at what 
 period does this arrangement appear to have taken place ? 
 On what formation do the cities of London and Paris stand ? 
 On what do the tertiary deposits rest ? For what is the coun. 
 try around Paris most remarkable ? What show evidences 
 of an irruption of water ? 
 
TERTIARY ROCKS. 133 
 
 acter of a great irruption from the south east, is 
 impressed on the summits, and in the direction of 
 the hills. In one word, no country can afford more 
 instruction, respecting the last revolutions which 
 have terminated the formation of the present con- 
 tinents." 
 
 The fossil shells found in the tertiary strata, most- 
 ly belong to genera now existing in our seas ; 
 yet slight variations of form, have induced natural- 
 ists to regard them as distinct from the living spe- 
 cies. 
 
 The water from the tertiary strata is not general- 
 ly pure, but often impregnated with various salts : 
 but good water may be generally obtained by boring 
 through these deposits, so as to allow the water to 
 rise from the lower 
 strata. The tertiary 
 strata being situated in 
 basin shaped hollows, 
 thus, pools, ponds, or 
 streams of water, situated at a, would let the water 
 penetrate between the strata, so that if they be bor- 
 ed at &, the water would rise to a level with that at 
 a. If b should lie below the level of a, the water 
 would spout up, or at least, run over, at the surface 
 of the earth at b. Good water is in this way often 
 obtained from a depth of several hundred feet, and 
 not only from boring through the tertiary rocks, but 
 
 Do any of the fossil shells of the tertiary strata belong to 
 genera now existing ? Is the water obtained from the ter- 
 tiary strata pure? With what is it often impregnated? 
 How may good water be obtained ? May water be obtained 
 from great depths by this means ? 
 
 12 ' 
 
134 TERTIARY ROCKS. 
 
 in any of the classes of rocks. It however requires 
 much judgment to determine whether water may be 
 obtained in this way, in any particular locality. 
 
 The tertiary strata of the Paris chalk basin, show 
 not only the remains of sea animals and land quad- 
 rupeds, but also those of birds, among which may 
 be mentioned the duck, pelican, curlew, woodcock, 
 starling, and sea-lark. Feathers have in some in- 
 stances been found, shewing distinctly their impres- 
 sions, in the gypsum. Fish are not unfrequently 
 found imbedded in these strata, but they are more 
 common in bituminous marls, and slates of the up- 
 per secondary series. 
 
 Fossil fish are found very abundantly in the slaty 
 marl quarries of Monte Bolca, near Verona ; 105 
 species according to Brocchi, or 90 according to 
 Blainville have been found in those quarries; and 
 many of them are different from any species known 
 to exist in the neighbouring seas, or even in any 
 part of the earth. The forms of the fishes are well 
 preserved, and particularly the bony parts. The 
 animal matter is indurated, mixed with earthy mat- 
 ter, and is of a brown colour, and is so thick as to 
 project from the stone and admit of being separated 
 from it. The animal matter is brittle, and breaks 
 with a glossy fracture, and bears some resemblance 
 to glue. The bones are sometimes converted to 
 calcareous spar. 
 
 Are the remains of birds ever found imbedded in rocks ? 
 
 Are fish found fossil ? Are they most common in the upper 
 
 f secondary, or tertiary strata ? Where have they been found 
 
 abundantly ? How many species have been found there 1 
 
 What peculiarities distinguish the animal matter ? 
 
DILUVIAL DEPOSITS. 135 
 
 Fossil fish have been found in a bituminous shale, 
 near Middletown, Conn, and in Sunderland, Mass., 
 in considerable numbers. Fishes appear to have 
 been suddenly and forcibly enveloped in the sub- 
 stance containing them, if we may judge from the 
 contorted posture into which they had thrown them- 
 selves, apparently with a view to escape the terrible 
 catastrophe of which they are monuments. 
 
 CHAPTER X. 
 DILUVIAL DEPOSITS. 
 
 The crumbling of rocks is constantly going on 
 from the effects of the weather : all bare and lofty 
 cliffs and mountains are gradually wearing down, 
 and the process continues, " until they are covered 
 with soil and vegetation, which protect them from 
 further decay." 
 
 "Besides the causes which at present operate 
 to reduce the most exposed and prominent parts of 
 the earth's surface, and transport their materiafs 
 into plains, or to the sea-shore, there are evident in- 
 dications of the destructive effects of ancient inun- 
 
 Have they been found in the United States? Do they 
 seem to have been destroyed suddenly ? Is there any thing 
 to indicate that a deluge has swept over the land ? What 
 are evidences of this ? 
 
136 DILUVIAL DEPOSITS. 
 
 nations, which have swept over the surface of the 
 present continents, excavated new valleys, torn off the 
 summits of the loftiest mountains, and spread their 
 ruins in immense fragments over distant regions. 
 
 " The sand, soil, or fragments, brought down hy 
 rivers and spread along their hanks, or at their 
 mouths, are called alluvial depositions. The blocks 
 of rock, and the beds of gravel spread or scattered 
 on the surface of the ground, composed of stone, or 
 fragments foreign to the district in which they are 
 spread, and which frequently cover the bones of 
 unknown species of quadrupeds, are called diluvial 
 depositions, viz : depositions which have been form- 
 ed by a deluge." [BakeweWs Geology.'] 
 
 The diluvial deposits are either superficial, or 
 buried only under alluvion. 
 
 The materials are usually coarse, and composed 
 of gravel, pebbles, and blocks, of a great variety of 
 rocks aggregated without any regularity. 
 
 These materials are sometimes cemented together 
 by carbonate of lime, or other mineral, that had 
 been in solution, and afterwards was deposited in 
 their interstices. Some of these rocks are conglom- 
 erates, pudding stone, and osseous breccias. The 
 travertins of this age have been formed entirely from 
 solution. 
 
 .Gravel and pebble beds contain the remains of 
 extinct quadrupeds, but few remains of man, or his 
 
 t 
 
 What are alluvial depositions? What are diluvial de- 
 posits ? What arc the materials of the diluvial composed of? 
 
 How are they sometimes cemented together ? What are 
 some of these rocks ? What of gravel and pebble beds ? 
 
DILUVIAL DEPOSITS. 137 
 
 arts. They are in situations where no powerful 
 currents can reach from actual existing causes. 
 Some of the tertiary conglomerates might be con- 
 founded with the diluvial deposits. 
 
 The bones and skeletons of large animals and 
 especially the mammoth, are found in diluvial gravel 
 in many countries. In Siberia the tusks of the fos- 
 sil elephant, are found in the diluvial banks of al- 
 most every river, and the ivory from these skeletons 
 is an article of export. 
 
 " It is said that the skeleton of a whale lies on the 
 top of the mountain Sandhorn, on the coast of the 
 northern sea. The mountain is 3000 feet high, and 
 there is no cause that could have conveyed the whale 
 to that elevation except a deluge rising to that 
 height." 
 
 In 1824 the remains of a whale were found on 
 the westernmost Staffen, a mountain in Finmark, 
 at an elevation of 800 feet above the ocean." [Sil- 
 limarfs Consistency of Geol. with Sacred History, 
 in BakeweWs Geol. 2d. Am. Ed. p. 411.] 
 
 The phenomena of the diluvial ruins are highly 
 important, inasmuch as they demonstrate the nature 
 of the causes that have modified the present surface 
 of our planet, and by the quantity of these wrecks* 
 we can form an estimate of the forces in action to 
 produce them. 
 
 What animal remains are found in diluvial gravel? On 
 what mountain is the skeleton of a whale said to be ? And 
 how is it accounted for ? Where has the remains of a whale 
 been found in 1824 ? how high is this mountain ? What do 
 the diluvial ruins demonstrate ? 
 
 12* 
 
138 DILUVIAL DEPOSITS. 
 
 The phenomena of erratic blocks are some of 
 the most striking, general, and inexplicable in geol- 
 ogy. Some of the erratic blocks contain 1500 cu- 
 bic metres, to 4000 tons weight. [Vido Brong- 
 niart, Tab. des Terr airs, p. 84.] 
 
 Ohio, in which the rocks are secondary lime- 
 stones, sandstones, &c., is found to have boulders* 
 of various primitive rocks, as granite, sienite, &c., 
 scattered abundantly over some parts of its surface, 
 and no rocks of these kinds, are known to be nearer 
 than on the north side of the great lakes. 
 
 The Alps, and many parts of Germany, Russia, 
 &c. have their surfaces strewed with huge blocks 
 and rounded masses of primitive rocks, which are 
 said to have been evidently brought from Denmark, 
 Sweden and Norway, for there, exactly the same 
 rocks, containing the same minerals, and present- 
 ing the same appearances, occur. 
 
 Similar appearances occur in every country. 
 Sand, gravel, and pebbles, are of still more frequent 
 occurrence, which appear to have been transported 
 from their original situations, and deposited in new 
 ones. Most of these materials have their angles 
 rounded off, and appear to have been rubbed and 
 worn by friction against each other, like the pebbles 
 in a river, or on the sea-shore. 
 
 What is said of erratic blocks ? What are boulders ? 
 
 * Boulders are the loose, rounded masses of rock that we see scat- 
 tered over and in the soil, in various parts of the country. Rocks are 
 said to be in place, when they are in native ledges, or strata. Boui- 
 ders are rocky masses, not in place. 
 
DILUVIAL DEPOSITS. 139 
 
 One remarkable circumstance in relation to these 
 traveled fragments is, that we often find them of 
 great magnitude, and separated from their parent 
 bed, by the intervention of deep valleys and seas ; 
 and it seems impossible, that the force of currents, 
 however impetuous, can have driven them up the 
 steep sides of mountains, or through the deep beds 
 of seas. 
 
 The explanation that seems more reasonable, is, 
 that they were transported on ice bergs, before the 
 continents were uncovered by the waters of the 
 deluge, and deposited where they are now found, by 
 the gradual melting of the ice after it had grounded, 
 or even when floating* Scoresby counted 500 ice 
 bergs in North latitude 69 and 70, and many of 
 them were loaded with beds of rock, earth and grav- 
 el, of great thickness. Such islands of ice have 
 been known to drift to the Azores, from the North, 
 and to the Cape of Good Hope, from the South. 
 [Phil. Magazine.'] 
 
 Other explanations that have been offered and are 
 most plausible, are : 
 
 1st. Deluc's, who suggested that these blocks had 
 been thrown into the air by the same power that had 
 elevated the mountains, and had fallen at different 
 distances according to the force and angle of pro- 
 jection. 
 
 2d. De Buch's, who supposes that they were in 
 
 What is remarkable in the situation of these rocks ? What 
 explanation is offered of their transportation ? Do ice bergs 
 now often transport large masses of rock far from their origi- 
 nal situation ? What is Deluc's explanation ? What is De 
 Buch's supposition ? 
 
140 DILUVIAL DEPOSITS. 
 
 their present place before the last great convulsion 
 of the earth's surface, and when on high mountains, 
 that the mountains have been elevated since that 
 period. 
 
 It is believed that these theories have been aban- 
 doned by all, and there are numerous facts which 
 militate against all the theories that have been pro- 
 posed, except that of transport by floating ice. 
 
 There is no difficulty in supposing the transport 
 of gravel, sand, or pebbles, by the action of run- 
 ning water, to the situations in which they are found, 
 when we take into view the violence of the cur- 
 rents which must have been produced during the 
 rise and fall of the waters of the deluge. 
 
 " In order to appreciate justly the effect of such 
 a tremendous rush of waters, we must compare 
 it not only with common tides, but with those more 
 violent ones with which we are acquainted." "Be- 
 tween the Mata Cape and the North Cape, in the 
 place where the great canal of the river Amazon is 
 most confined by the islands, the tide presents a, 
 singular phenomena. During the three days near- 
 est the full and new moons, (the times of the high 
 tides,) the sea, instead of employing six hours to 
 rise, attains its highest elevation in the space of one 
 or two minutes. It may be supposed that this is not 
 effected very quietly : a terrific noise is heard at the 
 distance of one or two leagues, which announces 
 the pororoca, or bore, (such is the name the Indians 
 
 Is there any difficulty in accounting for the transport of 
 gravel, sand and pebbles ? What is said of the pororoca of 
 the Amazon ? 
 
DILUVIAL DEPOSITS. 141 
 
 of the district give to this terrible tide.) As it ad- 
 vances, the noise increases, and presently one be- 
 holds a promontory of water, from 12 to 15 feet in 
 height ; then a second, then a third, and often a 
 fourth, which follow close on each other, and which 
 occupy the whole breadth of the canal. This surge 
 advances with prodigious rapidity, breaking down 
 and shaving clean away, every thing that opposes 
 it. Wherever it passes, the coast is laid as smooth 
 as if it had been intentionally and carefully swept. 
 [Sillimari's Outline, in BakeweWs Geology.'] 
 
 At the mouth of a river in Nova Scotia, a 
 schooner of 32 tons, laden with live stock, was 
 lying with her side to the tide, at the influx of the 
 bore, which was then about 10 feet in perpendicu- 
 lar height. No sooner had this mass of water 
 reached the vessel, than that great body was turned 
 over like a barrel, and presently disappeared. Af- 
 ter the tide had ebbed, the schooner was so totally 
 absorbed in the sand, that the upper rail of the deck 
 was alone visible." 
 
 " The tides in the Bay of Fundy are said to rise 
 sixty feet, to come roaring in like a mighty rushing 
 flood, and that people and animals upon the beach, 
 sometimes with difficulty escape w r ith their lives." * 
 
 "On the 14th Oct. 1822, a wave, which, during 
 a storm, broke against the pier of Ramsgate, and 
 was dashed upwards to a height of about 14 feet, 
 fell again upon the stone pavement of the pier head ; 
 and, by the force of its reaction, raised a 361b. car- 
 ronade, with its carriage, over a stone ledge, and 
 
 What is said of the effects of the tide in the Bay of Fundy ? 
 
142 DILUVIAL DEPOSITS. 
 
 precipitated it into the sea." The efforts of 20 
 men would have been required to produce the same 
 effect. 
 
 "In the great tempest of Sept. 1815, among ma- 
 ny similar effects, which happened all along the 
 shores of New England, a vast ridgy wave, raised 
 by the hurricane, came suddenly, in an overwhelm- 
 ing deluge, upon the lower town of Providence, in 
 Rhode Island, and by its force, entire rows of houses, 
 and stores, and warehouses, were, in a few minutes, 
 prostrated. Ships of 300 and 400 tons, were thrown 
 upon the wharves, knocking down large buildings 
 by their momentum : some were carried into the 
 town, thrusting their jib booms in at the 2d and 3d 
 stories of houses ; others were lodged in the streets ; 
 and a number, and those some of the largest class, 
 (among them the Ganges, formerly a sloop of war,) 
 after carrying away a strong bridge, were driven 
 through a bay, usually too shallow, even for small 
 craft, and were thrown up high and dry, upon a 
 beach, where the salt water has never come again." 
 [Silliman's Outline in BakeweWs Geology.] 
 
 The effects of torrents, and of lakes bursting their 
 boundaries, are still more striking, and I beg leave 
 to refer the reader to the American Journal of Sci- 
 ence, vol. iv, p. 125, and xv, art. ii. xi, p. 39, for 
 accounts of such phenomena, which have occurred 
 within a few years, and in our own country. 
 
 The evidences of the deluge are imprinted in an 
 imperishable manner, on all parts of the earth, in 
 
 What were the effects of the wave that rushed into the 
 town of Providence during the storm of 1815 ? 
 
DILUVIAL DEPOSITS. 143 
 
 the transported materials, which have been spoken 
 of, and in the valleys scooped out of the originally 
 continuous strata, of which mention has been made 
 in the chapter on stratification. Supposing the 
 highest elevation of the waters to have been 51-2 
 miles : as they were 40 days in rising, they rose at 
 the rate of 181 feet in the time of a common flood, 
 or ebb tide. 
 
 If we now glance at the effects of the tides which 
 have been mentioned in the Amazon ; on the coast 
 of Nova Scotia; of the storm of 1815, in New 
 England ; that on the Catskills, in 1819 ; and that 
 on the White Mountains, in 1826, how much more 
 powerful must have been the effects, where the water 
 was rising continually, and acquiring additional 
 force and velocity, during its 40 days rise of the 
 deluge. 
 
 " It is not easy to exalt the imagination to the 
 adequate conception of the terrors of that awful 
 catastrophe. The inconceivably violent torrents 
 and cateracts, every where descending from the 
 hills and mountains, and meeting a tide, rising at 
 the rate of more than 700 feet in a day, must have 
 been resisted and aggavated in force, wherever it 
 encountered the land, and still more by the hills a4 
 the mountain ridges. Impelled with resistless vio 
 lence it must have swept over the surface, with a 
 force vastly greater than any thing we now know, 
 of the mightiest rushing waters. It evidently roll- 
 
 Do valleys appear to have been scooped out by the deluge t 
 Must the waters of the deluge have risen more rapidly than 
 our highest tides ? 
 
144 DILUVIAL DEPOSITS. 
 
 ed every where over the various inequalities of the 
 land in tremendous agitated billows ; and where it 
 was narrowed by ridges, and hills, and mountains, 
 and thus forced through valleys and defiles, it must 
 have presented innumerable raging torrents and ca- 
 taracts, of awful height, force and magnitude, com- 
 pared with which, even Niagara would be insignifi- 
 cant. " [Sillimaii's Outline. ] 
 
 The diluvial deposits in some parts of the earth, 
 are rich in metals, ores, and gems. 
 
 Deposits containing these substances are gene- 
 rally loose, or but slightly aggregated, composed of 
 sand, gravel, pebbles and boulders, more or less 
 rounded by attrition. 
 
 The materials composing these rich deposits, is 
 mostly a siliceous sand or gravel, which is often 
 highly ferruginous. The beds are in many in- 
 stances of considerable thickness, filling broad val- 
 leys ; covering elevated plains and hills of moderate 
 declivity. 
 
 The minerals generally found in these deposits, 
 are hyaline quartz, amethysts, jasper, and titanife- 
 rous iron sand. 
 
 Of gems there are crystals with worn edges, as 
 sapphire, ruby, spinelles, crysoberyl, topaz, zircons, 
 and diamond. 
 
 Diamonds have been found only in Brazil, Borneo, 
 India, and Russia. 
 
 In what are the diluvial deposits rich ? What is the ma- 
 terial composing them ? What of the beds in which they 
 are found ? What kinds of minerals are generally found in 
 these deposits ? What kinds of gems ? 
 
DILUVIAL DEPOSITS. 145 
 
 Of the metals ; gold, platinum, several metals as- 
 sociated with platinum, red oxide of titanium, mag. 
 netic iron sand, micaceous and specular iron ore, 
 and the oxide of tin are the most important. 
 
 Gold is found most abundantly in the washings 
 in Russia in Asia, in Brazil, South America, and in 
 the southern and middle States of the United States. 
 
 Platinum is found in South America, and in Asia 
 at the foot of the Oural mountains. 
 
 Gold is always found in connection with platinum, 
 but the reverse is not always true. 
 
 Oxide of tin occurs in granitic gravel, which is 
 generally in the vicinity of the rocks from which it 
 was derived. 
 
 Caves have been found in England, France, and 
 Germany, containing immense numbers of the bones 
 of animals, which, in some, are imbedded under a 
 kind of yellowish earth, like that which is supposed 
 to have been deposited while the waters were rest- 
 ing upon the earth, during the deluge. 
 
 Some of these caves appear to have been the dens 
 of antediluvial carnivorous animals, and into others 
 it appears that the animals may have retired to es- 
 cape the deluge ; or may have fallen in, or been 
 washed in through fissures communicating with the 
 surface of the earth. 
 
 The bones of some of the animals show the marks 
 
 What kinds of metals ? In what countries are they mostly 
 found ? Are the bones of animals found in great numbers in 
 the caves of England, Germany and France ? Are these in 
 the loose earth of recent deposit, or in diluvial mud ? What do 
 some of th jse caves appear to have been ? What do some of 
 the bones show ? 
 
 13 
 
146 DILUVIAL DEPOSITS. 
 
 of teeth, as though they had been gnawed ; and the 
 bones of the hyena, bear, wolf, fox, dog, horse, ox, 
 and a great variety of animals are found in them. 
 The earth, in which these bones are imbedded, is 
 generally covered by a stony mass, since formed. 
 In some of the caves, all the earth appears to have 
 been formed by animal decomposition. 
 
 Bone breccias, fissures, and caverns. These are 
 generally classed with diluvial deposits, although it 
 is probable many of them are more recent. 
 
 The fissures and caves containing the bones, and 
 bone breccias, are in limestone ; and the Jura lime- 
 stone is the rock in which they are most abundant. 
 
 The fissures are filled with fragments of rock, 
 some rounded, some angular, and cemented together 
 by finer materials of the same kind, and calcareous 
 matter deposited in the interstices from solution in 
 water. The colour is variable ; but red is most 
 common from carbonate and oxide of iron. The 
 bones are those of vertebrated animals and mostly 
 of mammalia ; some are rounded and worn, some 
 broken, and others are perfect, and imbedded in the 
 breccia. 
 
 Is the earth in which these bones are imbedded, ever cov- 
 ered by a stony mass ? In some of the caves, does all the 
 earth appear to have been formed of animal matter ? What 
 are generally classed with diluvial deposits ? What is pro- 
 bable respecting them ? In what rock are they most abun- 
 dant ? With what are the fissures filled ? How are these 
 fragments cemented together ? What colour do they pre- 
 sent ? What species of bones are these ? How do they ap 
 pear? 
 
DILUVIAL DEPOSITS. 147 
 
 Land and fresh water shells are not uncommon 
 in these breccias ; and bones of birds are sometimes 
 also found. The fissures always communicate with 
 the surface of the earth ; or at least, none have been 
 cited as closed in every direction by solid beds of 
 rock, without having been since found to have 
 evidently communicated. 
 
 Of the organic remains of the breccias of the fis- 
 sures, the palaeotherium, chaeropotamus, deer, ante- 
 lope, cat, two species of bear, and the rabbit are 
 among the most common. The fissures in which 
 they are contained have their angles rounded, and 
 the concave cavities in the sides, show as if they had 
 once been the passages through which currents of 
 water had flowed. This would account for some of 
 the fragments and bones being rounded in their 
 forms. Many of the animals probably fell into or 
 were lost in the fissures, and unable to escape. 
 
 Bone caves are subterranean sinuous caverns, pre- 
 senting in different parts of their course, expansions 
 and contractions in breadth and height. The sides 
 are not parallel, but appear as if worn and corroded 
 by the action of water, or other solvent material. 
 They are of various degrees of declivity from the 
 surface, some penetrating horizontally from the base 
 or sides of hills, others at some intermediate angle/ 
 or vertically. 
 
 Are shells and bones of birds sometimes found ? With what 
 do th e fissures communicate ? What are the most common 
 of the organic remains of the breccias of the fissures ? What 
 do the fissures in which they are contained show ? What 
 would this account for ? What are bone caves ? How are 
 the sides formed ? 
 
148 DILUVIAL DEPOSITS. 
 
 These caverns generally show the naked lime- 
 stone in which they are contained ; and they are 
 more or less filled with two kinds of rock of different 
 composition and origin. These are, 
 
 1st. Earthy materials sometimes entirely loose, 
 mingled with fragments of rock and bones, occu- 
 pying the inferior parts of the cavern. 
 
 2cl. Crystalline calcareous concretions, called sta- 
 lactites, and stalagmites, which cover the roof, sides, 
 and floor, entirely, or in part, and often form a thick 
 crust over the earth, and fragments of rock and 
 bones. Often the materials of the first are cement- 
 ed together by the calcareous depositions of the se- 
 cond, in a breccia, similar to the bone breccia of 
 the fissures. The bones are scarcely altered. Of 
 the remains found in caverns three-fourths belong to 
 bears, one-sixth to the hyena, and one- twelfth to the 
 remaining animals. These are the elephant, rhino- 
 ceros, horse, ox, hog, camel, sheep, cat, two species 
 of weazel ; pole cat, badger, wolf, rat, hare, and 
 birds. 
 
 Some human bones have been found in caves of 
 this description in France, so situated as to induce 
 the idea that the subjects of them were destroyed by 
 the deluge. Similar relicts have been discovered in 
 diluvial gravel, at the depth of about 50 feet ; and 
 
 What do these caverns show ? What are the rocks with 
 which these caverns are filled composed of ? Are they often 
 cemented together ? What are the proportions of the remains 
 of the different animals? Have human bones been found in 
 caves ? What idea does their situation induce ? Have human 
 remains heen found in diluvial gravel ? At what depth ? 
 
ALLUVIAL DEPOSITS. 149 
 
 remains of this kind have also been found imbedded 
 in a rock of recent origin, and which is even now 
 in the process of formation, enclosing every thing 
 thrown upon it by the surf. 
 
 It is a remarkable fact, that, notwithstanding the 
 great variety of fossils observed in the rocks, the 
 remains of man are not found fossil until we come 
 to the diluvial deposits. Geological facts show, that 
 the various plants and animals were created in the 
 some order as mentioned in the Mosaic account, and 
 that man was created last, as we find his remains 
 only in those deposits laid down since all those great 
 changes and convulsions, which destroyed so many 
 millions of millions of animated beings, and formed 
 some of the rocks of their remains. 
 
 CHAPTER XI. 
 ALLUVIAL DEPOSITS. 
 
 These deposits are the most superficial of all the 
 formations ; and the materials forming them gene-* 
 rally indicate that they were deposited from water ; 
 and they appear in most cases, to have separated 
 from tranquil water rather than from violent cur- 
 rents. 
 
 Have the remains of man been found imbedded in rock ? 
 In what kind of rock ? In what deposits only do we find the 
 remains of the human race ? What do the alluvial deposits 
 indicate ? How do they appear in most cases ? 
 13* 
 
150 ALLUVIAL DEPOSITS. 
 
 Alluvial deposits are forming every day. They 
 envelope the remains of animals that still exist on 
 the surface which they contribute to form ; and they 
 are also mingled in many places, with the remains 
 of animals which have lived in recent times, and 
 have disappeared, either by the effects of civilization 
 or other local causes. 
 
 These remains are hardly altered ; being perhaps 
 blackened or whitened, according to the influences 
 to which they may have been subjected. In allu- 
 vion we find the remains of human beings, of their in- 
 dustry and arts. The stone arrow heads, axes, and 
 other cutting instruments, fragments of pottery, re- 
 mains of furnaces, and the metals smelted under the 
 surface are familiar to every one. The alluvial beds 
 taken as masses, are all of loose earth, and are never 
 covered by rocky beds. Tufa is sometimes deposit, 
 ed from calcareous springs over more ancient allu- 
 vion, but the beds are always of small extent. 
 
 It is often difficult to distinguish between the allu- 
 vial and diluvial deposits, but the distinction is in 
 general of little consequence. All those causes 
 which are at present in action to produce changes 
 upon the surface of the earth, such as the transport 
 of materials by torrents, rains, streams, tides, cur- 
 
 Are alluvial deposits often formed ? What do they en- 
 velope? With what are they mingled in many places? 
 Are the remains of man and his arts abundant in this forma, 
 tion ? What of alluvial beds ? Is it always easy to distin- 
 guish between the alluvial and diluvial deposits ? What are 
 the causes of alluvial deposits? 
 
ALLUVIAL DEPOSITS. 151 
 
 rents in the ocean, winds, springs, and the labours of 
 animals, as shell fish, and corals, in elevating banks 
 and reefs in the ocean ; the growth and decay of 
 plants, as in peat-bogs, and swamps ; the formation 
 of bog iron ore; and calcareous depositions from 
 springs, are classed as alluvial ; while all those ma- 
 terials which have been transported to situations 
 where the waters, under existing causes, cannot 
 reach them, the scooping out of some valleys, and 
 uncapping of some mountains, are referred to dilu- 
 vial agency. Torrents often remove masses of 
 rock, of many tons weight, to considerable dis- 
 tances ; tear up trees, and bury them under deep 
 masses of rocks, pebbles, gravel and sand. Rains 
 wash off the loose materials on the hills : some of 
 this is carried into the larger streams ; and these, 
 when the waters are high, wear away the banks in 
 some places, and deposit the materials in others. 
 Thus there is a constant tendency to level the 
 country, wear down its inequalities, and deposit the 
 materials in the sea. The making of land, by the 
 deposit of materials thus brought down by rivers, 
 is well known, and illustrated by the Mississippi, 
 Ganges, and many others. The mouths of the Mis- 
 sissippi are more than 100 miles from its original 
 entrance into the Gulf of Mexico, and for many hun- 
 dreds of miles above, all the land seen from its banks, 
 
 How do you distinguish diluvial from alluvial deposits ? 
 What is the constant tendency of rains and streams ? Do 
 rivers ever deposit their materials in the sea ? Are the 
 mouths of the Mississippi far from the original entrance of 
 the river to the Gulf of Mexico ? Are the other alluvial 
 deposits of the Mississippi extensive ? 
 
152 A.LLUVIAL DEPOSITS. 
 
 with the exception of now and then a sand or clay 
 bluff, is alluvial. 
 
 M. Lardy has described a fall of a part of the 
 Dent du midi, one of the high Alps, which took place 
 on the 26th. Aug. 1835. 
 
 On the 25th. there was a violent storm all around 
 the mountain, which was often struck by lightning. 
 On the 26th. a large portion of the peak broke off 
 from the eastern edge, and fell with a dreadful crash 
 upon the glacier on the southern side of the moun- 
 tain, and in its descent drew along with it an im- 
 mense portion of this glacier. This enormous mass 
 of mixed stone and ice fell into a deep ravine, through 
 which the torrent of St. Bartholemy flows. A mass 
 as it were a mountain of black viscid mire speedily 
 flowed from the gorge of the ravine, and bore on its 
 surface vast blocks and masses of solid rock. This 
 semi-liquid mass, crossed the valley towards the 
 Rhone like a flow of lava, crushing and bearing 
 away a forest of pines in its course. The Rhone 
 was temporarily dammed up. The road became im- 
 passable, and a new road was constructed across the 
 tremulous mass, with fascines and faggots. It was 
 a frightful scene, to behold a deep valley thus filled 
 up with a mass of flowing frozen mire, floating enor- 
 mous rocks upon its surface, and which contained 
 scarce any water except in a solid state. [Ed. Phil. 
 Jour. Oct. 1836, p. 372.] 
 
 On the 28th. Aug. about three P. M. 1823, the 
 
 In what year did the fall of a part of the Dent du midi, take 
 place ? How is the catastrophe described ? When did the 
 land slip in Charaplain occur ? 
 
ALLUVIAL DEPOSITS. 153 
 
 inhabitants of the village Hayolle in the parish of 
 Champlain, (L. C.) were alarmed by a tract of land 
 containing a superfices of 207 arpents, suddenly 
 sliding about 360 yards, and precipitating itself into 
 the Champlain river, which it dammed p for 1300 
 yards. In its progress, houses, barns, trees, and 
 whatever lay in its course, were overwhelmed. The 
 catastrophe was accompanied by an appalling sound ; 
 arid a dense vapour filled the atmosphere, oppressing 
 those who witnessed this convulsion almost to suffo- 
 cation. A man who was on the ground at the time, 
 was removed with it to a considerable distance, and 
 buried up to the neck, but was extricated from his 
 perilous situation without having sustained serious 
 injury. [Quebec Gazette, and Bost. Jour. Sc. i. 
 p. 301.] 
 
 Glaciers are masses of snow and ice more or less 
 consolidated, which accumulate above the limit of 
 perpetual snow on high mountains, either on their 
 summit and sides or in the valleys. 
 
 The appearance of the mass varies according to 
 the circumstances under which it was formed. If 
 you can conceive the ocean consolidated when roll, 
 ing its swell along under the action of a gentle breeze, 
 a boundless mirror of ice, and snow drifts magnified 
 to high hills, you may have a faint idea of the forms 
 in which glaciers are presented to the eye ; "but 
 nothing less than the actual view can give a con- 
 ception of the amazement, if not the terror with 
 
 How many yards did it slide ? What is further said of it ? 
 What are Glaciers ? What gives a faint idea of the forms 
 in which glaciers are presented to the eye ? 
 
154 ALLUVIAL DEPOSITS. 
 
 which the appearance is first beheld. The traveller 
 stands in a new world, surrounded by new scenes ; 
 no living being is there, and no sounds but his own 
 feeble voice and the thunder of the tumbling ava- 
 lanches ; not a flower or tree can be seen except the 
 lonely pine, which seems left alone to mourn over 
 the grave of nature." 
 
 " But even this desolate region has its use in the 
 economy of nature, for it is the reservoir of those 
 springs which distribute fertility through the valleys 
 and plains ; and gives that in gentle streams which 
 would otherwise rush headlong in its fury to the 
 valleys, and leave ruin and desolation in its path." 
 [Phys. Condition of the Earth, p. 339.] 
 
 Biggsby in describing the geology of Lake Huron, 
 says : In the spring the ice removes fragments of 
 great size. During the winter it surrounds those 
 which are placed in the shallows, and on being 
 broken up by the mild weather of spring, by the rise 
 of water which takes place in consequence of the 
 blowing of the wind, they are either carried higher 
 on the shore, leaving a furrow behind them, or they 
 are moved off with the field of ice to which they 
 are attached ; and on the melting of the ice deposit- 
 ed on some other shore more or less distant from 
 their original situation. Rolled stones of some yards 
 in diameter are thus removed. [Am. Jour. Sc. iii. 
 p. 256.] 
 
 The alluvial deposits projecting into the sea, and 
 
 Of what use are glaciers ? What is said respecting the 
 transporation of blocks by ice ? 
 
ALLUVIAL DEPOSITS. 155 
 
 deposited by rivers, are called deltas, as the delta of 
 the Nile, of the Ganges, of the Mississippi, Rhone, 
 Po, Volga, and the Danube. The delta of the 
 Ganges commences 220 miles in a direct line from 
 the ocean. 
 
 Adria, which was once a port on the Adriatic sea, 
 is now 20 miles inland. The waters of the Ganges, 
 and Mississippi, are so turbid, when in flood, as to 
 give about one quarter their volumes of sediment. 
 
 Rivers which project their deltas into the sea, 
 have generally a tendency to raise their beds in the 
 lower part of their course, by the partial deposit of 
 the materials brought down. This is more particu- 
 larly the case with the Po, which is prevented from 
 overflowing the country by dykes. The bed of that 
 river has risen so much as to be higher than the 
 tops of the houses of Ferrara. In Holland, the same 
 phenomenon is observed, but not on so great a scale. 
 The rivers, in fact, run in a canal on the top of a hill. 
 
 Since the Mississippi has been dyked, the same 
 effect may be perceived, but to a small extent. When 
 sailing along the Mississippi, during high water, 
 you appear to be above the surrounding country ; 
 the dykes appear to be only two or three feet high, 
 but on landing, you observe that they are much 
 
 What are deltas ? What deltas are remarkable ? How 
 far does the delta of the Ganges commence from the ocean ? 
 How far is the ancient port of Adria from the sea ? Are the 
 waters of any rivers very turbid ? What ones are particu- 
 larly so ? What tendency have rivers which project deltas 
 into the sea ? What river particularly illustrates this fact ? 
 Is the same effect observed in other places ? Does the Mis. 
 sissippi show this in any degree ? 
 
156 ALLUVIAL DEPOSITS. 
 
 higher on the land, than on the river side. The 
 reason is, that the space between the dyke and the 
 river, has been raised by deposits from the river, to 
 a height equal to the difference of.level between the 
 land on the different sides of the dyke ; and the bed 
 of the stream rises in the same proportion as the 
 banks. 
 
 The transporting power of tides and currents in 
 the ocean, must be taken into consideration, as con- 
 nected with alluvial deposits. Much of the matter 
 brought down by rivers, is borne away by tidal cur 
 rents. These currents acting on the shore, in con 
 nection with the waves, remove materials from one 
 situation, and deposit them in another. 
 
 " The power even of a small rivulet when swollen 
 by rain was lately exemplified in the College, a 
 small stream which flows with a moderate declivity 
 from the eastern water shed of the Cheviot hills. 
 Several thousand tons weight of gravel and sand 
 were transported, to the plain of the Till ; and a 
 bridge then in progress of building was carried 
 away, some of the arch stones of which, weighing 
 from half to three-quarters of a ton each, were pro- 
 pelled two miles down the rivulet. On the same 
 occasion the current tore away from the abutment 
 of a mill-dam a large block of greenstone porphyry, 
 weighing nearly two tons, and transported it to the 
 distance of a quarter of a mile. Instances are men- 
 tioned as occurring repeatedly in which from 1000 
 
 Do the tides and currents of the ocean transport alluvion ? 
 What effects were produced by the action of a rivulet when 
 swollen by rain ? 
 
ALLUVIAL DEPOSITS. 157 
 
 to 3000 tons of gravel are in like manner removed 
 to great distances in one day." [LyeE's Geol. i. 
 p. 201., and proceedings Geol. Soc. Lond. No. xii. 
 p. 829.] 
 
 " The river Don has forced a mass of 400 or 500 
 tons of stones many of them 200 or 300 Ib. weight, 
 up an inclined plane, rising 6 feet in 8 or 10 yards, 
 and left them in a heap three feet deep on a flat 
 ground." [Quar. Jour. N. S. xii. p. 331. LyeWs 
 Prin. of Geol. i. p. 201.] 
 
 When the materials are of a loose nature, like 
 sand, clay, or soft rock, the wearing away of the 
 head-lands, against which the currents beat, is very 
 rapid, but if pebbles, or other hard materials be con- 
 tained in the banks, the lighter or softer materials 
 are removed, and the hard ones gradually form a 
 slope, which protects the shore in a great degree 
 from further action. 
 
 The action of wind in transporting materials from 
 one situation to another, is more important than 
 one would be led to imagine, without a knowledge 
 of facts. 
 
 " Extensive tracts of cultivated ground are some- 
 times converted into sandy deserts, by the drifting 
 of the sea-sand inland. The process by which this 
 is effected, is taking place in many situations. Dur- 
 ing high winds, the sand is driven from the sea-shore 
 
 What is said of the force of the river Don ? Are head- 
 lands washed rapidly away by the action of the waves and 
 currents ? What serves finally to protect them from further 
 action ? Is wind ever an agent in transporting alluvial mat- 
 ter ? What are the effects produced by the drifting of sand ? 
 How is the process effected on the sea shore ? 
 14 
 
158 ALLUVIAL DEPOSITS. 
 
 to a certain distance, leaving an elevated ridge at the 
 farther boundary of the drift. Succeeding winds 
 blow the sand forwards, and at the same time bring 
 fresh sand from the shore to supply its place. Trees, 
 houses, and even villages, have been surrounded and 
 covered with sand, in some parts of Ireland and 
 England, within the last century." 
 . Instances of these encroachments may be seen 
 on many parts of our own coast. A particular in- 
 stance of a light-house, on the coast of Virginia, 
 being partly covered, and the bank progressing into 
 the country, with a steep front of twenty or thirty 
 feet, burying trees and every thing else in its course, 
 is described in the American Philosophical Trans- 
 actions, Vol. iv. p. 439., and is well worth the at- 
 tention of the curious reader. 
 
 It is well known that a considerable portion of 
 Egypt is buried by the sands drifted upon it, and 
 that the Red Sea is in many places rendered quite 
 shoal by coral reefs, and by the sand drifted into it. 
 The sand-storms of the deserts, have often been 
 described. 
 
 During the expedition of Gen. Atkinson to the 
 Yellow Stone River, in 1825, a forest of petrified 
 trees was observed, standing erect, but with their 
 smaller limbs broken off, and scattered on the sandy 
 desert beneath them. They had probably been ori- 
 ginally covered by sand, drifted over them either by 
 wind or by water, and remained thus long enough 
 
 Are houses, or villages, ever buried ? What is said of the 
 light house in Virginia ? What is said of Egypt, and of the 
 Red Sea ? What is said of the petrified forest ? 
 
ALLUVIAL DEPOSITS. 159 
 
 to become petrified. The loose sand appears after- 
 wards to have been drifted away by the wind, leav- 
 ing them monuments of the changes of the earth's 
 surface. 
 
 Shoals often become sensibly more shallow, by the 
 combined effects of shell-fish, and other marine ani- 
 mals, living, growing, and afterwards leaving their 
 remains as a basis for others to live and die upon 
 successively. Coral reefs are produced in such 
 abundance in some parts of the Pacific and Indian 
 oceans, as to obstruct the navigation, although the 
 animals employed in building them are so small as 
 to be hardly visible to the naked eye. 
 
 Mr. Uobert in his account of the geology of 
 Iceland, mentions that in the vicinity of the gey- 
 sers, tho silicious concretionary deposits, form a 
 mass no less than 4 leagues in length. \_Ed Phil. 
 Jour. Oct. 1836. p. 372.] 
 
 Peat is a substance generally classed with allu- 
 vial soils, although it is a vegetable production. 
 
 Peat is generally situated in low, wet grounds, 
 but is sometimes found on the declivities of moun- 
 tains. The condition that seems to be essential to 
 the formation of peat, is, that the soil should not be 
 permeable, and that the water which covers it should 
 be neither stagnant, nor too rapidly renewed; and 
 that the vegetables should not rot, but experience a 
 
 What explanation is offered of this phenomenon ? What 
 is said o.-' shoals? Are coral reefs common? How large 
 are the animals that build these reefs? What is peat? 
 Where \-.\ peat generally situated ? What condition seems 
 essential to its formation 1 
 
160 ALLUVIAL DEPOSITS. 
 
 peculiar change anologous to tanning. [Brong- 
 niart Tableau des Terr airs, p. 37.] 
 
 Peat is rarely found in the tropics, but abounds in 
 most cold climates. It is said that Ireland has one- 
 tenth of its surface covered with peat. In the 
 Northern States of the United States it is very 
 abundant, in the South, and Southwestern it is rare- 
 ly seen. The organic matters that in a favourable 
 location would give rise to peat, are destroyed by 
 insects, or by putrefaction. 
 
 Peat meadows generally exhibit a wet, spongy 
 surface, and when capable of supporting much 
 weight, its surface will shake and tremble for 
 some distance around, by walking or jumping upon 
 it. Good peat cuts easily and clear with the spade ; 
 but if it resist the spade with a degree of elasticity, 
 it is found to be less compact when dry, and of an 
 inferior quality. The best kinds, burn with a clear 
 flame, leaving light colored ashes ; but the poorer 
 kinds often emit a disagreeable smell, and leave a 
 heavy, red-colored ash. 
 
 " The process by which the mosses are converted 
 into peat, is clearly seen in one of them, (the sphag- 
 num palustre.) As the lower extremity of the plant 
 dies, the upper sends forth fresh roots, like most of 
 the mosses, the individual thus in a manner becom- 
 ing immortal, and supplying a perpetual fund of de- 
 composing vegetable matter. A similar process, 
 
 What is the proportion of peat in Ireland ? What is the 
 appearance of peat meadows ? If you walk or jump on them, 
 what is observed ? What are the characters of good peat ? 
 How can you distinguish the good from that of inferior 
 quality ? Explain the formation of peat ? 
 
TRAP ROCKS. 163 
 
 perpendicular cliffs of several hundred feet in 
 height. 
 
 In the sketch above, columnar trap is represented 
 as r ; sting unconformably, on inclined strata. A dyke 
 of the same kind of rock is shewn, cutting through 
 the other rocks, and a bed connected with the dyke 
 lying between, and separating them. " It is obvious 
 that these unconformable rocks were formed and de- 
 posited at a subsequent period to that in which the 
 lower rocks were consolidated, and their beds had 
 acquired their present inclined positions." 
 
 The term trap is derived from the Swedish word 
 trappa, a stair, because these rocks often divide into 
 regular forms resembling the steps of a stair. These 
 rocks, composed of feldspar and hornblende, or of 
 hornblende and augite, are called greenstone, sienitic 
 greenstone, basalt, clinkstone, pitchstone, amygda- 
 loid, wacke, ancT porphyry. 
 
 Greenstone is essentially composed of feldspar 
 and hornblende, in the state of grains or small crys- 
 tals, the proportions varying, but the hornblende 
 generally predominates. The grains are sometimes 
 so small that the different minerals cannot be dis- 
 tinguished from each other. The rock derives its 
 name from its being frequently of a greenish color, 
 especially when moistened. When fine grained it 
 generally exhibits a columnar structure, as in the 
 East and West rocks near New Haven, and the 
 
 At what period were these rocks deposited ? From what 
 is the term trap derived ? Describe greenstone ? Does it 
 ever show the columnar structure ? Where may this be ob- 
 served? 
 
164 TRAP ROCKS. 
 
 Palisades on the Hudson river, and Mount Holyoke, 
 near Northampton, Mass. 
 
 Greenstone is sienitic when it is coarse grained, 
 and becomes sienite when feldspar predominates. 
 Basalt is a compact, homogenous mass of rock com- 
 posed of feldspar and hornblende or augite. It has 
 a greenish or brownish black color, and is very 
 tough or difficult to break, but can be scratched with 
 the point of a knife. 
 
 It melts easily into a black or dark green glass, 
 and is extensively used in France, for the manufac- 
 ture of glass bottles. The iron contained in it, is, 
 by exposure to the weather, further oxidized, and 
 causes the yellowish or brownish red colour that it 
 usually presents on its surface. 
 
 When basalt is slaty, or the feldspar predomin- 
 ates, it becomes clinkstone: when earthy in its 
 texture and mixed with green earth, it is called 
 wacke. When basalt or wacke contain rounded 
 cavities entirely or partly filled with other miner- 
 als, they form amygdaloid. Basalt is generally 
 columnar in its form, but sometimes is seen in large 
 tabular, or in globular masses. The general aspect 
 of the trap rocks where they form large masses, is 
 such as at once to attract the attention of the 
 traveller. 
 
 The porphyry and basalt on the Andes, says Hum- 
 bolt, "are arranged in regular columns, which strike 
 
 Describe basalt ? For what is it used ? What change is 
 observed in its appearance when long exposed to the weather ? 
 What is clinkstone ? What is amygdaloid ? Is basalt colum- 
 nar ? What is the general aspect of the trap rocks ? What 
 is said of the porphyry and basalt of the Andes ? 
 
TRAP ROCKS. 161 
 
 though less distinct, takes place in many of the 
 rushes and grasses, the ancient roots dying together 
 with the older leaves ; while an annual renovation 
 of both, perpetuates the existence of the plant. 
 Where the living plant is still in contact with peat, 
 the roots of the rushes and ligneous vegetables are 
 found vacillating between life and death, in a spon- 
 gy, half decomposed mass. Lower down, the pul- 
 verized carbonaceous matter is seen mixed with 
 similar fibres, still resisting decomposition. These 
 gradually disappear, and at length, a finely powder- 
 ed substance alone is found ; the process being com- 
 pleted by the total destruction of all organized bo- 
 dies." " The best peat is that of which the decom- 
 position is most complete, and the specific gravity 
 and compactness, the greatest." [Bakewell's Geo- 
 
 CHAPTER XII. 
 TRAP ROCKS. 
 
 All the REGULAR classes of rocks have now been 
 considered ; that is, all the rocks that are superpos- 
 ed one above the other, in a regular order of super- 
 position. It must not, however, be inferred, that the 
 rocks are all present in every situation. Some of 
 them are absent from almost every locality : but 
 where two or more of them occur together, they are 
 
 Are all the classes of rock present in every locality ? Where 
 any two of them occur together, how are they laid upon each 
 ether? 
 
 14* 
 
162 
 
 TRAP ROCKS. 
 
 laid over each other in the order in which they 
 have been described. For instance, the coal forma- 
 tion, wherever it is found, lies above the primitive 
 rocks, and if the transition rocks be present, it lies 
 above them also. If the transition rocks be absent, the 
 coal formation rests on the primitive rocks, as is the 
 case with the coal near Richmond in Virginia. 
 
 Diluvial and alluvial deposits often rest on the 
 primitive rocks, all the other classes being absent ; 
 but these deposits are never found under the transi- 
 tion, secondary, or tertiary rocks. 
 
 Two more classes of rocks remain to be describ- 
 ed, which have no regular situation in connection 
 with the other rocks, but are distributed in beds and 
 masses indiscriminately among them. They are 
 called Trap and volcanic rocks. 
 
 Trap rocks are mostly composed either of horn- 
 blende and feldspar, or augite and feldspar. " These 
 rocks although they sometimes occur imbedded in 
 the conformable rocks, more frequently cover them 
 in an unconformable position, composing thick, un- 
 stratified beds, and often 
 mountain masses of vast 
 size, which have, not un- 
 frequently, a columnar 
 structure," and present 
 
 For instance, is the coal formation ever found below primi- 
 tive rocks? Is it ever found lying upon primitive rocks? 
 Do the alluvial and diluvial deposits ever rest directly upon 
 the primitive rocks ? Are these deposits ever found under 
 the secondary, transition, or tertiary rocks ? Of what are 
 trap rocks mostly composed ? Do these rocks rest conform, 
 ably upon the others ? What structure do these rocks often 
 have ? Does trap ever occur imbedded conformably in other 
 rocks ? 
 
TRAP ROCKS. 165 
 
 the eye of the traveller like immense castles lifted 
 into the sky." " Were it allowed to express a geo- 
 logical fact in familiar terms, it might be said that 
 all the members of the trap family give indications 
 of a fiery character, and of having been trouble- 
 some neighbours to the adjacent rocks, disturbing 
 them and even changing their nature, when they 
 are closely associated. Besides occurring in over- 
 lying unconformable masses, all trap rocks with 
 porphyry, which may be placed at their head, are 
 occasionally found intersecting other rocks like ver- 
 tical walls." 
 
 Walls and dykes are synonymous in some parts 
 of England, from which these veins of trap rocks 
 take their name. The substance of dykes is gene- 
 rally basalt. Dykes have been very much studied, 
 on account of their cutting through the coal fields 
 in various directions, and causing great derange- 
 ment in the positions of the strata. 
 
 This derangement has been referred to in the 
 chapter on stratification. Dykes vary in thickness 
 from a few inches to several hundred feet. "The 
 extent to which they stretch across a country has 
 seldom been explored beyond the mining districts, 
 where a knowledge of them is important, on account 
 of the disturbances which they occasion in the stra- 
 ta." " The strata are almost always thrown down 
 on one side of a dyke, and elevated on the other, but 
 the dislocation is not proportioned to its breadth." 
 " Trap dykes are generally harder than the rocks 
 
 What is the effect of trap dykes on the strata ? Do basaltic 
 dykes ever appear above the surface of the earth ? 
 
166 TRAP ROCKS. 
 
 that they intersect; and when the latter are partial- 
 ly decomposed, often remain, forming vast walls of 
 stone that rise above the surface of the ground." 
 
 Walls of this kind extend for miles along the 
 country in some parts of England. They extend 
 into the sea, forming reefs of rocks, and across riv- 
 ers, making falls or fords. The natural walls of 
 North Carolina are basaltic dykes, formed of co- 
 lumnar or prismatic mass- 
 es fitting close to each 
 other, and lying with their 
 
 lengths across the wall, and 
 
 shewing their ends on its sides, as represented in the 
 sketch. 
 
 When these walls were first observed, they were 
 supposed to be artificial constructions, from the re- 
 gularity of form of the separate pieces." "Dykes 
 being impervious to water, they obstruct its passage 
 along the porous strata, and occasion it to rise ; 
 hence it frequently happens that numerous springs 
 make their appearance along the course of a dyke, 
 by which it may be detected when there is no other 
 indication of it visible upon the surface." 
 
 The effects of basaltic dykes on the different 
 rocks through which they pass, are worthy of re- 
 mark. There is one basaltic dyke in England that 
 has been traced 70 miles, and intersects various 
 
 Are these natural walls of any great extent ? Have they 
 been observed in the United States ? By what appearance 
 on the surface may dykes be recognized, when they are not 
 visible ? What are the effects of the great basaltic dyke of 
 England, upon the transition rocks, and upon the coal through 
 which it passes ? 
 
TRAP ROCKS. 167 
 
 strata of rocks of different ages. Where it is in 
 contact with transition limestone, the latter is more 
 crystalline, a fact of geological importance. " Where 
 it crosses the coal strata and comes in contact with 
 the seams of coal, the substance of the coal for sev- 
 eral feet is converted into soot. At a greater dis- 
 tance from the basalt, the coal is reduced to a coke 
 or cinder, which burns without smoke, and with a 
 clear and durable heat. At the distance Of fifty 
 feet from the dyke, the coal is found in its natural 
 unaltered state. It is particularly remarkable, that 
 the roof immediately above the coal is covered with 
 bright crystals of sulphur. Dykes, when they cut 
 through chalk, convert it into a highly crystalline 
 limestone, where these rocks come in contact. 
 Shale is changed to a flinty slate, and sandstones 
 become of a brick red colour." 
 
 It may be well to mention some experiments that 
 have been made, which serve, in some degree, to 
 elucidate the probable mode of formation of the trap 
 rocks. 
 
 " All trap rocks are fusible, * and most of them 
 form a blackish green glass after melting : hence it 
 was inferred, that trap rocks had never been in a 
 state of fusion, for if they had they would have been 
 rendered vitreous, f * 
 
 Sir James Hall, however, reflecting on the very 
 
 What crystals are attached to the roof? What are th? 
 effects of basaltic dykes on chalk, shale and sandstones, when 
 they intersect them ? 
 
 * Bodies are said to be/tm&Ze, when they can be melted, 
 t Bodies are said to be vitreous, when they break with a smooth 
 surface like glass. 
 
168 TRAP ROCKS. 
 
 long period of refrigeration* that vast masses of 
 melted rock would necessarily require before they 
 were cooled to the common temperature of the earth, 
 was induced to make experiments on lava and ba- 
 salt ; from which it was ascertained, that if a small 
 portion of liquid lava were suddenly cooled, it form- 
 ed a black glass, as was well known to be the case 
 with basalt ; but if the process of cooling were slow, 
 both melted lava and basaltic became stone. When 
 the glass which had been formed by sudden cooling 
 was melted again, and suffered to cool very gra- 
 dually, it lost its vitreous character, and was con- 
 verted into a substance resembling basalt. 
 
 Mr. Gregory Watt made some experiments on the 
 fusion and refrigeration of basalt in one of his father's 
 furnaces, which throws much additional light on the 
 formation of the globular and columnar structure of 
 basaltic rocks. He fused 700 Ibs. of the Dudley 
 basalt, called Rowley ragg, and kept it in the fur- 
 nace several days after the fire was reduced. It 
 melted into a dark coloured glass, with less heat 
 than was necessary to melt the same quantity of pig 
 iron. In this glass, small globules were formed 
 which afterwards disappeared ; and as the cooling 
 proceeded the mass was changed from a vitreous to 
 a stony substance : other globes were again formed 
 within the stony mass, which continued to enlarge 
 until their sides touched and pressed against each 
 
 What experiments have been made which tend to eluci. 
 date the formation of trap rocks ? 
 
 * Refrigeration means the cooling of a body. 
 
TRAP ROCKS. 169 
 
 other, by which pressure the globes formed poly, 
 gonal* prisms. f If part of the mass were cooled 
 before the globular structure was destroyed, these 
 globes were harder than the surrounding stone, and 
 broke in concentric layers. In this manner the 
 balls of basalt and porphyry which fall out of decom- 
 posing rocks were probably formed : they derived 
 their superior hardness from the crystalline arrange- 
 ment of the particles when in a melted state. When 
 these globes were enlarged by a continuation of the 
 same process, they might press upon each other and 
 form prisms. The upper prisms, pressing by their 
 weight upon the lower, might form conca- 
 vities, or sockets, into which they would sink 
 and remain jointed, or articulated together : 
 such is frequently the structure of basaltic 
 columns," thus 
 
 " Another experiment made by Sir James 
 Hall, on the crystallization of common limestone by 
 heat, and its conversion into marble, tends to eluci- 
 date the effects produced by basaltic rocks on lime- 
 stone and chalk, before mentioned. Dr. Hutton had 
 advanced the opinion, that the beds of limestone 
 were formed of the shells and exuviae of marine ani- 
 mals, which had been melted by central fire, and 
 crystallized." * 
 
 " It was, however, objected to this theory, that the 
 well known action of fire on limestone rocks would 
 
 * A polygon is a figure having several sides : for instance, a square 
 is a polygon of four sides. 
 
 t A prism is a solid body having seversl sides, and of equal size from 
 one end to the other : for instance, the beams and posts of buildings 
 are four-sided prisms, A prism may have any number of sides above 
 tbree. 
 
 15 
 
170 TRAP ROCKS. 
 
 expel the carbonic acid, and make them soft and pul- 
 verulent, as we see in making lime from limestone. 
 
 This objection was answered, by saying, that these 
 beds of shells, &c. were heated under the pressure 
 of the ocean which for so long time covered the land, 
 and that this pressure would prevent the escape of 
 the carbonic acid, and render the limestone fusible. 
 This was regarded as mere hypothesis for some time, 
 but Sir James Hall determined to try its validity by 
 experiments." 
 
 Having calculated the resistance which a column 
 of water, 1500 feet, or any given depth, would pre- 
 sent to the escape of the carbonic acid of the lime- 
 stone, he inclosed a quantity of powdered chalk in 
 a gunbarrel, and confined it in such a manner as to 
 present an equal degree of resistance. He subjected 
 the powdered chalk, thus confined, for some time to 
 the action of a furnace ; it was then drawn out and 
 cooled, and was found converted into crystalline lime- 
 stone or marble ; and in one instance whe^e the 
 chalk inclosed a shell, the shell had acquired a crys- 
 talline texture without loosing its form. Hence, 
 when chalk or limestone is found to have a crystal- 
 line texture in contact with trap rocks, we may, 
 with a high degree of probability, infer that the 
 limestone had been fused by the trap. 
 
 "The constant occurrence of dykes in basaltic 
 districts, gives a high degree of probability to the 
 opinion, that overlying unconformable trap rocks 
 have been erupted in a melted state like lava, and 
 
 What is supposed to have been the origin of the uncoil- 
 formable overlying trap rocks 1 
 
TRAP ROCKS. 171 
 
 poured over the surface of the ground." Basaltic 
 columns are frequently seen in countries that are 
 the seat of volcanic fires, but they occur also in 
 countries remote from any known volcanos. 
 
 Organic remains are sometimes found enveloped 
 in basalt, but this admits of an easy explanation, by 
 supposing the basalt to have flowed like lava on th'e 
 bottom of the ocean, enclosing every thing with 
 which it came in contact. A recapitulation of all 
 the facts bearing upon the origin of the trap rocks, 
 would afford a mass of evidence sufficient to con- 
 vince the most sceptical, of their igneous origin. 
 
 " The reason why geologists were so long opposed 
 to the igneous origin of trap rocks, may partly be 
 explained by attachment to received theories, and 
 partly by the reluctance to admit a condition of our 
 planet, so remote from present experience. It was 
 thought an ample claim on our credulity, when 
 we were required to believe that all the habitable 
 parts of the globe had been for ages submerged in 
 the ocean, without requiring the further belief, that 
 countries now remote from active volcanos, had 
 been repeatedly subject to the agency of subter- 
 ranean fire. Yet both these positions must be grant- 
 ed, if we will allow a legitimate induction from es- 
 tablished facts." [BakeweWs Geology.'] 
 
 Are basaltic columns often found in volcanic districts ? 
 Are organic remains ever enclosed in basalt ? How is this 
 fact explained ? What conclusions must be drawn jf we 
 allow a legitimate induction from established facts. 
 
172 EARTHQUAKES, &C. 
 
 CHAPTER XIII. 
 
 EARTHQUAKES, VOLCANIC PHENOMENA, AND VOL- 
 CANIC ROCKS. 
 
 " Accustomed to view the hills in our own coun- 
 try in a state of profound repose, presenting the same 
 unvaried outline in each succeeding year, we can 
 scarcely conceive the possibility of a whole district 
 being covered with new mountains, and another soil, 
 in the space of a single night : yet such changes 
 have been produced, by the united agency of earth- 
 quakes and volcanos, within the limits of authentic 
 history." 
 
 Earthquakes seem to be mere vibrations of the 
 crust of the globe, when rent and upheaved by vol. 
 canic action. Earthquakes and volcanos seem to 
 be the effect of the same cause. They frequently 
 accompany each other, and in all instances that 
 have been observed, the first eruption of a volcano 
 is preceeded by an earthquake of greater or less ex- 
 tent. 
 
 Volcanos do not make their appearance in every 
 country where the shock of an earthquake is felt ; 
 but earthquakes are more frequent in volcanic dis- 
 tricts than in any other. Earthquakes are almost 
 
 What are earthquakes? Do earthquakes and volcanos 
 ever accompany each other ? and do they depend upon the 
 same cause? In what districts do earthquakes most fre- 
 quently occur ? What are earthquakes almost always pre- 
 ceded by ? 
 
EARTH QITAKES, &C. 173 
 
 always preceded by an uncommon agitation of the 
 waters of the ocean, and of lakes. Springs send 
 forth torrents of mud, accompanied by a disagree- 
 able smell ; or perhaps they disappear entirely. The 
 cattle discover much alarm, and seem to be instinc- 
 tively aware of approaching calamity. 
 
 A deep rumbling noise like that of many carriages 
 rolling over a rough pavement, a rushing sound like 
 the wind, or a tremendous explosion like the dis- 
 charge of artillery, immediately precede the shock, 
 which suddenly heaves the ground upwards, or tosses 
 from side to side with violent and successive vibra- 
 tions. The ground often heaves in undulations like 
 the waves of the ocean : large chasms and fissures 
 are made in the ground, through which smoke and 
 flames are seen to issue : these sometimes break out 
 where no chasms can be perceived. More frequent- 
 ly, stones or torrents of water are ejected from these 
 openings. 
 
 In violent earthquakes, the chasms are so exten- 
 sive, that large cities have in a moment sunk down 
 and forever disappeared, leaving a lake of water in 
 their place. Such was the fate of Euphemia in 
 Calabria, in 1638, as described by Kircher who was 
 approaching the place, when the agitation of the 
 ocean obliged him to land at Lopizicum. , 
 
 " Here, (says he,) scenes of ruin every where ap- 
 peared around me ; but my attention was quickly 
 turned from remote to more contiguous danger, by 
 
 What noise is perceived before an earthquake ? How is 
 the ground affected ? Are the chasms produced by earth- 
 quakes ever very extensive ? 
 
 15* 
 
174 EARTHQUAKES, &C. 
 
 a deep rumbling sound which every moment grew 
 louder. The place where we stood shook most 
 dreadfully : after some time, the violent paroxysm 
 ceasing, I stood up, and turning my eyes to look for 
 Euphemia, saw only a frightful black cloud. We 
 waited till it had passed away, when nothing but a 
 dismal and putrid lake was to be seen where the city 
 once stood." 
 
 A shock rarely lasts more than a minute, but often 
 there is a succession of shocks, with intervals of 
 some duration. 
 
 " The extent to which earthquakes produce sen- 
 sible effects on the waters and springs in distant 
 parts of the world, is truly remarkable. 
 
 During the earthquake of Lisbon, in 1755, almost 
 all the springs and lakes in England, and every part 
 of Europe, were violently agitated, many of them 
 throwing up mud and sand, and emitting a fetid 
 odour. On the morning of the earthquake, the hot 
 springs of Toplitz in Bohemia, suddenly ceased to 
 flow for a minute, and then burst forth with prodi- 
 gious violence, throwing up turbid water, the tem- 
 perature of which was higher than before, and is 
 said to have continued so ever since. The hot baths 
 at Bristol, England, were coloured red, and rendered 
 unfit for use, for some time afterward. The waters 
 of Lake Ontario were violently agitated at the same 
 time," 
 
 The space over which the vibration of the earth 
 
 How long do the shocks continue ? Do they ever rapidly 
 succeed each other ? Are earthquakes ever felt over exten- 
 sive portions of the globe ? 
 
EARTHQUAKES, &C. 175 
 
 is ielt during earthquakes, is often very great, but 
 generally more extended in one direction than ano- 
 ther ; " and where a succession of earthquakes has 
 taken place in the same districts, it is observed that 
 the noise and shock approach from the same quarter." 
 
 Although earthquakes are more common in vol. 
 canic districts than in others, yet the shocks are not 
 the most violent in the vicinity of volcanos ; on the 
 contrary, they are stronger in the more distant part 
 of a volcanic country. The ground, generally, is 
 agitated with greater force, as the surface has a 
 smaller number of apertures communicating with 
 the interior. 
 
 Extensive earthquakes are sometimes attended by 
 volcanic action simultaneously in various parts of 
 the earth, which seems to indicate a .cause deep 
 seated, and of such a nature as to be capable of 
 transmitting the vibrations and pressure, from one 
 portion of the earth to another with great rapidity. 
 
 " The frequency of earthquakes at particular pe- 
 riods, is worthy of notice. In the 4th and 5th cen- 
 turies, some of the most civilized parts of the world 
 were almost desolated by these awful visitations. 
 Thrace, Asia Minor, and Syria, according to cotem- 
 porary historians, suffered most severely : the earth, 
 was agitated continually for long periods, and flames 
 were seen to burst forth from the earth over a vast 
 extent of surface. 
 
 On the 26th of January, A. D. 447, subterranean 
 
 Are the shocks as violent in volcanic districts as in others ? 
 Have earthquakes been more frequent at particular periods 
 than at others ? 
 
176 EARTHQUAKES, &C. 
 
 thunders were heard from the Black to the Red Sea, 
 and the earth was convulsed without intermission for 
 the space of six months : in many places the air 
 seemed to be on fire towns and large tracts of 
 ground were swallowed up in Phrygia. 
 
 On the 20th of May, A. D. 520, the city of An- 
 tioch was overturned by a dreadful earthquake, and 
 250,000 of its inhabitants are said to have been 
 crushed in its ruins. A raging fire covered the 
 ground on which the city was built, and the district 
 around, spreading over an extent of forty-two miles 
 in diameter, and a surface of 1400 square miles." 
 
 " About the middle of the last century, after the 
 earthquake at Lisbon,, in 1755, Europe, Africa and 
 America, were for some time repeatedly agitated by 
 subterranean explosions. Mount ^Etna, which had 
 been in a state of profound repose for eighty years, 
 broke out with great activity ; and, according to 
 Humboldt, some of the most tremendous earthquakes 
 and volvanic eruptions ever recorded in history, 
 were witnessed in Mexico. 
 
 In the night of the 19th of September, 1759, a 
 vast volcano broke out in a lofty cultivated plain," 
 in Mexico. A tract of ground about 4 miles square 
 swelled up like a bladder to a height of 524 feet, and 
 in the centre of a thousand burning cones six large 
 masses elevated themselves, forming hills more than 
 1200 feet in height. The most elevated of these six 
 mountains is 1695 feet high, and is known as the 
 volcano of Jorullo.* 
 
 * During an earthquake in 1822, 100 miles in length of the east coast 
 of Chili, in South America, was raised from 3 to 4 feet above its for- ' 
 mer level. The whole space from the sea to the mountains was rais- \ 
 
EARTHQUAKES, &C. 177 
 
 "More recently (in 1812) the tremendous earth- 
 quakes in Caraccas were followed by an eruption 
 in the Island of St. Vincents, from a volcano that 
 had not been burning since the year 1718, and vio- 
 lent oscillations of the ground were felt, both in the 
 islands and on the coasts of America." It was at 
 this time that earthquakes were so violent in the 
 valley of the Mississippi. 
 
 "In very violent earthquakes, the secondary strata 
 are broken or agitated, but proofs are not wanting 
 of lesser vibrations, being stopped by their pressure. 
 Hurnboldt says, he has seen workmen hasten from 
 the mines of Mar ien burg in Saxony, alarmed by 
 agitations of the earth that were not felt at the sur- 
 face. During the earthquake of Lisbon, the miners 
 in Derbyshire felt the rocks muve and, heard noises 
 which were scarcely perceived by those above. 
 
 That an expansive force acting from beneath is 
 the proximate cause of earthquakes, can scarcely 
 be denied ; and the prodigious power of steam, when 
 suddenly generated, seems equal to their production, 
 if the quantity be sufficiently great. The great 
 power of steam at high temperatures is well known, 
 
 In violent earthquakes, are the strata ever broken ? Afe 
 shocks ever perceived below the surface that are not felt by 
 those on the surface ? What is supposed to produce earth- 
 quakes ? 
 
178 EARTHQUAKES, &C. 
 
 and there can be no difficulty in admitting, that, if 
 a current of subterranean water were to find access 
 to a mass of lava many miles in extent, and most in- 
 tensely heated, it would produce an earthquake more 
 or less violent, in proportion to the quantity of steam 
 generated, and its distance from the surface." 
 
 Coal mines are sometimes blown up in conse- 
 quence of the mixture of carbureted hydrogen gas 
 and air, coming in contact with the miner's lamp. 
 Hundreds of lives are thus sometimes destroyed by 
 a single explosion, the mine becoming an immense 
 piece of artillery, and every object in and near the 
 shaft is thrown out with prodigious violence. The 
 force of the explosion is so great as to shake the 
 ground like an earthquake for miles around. 
 
 The Drainer will always feel grateful to Sir Hum- 
 phrey Davy, the inventor of the safety lamp. This 
 is a lamp covered by a frame of wire gauze, through 
 which the flame cannot communicate, so as to ex- 
 plode the gas on its exterior. The miner can now 
 penetrate a work in the mine, where, before, it would 
 have been certain death to approach. 
 
 " The horrid crash, like the rattling of carriages, 
 which precedes earthquakes, may be occasioned by 
 the rending of the rocks, or parting of the strata, 
 through which the confined vapour is working a 
 passage." 
 
 That the rising and falling of the earth during 
 
 What effects are produced by the explosion of coal mines ? 
 Who was the inventor of the safety lamp ? What is the 
 safety lamp ? What is its use ? What causes the crackling, 
 rumbling noise before earthquakes ? What evidence have we 
 that the earth actually rises and falls during an earthquake ? 
 
EARTHQUAKES, &C. 179 
 
 earthquakes is not imaginary, is demonstrated by 
 the facts observed on the sea shore. The water is 
 often seen to recede far from the shore and then re- 
 turn with redoubled violence. The effect is pro- 
 duced by the rising of the earth, which causes the 
 waters to flow off, and on its sinking again, they 
 return in high, ridgy, overwhelming waves. When 
 Lisbon was destroyed, the return wave was fifty feet 
 in height. 
 
 Volcanos are openings made in the earth's sur- 
 face by internal fires, and they may be considered 
 as so many safety valves, of the districts in which 
 they are found. They regularly, or at intervals, 
 throw out smoke, vapour, flame, large stones, sand, 
 and melted stone called lava. Some volcanos throw 
 out torrents of mud and boiling water. 
 
 Volcanos most frequently exist in the vicinity of 
 the sea or large lakes, and also break out from un- 
 fathomable depths below the surface, and form new 
 islands and reefs of rock. Humboklt remarks that 
 all the ancient, as well as recent volcanic vents of 
 the Andes, have opened in the midst of trap,por- 
 phyritic, and trachytic rocks. [Humboldt on 
 Rocks, p. 33.] 
 
 When a volcano breaks out in a new situation, it 
 is preceded by violent earthquakes, the heated sur- 
 face of the ground frequently swells and heaves up, 
 until a fissure or rent is formed, sometimes of vast 
 extent. Through this opening, masses of rock, with 
 
 What are volcanos ? What do they eject ? How are most 
 volcanos located in relation to the sea ? By what is volcanic 
 action preceded ? 
 
180 EARTHQUAKES, &C. 
 
 flame, smoke and lava, are thrown out and choke 
 up part of the passage and confine the eruption to 
 one or more apertures, round which conical hills or 
 mountains are formed. 
 
 The cause of the conical form so common to 
 volcanic mountains must be obvious to all, who are 
 acquainted with the circumstances attending an 
 eruption. The ejected matter falling, accumulates 
 around the opening in a circular bank, which con- 
 tinues to increase by the fresh addition of materials, 
 until finally it forms a hill or mountain, with a deep 
 cavity in its centre. 
 
 The concavity in the centre is called the crater 
 and is shaped like a bowl or funnel, shelving steeply 
 down from the edge to the bottom. 
 
 Immense volumes of aqueous vapours, are evolv- 
 ed from a crater during an eruption, and even for a 
 long time after the discharge of the lava and sco- 
 rise, have ceased. 
 
 These vapours are condensed in the cool atmos- 
 phere, and heavy rains are produced in conse- 
 quence. The lightning darts amidst the clouds of 
 smoke, and the thunder peals, as if in mockery of 
 the louder thunders of the volcano. 
 
 The heavy rains falling on a surface thick cover- 
 ed with the fine ashes and loose scoriae, sweep them 
 along in a flood of mud, which frequently does far 
 more mischief than the lava or the earthquakes. 
 
 Explain the cause of the conical form of volcanic moun- 
 tains? What is the crater of a volcano? What vapours 
 are most abundantly evolved from volcanos ? What effects 
 are produced by the rapid condensation of these vapours ? 
 
EARTHQUAKES, &C. 181 
 
 In 1822 one of these mud streams descended from 
 Mount Vesuvius, and after destroying much culti- 
 vated ground, it flowed into the streets of St. Sebas- 
 tian, and Massa, where it filled several streets, and 
 some houses, and destroyed the lives of seven per- 
 sons. [Comstock's GeoL p. 94.] 
 
 This mud frequently concretes into a light kind 
 of rock which is much used in building wide arch- 
 es, on account of its lightness and strength. The 
 volcanos in the Andes are said to throw out water 
 and rnud more frequently than lava. The deluge 
 of water does not always come from the interior of 
 the earth, but sometimes from the snow on the sum- 
 mit of the mountain being rapidly dissolved. 
 
 Interior cavities of vast extent and depth are 
 sometimes opened during an eruption, and the wa- 
 ter with which they were filled coming in contact 
 with ignited lava is forcibly driven out ; and, ac- 
 cording to Humboldt, carries along with it a large 
 quantity of small fishes. These fishes are of the 
 same species that inhabit the neighbouring brooks 
 and lakes : the number thrown out is often so great 
 that their putrefaction contaminates the air, and 
 occasions serious maladies among the inhabitants 
 of the adjacent country. . 
 
 The muddy eruptions of the Andes cover large 
 tracts of country with a bituminous inflammable 
 material, which is used by the inhabitants for fuel. 
 It is called moya. 
 
 Do volcanos ever throw out mud and water ? Does the 
 water ever contain fishes? Are they similar to those of the 
 adjacent lakes ? What is moya ? 
 16 
 
182 EARTHQUAKES, &C. 
 
 Boiling and hot springs must be classed with vol- 
 canic phenomena. They are most common in vol- 
 canic districts. The Geysers of Iceland, which 
 throw up hot water to a considerable height in the 
 air, are well known. 
 
 Hot springs are common in some parts of Europe, 
 and in some places the heat is applied to various 
 economical purposes, as for warming houses, hatch- 
 ing eggs, &c. 
 
 Hot springs have been observed in several places 
 in the United States. In Arkansas, on the Washita 
 river, a considerable number of these springs break 
 out from the side of a hill, and in a ravine between 
 two hills. They are about 70 in number, and vary 
 in their temperature from 90 to 140 degrees, Fah- 
 renheit's thermometer. 
 
 "The indications ol an approaching eruption 
 fro-m a dormant volcano, are, an increase of smoke 
 from the summit, which sometimes rises to a vast 
 height branching in the form of a pine tree. Tre- 
 mendous explosions, like the firing of artillery, com- 
 mence after the increase of smoke, and are succeed- 
 ed by red coloured flames* and showers of stones. 
 At length, the lava flows out from the top of the 
 crater, or breaks out from fissures in the sides of 
 
 Are boiling springs classed with volcanic phenomena ? Is 
 the heat of hot springs ever employed for useful purposes ? 
 Have hot springs been observed in the United States ? Where 
 have several been found ? What are the indications of an ap- 
 proaching eruption from a dormant volcano ? 
 
 * The flame of volcanos, as it has been called, is found to be the RE- 
 FLECTION or LIGHT from the lava and heated materials, gn ttye clouds 
 of dust and vapors evolved during the eruption, 
 
EARTHQUAKES, &C. 183 
 
 the mountain, and covers the neighbouring plains 
 with melted matter, which, becoming Consolidated, 
 forms a stony mass, often not less than some hun- 
 dred square miles in extent, and several yards in 
 thickness. 
 
 The eruption of lava has been known to continue 
 several months. Intensely black clouds, composed 
 of a kind of dark coloured sand or powder, impro- 
 perly called ashes, are thrown out of the crater after 
 the lava ceases to flow, and sometimes involve the 
 surrounding country in total darkness at noonday. 
 Towards the conclusion, the colour of the volcanic 
 sand changes to white : it consists of pumice in a 
 finely comminuted state." During an eruption of 
 jEtna, a space of 150 miles in circuit was covered 
 with a layer of volcanic sand 12 feet deep. 
 
 " When the lava flows freely, the earthquakes and 
 explosions become less violent ; which proves that 
 they were occasioned by the confinement of the 
 erupted matter, both gaseous and solid. The smoke 
 and vapour of volcanos are highly electrical. The 
 quantity of lava thrown out during a single erup- 
 tion of a volcano, seems almost incredible to those 
 who have not observed volcanic countries. Kircher, 
 in 1660, says, the ejections of Mount ./Etna would,* 
 if collected, form a mass twenty times as large as 
 the mountain itself ; and a few years afterwards, 
 viz. in 1669, the same mountain covered with a 
 fresh current of lava 84 square miles ; and again, 
 in 1775, according to Dolomieu, the same volcano 
 
 What are the appearances and effects of an eruption ? Is 
 the quantity of ejected matter ever very great ? 
 
184 EARTHQUAKES, &C. 
 
 poured out another stream oflava 12 miles in length, 
 l\ in hreath, and 200 feet deep." 
 
 Hence it is evident, that the seat of the fire is not 
 in the mountain itself, but deep in the earth *: the 
 volcano is not the furnace, hut the chimney ; and 
 it will be necessary to bear this in mind, if we 
 would form an adequate idea of the extensive effects 
 of volcanic action. During the eruption of Skapta 
 Jokul in Iceland, in 1783, two immense lava cur- 
 rents were discharged, one 40, the other 50 miles in 
 length, averaging 11 miles in breath, and 50 feet in 
 thickness. 
 
 "The most extraordinary volcanic eruption re- 
 corded in history, for the extent of its effects, took 
 place in Sumbawa, one of the Molucca Islands, in 
 April, 1815. This eruption extended perceptible 
 evidences of its existence over the whole of the 
 Molucca Islands, over Java, a considerable portion 
 of Celebes, Sumatra and Borneo, to a circumference 
 of a thousand statute miles from its centre, by tre- 
 mulous motions and the report of explosions ; while 
 within the range of its more immediate activity, 
 embracing a space of 300 miles around, it produced 
 the most astonishing effects, and excited the most 
 alarming apprehensions. 
 
 In Java, at the distance of 300 miles, it seemed 
 to be awfully present. The sky was overcast at 
 noonday with clouds of ashes ; the sun was envelop- 
 ed in an atmosphere, whose palpable density he was 
 unable to penetrate ; showers of ashes covered the 
 
 Is the volcanic mountain the seat of volcanic fire ? Are 
 the explosions of volcanos heard at great distances 1 
 
EARTHQUAKES, &C. 185 
 
 houses, the streets and the fields, to the depth of 
 several inches ; and amid this darkness, explosions 
 were heard at intervals like the report of artillery, 
 or the noise of distant thunder. 
 
 So fully did the resemblance of the noises to the 
 report of cannon impress the minds of some officers, 
 that from an apprehension of pirates on the coast, 
 vessels were despatched to afford relief. Supersti- 
 tion, on the other hand, was busy at work on the 
 minds of the natives, and attributed the reports to 
 an artillery of a different description to that of pi- 
 rates. All conceived that the effects experienced 
 might be caused by eruptions of some of the numer- 
 ous volcanos on the Island ; but no one could have 
 conjectured that the showers of ashes which dark- 
 ened and covered the ground of the eastern districts 
 of Java, could have proceeded from a mountain 
 in Sumbavva, at the distance of several hundred 
 miles." 
 
 From Sumbawa to the part of Java where the 
 sound was noticed, is 970 geographical miles. The 
 greatest distance to which the eruption of a volcano 
 had been previously heard, is 600 miles ; the explo- 
 sions of Cotopaxi are sometimes sensibly heard at 
 that distance from the volcano, which is one of the 
 largest and highest on the American continent. 
 
 Crater of Vesuvius after the eruption of 1822. 
 The vast crater which was emptied by the violent 
 action of the volcano, " presents an aspect very dif- 
 ferent from that which is usually assumed by the 
 
 Describe the appearance of the crater of Vesuvius after the 
 eruption of 1822 ? 
 
 16* 
 
186 EARTHQUAKES, &C. 
 
 concavities of volcanic cones. These generally ap- 
 pear in the regular form of an inverted cone, whose 
 sides slope at about the same angle to the horizon, 
 as those of the outer cone. This is, indeed, invari- 
 ably the case, with every cone which is produced 
 by a single volcanic eruption. 
 
 " That of Vesuvius, however, resulting from the 
 accumulated products of perhaps many hundred 
 eruptions, must consist of numerous beds of scoriae, 
 and fragmentary lava, alternating with strata of 
 lava rock, which at intervals have been poured in 
 fiery torrents down its outer slope ; and congealing 
 there, have remained like so many massive ribs to 
 give strength and solidity to the structure. 
 
 " Through this succession of beds, then, has the 
 present crater been forcibly hollowed out by the ex- 
 plosive energy of the volcano. It appears as a tre- 
 mendous abyss of enormous proportions, surround- 
 ed by craggy precipices, that rise almost vertically 
 from the rude heaps of fallen fragments which form 
 its floor, and conceal the volcanic orifice. The ex- 
 treme periphery of the crater in some places, juts 
 over these precipices, so that on attaining its mar- 
 gin you look directly down into the gaping cavity.'' 
 
 The cliffs that encircle the great cavity, by no 
 means follow any regularity of curve, but project or 
 recede in saleint, and retiring angles. Their abrupt 
 faces which are rocky, jagged, and unpicturesque 
 in the extreme, present sections of many currents 
 of lava, some of which are of great thickness and 
 
 In what respect does this differ from every other crater that 
 is produced by a single eruption ? 
 
EARTHQUAKES, &C. 187 
 
 extent, lying one above the other in a direction more 
 or less approaching to the horizontal. Most of them 
 offer a columnar division, of the most marked and 
 decisive kind. Some are almost as regularly pris- 
 matic as any ranges of the older basalts. In some, 
 the spheroidal concretionary structure on a large 
 scale, is equally conspicuous. Between the currents 
 of lava are interposed shapeless beds of volcanic 
 conglomerate, consisting of fragments of all sizes, 
 heaped together in chaotic confusion. These, as 
 well as the beds of lava, are occasionally intersected 
 by vertical, or nearly vertical dykes, similar to those 
 of^Etna, Monte Sonuma, dec. 
 
 In 1828, a shock of an earthquake was felt at the 
 island of Pantellaria, a volcanic island, 56 miles 
 from Sicily, and 36 from Africa ; and at the same 
 time a violent blast of hot suffocating air, blew off 
 from the island for 15 minutes. At Naples, a simi- 
 lar sudden, transient gust, of hot wind, rushed down 
 the bay of Naples, towards Castellamare, proceeding 
 to a different point of compass the same evening ; and 
 Vesuvius which had been for some time slightly 
 agitated, threw up a jet of flame, and smoke, and 
 then resumed its former state of partial tranquillity. 
 The shock of an earthquake was at the same time 
 felt at Ischia. [Reports of British As. 1832, p. 
 586.] 
 
 "The long period of repose which sometimes takes 
 place between two eruptions of the same volcano, 
 is particularly remarkable. From the building of 
 
 Do volcanos act simultaneously ? Do volcanos ever re- 
 main dormant for any great length of time ? 
 
188 EARTHQUAKES, &C. 
 
 Rome to the 79th year of the Christian era, no men- 
 tion is made of Vesuvius, though it had evidently 
 been in a prior state of activity, as Horculaneum 
 and Pompeii, which were destroyed by the eruption 
 of that year, are paved with lava. 
 
 "From the 12th to the 16th century it remained 
 quiet for nearly 400 years, and the crater was over- 
 grown with lofty trees. The crater was descended 
 by Bracchini, an Italian writer, prior to the great 
 eruption of 1631 : the bottom was at that time a 
 vast plain, surrounded with caverns and grottos. 
 jEtna has continued burning since the time of the 
 poet Pindar, with occasional intervals of repose, 
 seldom exceeding 30 or 40 years. 
 
 " Submarine volcanos are preceded by a violent 
 boiling and agitation of the water, and by the dis- 
 charge of volumes of gas and vapour, which take 
 fire and roll in sheets of flame over the surface of 
 the waves. Masses of rock are darted through the 
 water with great violence, and accumulate till they 
 form new islands. Sometimes the crater of the 
 volcano rises out of the sea during an eruption. 
 
 " In 1783, a submarine volcano broke out near Ice- 
 land, which formed a new island : it raged for seve- 
 ral months with great fury, and then sunk and dis- 
 appeared. Immediately after the volcanic island 
 ceased its action, the great eruption <of Skapta Jokul 
 commenced 200 miles distant. In 1811, a small 
 island was formed by a submarine volcano at a little 
 distance from St. Michael's, one of the Azores." It 
 
 By what are submarine volcanos preceded? Are vol- 
 canic islands often raised from the sea ? 
 
EARTHQUAKES, &C. 189 
 
 has now sank, and has 500 feet of water over it. 
 In 1831, a small volcanic island appeared in the 
 Mediterranean Sea, exhibiting various volcanic phe- 
 nomena, but it has since disappeared, leaving a 
 shoal in its place.* The appearance of new vol- 
 canic islands above the ocean is not of rare occur- 
 rence : very many such events are recorded in his- 
 tory. 
 
 Among the volcanic islands which have disap- 
 peared in whole or in part, the most remarkable is 
 that which, in 1719 was raised near Tercera. In 
 Nov. 1720, it was visible to a distance of 7 or 8 
 leagues, and was 3 leagues in diameter. In 1723 
 it disappeared, and sunk to the depth of nearly 500 
 feet. [Brongniart Ter. p. 198.] 
 
 Sabrina, which was elevated near , the Azores, 
 disappeared in a short time ; but this was perhaps 
 rather owing to the nature of the materials forming 
 it, than to the sinking of the island. It was com- 
 posed of loose cinders. 
 
 The rocks near Santorini were said, in (1836) to 
 be rapidly rising, so than an island is likely soon 
 to appear. 
 
 " If the sea, or large lakes, have once covered our 
 continents, it follows, that the greater part of the 
 present and ancient volcanos were once submarine.*" 
 
 Name some instances in proof of their appearance and dis. 
 appearance ? Do any of the volcanos on the land appear to 
 have been once submarine ? 
 
 * The shoal has now, in 1833, disappeared, and there is a consider- 
 able depth of water where the shoal was. 
 
190 EARTHQUAKES, &C. 
 
 Many facts indicate that JEtna was once a subma- 
 rine volcano. 
 
 " Volcanos frequently occur in groups, sometimes 
 arranged along a line as if they had originally been 
 formed over one vast chasm. The volcanos in 
 South America, Hurnboldt observes, instead of being 
 isolated or dispersed in irregular groups, as in 
 Europe, are arranged in rows, like the extinct vol- 
 canos of Auvergne, or the volcanos of Java ; some- 
 times in one line, and sometimes in two parallel 
 lines." 
 
 There are instances of volcanos having been en- 
 tirely engulphed in the chasms beneath them. The 
 volcano of the Pic in the Island of Timor, one of 
 the Moluccas, is known to have served as a prodigi- 
 ous watch-light, which was seen at sea at the dis- 
 tance of 300 miles. In the year 1638, the moun- 
 tain, during a violent eruption, entirely disappeared, 
 and in its place there is now a lake. Many of the 
 circular lakes in the south of Italy are supposed to 
 have been formed by the sinking down of volcanos. 
 
 The Papandayang was formerly one of the largest 
 volcanos on the Island of Java, but the greatest part 
 of it was swallowed up in the earth after a short but 
 very severe combustion in 1772. The account of 
 this event says : " Near midnight, between the llth 
 and 12th of August, there was observed about the 
 mountain an uncommonly luminous cloud, by which 
 it appeared to be completely enveloped. The in- 
 
 Do volcanos occur in groups ? How are they frequently 
 arranged? Have volcanic mountains ever sunk into the 
 earth under them ? 
 
EARTHQUAKES, &C. 191 
 
 habitants, as well about the fort as on the declivities 
 of the mountain, alarmed by this appearance, betook 
 themselves to flight, but before they could all save 
 themselves the mountain began to give way, and the 
 greatest part of it actually fell in and disappeared 
 in the earth. At the same time a tremendous noise 
 was heard, resembling the discharge of the heaviest 
 cannon. It was estimated that an extent of ground 
 of the mountain itself, and its immediate environs, 
 15 miles long and full 6 broad, was, by this commo- 
 tion, swallowed up in the bowels of the earth, and 
 about 3000 people perished." 
 
 There are very many evidences that volcanic ac- 
 tion has been far more active in former periods of 
 time than at present. " The craters of many an- 
 cient volcanos are of far greater extent than the 
 present ones. Vesuvius is a comparatively small 
 cone, raised within the crater of a larger volcano. 
 The cone of the Peak of Teneriffe stands within a 
 volcanic plain containing 36 square miles of sur- 
 face, surrounded by perpendicular precipices and 
 mountains, which were the border of the ancient 
 crater." 
 
 All these craters, according to M. Humboldt, are 
 diminutive apertures, compared with the immense 
 chasms through which, in remote ages, subterra- 
 nean fire has forced a passage through the crust of 
 the globe. Many of the ancient volcanic rocks 
 have not flowed in currents from limited apertures 
 
 Do volcanos appear to have been more active in former 
 times than at present ? Do the ancient volcanic rocks ap- 
 pear to have flowed in currents as at present ? 
 
192 EARTHQUAKES, &C. 
 
 like modern lavas. " The volcanic porphyries on 
 the back of the Cordilleras," says M. Humboldt, 
 " are undoubtedly of igneous origin ; but the mode 
 of their formation is not like modern laves. The 
 action of volcanic fire by an insolated cone or crater 
 of a modern volcano, differs necessarily from the 
 action of this fire, through the fractured crust of the 
 globe. 
 
 The only hard crystalline rocks forming at the 
 present day are volcanic ; and if we trace the con- 
 nexion that exists between the modern and ancient 
 volcanic rocks, and between the latter and the rocks 
 of trap and porphyry, among the ancient rock for- 
 mations, we shall extend the dominion of fire over 
 a large part of the globe. 
 
 Volcanic rocks are principally composed of feld- 
 spar and augite, very minutely intermixed, and they 
 vary in their appearance, as one or the other of these 
 minerals predominates. The lavas in which feld- 
 spar abounds, have generally a whitish or grayish 
 colour, and melt into a white glass : those in which 
 augite predominates are dark coloured, and melt 
 into a black glass. 
 
 Various mineral substances are found imbedded 
 in volcanic rocks or in their fissures, as ores of iron 
 bitumen, mica, garnet divine, iron pyrites, &c. 
 The different structures of lava, as vitreous, com- 
 pact, stony *and scoriaceous or spongy, depend on 
 the different circumstances attending its cooling. 
 
 Of what are volcanic rocks composed ? Are many miner- 
 al substances found in volcanic rocks ? Upon what circum- 
 stances does the difference in the structure of lava depend ? 
 
EARTHQUAKES, &C. 193 
 
 if cooled rapidly, it is vitreous ; if slowly, under 
 pressure, it is compact or stony, and the surface of 
 lava currents is generally scoraceous or spongy. 
 
 Pumice is a whitish fibrous spongy lava, and so 
 light as to swim on water. Immense quantities of 
 pumice are sometimes thrown up by submarine vol- 
 canos. It has been seen floating upon the sea over 
 a space of 300 miles, at a great distance from any 
 known volcanos ; and hence it may be inferred, that 
 submarine volcanos sometimes break out at such 
 vast depths under the ocean, that none of their pro- 
 ducts reach the surface, except such as are lighter 
 than water. 
 
 Another product of volcanos is sulphur. In the 
 craters of some extinct volcanos, it occurs in great 
 abundance, and is quarried out like stone from a 
 common quarry. The solfa-tara, near Naples, is 
 an example, and various salts are made in them, as 
 alum, sal-ammoniac, &c. 
 
 Trachyte is the name given to a whitish volcanic 
 rock, the grains being sometimes very minute, and 
 has then a glistening lustre. It is mostly composed 
 of feldspar, and sometimes becomes porphyritic, and 
 sometimes passes into clinkstone. 
 
 The volcanic, trap, and primitive rocks, pass into* 
 each other by almost insensible shades, and it seems 
 almost impossible to conceive that the same cause 
 which has produced one, has not also produced the 
 
 Has pumice ever been found floating far from any known 
 volcanos ? What do you infer from this ? Where is sulphur 
 found ? What is trachyte ? Do the trap and volcanic rocks 
 pass into each other ? And do these graduate into the primi- 
 tive rocks ? What consequences seem to follow ? 
 17 
 
194 RECAPITULATION. 
 
 other; but at different times and under different 
 circumstances. 
 
 CHAPTER XIV. 
 
 RECAPITULATION OF THE PRINCIPAL FACTS OP 
 
 GEOLOGY, AND A SLIGHT DISCUSSION OF 
 
 SOME THEORIES. 
 
 1. The earth's surface is composed of various 
 layers of sand, clay, and rock, and various mix- 
 tures of these. 
 
 2. Rock is found at a depth varying at different ! 
 places, but after the solid rock is once reached, it 
 continues as far as the power of man has enabled 
 him to penetrate. 
 
 3. There are many kinds of rock, each having 
 its peculiar characters. 
 
 4. These rocks have particular positions in re- 
 gard to each other, so that when several occur 
 together, they lie one over the other in a certain 
 order, which is never inverted. 
 
 5. Rocks sometimes alternate with each other, 
 and then they are repeated in the same order in 
 each successive series. 
 
 6. The layers of rocks are not always level, but 
 
 Of what is the earth's surface composed ? Is rock always 
 found below the susface ? Are there many kinds of rock ? 
 Have they particular positions in regard to each other ? Do 
 they ever alternate ? Are the layers always level ? 
 
RECAPITULATION. 195 
 
 are often more or less inclined, and often they are 
 nearly vertical. 
 
 7. The layers are not always plane, but some- 
 times present a curved and bent form. 
 
 8. Horizontal layers of rock sometimes rest or 
 lie upon those that are inclined, but the reverse is 
 not observed. 
 
 9. The strata of rock often present the appear- 
 ance of having been cracked through like ice, and 
 the fissures filled up with stony matter, by which 
 the rocks are again cemented together. 
 
 10. Veins containing the same minerals, gene- 
 rally traverse the rocks in particular districts in the 
 same direction. 
 
 11. Several sets of veins are sometimes observed 
 in the same rocks, each set having its particular 
 minerals, and by their intersections, the relative 
 ages of each may be determined. 
 
 12. In the vicinity of these veins, fissures, faults, 
 and dykes, the rocky masses often appear to have 
 been moved from their original position. They 
 seem to have been tilted in a direction different 
 from the mass with which they have been connect- 
 ed, or to have slipped down to a lower level. 
 
 13. The stony material of the veins and dykes is * 
 
 Are they always plane ? Do horizontal layers ever rest 
 upon inclined ones ? Is the reverse observed ? Do the 
 strata appear to have been cracked through and cemented 
 together again ? Do particular veins follow particular direc- 
 tions ? Is more than one set of veins ever observed in the 
 ! same rock ? What appearance is observed near veins, faults, 
 'dykes, &c. ? Is the stony material of veins always different 
 from the rock through which it passes ? 
 
196 RECAPITULATION. 
 
 sometimes of the same kind as the rock, but fre- 
 quently it is different, and sometimes is composed 
 of metallic ores. 
 
 14. There are two great classes of rocks distinct 
 from each other in their characters. One is com? 
 posed of mineral substances more or less crystal- 
 line in their texture, and never contains the remains 
 of animals or plants imbedded in its mass ; the 
 other is composed of fragments and comminuted 
 parts of the first, of sand, gravel, or clay aggregat- 
 ed and cemented together, containing sometimes 
 wood, various remains of animals and plants, or of 
 limestone, which is often almost entirely composed 
 of shells and the remains of various marine ani- 
 mals. 
 
 15. The rocks containing the remains of animals 
 and plants, always lie over those that do not con- 
 tain them. 
 
 16. There are many rocks containing organic 
 remains, and each of the series of formations of 
 these rocks, is characterized by certain groups of 
 fossils, as well as by its mineralogical characters. 
 
 17. The fossils imbedded in the rocks lying low- 
 est in the series, are almost entirely different from 
 any now known to exist in our seas, or on our Isl- 
 ands or continents. 
 
 18. The fossil organic remains imbedded in the 
 
 How many great classes of rock occur 1 How are they 
 distinguished from each other 1 What is the position of the 
 fossiliferous rocks with regard to those which are not so ? 
 Do many of the rocks contain fossils ? and how are they 
 characterized ? How do the fossils in the lowest rocks con- 
 taining them, compare with those now existing ? 
 
RECAPITULATION. 197 
 
 rocks which lie higher in the series, approximate 
 more towards existing species, and in the rocks of 
 more recent origin, many of the species are simi- 
 lar, and perhaps identical, to species known to be in 
 existence. 
 
 19. The rocky strata generally have their outcrop 
 parallel to the principal mountain range, and they 
 slope off from it on each side. 
 
 20. Certain minerals are almost constantly asso- 
 ciated with certain other minerals, or in particular 
 rocks, so that if some of them be found, the others 
 may probably be found by search. 
 
 21. Volcanic agency has been often exerted to 
 raise enormous masses of minerals and rocks from 
 a lower to a higher level, sometimes in a fluid form 
 as lava, and sometimes in the solid state, as volcanic 
 islands and mountains, and even large tracts of 
 country. 
 
 22. Many parts of the surface of our planet, 
 have bee'n repeatedly deluged by eruptions of lava. 
 
 23. Volcanos of the present time rarely produce 
 as compact lavas as formerly. 
 
 24. Volcanos are now nearly inactive, in com- 
 parison with their former state. 
 
 25. The temperature from the surface of the 
 
 How is it in the more recent rocks ? What is the general 
 direction of the outcrop of strata ? Are certain minerals as- 
 sociated with each other ? Has volcanic agency ever been 
 exerted to raise islands and mountains ? Do any parts of the 
 earth appear to have been repeatedly deluged with lava? 
 How do recent lavas compare with the ancient ones ? Are 
 volcanos as active as they were formerly ? Is the tempera- 
 ture of the earth variable near its surface ? 
 17* 
 
198 RECAPITULATION. 
 
 earth to a depth of from 20 to 60 feet, is variable 
 from the effect of the seasons and the filtering of 
 spring water, but below that, the temperature is con- 
 stant at the same point. 
 
 26. The temperature of the earth is variable at 
 different places at equal depths, but it constantly 
 increases in intensity as we descend farther. 
 
 27. This increase of temperature, varies from 
 one to two degrees of Fahrenheit's thermometer, 
 for every 100 feet in depth. 
 
 28. The surface of the earth shows that it has 
 been subjected to the action of powerful currents 
 of water, since all the regular rock formations were 
 deposited. 
 
 29. In the deposits from this inundation, the re- 
 mains of innumerable animals, nearly similar to 
 those now existing, were entombed. 
 
 30. Local deposits are now forming from the 
 action of rain, streams, currents, winds, and ani- 
 mals, tending to modify and alter the present suv 
 face of the earth. 
 
 These are some of the principal facts upon which 
 geology rests as a science. Geology is a science 
 of facts, and has no necessar3 r connection with any 
 
 To what depth ? From what causes ? Is it variable at 
 equal depths in different places ? At the same point, how 
 does the temperature compare at different times ? As you 
 descend further into the earth, how do the temperatures com. 
 pare ? How much does the temperature increase ? What 
 does the surface of the earth show ? What are found in the 
 deposits of this inundation ? Are local deposits now form, 
 ing ? From what causes has geology any necessary connec- 
 tion with theory ? 
 
RE CAPITULATION. 1 99 
 
 of the various theories, which have been brought 
 forward at different times to account for the forma- 
 tionW the earth. Those theories were framed by 
 their authors after having observed a few facts, and 
 then giving a free course to their imaginations to 
 carry them to their results. 
 
 Theories are useful to the progress of any sci- 
 ence, by condensing facts, and by producing an ac- 
 cumulation of them " for the purposes of support or 
 attack." [Cleveland's Mineralogy, p. 719.] 
 
 There are two theories that agitated the scien- 
 tific world for some time, and which ought not to be 
 passed over in silence. They are founded on facts 
 which are not to be misunderstood. Geologists do 
 not admit either of them to the exclusion of the 
 other, but adopt such parts of each, as are support- 
 ed by established facts and strong probabilities. 
 
 The reader has seen that fire and water are the 
 active agents in producing changes on the earth's 
 surface at present. It was owing to a difference of 
 opinion among geologists, as to whether caloric, or 
 water, was formerly the agent causing the changes 
 which are indicated by the various geological phe- 
 nomena, that these two theories, the Huttonian and 
 Wernerian, were formed. They are also frequent* 
 ly called the Vulcanian and Neptunian theories. 
 
 Before proceeding to the theories themselves, it 
 
 Of what use are theories ? Have any particular theories 
 excited much discussion ? Are they founded on facts ? Do 
 geologists admit either of them fully ? What parts of them 
 are admitted ? What causes are now effecting changes upon 
 the earth's surface ? What gave rise to the two theories re- 
 ferred to ? What are they called ? 
 
200 WERNERIAN THEORY. 
 
 may be well to mention some points upon which 
 they depend, and which are supported by the strong, 
 est evidence. 
 
 1. " The minerals, which compose the external 
 crust of the globe, from the summit of the highest 
 mountain to the lowest point hitherto explored, must, 
 at some former period, have been in a fluid state ; 
 and the solvent, must, unquestionably, have been 
 caloric, or water." 
 
 2. " The distinctly crystalline structure of most 
 of the primitive rocks, and the numerous regular 
 crystals which they contain, decidedly indicate a 
 previous state of fluidity." 
 
 3. " The numerous organic remains, which exist 
 in secondary rocks, unquestionably prove, that such 
 rocks have been deposited from water. It is well 
 known, that different sorts of secondary rocks have 
 been deposited at different periods. And it is equal- 
 ly evident, from an inspection of the organic re- 
 mains in secondary rocks, that this ancient sea was 
 successively peopled by different races of animals." 
 [Cleaveland. 722.] 
 
 WERNERIAN THEORY. 
 At some former period this globe has, for a long 
 
 What appears to have been the state of the materials of the 
 earth at some former period ? What is the structure of the 
 primitive rocks ? What are found in the secondary rocks ? 
 What does the fact prove ? Were these rocks deposited at 
 different periods ? Does the sea appear to have been peo- 
 pled by different races in succession ? What is the Wer- 
 nerian theory ? 
 
WERNERIAN THEORY. 201 
 
 time, been covered with water to a greater depth, 
 than the original altitude of the highest mountains. 
 This immense body of water ,was then tranquil, or 
 very nearly so, and contained in solution all the 
 materials of which the present crust of the globe 
 is composed. In this state, chemical deposits, ex- 
 hibiting more or less of a crystalline structure, were 
 gradually made, and invested the nucleus of the 
 globe. 
 
 " These chemical deposits constitute the primitive 
 rocks, consisting of granite, gneiss, mica slate, 
 granular limestone, &c. and are distinguished by 
 their crystalline structure, and by the total absence 
 of organic remains. During this period, most of 
 the highest mountains were formed ; for their sum- 
 mits consist of primitive rocks. But, by a gradual 
 subsidence of the waters, the summits of the high- 
 est mountains were left naked ; the tranquility of 
 the waters was disturbed, and currents were conse- 
 quently produced. By these currents, the naked 
 rocks would be worn and partially disintegrated ; 
 and the grains or fragments thus produced, would 
 be diffused through the mass of water. 
 
 "The rocks formed at this period, would, of course, 
 consist partly of chemical and partly of mechanical 
 deposits. They would also lie over the primitive 
 rocks ; but, in consequence of the diminished alti- 
 tude of the waters, they would appear at a lower 
 level, often resting on the declivities of primitive 
 mountains. Many of the rocks of this period con- 
 tain organic remains of marine animals and marine 
 plants. 
 
 " As organic remains make their first appearance 
 
202 WERNERIAN THEORY. 
 
 in the rocks of this period, it is supposed, that the 
 rocky shores, which had recently emerged from the 
 great deep, were passing to a habitable state. Hence 
 this class embraces what are called transition rocks, 
 consisting of graywacke, some varieties of lime- 
 stone, greenstone, argillite," &c. 
 
 " But the level of the great ocean still continuing 
 to sink, more extensive portions of the earth were 
 left exposed to the increasing violence of the cur- 
 rents, and the solution which was originally chemi- 
 cal, now became in a great degree composed of 
 grains or comminuted fragments, detached from the 
 older rocks. 
 
 " Hence the minerals of this period consist chiefly 
 of mechanical deposits. They lie over the two pre- 
 ceding classes, but still appear at a lower level, in 
 censequence of a greater subsidence of the waters. 
 Hence, also, they are found near the base of high 
 mountains, or in hills of moderate height, or in val- 
 lies, or under plains, sometimes at a great distance 
 below the earth's surface. This class is composed 
 of the secondary rocks, and embraces sandstone, 
 most varieties of compact limestone and of gyp- 
 sum, chalk, basalt, some varieties of greenstone, 
 coal, &c. 
 
 " Extensive portions of the crust of the globe had 
 now become dry : new species and genera of ani- 
 mals inhabited the waters, or dwelt on the land, 
 while numerous vegetables adorned the shores and 
 other parts of the earth's surface. Hence the se- 
 condary rocks abound with organic remains, both 
 of animals and vegetables. Hence, also, the abun. 
 
HUTTONIAN THEORY. 203 
 
 dance of bituminous substances in this class hav- 
 ing proceeeded from the decay of organized bodies. 
 
 " There are a few exceptions to the general fact 
 concerning the low level, at which the secondary 
 rocks usually appear ; for they sometimes rest on 
 the summits of mountains highly elevated. Basalt 
 and wacke are among the secondary rocks thus 
 found. These elevated strata of secondary rocks 
 are supposed by Werner to have been deposited 
 during a second and sudden rise of the ocean, after 
 it had once greatly subsided. 
 
 " The preceding deposits of rocks are supposed to 
 have been universal formations, " like the coats of 
 an onion. But various subsequent revolutions and 
 changes, have, in many instances, destroyed or con- 
 cealed the continuity of strata. This universality 
 in the formations of rocks, is an important point in 
 this system. Two other classes of comparatively 
 small extent, viz : alluvial deposits and volcanic 
 ejections, complete the series of mineral forma- 
 tions." [Cleaveland, p. 723.] 
 
 HUTTONIAN THEORY. 
 
 " In the the theory of Dr. Hutton, caloric is the 
 most important agent. This theory supposes the 
 solid crust of the present globe, to have proceeded 
 from the disintegration and destruction of former 
 continents by the gradual action of the atmosphere 
 and water that the ruins of those ancient conti- 
 nents were transported by water, and deposited at 
 
 Give the Huttonian theory ? 
 
204 RECAPITULATION. 
 
 the bottom of the ancient seas and that these he- 
 terogeneous materials, thus deposited, were consoli. 
 dated by the action of subterraneous fire : and, by 
 the same agent, were subsequently elevated to form 
 the present continents. 
 
 "It further supposes, that gneiss and other stratifi- 
 ed rocks, were only softened, elevated, and some- 
 times variously inclined, while granite and other 
 unstratified minerals, were completely fused, and, 
 in many cases, forced upward by this powerful 
 agent through the superincumbent strata. Hence 
 we find granite summits surrounded by gneiss, mica 
 slate, &c. Hence, also, metallic veins were filled 
 from below by injections of melted matter. 
 
 " By a similar process, this theory provides for the 
 disintegration and partial destruction of existing 
 mountains and continents, and for their transporta- 
 tion to the bottom of present oceans, from which, b/ 
 the action of subterraneous fire, they are again to 
 be raised and constitute new and future continents." 
 [Cleavdand, p. 726.] 
 
 The Wernerian theory is, in many parts, founded 
 on a close observation of facts ; but it is so inter- 
 woven with hypothetical points, which are not con- 
 firmed by succeeding observations in other parts of * 
 ' the world, that it cannot be received. It is not all 
 true, and it does not account for all the facts. 
 
 The Huttonian theory consists of inferences 
 drawn from facts, but the deductions are some- 
 Is the Wernerian theory founded on facts ? Are his theo- 
 retical conclusions confirmed ? Are the deductions of the 
 Huttonian theory carried farther than facts warrant ? 
 
RECAPITULATION. 205 
 
 times carried farther than the facts warrant. It 
 supposes the present continents derived from the 
 wrecks of older ones, because we find a large por- 
 tion of the rocks upon the surface of the earth form- 
 ed of the fragments of others cemented together, 
 and often filled with the remains of animals that 
 once inhabited the sea. 
 
 But whether volcanic agency has caused those 
 lands to be elevated, which have evidently been for 
 a long period under the surface of the ocean, is a 
 point which is not conceded by all. It is, however, 
 rendered highly probable by some facts which have 
 been mentioned under the head of volcanos and 
 earthquakes. 
 
 The Huttonian theory supposes the secondary 
 rocks, after they were formed in the bed of the 
 ocean, to have been indurated by subterranean heat, 
 before they were raised to become islands and con- 
 tinents. Some experiments by Sir James Hall, 
 which have been already mentioned, render this 
 supposition probable. 
 
 The Huttonian theory supposes the earth to 
 have once been in a melted state, and to have cool- 
 ed gradually. 
 
 The phenomena of volcanos and veins, and the 
 constantly increasing temperature observed in pen- 
 etrating below the surface, seem to justify the con- 
 clusion that the earth has been fluid, and that it 
 still may be so at a considerable depth below its 
 surface. 
 
 Are his deductions rendered highly probable ? What justi- 
 fies the conclusion that the earth has been in a melted state ? 
 18 
 
206 RECAPITULATION. 
 
 Since the discovery by Sir Humphrey Davy that 
 the alkalies and earths are metallic oxides, some 
 have supposed the interior of the earth to be a mass 
 of the earthy and alkaline metals. Many of these 
 metals when in contact with water decompose it, 
 and burn with the evolution of immense heat. Large 
 quantities of gaseous matter and vapour are pro- 
 duced. 
 
 If the waters of the ocean were to filter through 
 the fissures of the rocks and come in contact with 
 such materials as many suppose to constitute the 
 interior of the earth, intense heat would be evolved, 
 the materials would be melted, if they were not so 
 already, highly elastic vapours and gasses would be 
 formed in immense quantities, and all the phenom- 
 ena of volcanos and earthquakes would be produc- 
 ed. The effects would account for most of the facts 
 observed, as in metallic and other veins, dislocation, 
 obliquity, contortion of strata, &c. 
 
 In concluding this sketch of geology, it may not 
 be amiss to give Prof. Sillirnan's views of volcanic 
 phenomena, and they are also applicable to the ex- 
 planation of most geological facts. His views are 
 not entirely original, but have been extended much 
 beyond the suggestions which led to them. 
 
 " The act of creative energy, admitted alike by 
 religion and philosophy, necessarily implies the pro- 
 duction of all the elements of which our physical 
 universe is composed. How far these elements 
 
 Of what is the interior of the earth supposed by some to be 
 mposed ? What woul " 
 >on this supposition ? 
 of the facts of geology ? 
 
 i composed ? What would be the theory of volcanic action 
 I upon this supposition ? Would the effects account for most 
 
RECAPITULATION. 207 
 
 were originally united in binary, ternary, or still 
 more complex combinations, we cannot possibly 
 know. The revelation of this fact, not being ne- 
 cessary to our moral direction, has been withheld 
 by the Creator, and we know only, that, ' In the 
 beginning, God created the heavens and the earth.' 
 As to the actual condition of the elements, at that 
 primeval period, science may fairly inquire, and is 
 justified in reasoning within the limits prescribed 
 by our moral condition and intellectual powers. 
 
 " If we suppose that the first condition of the 
 created elements of our planet, was in a state of 
 freedom ; the globe beihg a mass of uncombined 
 combustibles and metals, and that the waters, the 
 atmosphere, and chlorine, and iodine, and perhaps 
 hydrogen, were suddenly added ; it will be obvious, 
 from what we know of the properties of these ele- 
 ments, that the reaction, awakening energies before 
 dormant, would produce a general and intense igni- 
 tion, and a combustion of the whole surface of the 
 planet. 
 
 " Potassium, sodium and phosphorus would first 
 blaze, and would immediately communicate the heat 
 necessary to bring on the action between the other 
 metals and combustibles, in relation to the oxygeft 
 and chlorine, and in relation to each other. Thus 
 a general conflagration would be the first step in 
 chemical action. 
 
 " In this manner mi^ht be formed the fixed alka- 
 
 What are Prof. Silliman's views upon the supposition that 
 the interior of the earth is composed of the alkaline and 
 earthy metals ? 
 
208 RECAPITULATION. 
 
 lies, the earths and stones and rocks, the metallic 
 oxides properly so called, the sulphurets and phos- 
 phurets of the metals, carburet of iron, the 
 acids, including the muriatic, and ultimately, the 
 salts, and chlorides, alkaline, earthy and metallic, 
 and many other compounds resulting either from a 
 primary or secondary action. 
 
 "In such circumstances, there would also be 
 great commotion : steam, vapours and gases would 
 be suddenly evolved in vast quantities, with explosive 
 violence ; the imponderable agents, heat, light, elec- 
 tricity and magnetism, and attraction, in various 
 forms, would be active in an inconceivable degree, 
 and the recently oxidized crust of the earth would 
 be torn with violence, producing fissures and cav- 
 erns, dislocations and contortions, and obliquity of 
 strata ; and it would every where bear marks of an 
 energy then general, but now only local, and occa- 
 sional. 
 
 " It is however obvious, that this intense action 
 would set bounds to itself; and that the chemical 
 combinations would cease, when the crust of in- 
 combustible matter thus formed, had become suffi- 
 ciently thick and firm, to protect the metals and 
 combustibles beneath, from the water and air, and 
 other active agents. 
 
 " As we are not now giving a theory of the earth, 
 but merely stating the conditions of a problem, we 
 forbear to descant upon many obvious collateral 
 topics, or to pursue the primitive rock formations 
 through the vicissitudes which might have attended 
 them. We do not even say, that we believe that 
 such events as we have attempted to describe, did 
 
RECAPITULATION. 209 
 
 actually happen ; we say only that their existence 
 is consistent with the known properties of the chem- 
 ical elements, and with the physical laws of our 
 planet. 
 
 " Supposing that such was the actual state of 
 things, it is obvious that the oxidated crust of the 
 globe would still cover a nucleus, consisting of me- 
 tallic and inflammable matter. Of course, when- 
 ever air and water, or saline and acid fluids, might 
 chance to penetrate to this internal magazine, the 
 same violent action which we have already suppos- 
 ed to have happened upon the surface, would recur, 
 and the confinement and pressure of the incumbent 
 strata, increasing the effects a thousand fold, would 
 necessarily produce the phenomena of earthquakes 
 and volcanos. 
 
 " Still, it is equally obvious, that every recurrence 
 of such events, must oxidize the earth deeper and 
 deeper, and if the point should ever be attained, when 
 water or air ceased to reach the inflammable nu- 
 cleus, or the nucleus were all oxidized, the phenomena 
 must cease, and every approximation towards this 
 point would render them less frequent. 
 
 " Does this correspond with the actual history of 
 these events ? Are they now less frequent, than jn 
 the early ages of our planet ? The extensive re- 
 gions occupied by rocks of acknowledged igneous 
 origin, but where fire is not now active, would seem 
 to favour this idea ; but the answer to this question 
 must depend so much upon the theoretical views en- 
 tertained of the formation of granite, and of the other 
 primitive rocks, that it may be impossible, at present, 
 to bring it to a decision, 
 
 18* 
 
210 RECAPITULATION. 
 
 " Whatever we may think of the hypothesis, now 
 detailed, may we not suppose, with sufficient proba- 
 bility, that those voltaic powers which we know to 
 exist whose action we can command, and whose 
 effects having been first observed within the me- 
 hiory of the present generation, now fills us with as- 
 tonishment are constantly active in producing the 
 phenomena of earthquakes and volcanos ? 
 
 " Arrangements of metals and fluids are the com- 
 mon means by which we evolve this wonderful 
 power, in our laboratories ; and it would seem that 
 nothing more than juxta-position, in a certain order, 
 is necessary to the effect. Even substances appa- 
 rently dry and inert with respect to each other, will 
 produce a permanent, and, in proportion to the 
 means employed, a powerful effect ; as in the col- 
 umns of De Luc and Zamboni. 
 
 " It would seem indeed that metals and fluids are 
 not necessary to the effect. Arrangements of al- 
 most any substances that are of different natures, 
 will cause the evolution of this power. Whoever 
 has witnessed the overwhelming brilliancy and in- 
 tense energy of the great galvanic combinations, 
 especially of the deflagrator of Dr. Hare, and con- 
 siders how very trifling in extent are our largest 
 combinations of apparatus, compared with those 
 natural arrangements of earths, salts, metals and 
 fluids, which we know to exist in the earth, in cir- 
 cumstances similar to those, which, in our labora- 
 
 What is said of the effect of the voltaic powers ? . Are 
 such phenomena produced by the different rocky, earthy and 
 fluid materials of the globe ? Would the theory account for 
 most of the observed facts of geology ? 
 
RECAPITULATION. 211 
 
 lories, are effectual in causing this power to appear, 
 will not be slow to believe, that it may be in the 
 earth perpetually evolved and perpetually renewed; 
 and now mitigated, suppressed or revived, accord- 
 ing to circumstances influencing the particular state 
 of things at particular places. 
 
 " In our laboratories, we see emanating from this 
 source, intense light, irresistible heat, magnetism in 
 great energy, and above all a decomposing power, 
 which commands equally all the elements and prox- 
 imate principles in all their combinations. 
 
 " Sir Humphrey Davy, after discovering that the 
 supporters of combustion and the acids, were all 
 evolved at the positive pole, and the combustibles 
 and metals, and their oxidated products, at the ne- 
 gative proved, that even the firmest rocks and 
 stones could not resist this power, their immediate 
 principles and elements being separated by its en- 
 ergy. 
 
 " The decomposition of the alkalies, earths, and 
 other metallic oxides, being a direct and now fami- 
 liar effect of voltaic energy their metals being set 
 at liberty, and being combustible both in air and 
 water elastic agents produced by this power, and 
 rarified by heat, being also attendant on these de- 
 compositions, it would seem that the first principles* 
 are fully established by experiment, and that no- 
 thing is hypothetical, but the application to the phe- 
 nomena of earthquakes and volcanos. 
 
 " It appears an important recommendation of the 
 present view, that causes are here provided which 
 admit of indefinite continuation, and of unlimited 
 renovation. There appears no reason why, on the 
 
212 RECAPITULATION. 
 
 whole, the phenomena should cease, as long as the 
 earth exists. It has therefore the great Newtonian 
 requisites of a good theory ; its principles are true, 
 and it is sufficient." [Silliman's outline in the 1st 
 American edition of BakeweWs Geology, pp. 115 
 119.] 
 
USEFUL APPLICATION OF GEOLOGY. 
 
 I. AGRICULTURE. 
 
 Almost every farmer is practically acquainted 
 with the fact, that the value of a soil is dependent 
 upon the nature of the materials of which it is form- 
 ed, its texture, and the rocky, or earthy substratum. 
 
 Soils are commonly divided into heavy or clayey 
 soils; light, or sandy, loamy or warm soils; and 
 cold or wet soils ; and these variations are due to 
 two general causes, viz : the nature of the materials 
 forming the soil, and the substratum. 
 
 Soils result from the disintegration and decompo- 
 sition of the subjacent materials, and the mixture 
 of this earthy matter with decomposed vegetable 
 substances ; with the excrements of animals ; with 
 the remains of insects and worms which once in-* 
 habited the surface ; and with parts of quadrupeds 
 and birds which have perished, and whose remains 
 have not been altogether removed by those insects, 
 birds, and animals, which prey upon putrid animal 
 matter. 
 
 " As we are almost exclusively dependent upon 
 the soil, for those articles of food and raiment, ne- 
 cessary to the supply of our animal wants ; and as 
 
214 AGRICULTURE. 
 
 the annual products of the soil form the largest item 
 in the increasing wealth of the country, it is deemed 
 expedient to consider this subject with some atten- 
 tion. 
 
 All the richest and most densely populated agri- 
 cultural districts, are on the transition, secondary, 
 tertiary, and alluvial formations. Soils, with the 
 exception of those resulting from alluvial depositions, 
 are derived from the disintegration and decomposi- 
 tion of the subjacent materials, and they depend in 
 a great degree, for their qualities, upon their me- 
 chanical and chemical constitution ; hence the 
 geology of a territory is a necessary pre-requisite in 
 estimating the agricultural characters and value of 
 its soils. 
 
 The variations in the productiveness of soils, are 
 due to two general causes, viz : 
 
 1st. The mechanical texture of the soils. 
 2d. Their chemical composition. 
 
 1st. The texture of a soil is a character of more 
 importance than is generally supposed. To form a 
 good soil, its texture should he such as to retain a 
 suitable quantity of moisture for the nourishment of 
 vegetation, and be neither so clayey as to bake and 
 crack in the heat of the sun, or heave by the action 
 of frost ; nor so sandy as to become parched, and 
 be mere dust at the depth, to which the roots of 
 plants penetrate. Argillaceous soils have so strong 
 an affinity for water, as to retain a small portion 
 even when heated. There should be a sufficient 
 quantity of clay in soils, to enable them to retain 3 
 or 4 per cent of water when dry, and to convert the 
 
AGRICULTURE. 215 
 
 other materials into a loam. Perhaps a light loam, 
 properly treated, produces the best crops. 
 
 It is also necessary to consider the substratum, in 
 judging of the productiveness of any particular soil. 
 If it be clay, or rock without fissures, the soil, how- 
 ever good in its texture and other qualities, will pro- 
 bably be "cold and wet." If the sub-soil be gravel 
 or sand, the surface soil is frequently too dry, unless 
 it be a loam so heavy, as to retain a sufficient quan- 
 tity of moisture for vegetation. 
 
 When a clay sub-soil occurs, it often alternates 
 with beds of gravel and sand. Advantage may often 
 be taken of this geological fact to drain wet soils, 
 either by boring, or sinking wells through the clay, 
 into the gravel or sand below, so that the water will 
 find an outlet in the springs at a lower level, where 
 these strata emerge on the sides of hills or ravines. 
 In this way, stagnant ponds and marshes may be 
 drained, not only so as to reclaim unproductive 
 lands, but to render the surrounding country more 
 healthful. These principles may be practically ap- 
 plied in many parts of the country. 
 
 However poor the texture of a soil, it can always 
 be brought to a proper state of cultivation by art ; 
 but, the value of produce, and the price of labour 
 will not often justify the expense. Light and heavy 
 soils may always be benefitted by a proper admixture 
 of clay or sand, as the case may require. That clay 
 and sand are almost always associated, is a geologi- 
 cal fact of much practical value in agriculture, as 
 well as in the arts. The occurrence of one, ('unless 
 from the effect of some local cause,) is a pretty sure 
 indication that the other may be found in the vici- 
 
216 CHEMICAL COMPOSITION OF SOILS. 
 
 nity. Light dry soils are often injured by removing 
 the small loose stones, which, instead of being an in- 
 jury, are in reality an advantage, as they not only 
 prevent the evaporation of moisture below the sur- 
 face, by shading the ground ; but, by their slow de- 
 composition, furnish stimulants and food for vegeta- 
 tion, these acting as a permanent manure. 
 
 2d. CHEMICAL COMPOSITION OF SOILS. 
 
 The chemical as well as the mechanical composi- 
 tion of soils, exerts a powerful influence on vegeta- 
 tion. Salts, alkalies, and alkaline earths, act as 
 stimulants if used moderately ; but if in excess, they 
 are injurious. Many soils contain calcareous rocks, 
 stones, or pebbles, which are continually undergoing 
 disintegration and solution by atmospherical agents ; 
 and thus serve as permanent mineral manures. 
 Other soils abound in stones derived from such rocks 
 as contain potassa as a constituent, and by their 
 decomposition, furnish this alkali, in solution to the 
 roots of plants, by which it is absorbed and carried 
 into the circulation, and there acting as a stimulant, 
 remains combined with some vegetable acid. The 
 decomposition of gravel, pebbles and rock has been 
 observed to be a benefit to vegetation ; and as the 
 rapidity of decomposition depends upon the surface 
 exposed, it follows, that if such materials be ground 
 fine and sowed upon the soil, like plaster of paris, 
 a more decided benefit would be the result. This 
 has been partially tried with success ; and it is to 
 be hoped that intelligent farmers will give it a more 
 thorough trial. 
 
PERMANENCY OF SOILS. 217 
 
 Iron in some states of combination, exercises a 
 beneficial influence on vegetation ; yellowish and 
 reddish soils almost always contain iron, and are 
 generally productive. " [Mathers Geological Re- 
 ports to New York and to Ohio.] 
 
 PERMANENCY OF SOILS. 
 
 The permanency of a soil is dependent upon its 
 tendency to wash, and its vegetable cover. If the 
 soil be of such a texture as to wash easily, it can- 
 not be permanent on steep slopes of hills, unless 
 they remain constantly covered with grass sward, 
 or forests, or other vegetable growth, the fibrous 
 rootlets of which, bind the earth together, and pre- 
 vent its removal. 
 
 The substratum must also be taken into conside- 
 ration, in judging of the probable permanency of a 
 soil which it is proposed to till. Many soils which 
 shed water to a certain extent without washing, 
 when covered by native forests or grass sward, be- 
 come so porous when tilled, as to absorb much water, 
 and if the substratum be clay or sloping rock which 
 does not permit the water to permeate it, the super, 
 incumbent soil slides into the valleys ; or else* 
 springs which result from this absorption, under- 
 mine the soil and gradually wash it away. 
 
 The rapid increase of the alluvial deposits of the 
 Hudson River, in proportion as the land brought 
 under cultivation is increased, is an example in point. 
 Above the Highlands of the Hudson, for 150 miles, 
 most of the immediate valley of the river is formed 
 of clay beds, which either form the surface, or under 
 19 
 
218 FOOD OF PLANTS. 
 
 lie it at a small depth. Every shower removes 
 large quantities of the finer materials from the 
 ploughed fields, and transports this earthy matter 
 into the streams, and these carry more or less into 
 the Hudson. Deep ravines are formed in the clay 
 lands, and they extend back more and more every 
 year, with lateral branches. The same holds true 
 with other soils than the clay, where they are loamy 
 or underlaid by rocks which are impermeable to 
 water. 
 
 FOOD OF PLANTS. 
 
 It is now a well ascertained fact that particular 
 mineral substances are necessary to the successful 
 cultivation of particular plants. As animals thrive, 
 or drag on a miserable existence according to the 
 kind and quantity of nutriment which they receive, 
 so with plants ; they must be cultivated in such 
 soils, as either naturally or artificially contain such 
 substances as are calculated to afford them suitable 
 nutriment, else they cannot thrive. Wheat for in- 
 stance, will grow in soils which do not contain lime, 
 but it is well known, that it yields a crop far inferior 
 in quantity and quality to that of a soil similar in 
 every respect, except that of its containing lime. 
 
 We do not intend here to discuss the adaptation 
 of particular plants to particular soils; we may 
 therefore be permitted to refer the reader to treatises 
 on agriculture for such information. 
 
 The soil is dependent to a great extent upon the 
 nature of the subjacent materials, and it is to the 
 mineralogical texture and chemical composition rather 
 
POOD OP PLANTS. 219 
 
 than the geological age of rocks, that the barrenness 
 or fertility of the soil is due. 
 
 Mr. De La Beche, one of the distinguished Eng- 
 lish geologists, very justly remarks.* " Taken, how- 
 ever, as masses of matter, the mineralogical struc- 
 ture of rocks is sufficiently constant throughout 
 moderate areas, so that if it be known as respects 
 one part of it, the other parts will not be found to 
 differ materially. 
 
 Hence, the agriculturist who examines a good 
 geological map, comprising a moderate area, may 
 feel assured that the respective soils, upon the vari- 
 ous rocks traced upon it, will possess the same gene- 
 ral characters under equal circumstances. If geolo- 
 gical maps be, as probably they will be, improved 
 by the insertion of symbols or signs in different 
 places, showing the mineralogical structure of the 
 rocks at such places, the information afforded to the 
 agriculturist will be still more complete." 
 
 " a. As a soil, composed of the same mineral sub- 
 stances, is of very different value to the agricultu- 
 rist according as it is either wet or dry, the observer 
 should direct his attention to those circumstances 
 which render it either the one or the other. Dis- 
 regarding for the present the general surface-drain- 
 age of a country, the dryness of a soil depends, 
 under equal evaporation and supplies of rain, upon 
 the facility with which its particles permit the per- 
 colation of water downwards, and this facility upon 
 the kind of rock beneath, as above noticed. 
 
 Sandstone rocks generally as might be expected, 
 
 * De La Beche, how to observe, p. 286. 
 
220 FOOD OF PLANTS. 
 
 afford a dry soil. This, however, is not the case 
 with all arenaceous rocks. In some, the mineral 
 matter, cementing the particles of sand together, is 
 so aluminous and abundant, that when the rock is 
 decomposed, the clayey matter overpowers the sand, 
 and a heavy tenacious soil is the result. 
 
 When the observer finds that the subjacent; rock 
 of a dry soil, is porous, and sandy, his remedy for 
 this kind of soil, if it be desirable, will be to do 
 
 something which shall retain moisture in the soil 
 
 . 
 
 itself as long as may be convenient ; since, once 
 arrived at the subjacent rock, it will be absorbed 
 freely by it. 
 
 Some addition must therefore be made to the soil, 
 either of a substance which readily absorbs mois- 
 ture from the atmosphere, to be consumed by the 
 vegetation, or of a mineral substance which shall 
 bind the particles of the soil more firmly together, 
 so that in a given time, a much less quantity of 
 water shall pass downwards to the absorbing rock 
 than if no such mineral substance had been added. 
 Soils thus circumstanced may be considered as well 
 drained beneath." 
 
 " When a dry soil is the produce, by decomposi- 
 tion, of a rock which does not freely absorb water, 
 additions to it, for the purposes of rendering it more 
 moist, require very great care. The observer will 
 generally find such soils shallow, and liable to be 
 washed away by rains. The rains run speedily off 
 where the physical features are favourable, and the 
 soil soon becomes dry from evaporation. 
 
 It is not a little interesting to observe the excel- 
 lent effect produced on such soils by the loose stones, 
 
FOOD OF PLANTS. 221 
 
 not unfrequently scattered over them. These retain 
 moisture in the soil by preventing the evaporation 
 which would otherwise take place ; and it is often 
 not a little curious to note the differences of corn- 
 crops on two adjacent farms, when the occupant on 
 one has removed the stones, and the other has allow- 
 ed them to remain, the advantage being so greatly 
 in favour of the latter. 
 
 " With regard to scattered stones on dry soils gene- 
 rally, it may be stated, that there are some so porous 
 that sufficient moisture would not remain in them 
 to reward the agriculturist for his labour, if they 
 were not abundantly covered with scattered stones. 
 In high lands they also serve to condense fogs and 
 low clouds, and thus add to the moisture of the sub- 
 jacent soil." 
 
 " b A wet, or heavy soil, mainly depends upon the 
 quantity of clayey matter afforded by the rock be- 
 neath it. The latter is very often, under such cir- 
 cumstances, a clay itself, or an argillaceous rock 
 readily converted into such a substance by the ad- 
 dition of sufficient moisture. 
 
 " The soil, therefore is held up by a sheet of rock 
 I impervious to water, and the necessary effects must 
 follow. Such soils are, however, scarcely ever good 
 in themselves ; but a good soil may be, and occa- 
 sionally is, supported by a bed of clay, the good 
 soil being due to the decomposition of a bed or 
 stratum, the mineral character of which was of the 
 proper kind. The bed of clay, or other bed im- 
 pervious to water, will, if the soil be not sufficient- 
 ly thick, cause the latter to be wet, and unfit for 
 purposes to which it might otherwise be dedicated. 
 19* 
 
222 
 
 FOOD OF PLANTS. 
 
 "The observer should ascertain the thickness of 
 the clay or other bed, and the nature of the rock 
 beneath it. If the bed of clay, supposing it to be 
 such, is not too thick, and the stratum beneath be 
 porous, he will be able, from the geological and phy- 
 sical characters of the country, to judge whether it 
 may be better to pierce through the clay bed, in many 
 places, leading radiating drains to the holes thus 
 formed, as drain generally in the usual way. When 
 there is an extensive and elevated table-land, here 
 and there cut by deep valleys, the former might be 
 the cheaper plan, though probably it has never, ex- 
 cept accidentally, been carried into practice. 
 
 " We have seen parts of a table-land formed of a 
 fair though gravelly soil, a resting upon a tenacious 
 clay, 6 drained naturally 
 
 upon this principle, by 
 means of pinnacles of 
 porous rock, c c which 
 pierced through the clay 
 in several places, and entered the gravelly soil above. 
 " The portions of soils above, and near the pinnacles 
 were kept fairly drained by the well known property 
 of porous rocks readily to absorb moisture, while 
 those portions of the soil which were too far from 
 the draining influence of the pinnacles, were wet 
 and heavy. 
 
 " If, upon the same principle, an agriculturist should 
 find it difficult and costly to drain a soil, placed un- 
 der the conditions above noticed, in the usual man- 
 ner, and that the part to be drained is situated as 
 at a, if he can deliver the water into the porous rock 
 
FOOD OF PLANTS. 
 
 223 
 
 e, c, by drilling numerous holes in the clay bed &, b, 
 such water would tend to percolate through the bed 
 c, c, and be delivered in springs into the valleys v, v, 
 if c, c, be supported by a bed d, d, impervious to 
 water. If the water be not stopped by such a bed, 
 then it will continue to percolate through the infe- 
 rior mass in the usual manner. To know that the 
 proper conditions obtain, necessarily requires com- 
 petent geological observation." 
 
 " c When an observer finds a heavy soil produced 
 by the decomposition of hard rocks, such as certain 
 sandstones and slates of the grauwacke series, or 
 others of the like mineralogical structure, be their 
 geological age what it may, he should direct his at- 
 tention to the stratification of the rocks affording 
 the principal materials for the soil, since the prac- 
 ticability of ameliorating the latter much depends 
 upon this circumstance. 
 
 " Let us suppose that the annexed section repre- 
 sents the stratification of a series of rocks affording 
 a heavy clay soil, so that the beds are horizontal at 
 
 0, contorted at 
 b, and dip at 
 a considerable 
 angle at c. 
 Nowsuppos- 
 
224 FOOD OF PLANTS. 
 
 ing them to be, as they generally are, nearly imper. 
 vious to water as beds, and that the soil is attempted 
 to be made lighter by artificial means over the whole 
 surface a, b, c, very different success will attend the 
 experiment at a, and at c, because a water support- 
 ing surface will still continue beneath the soil at a, 
 while the interstices between every bed at c 9 will 
 serve to drain the land. 
 
 " Consequently, if the soil be so lightened that 
 water can freely percolate down to the edges of the 
 beds at c, due care being taken to lay open such by 
 lines of drains, so that the upper portions of the in. 
 terstices are not choked by particles of clay, the 
 soil may be rendered far more dry than before. 
 
 " If an observer direct his attention to two soils 
 derived from similar rocks, the one situated upon 
 nearly horizontal strata, and the other upon the 
 edges of highly inclined beds, he will frequently per- 
 ceive that the former may be heavy and the latter 
 comparatively light, for the simple reason that one 
 is naturally drained and the other not." 
 
 " d Although a geologist may feel satisfied that 
 porous rock is situated beneath a water supporting 
 stratum, near the surface of land, the agriculturist 
 can scarcely be expected to be aware of the struc- 
 ture of the rocks beneath the few feet to which, in 
 his deepest ditches, he is in the habit of working. 
 
 " He may, however, greatly advance himself in a 
 knowledge of circumstances that may often prove 
 highly valuable to him, by consulting good geologi- 
 cal maps, constructed on a large scale, which will 
 give him the surface of land occupied by any given 
 rock, and then turn to the sections which ought to 
 
FOOD OF PLANTS. 225 
 
 accompany such maps, which will show him how the 
 rocks occur relatively to each other beneath the soil. 
 
 "Let him now consult the memoirs written to illus- 
 trate the map and sections ; and by carefully com- 
 bining the accounts given of the structure and com- 
 position of the rocks, as noticed in the memoirs, 
 first, with their relative position as shown in the 
 sections, and secondly, with the portions of surface 
 occupied by each respectively, as shown by the 
 maps, he will obtain, without embarrassing himself 
 with those questions which relate to the higher 
 branches of geology, a stock of knowledge respect- 
 ing the rocks beneath the soil in given districts, 
 which he can readily turn to good account in his 
 management of land, even when the authors of the 
 maps, sections, and memoirs may not' have con- 
 structed the former, or written the latter, with 
 reference to any advantage agriculture could derive 
 from geology. 
 
 " e Even a knowledge of the faults which frequent- 
 ly traverse countries may be turned to account by 
 an agriculturist in the drainage of land. Some of 
 these fissures or dislocations are pervious to water, 
 and act as main drains to portions of country, as is 
 well known to their cost by miners in metalliferous* 
 districts. Others are filled with substances, such 
 as clay, which prevent the passage of water on one 
 side of the fault to the others ; a circumstance highly 
 valuable in some coal districts, for by the intersec- 
 tion of several of these faults, masses of strata are 
 enclosed by them, and if the water be pumped up by 
 proper engines from such masses respectively, the 
 coal-worker has only to contend with the water in 
 
226 FOOD OF PLANTS. 
 
 any mass on which he may be occupied, a supply 
 from other adjacent masses being cut off by the sur- 
 rounding faults. It is obviously from the first kind 
 of faults that the agriculturist can derive any advan- 
 tage in the shape of drainage. 
 
 " Faults may be made to assist the drainage of 
 elevated table-lands, even when their continuations 
 across the valleys, which may cut into such table- 
 lands, afford an abundant supply of water to the 
 surface, as will be seen by the annexed diagram. 
 
 Let the line a, Z>, be a level, at which a fault contains 
 an abundance of water, which is readily discharged 
 upon the surface of the valleys i?, u, that cut the sur- 
 face of land beneath this level. Then if c, d, be 
 table-lands into which the fault cuts upwards, the 
 water conducted into it on such table-lands, either 
 naturally or artificially, will tend to percolate down- 
 wards to the level whatever its relative height may 
 be, at which a quantity of water is sustained in the 
 fissures, and which we have supposed to be repre- 
 sented by the line a, 6." 
 
 "f As the nature of a soil so materially depends 
 upon the mineral composition and structure of the 
 rock beneath it ; an agriculturist should be alive to 
 the advantages he may derive from a mixture of the 
 materials of two or more rocks, in producing a soil, 
 which shall be better than that naturally found on 
 either respectively. 
 
FOOD OF PLANTS. 227 
 
 " This sometimes is done* when that kind of rock 
 commonly known as marl is near some soil to which 
 it is considered a valuable addition ; the marl being 
 taken from the marl rock and distributed over the 
 soil. In this the agriculturist does no more than 
 add mineral matter to his soil ; which, in point of 
 fact, had not been afforded either at all, or in the 
 proper quantity, by the decomposition of the rock 
 beneath it. 
 
 " Many other valuable mixtures than these might 
 be made from the materials of rocks, frequently ad- 
 jacent to each other, either as regards the surface of 
 land, or depth beneath such surface. Some of these 
 mixtures are so obvious, that while examining the 
 geological structure of some countries, we have been 
 surprised that the accidental mixtures of the com- 
 ponent parts of two adjacent rocks at the lines of 
 their junction, and which demonstrate by their ad- 
 vantages the superior fertility upon them, have not 
 induced agriculturists to inquire a little into the 
 cause of them. 
 
 " Carbonate of lime cannot naturally exist in soils 
 derived from rocks which do not contain it, at least 
 any portion found in them must be derived from the 
 remains of snail-shells and the like. Now, the rocks * 
 which do not contain carbonate of lime are very 
 numerous, particularly among a variety of the older 
 series ; and as the presence of carbonate of lime in 
 a soil is so valuable to the agriculturist, it is ob- 
 viously a mineral substance which it becomes his 
 interest to add to one that contains little or none 
 of it. 
 
 The application of lime in its burnt state to soils 
 

 228 FOOD OF PLANTS. 
 
 is so common, that we should not notice the fact if 
 we had not often witnessed farmers dosing their land 
 to excess with it, without the smallest regard to any 
 other mineral ingredient, or to those proportions ot 
 such ingredients which have been found to answer 
 but with different kinds of cultivation. Indeed, as 
 far as regards the large majority of farmers, they 
 seem to consider that all plants are to be fed alike, 
 and that what is good for one must be so for ano- 
 ther." 
 
 " g Given rocks, viewed mineralogically, afford- 
 ing like soils by their surface decomposition, the ob- 
 server should direct his attention to the various 
 plants which flourish best on each respectively, 
 according to the climates in which they may be 
 situated. This subject which may be termed geolo- 
 gical botany, has already been advanced by many 
 local researches, but hitherto no very extended views 
 have been found upon them. It can scarcely be 
 otherwise than one in which agriculturists should be 
 deeply interested. 
 
 " In this way, some plants are found to be of little 
 value when cultivated off given rocks. The pimento 
 or allspice tree of Jamaica may be taken as a good 
 instance of this fact, since it is only profitably cul- 
 tivated upon the white limestone formation of that 
 island. Again, other kinds of cultivation, though 
 they may to a certain extent succeed on several 
 kinds of rocks, are found to afford far more profit- 
 able returns upon one or two in particular. 
 
 " Even alluvial soils differ in value, as might indeed 
 be anticipated, since patches of them are respective- 
 ly formed of the wash, if we may use the expression, , 
 
ROADS. 229 
 
 of districts which may, and generally do vary as to 
 the rocks of which they are composed. 
 
 " Some soils are underrated because they will not 
 readily afford good returns, as regards all, or the 
 greater part, of the cultivation attempted upon them. 
 We will not, however, occupy more of our space 
 with this subject. The connexion of the 'due of 
 the soil and the kind of rock beneath it, will con- 
 stantly be forced upon the observer, and he lias only 
 to register and classify such facts to obtain a fund 
 of valuable information on this head," 
 
 II. ROADS, 
 
 " That the expense of constructing a new road, or 
 of maintaining an old one in good order, greatly de- 
 pends upon the kind of ground under it, upon the 
 facility with which proper stone may be obtained 
 for it, and upon the stability of the various cuts 
 which it may be found necessary to make in the 
 rocks, is well known. It is not, however, so well 
 known that these circumstances depend upon the* 
 geological structure of a country, and that a know- 
 ledge of this structure would enable those who pos. 
 sessed it to determine whether one line of new road 
 would be more costly than another ; whether, when 
 it becomes a question to patch up an old line of 
 road or construct a new one, the one or the other 
 will be ultimately found least expensive ; and that 
 some kinds of stone should be employed upon roads 
 20 
 
230 ROADS. 
 
 in preference to others, when several kinds can be 
 readily obtained." 
 
 " Roads generally are planned with regard to lit- 
 tle else than levels and distances ; and if there be a 
 small advantage in this respect between two lines in 
 favour of one, that line will be selected, though often 
 a fair amount of geological knowledge would be suf- 
 ficient to show that the expense, not only of form- 
 ing, but also of keeping up this road, will be far 
 greater than for the other. Good geological maps 
 are in this respect highly valuable, as they enable 
 those who have to decide upon subjects connected 
 with roads to see at once the kind of rocks over 
 which a projected line of road is intended to pass. 
 They also point out the proximity of rocks which 
 may afford good materials for stoning either new or 
 old roads." 
 
 " a In cutting through stratified rocks, it should 
 be recollected that lines of springs may be inter- 
 sected which may prove injurious to the road ; and 
 also that, by inattention, a hard supporting stratum 
 may be cut through, and the road thrown upon a 
 clay or other loose substance, by which much un- 
 necessary expense will be incurred in order to ren- 
 der the bottom firm. In all deep cuttings to lower 
 hills, the observer should note the mineral structure 
 of the rock cut through, so that, when it becomes 
 exposed to the atmosphere, the slopes given to the 
 sides may be found sufficient, and the drainage of 
 the road preserved." 
 
 " b In choosing materials for macadamized roads, 
 the observer should recollect that the stones placed 
 on them are exposed, not only to friction, but also 
 
ROADS. 231 
 
 to the pounding or crushing action of the weights 
 which roll over them, and consequently that a tough 
 as well as hard substance is required. Now, rocks 
 differ exceedingly in these qualities ; and those per- 
 sons who have paid attention to the kind of stones 
 thrown on roads must have remarked how frequently 
 hard stones are preferred by surveyors and others, 
 when tough materials were to be obtained equally 
 near and cheap. Rocks which are composed of 
 substances of unequal degrees of toughness, are 
 greatly inferior to those which are of the same tex- 
 ture throughout : thus granites generally afford road- 
 stones inferior to a great variety of trappean rocks. 
 Such roads soon become either dusty or muddy, 
 according to the weather. 
 
 "Those granites in which the feldspar is well crya- 
 talized are the worst for the purposes of stoning roads, 
 since this mineral then soon crumbles under pres- 
 sure, while the granites in which hornblende pre- 
 vails, and the feldspar is more compact, are the best 
 The trappean rocks vary considerably in their value 
 as road-stones ; even the same quarry will afford 
 materials of different degrees of toughness. Some 
 greenstones are particularly valuable in this respect,* 
 as also certain diallage and hypersthene rocks. 
 
 " When no better instrument is at hand, a large 
 iron pestle and mortar may be used with advantage 
 in ascertaining the relative toughness of stones. If 
 an observer will take specimens of those intended 
 for examination, of the size of the stones usually 
 thrown on the roads, and then proceed to pound 
 them, taking one specimen at a time, he will soon 
 obtain a rough estimate of their relative values. 
 
232 EOADS. 
 
 Machines for ascertaining the relative superiority 
 of road -stones have been invented, and there would 
 be no difficulty in constructing those which would 
 show their relative degrees of toughness with con- 
 siderable precision. 
 
 " By stoning a road with proper tough materials, 
 we not only reduce the expences of its maintainance 
 but also the annual amount of hindrance caused by 
 the more frequent supply of rough new stones, which 
 tend so much to retard the progress of wheel-car- 
 riages, and add to the labour of the horses that draw 
 them." 
 
 " c The difference in the durability of road ma- 
 terials, obtained from different beds of the stratified 
 rocks, is so considerable, that those charged with 
 their supply, in districts where such rocks prevail, 
 should make themselves acquainted with their strike 
 and dip. The instances in which much unneces- 
 sary expense might be avoided, by this simple ap- 
 plication of geological knowledge, are far more 
 numerous than would readily be credited by those 
 who have not directed their attention to the sub- 
 ject." 
 
 " d In all cases, whether of stratified or massive 
 rocks, the observer should be careful that the stones 
 employed for roads are not taken from the upper or 
 weathered portions of quarries, where they have been 
 more or less exposed to atmospheric decomposing 
 causes, and consequently are not so valuable for the 
 purposes required as those taken from situations 
 where these decomposing causes have scarcely been 
 felt." 
 
 " e In cutting roads on the sides of hills, the ob- 
 
ROADS. 
 
 233 
 
 server should in many cases note the dip of the beds, 
 and their general structure, if the subjacent rocks 
 be stratified, with considerable care ; otherwise much 
 mischief may ensue. 
 
 " Let the annexed diagram represent the section 
 of a hill, composed of beds which dip in one direc- 
 
 d b 
 
 tion. Let c, d, be a bed of sandstone resting upon 
 a soft clay, a, b. Now if a cut, e, be made in the 
 hill, the continuity of c, d, will be destroyed, and 
 the part d, will tend to slide down upon the cut e. 
 If a cut,/, be made on the other side of the hill, and 
 a similar arrangement of beds exist there, no such 
 tendency of the upper to slide upon the lower beds 
 will be produced. 
 
 " Hence not only in such instances as that above 
 noticed, but also in districts of certain slate and 
 other rocks, where the cohesion between the laminae 
 orbed is slight, and the dipsomewhat highly inclined, 
 a preference should be given, when cuts are made 
 for roads, to those sides of valleys or hills as the case 
 may be, where the strata dip inwards into the mass 
 of the hill or mountain as at/." 
 
 20* 
 
234 CANALS. 
 
 III. CANALS. 
 
 " In projecting lines of canals, particularly when 
 tunnels are to be constructed, a knowledge of the ge- 
 ological structure of the country is not less necessary 
 than in the case of roads. The probability of meet- 
 ing with springs of water, the porous or impervious 
 character, as regards water, of the rocks to be tra- 
 versed, and the kinds of rock which will be encoun- 
 tered in cutting, may all in a great degree be fore- 
 seen by those who have examined the geological 
 structure of the district. 
 
 " Hence good geological maps will be found of 
 great value to those who are about to form canals. 
 They also point out the various mineral substances 
 which may advantageously be brought to the canal 
 for the purposes of traffic. From a knowledge of 
 this kind, canals have been made to pass by or 
 through tracts of country where lime stones, coal, 
 or metals are discovered." 
 
 " Canals, as is well known, are often found to be 
 more costly than was anticipated, from the simple 
 fact that some of the rocks traversed, readily absorb 
 water, and it therefore becomes necessary to incur 
 the expense of rendering the canal-bed water-tight. 
 
 " Where the supply of water is limited, the pres- 
 ence of an extended line of porous rock is a serious 
 difficulty. It is one, however, which might some- 
 times be avoided by a competent knowledge of the 
 geological structure of the district traversed, for 
 such knowledge would enable the engineer so to form 
 
WELLS. 235 
 
 his plan as to avoid the porous rocks as much as 
 possible. 
 
 " It should be recollected that a knowledge of the 
 rocks on the surface will not give that of those 
 which may be cut into the line of a canal, unless it 
 be coupled with such information, respecting the 
 mode in which the rocks of the district occur, that 
 the observer shall be aware of those kinds which 
 will probably be found at given depths in different 
 places. A fine retentive clay may exist on the sur- 
 face and rest upon a porous sandstone ; and there- 
 fore, in following the levels, the former may be cut 
 through, and the canal-bed be based on the latter." 
 
 IV. WELLS. 
 
 " The geological observer will find no difficulty 
 in applying his knowledge to the probability or im- 
 probability of obtaining water by means of wells in 
 given situations. The most important are those 
 named Artesian, which are perpendicular borings 
 made into the earth to various depths, and from 
 which large and constant supplies of water, which 
 flow over the land in streams, are often procured in 
 districts where this necessary of life is otherwise 
 obtained either of bad quality or in small quanti- 
 ties." 
 
 " a The observer, neglecting those springs of wa- 
 ter which rise from faults, and those which gush out 
 in greater or less abundance from limestone and 
 other cavernous rocks, has only to recollect that the 
 
236 WELLS. 
 
 more common springs are produced by the percola- 
 tion of rain-water through porous to impervious 
 beds, where they are stopped, and he will readily be 
 enabled to judge of the facility or difficulty there 
 may be in procuring water by means of wells in a 
 given district. 
 
 " Let the annexed sketch represent the section of 
 
 1 
 
 a hill composed of a porous siliceous sandstone a, 
 a clay bed b, a porous and somewhat calcareous 
 sandstone c, and another clay d, and the rocks be 
 uncovered by gravel in the valley f, while porous 
 gravel is found in the valley g. 
 
 " Now, to obtain water by means of wells it would 
 be necessary to sink through a on the top of the 
 hill to the clay b, where the rain-water which has 
 percolated through a will be stopped. This line of 
 water will probably be shown by a line of springs 
 in the valley f; but the springs which will equally 
 flow from it in the valley g (for the sake of illustra- 
 tion we suppose the strata horizontal) will be con- 
 cealed beneath the gravel e, and will percolate be- 
 tween the clay and it to the porous sandstone c, on 
 that side. 
 
 " A well therefore formed at 2, through the gravel, 
 would reach the same line of water as is obtained 
 at 1, and forms springs in the valley f. A well 
 pierced at 3 in the valley /would afford the water 
 
WELLS. 237 
 
 stopped by the clay-bed d, and the water in it would 
 probably differ in quality from that obtained in the 
 line above 6, because it has traversed a different 
 kind of rock. 
 
 " To reach the same line of water in the valley g, 
 it would be necessary to pierce through the gravel 
 e, and the sandstone c ; and if a thin clay parting 
 should separate e from c, derived from the bed b in 
 that direction, the well 4 would first give the line of 
 water above b, and afterwards that above d." 
 
 66 b The observer will readily conceive a variety 
 of circumstances which may modify a supply of 
 well-water in different localities ; but by paying 
 attention to the geological structure of each, so as 
 to obtain a knowledge of the true relative positions 
 of the porous and impervious beds, the influence of 
 faults, if such occur, being duly considered, he will 
 find little difficulty on this head." 
 
 "c Care should be taken, when the impervious 
 bed supporting a line of water is thin, not to cut 
 through it ; for by so doing the water will be let 
 out into the rock beneath, if that be porous." 
 
 "d Among highly inclined, and even vertical 
 strata, water may sometimes be obtained at diffe- 
 rent levels, from the saturation of slate or other beds 
 to a certain degree pervious to water at such levels ; 
 so that if a well be formed in such situations, the 
 water will percolate into the cavity and fill it up to 
 the height to which the line of saturation extends. 
 The observer may frequently find little cavities 
 formed in highly inclined or vertical beds of slate, 
 in the vicinity of cottages in slate districts, which 
 are filled on this principle." 
 
238 MINING. 
 
 V. MINING. 
 
 " It is not our intention to enter upon the com- 
 plicated subject of mining, further than to point out 
 the necessity of geological knowledge, on the part 
 of those who seek metals or coals in districts where 
 they have not been hitherto found. The sums of 
 money thrown away, more particularly in the search 
 of coal, which this knowledge would have saved,, 
 must be collectively very considerable. A little 
 black shale, or a piece of lignite, is often sufficient 
 to cause the expenditure of thousands, in localities 
 where there is not the slightest probability of suc- 
 cess. 
 
 " In the search for metals, matters are frequently 
 not much better. It may be true, and *no doubt is 
 so, that particular metals and coal are not, as waSy 
 once supposed confined (viewing the surface of the 
 earth generally) to rocks formed at particular geolo- 
 gical epochs ; but it may be safely stated that, in 
 given areas, both metals and coal will be found to 
 have given geological positions." 
 
 " a In the search for coals, observers should be 
 guided by the knowledge of the geological structure 
 of given areas, in whatever part of the world these 
 areas may occur. A knowledge of the general 
 geological structure of eastern Australia will no 
 doubt one day enable the geologists of that country 
 to direct the search for coal in given rocks, and to 
 advise the discontinuance of them in others, pre- 
 cisely as English geologists would advise the search 
 
MINING. 239 
 
 for coal in the proper places, and tell those who seek 
 for it in numerous other situations where it has 
 been sought, that they were throwing away time, 
 labour and money." 
 
 " b With regard to metals, a knowledge of the 
 geological structure of given areas is also requisite. 
 As the rocks of the same epoch often change their 
 mineral character in horizontal distances, so also their 
 metalliferous character is found not to be constant 
 throughout extensive areas. A due consideration 
 of this subject would, however, lead us into discus, 
 sions foreign to the object of this work. It will be 
 sufficient to state, that the knowledge of the geolo- 
 gical structure of the British Islands, France, Ger- 
 many, or any other country, will enable the geolo- 
 gical observers in their respective portions of the 
 earth's surface to state, that given rocks, or given 
 modes of their occurrence, may afford useful metals, 
 while in other rocks or situations the search for 
 them can scarcely be otherwise than fruitless." 
 
 "c We may here notice the singular circum- 
 stance, that in this country, where so much capital 
 is invested in metalliferous mines and collieries, 
 there should be no national school, or college of 
 mines, though the great utility of such establish-, 
 ments is amply proved by experience in foreign 
 countries, where for the most part the capital thus 
 invested is comparatively trifling. British miners 
 and coal- workers are compelled to pick up their in- 
 formation how they can. If by good fortune young 
 men are placed under those who value science, and 
 are aware of the advantages which may be derived 
 from it, they have certainly little reason to com- 
 
240 BUILDINGS. 
 
 plain ; but, unfortunately this is not the lot of the 
 many. A college of mines, properly conducted, 
 would be alike beneficial to those who invest their 
 money in mines and collieries, and those who work 
 them. It could, indeed, scarcely be otherwise than 
 a national benefit. Hitherto, however, the attempts 
 which have been made to call the attention of govern- 
 ment to this subject have been unsuccessful." 
 
 VI. BUILDINGS. 
 
 " Disregarding private dwellings, on which such 
 various materials are employed, according to the 
 motives that lead to their erection, it may be fairly 
 stated, that a knowledge of the general structure of 
 rocks, and the situations whence the best materials 
 may be obtained, is essential to those who are either 
 charged with, or direct, public works. A stone 
 which may be sufficiently durable if plunged beneath 
 water, may not be so when kept alternately wet and 
 dry by the rise and fall of water in a river or on a 
 tidal coast, or when wholly exposed to the action 
 of the atmosphere. A somewhat porous sandstone, 
 for instance, may do well when kept constantly un- 
 der- water ; but the same rock when exposed to the 
 atmosphere, more particularly in climates subject 
 to frost, might gradually crumble away from causes 
 previously noticed." 
 
 " a The observer desirous of selecting a stone to 
 be exposed to atmospheric influences would do well 
 to study the mode in which it is weathered in the 
 
BUILDINGS. 241 
 
 locality whence it is obtained. He may learn which 
 part, if it be a compound rock, is liable to give way 
 before such influences, and the conditions under 
 which it does so. Granite generally is considered 
 a proper material for national monuments. Some 
 granites, however, though they may be hard and 
 difficult to work, when first taken from the quarry, 
 are among the worst building materials, in conse- 
 quence of the facility with which the feldspar in 
 them decomposes, when exposed to the action of a wet 
 atmosphere, in a climate which may be warm dur- 
 ing part of the year, and cold during the other." 
 
 " Rocks which readily absorb moisture, such as 
 many of those which are termed free stones, are ex- 
 ceedingly bad for the external portions of exposed pub- 
 lic buildings ; since in countries where frosts occur, 
 the freezing of the water in the wet surface continual- 
 ly peels off the latter, and eventually destroys the or- 
 namental work carved upon it. It should be recol- 
 lected that free stones, so termed because they are 
 easily worked, are often valued because they may 
 be cut readily when first taken from the quarry, and 
 subsequently become harder when exposed to the 
 atmosphere ; and that this quality arises from the 
 evaporation of the water contained in the stone 
 when forming part of the natural rock. Now, some 
 of these freestones again readily absorb moisture, 
 while others do not : hence the latter should be pre- 
 ferred ; and an observer should ascertain this fact 
 by experiment before any given freestone is se- 
 lected." 
 
 " Some freestones are formed of particles of sand 
 cemented together by different substances, the ce- 
 21 
 
242 BUILDINGS. 
 
 meriting matter being sometimes siliceous, at others 
 calcareous, and at others again formed of oxide of 
 iron. In the first case, the freestone would not 
 suffer from the chemical action of atmospheric in- 
 fluences upon it ; while in the second, rain-water 
 containing carbonic acid would tend to dissolve the 
 calcareous matter, and deprive the sand of its ce- 
 ment ; and in the third, the action of atmospheric 
 influences, would tend to render the material un- 
 sightly by staining it with iron-rust." 
 
 " The little attention that has been paid in the 
 erection of national monuments in this country, to 
 the durability of the materials of which they are 
 constructed, is well known. There is no want of 
 good materials, if they would be sought out ; and it 
 often occurs to the geologist to find them." 
 
 " b In selecting stone for artificial harbors, break- 
 waters, quays, and bridges, the observer should note 
 those lands which best suit the different parts of 
 the work to be executed. Where a pier or break- 
 water has to resist the action of heavy breakers, 
 charged with the pebbles of a beach, a harder ma- 
 terial becomes necessary than when it has only to 
 encounter the action of breakers not so charged, 
 In both cases the weight of a stone is an important 
 consideration, since the greater the weight in the 
 same bulk, the greater the resistance to removal from 
 the flow of a breaker, other things being equal. An 
 observer, therefore, should ascertain the specific 
 gravity of a stone he may be desirous of employing. 
 Several kinds of stone, otherwise equally good, may 
 f vary much in this respect ; so that a pier of given 
 
BUILDINGS. 243 
 
 dimensions may differ considerably from another in 
 weight according to the material employed." 
 
 " In constructing piers, quays, and bridges, where 
 the water level varies, materials which may be good 
 for one part of the work may not be so for other 
 portions. Many rocks which may be advantage- 
 ously employed in situations constantly under wa- 
 ter, will be found liable to decomposition when ex- 
 posed to the atmosphere, particularly in those por- 
 tions kept alternately wet and dry by the rise and 
 fall of tides, or other causes producing changes in 
 the level of the water. An observer may often ob- 
 tain information on this head, by studying the con- 
 dition of rocks on the banks of rivers, and on the 
 sea-shore, and geologists are thus frequently aware 
 of many situations where quarries for the purposes 
 iibove mentioned may be advantageously opened."* 
 
 * De La Beche, how to observe. 
 
SKETCH 
 
 OF THE 
 
 HISTORY OF GEOLOGY. 
 
 We learn, that the speculative part of Geology, 
 engaged the attention of mankind at a very early 
 period. 
 
 The priests of Egypt maintained the aqueous 
 origin of the globe ; Thales taught that the solid 
 materials of the Earth were deposited from water ; 
 Zeno that fire was the " prima materia," and the 
 Earth formed from it. 
 
 In the limited number of physical subjects that 
 engaged the attention of classical antiquity, we can 
 include but a few insulated phenomena that come 
 within the limits of Geology. 
 
 Such striking natural appearances as earthquakes 
 and volcanos, could not escape notice, and we find 
 crude theories to account for them in various authors. 
 
 The formation of new land by the mud brought 
 down and deposited by rivers, the appearance of 
 new islands in the ocean, and the encroachment of 
 the sea, on the land, are not unfrequently mentioned 
 by Pliny, Aristotle, and Strabo. 
 
 With one of the great facts of geological investi 
 
 Jl 
 
 1 
 
HISTORY OF GEOLOGY. 245 
 
 gation and speculation they were also acquainted. 
 This fact, is, that shells, and various other organic 
 remains, occur in immense quantities, embedded in 
 the solid rock, and often at a great depth below the 
 surface ; but it seems to have excited little of their 
 attention or curiosity. 
 
 It seems singular that this fact, which would have 
 afforded demonstrative evidence of the favorite dog- 
 ma of some of their schools, that the face of nature 
 was continually changing, and what was now dry 
 land, was once covered by the sea, should have been 
 overlooked. 
 
 Ovid alone, with a view to illustrate the above 
 doctrine, puts into the mouth of Pythagoras, the 
 words, 
 
 " Vidi factas ex asquore terras 
 
 " Et procul a pelago conchae jacuere marinae." 
 
 In some of their physical notions, we perceive the 
 germs of more modern theories, or at least, the theo- 
 ries have been formed from an imperfect observa- 
 tion of similar facts. 
 
 The theory adopted and adorned by Buffon, who 
 appears to have consider the displacement of the sea 
 as a periodical revolution of nature ; and the wfld 
 but splendid conception embraced by many of the 
 ancient schools, and particularly by the Stoics, that 
 the Earth had experienced frequent destructions and 
 renovations, through the agency of igneous and 
 aqueous devastations, recurring after distant inter- 
 vals of time, reminds us, in many points, of the 
 Huttonian theory of the Earth. It seems more con- 
 
 21* 
 
246 HISTORY OF GEOLOGY. 
 
 sistent, however, with the general tenor of their phi- 
 losophical speculations, to believe that it was de- 
 duced from their high " a priori" principles, rather 
 than from any train of inductive reasoning, founded 
 on observation. 
 
 Middle Ages. 
 
 In the middle ages, the Arabian writers seem to 
 have cultivated mineralogy with some success. 
 
 Tenth Century. 
 
 Avicenna, at the close of the 10th century, was 
 the first who laid the foundation of a rational ar- 
 rangement of minerals. 
 
 Several Italian writers noticed the appearance of 
 fossil shells in their hills at an early period. 
 
 Fifteenth Century. 
 
 In the 15th century, Alessandro degli Alessandri, 
 proposed the hypothesis, that the axis of the Earth's 
 rotation, might, originally, have had a different po- 
 sition from the present one, as a means of account, 
 ing for the change in the land and sea. 
 
 Sixteenth Century. 
 
 Fracastero, in 1517 enters at large into a discus, 
 sion of the land having been covered by water, and 
 he arrives at the conclusion, that the phenomena 
 are such as cannot be explained by a transient con- 
 vulsion, such as the deluge alone. 
 
 The change in the axis of the Earth, found an 
 advocate in more recent times in Voltaire, who be- 
 lieved in the wild tradition of the Egyptians, that 
 
HISTORY OF GEOLOGY. 247 
 
 the sun had twice risen in the west within the me- 
 nioiy of that nation, and ascribed this, to a revolu- 
 tion of the Earth's axis around one of its equatorial 
 diameters, which he imagined was completed in 
 4,000,000 years. 
 
 It is however needless to add, that astronomical 
 observation does not afford the slightest ground for 
 these speculations ; the real change in the obliquity 
 of the ecliptic being confined within very narrow 
 limits, is inadequate to account for any geological 
 phenomena. 
 
 George Agricola, who flourished during the first 
 half of the 16th century, published on several 
 branches of mineralogy, and he illustrated in a full, 
 precise, and clear manner, the various, phenomena 
 of metalic veins. 
 
 Before the close of the 16th century, George 
 Owen, an Englishman, left behind him a valuable 
 manuscript work on the topography of his native 
 county. In this, we find the earliest attempt to 
 establish the important and fundamental geological 
 fact, that the same series of rocks succeed each 
 other in a regular order, through extensive tracts of 
 country ; but his work having remained in manu- 
 script until recently, shows us a striking instance 
 of those anticipations of subsequent discoveries, 
 which may be often observed in the history of 
 science, but cannot have contributed in any degree 
 to their advancement. 
 
 Seventeenth Century. 
 
 During the 17th century, we find little but theo- 
 retical writers without observation, as Burnet, or 
 
248 HISTORY OF GEOLOGY. 
 
 collectors without general views ; but Llwydd, ap- 
 pears to have been partially acquainted with the 
 fact, that particular shells occur in particular strata. 
 
 Lister, demands our attention, as the first pro- 
 poser of regular geological maps. The very idea 
 of this proposal, shows an acquaintance with the 
 regularity of geological structure, occurring over 
 extensive districts. Another important observation 
 in relation to him, is, that he was, in at least one in- 
 stance, led to the distinction of strata, by their or- 
 ganic remains. 
 
 Eighteenth Century. 
 
 Woodward's essay on the natural history of the 
 Earth in 1702, was the first thing published in Eng- 
 land that contained any important geological facts. 
 
 The discourses of Hooke on earthquakes in 1705, 
 the physico theological discourses of Ray in 1713, 
 and the new theory of the Earth by Whiston in 
 1722, were chiefly of a speculative nature. In 
 1723 we find the arrangement of the strata in regu- 
 lar zones, described by Hollo way (Phil. Trans.) and 
 by Mr. Packe in 1730 ; and about the same time 
 Strachey, described the coal district of Somerset, 
 shire, and he observed the inclined position of the 
 coal strata and the horizontal superincumbent rocks* 
 Strachey was also acquainted with the regular suc- 
 cession of strata. 
 
 Towards the middle of the 18th century, the scat- 
 tered rays of information are seen beginning to 
 converge into a stronger and more. steady light, 
 and to approximate to a regular system. 
 
 In 1740, DeMaillet, who had long resided in 
 Egypt, adopted the opinions of the ancient philoso 
 
HISTORY OF GEOLOGY. 249 
 
 phers, and having seen the waters by their earthy 
 depositions contribute to the extension and forma- 
 tion of land, he attempted a general explanation of 
 the formation of the Earth. 
 
 In 1746, Guettarcl first executed the idea pro- 
 posed by Lister years before, of geological maps, 
 but by attempting too much, he brought his method 
 into disrepute. 
 
 Lehman in 1756 was the first to establish firmly 
 the great distinctions between the primitive and se- 
 condary rocks. 
 
 In 1760, the Rev. J. Mitchell in a paper on the 
 causes and phenomena of earthquakes, gave the 
 whole doctrine of the regular succession of the 
 stratified masses, constituting the crust of the Earth, 
 and he observes that this structure is such, that we 
 may always meet with successive zones of the vari- 
 ous mineral masses, lying paralled to, and rising to- 
 wards the principal mountain range. 
 
 Fuchsel, a German writer, made known that cer- 
 tain rocks were not only characterized by their 
 mineralogical structure, but by their organic re. 
 mains, in two works he published in 1762 arid 1772. 
 He determined the relative positions of many of 
 the rocks. His theoretical geology is remarkable, 
 and far superior to that of Werner, which was after- 
 wards so generally adopted. See De La Beche, p. 
 181. 
 
 In 1778, Whitehurst's enquiry into the original 
 
 state of the Earth, although mostly theoretical and 
 
 speculative, contained some good observations on 
 
 the geological structure of some parts of England. 
 
 James Douglass, in 1785, published a dissertation 
 
250 HISTORY OF GEOLOGY. 
 
 on the antiquity of the Earth, in which some or. 
 ganic remains were particularly considered. 
 
 In 1788, Hutton published his theory of the Earth, 
 and this is a work which has exerted a lasting in- 
 fluence over geologists. Hutton has the merit of 
 having first directed the attention of geologists to 
 the important fact of granite veins issuing appa- 
 rently from heels and strata of granite, and travers- 
 ing ail the surrounding rocks. 
 
 He also brought forward in a striking manner, 
 the circumstances that seem to show the igneous 
 origin of the trap rocks ; but the wildness of some 
 of his theoretical views, may well go to counter- 
 balance the utility of the facts he gathered from ob- 
 servation. 
 
 Werner published his researches in 1787, but his 
 system seems to have received accessions until 1796. 
 It is difficult to estimate his independent and real 
 merits, as he never published much of his system ; 
 we are informed of it only through his pupils. His 
 principal merits seem to have been in a superior 
 acquaintance with the mineralogical characters of 
 rocks, in having traced with minuteness the primi- 
 tive, transition, and secondary rocks, in that part 
 of Germany, and in reducing the hitherto irregular 
 elements of geological science, into a more strict 
 and systematic form. His theory must now appear 
 to almost all, as among the most unphilosophical 
 and unsuccessful yet framed, and his few remaining 
 adherents are one by one abandoning his most 
 characteristic opinions. 
 
 There appears to have been in the character of 
 Werner a concentration of all his powers to the ad- 
 
HISTORY OF GEOLOGY. 251 
 
 vancement of his favorite pursuit, and his zeal was 
 communicated to all his pupils. " Werner's mind 
 was at once imaginative and richly stored with mis- 
 cellaneous knowledge. He associated every thing 
 with his favourite science and in his excursive lect- 
 ures he pointed out all the economical uses of mine- 
 rals and their application to medicine ; the influ- 
 ence of the mineral composition of rocks upon the 
 soil, and of the soil upon the resources, wealth, and 
 civilization of man. " The qualities of certain stones 
 used in building, would lead him to descant on the 
 architecture of different ages and nations, and the 
 physical geography frequently invited him to treat of 
 military tactics. The charm of his manners and his 
 eloquence, kindled enthusiasm in the minds of his pu- 
 pils, many of whom only intended at first to acquire 
 a slight knowledge of mineralogy ; but when they 
 had once heard him, devoted themselves to it as the 
 business of their lives. In a few years a small school 
 of mines, before unheard of in Europe, was raised, to 
 the rank of a great university, and men already 
 distinguished in science studied the German lan- 
 guage, and came from the most distant countries to 
 hear the great oracle of Geology." [Cuvier, Eloge 
 de Werner, and LyeWs Principles of Geology. Vol. 
 I. p. 64.] 
 
 Werner, has, by his popularity, and the spirit of 
 enquiry he set on foot, probably done more for the 
 advancement of Geology, than any other individual, 
 and he has, perhaps, properly, been called, the Father 
 of the science. 
 
 The travels of Saussure in the Alps, afforded im- 
 portant contributions of geological science, and Pal- 
 
52 HISTORY OF GEOLOGY. 
 
 las, in his mineralogical surveys of the Russian Em 
 jure, has noted many important geological facts. 
 
 In 1790, Mr. Wm. Smith, a mining engineer, 
 commenced his geological researches, and in a few 
 years published local maps of a considerable por- 
 tion of England. His labours have done more to 
 advance this science in England, than those of any 
 other individual, and by many he is supposed to 
 have done as much for it as Werner. 
 
 Since the commencement of the 19th. century, 
 more materials have been collected to forward the 
 science of geology than had been before. A nu- 
 merous and ablest class of geologists have arisen 
 since that time in England, and another in France, 
 and the United States have produced some. The 
 principal of the English Geologists are, Buckland, 
 De La Beche, Conybeare, Phillips, Murchinson, 
 Lyell, Grenouch, Bakewell, Parkinson, Webster, 
 Sedgewick, McCulloch, Taylor, Fox, Stokes, Fit- 
 ton, and Warburton. 
 
 Among the French geologist who have done 
 most, may be mentioned Cuvier, the Brongniarts, 
 (father and son,) Boue, De Luc, Saussure, and Elei 
 de Beaumont. 
 
 In Germany, De Buch, Raumer, Ebel, Keferstein, 
 Brown, and many others might be mentioned in 
 various parts of Europe. In the United States, 
 Maclure, Silliman, Bruce, Mitchell, Hitchcock, 
 Morton, Eaton, James, Hayden, Olmstead, Gleav- 
 !and, Webster, Cist, Hildreth, Beck, Torrey, Eights, 
 Pierce, Dekay, Cooper, Cozzens, Vanuxem, Con- 
 rad, Emmons, Troost, Featherstonhaugh, Taylor, 
 Houghton, Owen, the Rodgers, Booth, and many 
 
HISTORY OF GEOLOGY. 253 
 
 others have been, and some of them are still, engag- 
 ed in developing the geology of our territory. 
 
 Mr. Maclure and Gen. S. Van Rensselaer, deserve 
 notice particularly ; the first for his great geological 
 survey of the United States, and his munificent do- 
 nations to the various scientific societies, of rare 
 arid valuable books ; the other for his liberality in 
 causing a geological survey to be made at his ex- 
 pense. These two men have given an impulse to the 
 science, that must result in the developement of the 
 geology and resources of this country. 
 
 Before geology ranked as a science, the efforts of 
 the early speculators were directed to the wild and 
 ample region of pure theory, connected with the 
 origin of the globe ; the connection of scriptural 
 history with physical events, and the traces and ef- 
 fects of the Noachian deluge. 
 
 The descriptive part of geology was then a blank. 
 For their soaring views, it would have appeared 
 beneath the dignity of science to classify rocks and 
 minerals, or descend into a minute comparison of 
 the organic remains entombed in the rocky strata, 
 with the existing species. Why should they ?s to 
 whom nature had revealed her ample page, scruti- 
 nize the " modus operandi," which, they imagined 
 would add little to a knowledge of general facts or 
 laws ? Why should the phenomena of active caus- 
 es be minutely examined, the destructive influence 
 of volcanos and earthquakes, or the devastating 
 operations of seas, and rivers, and torrents, when a 
 comet might so easily in imagination be summoned 
 to scorch the Earth from pole to pole, and by its 
 attraction submerge the continents and change the 
 22 
 
254 HISTORY OF GEOLOGY. 
 
 axis. No dynamical effect was too great for such 
 resources. As new phenomena arose, new under- 
 plots were added to the drama of creation, and so 
 remained until by new discoveries, new substitutions 
 were rendered necessary. An advancing state of 
 physical science, led men to correct the laxity 
 which the theories of the formation of the Earth 
 had assumed, in the time of Burnet and Whiston. 
 Werner and Hutton, both of whom gave much 
 weight to the fact of observation, raised a new 
 and very superior class of geologists. Whatever 
 may have been the errors of their theories, it ia 
 certain that their influence on the minds of men 
 has been of much importance in causing the ad- 
 vance of the science. Button's doctrine of the 
 consolidation of earthy materials by heat and pres- 
 sure, and Werner's theory of universal formations, 
 were brought to the tests of experiment and obser- 
 vation. The one was confirmed more satisfactorily 
 than could have been expected under facitious cir- 
 cumstances ; the other was shown to have origina- 
 ted in its utmost generality in the narrow views 
 of its ingenious but untra veiled author. One was 
 passed by in silent neglect, the other attracted 
 crowds of disciples from all parts of Europe. The 
 former of these men died when his theory had 
 hardly attracted notice, the latter, in the full career 
 of glory. Like the fabled Phenix, Button's theory 
 arose from his ashes, but from the time Werner 
 was laid in his grave, his was found wanting in the 
 generality which he had assigned it. 
 
 The acrimony, which the controversy between 
 the disciples of these two men produced, caused a 
 
HISTORY OF GEOLOGY. 255 
 
 reaction, and geologists resolved for a time to ban- 
 ish hypotheses, and, unbaissed by theory, endeavour 
 to view nature as she is ; and thus, men have be- 
 come habituated to using well their hands and eyes, 
 and amassing facts before theorizing. 
 
 The practical utility of the applications of geol- 
 ogy in agriculture, rninery, and engineering, and 
 developing the latent resources of the country, is 
 now so well understood, that more than half of the 
 States of the Union, are having geological surveys 
 made of their territories, and the others must, un- 
 doubtedly, ere long, follow in the train. Our youth 
 in common schools and academies, may be made a 
 more powerful engine to develope the resources of 
 our country, than all the geologists in the world 
 unaided. We wish our youth to be instructed in 
 the elements of geology, and to become familiar 
 with the common useful minerals and rocks. Could 
 we accomplish this, we would soon have three mil- 
 lions of pairs of eyes engaged in observing the re- 
 sources of our country instead of a few dozens. 
 Then, by means of experienced geologists, we might 
 hope to be able to combine and generalize the mul- 
 titudes of observations, and soon develope the fa 
 sources of our country ; and thus give a new im- 
 pulse to every branch of industry, while new fields 
 of enterprise would be opened for the multitudes 
 which are yet to people our extended territory. 
 
GLOSSARY 
 
 OF SOME 
 
 GEOLOGICAL TERMS, 
 
 FROM 
 
 LYELL'S GEOLOGY AND OTHER SOURCES. 
 
 Alluvial. The adjective of Alluvium. 
 
 Alluvion. A synonim of Alluvium. 
 
 Alluvium. Recent deposits of earth, sand, gravel, mud, 
 stones, peat, shell banks, shell marl, drift sand, &c., result- 
 ing from causes now in action. This term is generally ap- 
 plied to those deposits in which water is the principal agent. 
 
 Alum rocks. Rocks which, by decomposition, form Alum. 
 
 Amorphous. Bodies devoid of regular form. 
 
 Amygdaloid. A trap rock which is porous and spongy, 
 with rounded cavities scattered through its mass. Agates 
 and simple minerals are often contained in these cavities. 
 
 Anthracite. A species of mineral coal, hard, shining, 
 black, and devoid of bitumen. 
 
 Anticlinal. An anticlinal ridge or axis is where the strata 
 along a line dip contrariwise, like the sides of the roof of a 
 house. 
 
 Arenaceous. Sandy. 
 
 Argillaceous. Clayey. 
 
 Augite. A simple mineral of variable colour, from black 
 through green and gray to white. It is a constituent of 
 many volcanic and trappean rocks, and is also found in some 
 of the granitic rocks. 
 
 Avalanche. This term is usually applied to masses of ice 
 and snow which have slidden from the summits or sides of 
 22* 
 
258 
 
 GLOSSARY. 
 
 mountains. It is now also applied to slides of earth and 
 elay. 
 
 Basalt. One of the common trap rocks. It is composed 
 of Augite and feldspar, is hard, compact, and dark green or 
 black, and has often a regular columnar form. The palisades 
 of the Hudson show the columnar aspect of trap rocks. The 
 Giants' causeway is cited as an example of Basaltic rocks, 
 and the columnar structure is there very strikingly displayed. 
 
 Bitumen. Mineral pitch, which is often seen to ooze from 
 fossil coal when on fire. 
 
 Bituminous Shale. A slaty rock, containing bitumen, 
 and which occurs in the coal measures. 
 
 Blende. Sulphuret of Zinc. A common shining zinc ore. 
 
 Bluffs. High banks of earth or rock with a steep front. 
 The term is generally applied to high banks forming the 
 boundaries of a river, or river alluvions. 
 
 Botryoidal. Resembling a bunch of grapes in form. 
 
 Boulders. Rocks which have been transported from a dis- 
 tance, and more or less rounded by attrition or the action of 
 the weather. They lie upon the surface or loose in the soil, 
 and generally differ from the underlying rock in the neigh, 
 borhood. 
 
 Breccia. A rock composed of angular fragments cement- 
 ed together by lime or other substances. 
 
 Calc Sinter. A German term for depositions of limestone 
 from springs, and waters which contain this mineral in solu- 
 tion. 
 
 Calcareous rocks. A term synonimous with limestones. 
 
 Calcareous Spar. Crystallized carbonate of lime. 
 
 Carbon. The combustible element of coal. 
 
 Carbonates. Chemical compounds containing carbonic 
 acid, which is composed of oxygen and carbon. 
 
 Carbonic Acid. An acid gaseous compound, incapable of 
 supporting combustion, and deleterious to animal life. It is 
 common in caves and wells, and many incautious persons 
 loose their lives in consequence of descending, without first 
 ascertaining its presence by letting down a lighted candle. 
 Man cannot live where a candle will not burn freely. 
 
 Carboniferous. Coal bearing rocks. This term has been 
 applied to a formation belonging to an ancient group of secon- 
 
GLOSSARY, 259 
 
 dary rocks which contains coal. The term is now used in a 
 more enlarged sense, and may be applied to any rocks con- 
 taining coal. 
 
 Chert. A siliceous mineral, approaching to chalcedony, 
 flint and hornstone. It is usually found in limestone. 
 
 Chlorite. A soft green scaly mineral, slightly unctuous. 
 
 Chloritic Slate. Slate containing chlorite. 
 
 Clinkstone. A slaty feldspathic or basaltic rock, which is 
 sonorous when struck. 
 
 Cleavage. The separation of the laminoe of rocks and min. 
 erals in certain constant directions. They are not always 
 parallel to the planes of stratification, but are often mistaken 
 for them. 
 
 Coal formation. Coal measures. These terms are con. 
 sidered synonimous, and refer to the great deposit of coal in 
 the older secondary rocks, which has been called the " inde- 
 pendent coal formation." There are, however, deposits of 
 carbonaceous matter in all the geological periods, and several 
 of them might also be called coal formations. 
 
 Conformable. When strata are arranged parallel to each 
 other, like the leaves of a book, they are said to be conforma. 
 ble. Other strata lying across the edges of these may be con- 
 formable among themselves, but unconformable to the first 
 set of strata. 
 
 Conglomerate, or Puddingstone. Rocks composed of round, 
 ed masses, pebbles and gravel cemented together by a silice- 
 ous, calcareous, or argillaceous cement. 
 
 Cretaceous. Belonging to the Chalk formation. 
 
 Crop out and out crop. Terms employed by Geologists 
 and Mining Engineers, to express the emergence of rock, in 
 place, on the surface of the earth at the locality where it is 
 said to crop out. 
 
 Crystalline. An assemblage of imperfectly defined cry. 
 stals, like loaf sugar and common white marble. 
 
 Delta. Alluvial land formed at the mouths of rivers. 
 
 Denudation. A term used to express the bare state of the 
 rocks over which currents of water have formerly swept, and 
 laid the rocks bare, or excavated them to form valleys of de- 
 nudation. 
 
 Deoxidize. To separate oxygen from a body. 
 
260 GLOSSARY. 
 
 Dykes. A kind of vein intersecting the strata, and usually 
 filled with some unstratified igneous rock, such as granite, 
 trap or lava. These materials are supposed to have been in- 
 jected in a melted state into great rents or fissures in the 
 rocks. 
 
 Diluvium and Diluvion. Deposits of boulders, pebbles, 
 and gravel which many geologists have supposed were pro- 
 duced by a diluvial wave or deluge sweeping over the surface 
 of the earth. 
 
 Dip. Where strata are not horizontal, the direction in 
 which their planes sink or plunge, is called the direction of 
 the dip, and the angle of inclination, the angle of dip. 
 
 Dolomite. A magnesian limestone belonging to the pri- 
 mary class. It is usually granular in its structure, and of a 
 friable texture. 
 
 Dunes. Sand raised into hills and drifts by the wind. 
 
 Earth's Crust. The superficial parts of our planet which 
 are accessible to human observation. 
 
 Eocene. The strata deposited during the oldest of the ter- 
 tiary epochs, as, for example, the Paris Basin. 
 
 Estuaries. Inlets of the sea into the land. The tides and 
 fresh water streams mingle and flow into them. They in- 
 clude not only the portion of the sea adjacent to the mouths 
 of rivers, but extend to the limit of tide water on these streams. 
 
 Exuvia. In Geology, fossil remains. 
 
 Fault. A dislocation of strata, at which the layers on one 
 side of a dyke or fissure have slidden past the corresponding 
 ones on the other. These dislocations are often accompanied 
 by a dyke. They vary from a few lines to several hundred 
 feet. 
 
 Feldspar. One of the simple minerals, and, next to quartz, 
 one of the most abundant in nature. 
 
 Ferruginous. Containing iron. 
 
 Fluviatile. Belonging to a river. 
 
 Formation. A group of rocks which were formed during 
 a particular period, or which are referred to a common origin. 
 
 Fossils. The remains of animals and plants found buried 
 in the earth, or enclosed in rocks. Some of these are but 
 slightly changed, others are petrified and the organic replaced 
 by mineral matter ; some have decayed and left the impres- 
 
GLOSSARY 261 
 
 sion of the bodies, while others have been formed by mineral 
 matter deposited in the cavities left by the decay of the or- 
 ganic body. These last are called casts. The term petrifac- 
 tion is applied to those cases in which organic matter has 
 been replaced by mineral substances. The form and struc- 
 ture of the original body both remain. In casts the exterior 
 form alone is preserved. Fossils are also called organic re- 
 mains. 
 
 Fossiliferous. Containing organic remains. 
 
 Galena. An ore of lead composed of lead and sulphur. 
 
 Garnet. A simple mineral, which is usually red and crys- 
 tallised. It is abundant in most primitive rocks. 
 
 Gneiss. A stratified primary rock, composed of the same 
 materials as granite, but the mica is distributed in parallel 
 layers, which give it a striped aspect. 
 
 Geology. A science which has for its object to investigate 
 the structure of the earth, the materials of which it is com- 
 posed, the manner in which these are arranged, with regard 
 to each other ; and it considers the action of all natural causes 
 in producing changes, such as the effects of frost, rain, floods, 
 tides, currents, winds, earthquakes and volcanos. 
 
 Economical Geology refers to the applications of geological 
 facts and observations to the useful purposes of civilized life. 
 
 Granite. An unstratified rock, composed generally of 
 quartz, feldspar and mica, and it is usually associated with 
 the oldest of the stratified rocks. 
 
 Graywacke Grauwacke. A group of strata in the transi. 
 tion of rocks ; but the term has been so indefinitely applied, 
 that other names will probably be substituted. 
 
 Greenstone. A trap rock, composed of hornblend and feld. 
 spar, 
 
 Grit. A coarse-grained sandstone. 
 
 Gypsum. A mineral, composed of sulphuric acid and 
 lime, and extensively used as a stimulant manure, and for 
 making stucco and plaster casts, &c. It is also called Plas. 
 ter of Paris. 
 
 Hornblende. A mineral of a dark green or black colour, 
 and which is a constituent part of greenstone. 
 
 Hornstone. A siliceous mineral, approaching to flint in 
 its characters. 
 
262 GLOSSARY. 
 
 In Situ, In their original position where they were 
 formed. 
 
 Laminae. The thin layers into which strata are divided, 
 but to wiiich they are not always parallel. 
 
 Lacustrine. Belonging to a lake. Depositions formed in 
 ancient as well as modern lakes, are called lacustrine deposits. 
 
 Landslip. It is the removal of a portion of land down an 
 inclined surface. It is in consequence of the presence of 
 water beneath, which either washes away the support of the 
 superincumbent mass, or so saturates the materials that they 
 become a slippery paste. 
 
 Line of Bearing, is the direction of the intersection of the 
 planes of the strata with the plane of the horizon. 
 
 Lignite. Wood naturally carbonized and converted into a 
 kind of coal in the earth. 
 
 Littoral. Belonging to the shore. 
 
 Loam. A mixture of sand and clay. 
 
 Mural Escarpment. A Rocky cliff with a face nearly ver- 
 tical like a wall. 
 
 Mammillary. A surface studded with smooth small seg- 
 ments of spheres like the swell of the breasts. 
 
 Mammoth. An extinct species of the elephant. 
 
 Marl. By this term an argillaceous carbonate of lime is 
 usually implied. By custom, its signification is much more 
 extended, and means mineral substances, which act as stimu- 
 lating or fertilizing manures. There are clay marls, shell 
 marls, and various others. 
 
 Mastodon. A genus of extinct fossil animals allied to the 
 elephant. They are so called from the form of the grinders 
 which have their surfaces covered with conical mammillary 
 crests. 
 
 Matrix. The mineral mass in which a simple mineral is 
 imbeded, is called its matric or gangue. 
 
 Megatherium. A fossil extinct ; quadruped resembling a 
 gigantic sloth. 
 
 Mechanical origin Rocks of, Rocks composed of sand, peb- 
 bles or fragments, are so called, to distinguish them from 
 those of a uniform crystalline texture, which are of chemical 
 origin. 
 
 Mica. A simple mineral having a shining silvery surface, 
 
GLOSSARY. 263 
 
 and capable of being split into very thin elastic leaves or 
 scales. The brilliant scales in granite and gneiss are mica. 
 
 Mica Slate. One of the stratified rocks belonging to the 
 primary class. It is generally fissile, and is characterized by 
 being composed of mica and quartz, of which tho former 
 either predominates, or is disposed in layers, so that its flat 
 surfaces give it the appearance of predominating. 
 
 Miocene. Oae of the deposits of the tertiary epoch. It is 
 more recent than the eocene, and older than the plwcene. 
 
 Mollusca. Molluscous animals. " Animals, such as shell 
 fish, which, being devoid of bones, have soft bodies." 
 
 Mountain Limestone. " A series of limestone strata, of 
 which the geological position is immediately below the coal 
 measures, and witli which they also sometimes alternate." 
 
 Muriate of Soda. Common Salt. 
 
 Naphtha. A fluid volatile inflammable mineral, which is 
 common in volcanic districts, and in the vicinity of the Salt 
 Springs of the United States. 
 
 New Red Sand-stone. " A series of sandy and argillaceous, 
 and often calcareous strata, the prevailing colour of which is 
 brick red, but containing portions which are greenish grey. 
 These occur often in spots and stripes, so that the series has 
 sometimes been called, the variegated sandstone. The Euro- 
 pean, so called, lies in a geological position immediately above 
 the coal measures." 
 
 Nodule. A rounded, irregular shaped lump or mass. 
 
 Old Red Sand-stone. " A stratified rock, belonging to 
 the carboniferous group of Europe." 
 
 Oolite. " A lime-stone, so named, because it is composed 
 of rounded particles like the roe or eggs of fish. The name 
 is also applied to a large group of strata characterized by pe- 
 culiar fossils." 
 
 Organic Remains. Se ) Fossils. 
 
 Orthoceratite. The remains of an extinct genus of mol- 
 luscous animals, called Cephalopoda. The orthoceratites are 
 long, straight, conical chambered shells. 
 
 Out-crop. See Crop-out. 
 
 Out-liers. Hills or ranges of rock strata, occurring at 
 some distance from the general mass of the formations to 
 which they belong. Many of these have been caused by do* 
 
264 GLOSSARY. 
 
 nudation, having removed parts of the strata which once con. 
 nectcd the out-liers with the main mass of the formation. 
 
 Oxide. A combination of oxygen with another body. The 
 term is usually limited to such combinations as do not present 
 active acid or alkiline properties. 
 
 Palaeontology. A science which treats of fossil remains. 
 
 Pisolite. A calcareous mineral, composed of rounded con- 
 cretions like peas. 
 
 Pliocene. The upper, or more recent tertiary strata. This 
 group of strata is divided into the older and newer pliocene 
 rocks. 
 
 Petroleum. A liquid mineral pitch. It is common in the 
 region of salt springs in the United States. 
 
 Porphyry. A term applied to every species of unstratified 
 rock, in which detached crystals of feldspar are diffused 
 through a compact base of other mineral composition. 
 
 Productus. An extinct genus of fossil bivalve shells. 
 
 Plastic Clay. One of the beds of the Eocene period. The 
 plastic clay formation is mostly composed of sands with asso- 
 ciate beds of clay. 
 
 Pudding Stone. See Conglomerate. 
 
 Pyrites. A mineral, composed of sulphur and iron. It is 
 usually of a brass yellow, brilliant, often crystallized and fre- 
 quently mistaken for gold. 
 
 Quartz. A simple mineral, composed of silex. Rock 
 crystal is an example of this mineral. 
 
 Rock. All mineral beds, whether of sand, clay, or firmly 
 aggregated masses, are called rocks. 
 
 Sand-stone. A rock composed of aggregated grains of 
 sand. 
 
 Saurians. Animals belonging to the lizard tribe. 
 
 Schist. Slate. 
 
 Seams. "Thin layers which separate strata of greater 
 magnitude." 
 
 Secondary Strata. " An extensive series of the stratified 
 rocks, which compose the crust of the globe, with certain 
 characters in common, which distinguish them from another 
 series below them, called primary, and another above them, 
 called tertiary." 
 
 Sedimentary Rocks Are those which have been formed 
 
GLOSSARY. 265 
 
 6y their materials having been thrown down from a state of 
 suspension or solution in water. 
 
 Selenite. Crystalized gypsum. 
 
 Septaria. Flattened balls of stone, which have been more 
 or less cracked in different directions, and cemented together 
 by mineral matter which fills the fissures. 
 
 Serpentine. A rock composed principally of hydrated sili- 
 cate of magnesia. It is generally an unstratified rock. 
 
 Shale. An indurated slaty clay, which is very fissile. 
 
 Shell Marl Fresh water Shell Marl. A deposit of fresh 
 water shells, which have disintegrated into a grey or white 
 . pulverulent mass. 
 
 Shingle. The loose, water-worn gravel and pebbles on 
 shores and coasts. 
 
 Silex. The name of one of the pure earths which is the 
 base of flint, quartz, and most sands and sand-stones. 
 
 Silt. " The more comminuted sand, clay and earth, which 
 is transported by running water." 
 
 Simple Minerals Are composed of a single mineral sub- 
 stance. Rocks are generally aggregates of several simple 
 minerals cemented together. 
 
 Slate. A rock dividing into thin layers. 
 
 Stalactite. Concreted carbonate of lime, hanging from the 
 roofs of caves, and like icicles in form. 
 
 Stalagmites. Crusts and irregular shaped masses of con- 
 creted carbonate of lime, formed on the floors of caves, by 
 deposits from the dripping of water. 
 
 Stratification. An arrangement of rocks in strata. 
 
 Strata. Layers of rock parallel to each other. 
 
 Stratum. A layer of rocks ; one of the strata. 
 
 Strike. The direction in which the edges of strata crop 
 out. It is synonimous with line of bearing. 
 
 Syenite and Sienite. A granite rock, in which hornblende 
 replaces the mica. 
 
 Synclinal line and Synclinal axis. When the strata dip 
 downward in opposite directions, like the sides of a gutter. 
 
 Talus. In geology, a sloping heap of broken rocks and 
 stones at the foot of many cliffs. 
 
 Tertiary Strata. " A series of sedimentary rocks, with 
 characters which distinguish them from two other great series 
 23 
 
266 GLOSSARY. 
 
 of strata the secondary and primary which lie beneath 
 them." 
 
 Testacea. " Molluscous animals, having a shelly cover- 
 ing." 
 
 Tepid. Warm. 
 
 Thermal. Hot. 
 
 Thin out. Strata which diminish in thickness until they 
 disappear, are said to thin out. 
 
 Trap Trappean Rocks. Ancient volcanic rocks, com- 
 posed of feldspar, hornblende and augite. Basalt, greenstone, 
 amygdaloid and dolerite, are trap rocks. 
 
 Travertin. " A concretionary lime-stone, hard and semi- 
 crystalline, deposited from the water of springs." 
 
 Tufa Calcareous. " A porous rock, deposited by calca- 
 reous waters on exposure to air, and usually containing por- 
 tions of plants and other organic substances incrusted with 
 carbonate of lime." 
 
 Tufaceous. A texture of rock like that of tuff. 
 
 Tuff or Tufa. "An Italian name for a volcanic rock oi 
 an earthy texture." 
 
 Unconformable. See conformable. 
 
 Veins. Cracks and fissures in rocks filled with stony or 
 metallic matter. Most of the ores are abtained from metal- 
 lic veins. 
 
 Zoophytes. Coral sponges and other aquatic animals allied 
 to them. 
 
INDEX. 
 
 A. 
 
 Acicular crystals, 
 Acid, definition of, 
 
 carbonic, 
 
 sulphuric, . 
 
 sulphurous, 
 
 JElna, Mount, 
 
 lava of a single eruption, 
 
 once submarine, 
 
 volcanic sand of, 
 Air, 
 Agate, 
 Agricola, 
 Agriculture, 
 Alcyonia, 
 
 Alessandro degli Alessandri, 
 Alluvion, 
 Antimony, 
 Arsenic, 
 
 Atmosphere, ~, . " 
 
 Amber, , # . .. 
 
 Amygdaloid, " , * . 
 
 Anthracite, " ; .. V 
 
 Antioch destroyed, , , 
 
 Aristotle, ' ' * 
 
 Argillaceous odour, ^ 
 
 " slate, 
 
 Augite, 
 Avicemva, 
 Axis of the earth, change of, 
 
 
 66 
 
 
 49 
 
 
 50 
 
 
 49 
 
 
 49 
 
 
 188 
 
 
 183 
 
 
 190 
 
 
 183 
 
 
 49 
 
 
 52 
 
 
 247 
 
 
 213 
 
 
 124 
 
 
 246 
 
 87, 
 
 149, 217 
 
 
 57 
 
 
 56 
 
 
 55 
 
 
 113 
 
 
 163 
 
 
 113 
 
 
 176 
 
 
 244 
 
 
 72 
 
 
 98 
 
 
 66 
 
 
 246 
 
 
 19,247 
 
268 INDEX 
 
 B. 
 
 Bakewcll, ..... 252 
 
 Barium, ..... W'lS 
 
 Basalt, ..... 163,164 
 
 columnar, .... 164, 169 
 
 artificial formation of, . ' ; 
 
 globular, 
 
 tabular, ..... J*} 
 
 used for making glass bottles, . . Io4 
 
 Basin, chalk, . .; : f l * 
 
 Beaches ancient, . ~^ 
 
 Beds, definition of, . -'.., \' 
 
 Biggsby, . ^ < 27,154 
 
 Big bone lick, . , >, Jg 
 
 Birds, fossil, . 130>1 ?a 
 
 Bismuth, ' inft 
 Bituminous coal, . 
 
 sVialp ** 
 
 snaie, t 
 
 Black coal, ..... 1 ^ 
 
 " lead ' ' ' ' $'" ' 14 
 
 Bones of animals in diluvial gravel, ^ . - 14- 
 
 land animals, . jjj 
 animals gnawed, _. , ^^i s 
 
 man, . , | , g 
 
 saurian animals, . -. ,. "~ 
 
 Bone caves and Breccias, "V * * \. * 
 
 _. 5b 
 
 Boron, > k ' , . * - iqQ 
 
 Bromine, , .' 
 
 Brongniarts, ,-,- 
 Buckland, . . r . . 
 
 BufTon, , . 
 
 Building stones, how to select, 
 Burnett, , V r * . 
 
 Cadmium, 
 
INDEX. 269 
 
 Calcareous spar, .... 69 
 
 Calcium, . . . 48,49 
 
 Caloric, definition of, . . . .19 
 
 Canals, 234 
 
 Caraccas, ..... 177 
 
 Carbon, ..... 
 
 Carbonate of lime, .... 69 
 
 Carbonic acid, . . . .50 
 
 Cardona, salt mountain, . . . 117 
 
 Caves, bone, .... 145 
 
 Caverns in mountain limestone, . . .102 
 
 Cement, hydraulic, .... 122 
 
 Cerium, ..... 59 
 
 Chalk, formation, .... 126 
 
 Chalmers on geology, .... 39 
 
 Chili, coast of raised, * 176 
 
 Chlorine, . . . . .51 
 
 Chlorite, . . . . ' . 67 
 
 Chloritic granite, . . . .91 
 
 " slate, ..... 95 
 
 Chrome iron, . . ... . 71 
 
 " yellow, .... 
 
 Chromium, . . .57 
 
 Cist, 252 
 
 Classification of rocks, .... 
 
 " of Conybeare and Phillips, . 88 
 
 " of De La Beche, 
 
 Clay, composition of, ... 62 
 
 " description of, . . . Jl 
 
 " iron stone, . . . .105 
 
 " slate, ..... 98 
 
 Cleaveland, ..... 252 
 
 Clinkstone, .... 163, 164 
 
 Coal, 112 
 
 * anthracite, ..... 
 
 * bituminous, . . . .112 
 caking, ..... 112 
 charcoal, ..... 52 
 field, .... 108,109 
 " origin of, 109 
 
 23* 
 
270 INDEX. 
 
 Coal measures, ..... 105 
 
 mines, . . . . . 109 
 
 " explosion of, . . .178 
 
 of Pennsylvania, . . . .112 
 
 searching for, . . . .111 
 
 sea, 112 
 
 Tioga, :.. .. . . . 112 
 
 Virginia, .- * . . . 11% 
 
 Cobalt, . . ;.;''/ ... 58 
 
 Coccolite, ; : ' - . '- .* . . * 66 
 
 Columbium, . . . .57 
 
 Columnar structure, ,f . . . 166 
 
 trap, . : ; V- . . 169 
 
 Combination of bodies, . . 4& 
 
 Compact, definition of, *' . V . . 1? 
 
 feldspar, .- % - ' . . 92 
 
 " limestone, . , . ' "~ /' . 121 
 
 Conglomerate, . . . L . . 116 
 
 Contorted rocks, . . . .95 
 
 " stratification, ' . . r 77, 80 
 
 Conybeare, . '; Y " . .' -" . 252 
 
 Copper, ' ( . . 59 
 
 Coral rocks, . | . f .:-.-.* 124, 15!* 
 
 Cornelian, ' . . '"" 5S 
 Crust of the globe, 
 
 " comparison with the mass of the globe, . ./ 22 
 
 Crater of volcanos, '-'.., . . . 180 
 
 Crystal, . . * V '' . ^ , '^ 6S 
 
 Crystalline, . ;, . >v . "'." 18 
 
 Crystalline limestone, . - *"'.' 96 
 
 Cuvier, . . . . . .i r 252 
 
 D. 
 
 Day, interpretation of, , 31,38 
 
 De La Beche, . . . ^ . 25Q 
 
 De La Heche's classification of rocks, . 8b 
 
 Delta, . ll* 
 
 DeLuc, . . ;" . . 2&1? 
 
 De Maillet, ... .24? 
 
INDEX. 271 
 
 Density, mean of the earth, ... 18 
 
 Diamond, ..... 52 
 
 Diluvion, . ^ . .87 
 
 " description of, . . . .135 
 
 " distinguished from alluvion, . 136, 150 
 
 Dip, 75 
 
 " calculation of, .... 78 
 
 " line of, .... 75 
 
 " apparent, apt to be mistaken for the true, 
 
 Dislocation of strata, . . . 82, 165 
 
 Disseminated, . . . . .17 
 
 Douglass, ..... 249 
 
 Drainage of soils, . . 215, 219, 222, 225 
 
 Drowning, ..... 50 
 
 Dyke, .... 82, 170 
 
 " definition of and description, . . 164 
 
 Dykes of Carolina, . . . .166 
 
 " on the banks of rivers, . '. . 155 
 
 " of trap, . . . . .164 
 
 " " effects of on rocks, . . 166 
 
 E. 
 
 Earth, what made of, . >; . . 15 
 
 Earthquakes, . . . . .172 
 
 " Antioch destroyed by, . . 176 
 
 " of Caraccas, . . . 177 
 
 " causes of, . . . JL77 
 
 " coast of Chili raised by, . . 176 
 
 " Euphemia destroyed by, . . 173 
 
 " extent of effects, . . .174 
 
 " frequent at particular times . 175 
 
 " of Lisbon, . . 174,176 
 
 " of the Mississippi, . . . 177 
 
 '* most common in volcanic districts, 172, 175 
 
 " oscillations of the ground, . . 178 
 
 " Temple of Serapis sunk and raised, 1,77 
 
 Earths, ..... 53 
 
 " alkaline, . . . . .53 
 
 Earthy fracture, . . . .71 
 
272 
 
 INDEX. 
 
 East Rock of New Haven, 
 
 Eaton, Professor, 
 
 Ebel, 
 
 Ecliptic, obliquity of, 
 
 Elastic bodies, 
 
 Electrified bodies, 
 
 Elementary bodies, 
 
 Elevation of continents, 
 
 Elevated beds, 
 
 Elie de Beaumont, 
 
 Encrinites, 
 
 Encrinal limestone, 
 
 E peris, salt mine of, 
 
 Epochs, 
 
 Erratic blocks, 
 
 Eurite, . I* 
 
 F. 
 
 Fault, '" . V : 
 
 Feldspar, . / ,, 
 
 " description of> 
 " compact, * 
 
 Ferns, impressions of, . , 
 
 Firestone, 
 Fissile, 
 Flint, 
 
 " composition of, 
 
 Fluorine, 
 
 Fluoric acid, i 
 
 Fluor spar, '....'. - 
 
 Forest, petrified, 
 Formations, I 
 
 Fossil birds, . A & 
 
 " fish, 
 Fossils abound in some rocks, 
 
 " at great depths, . 
 
 defined, ' . 
 
 " different genera in different rocks, 
 
 " monuments of changes, 
 
INDEX. 273 
 
 Fossils of salt licks, . . . ^ 119 
 
 Fracastero, ... . 246 
 
 Fracture, ..... 71 
 
 Free atones, . . . . .105 
 
 Fox, 252 
 
 Fuchsell, ..... 249 
 
 G. 
 
 Ganges, ..... 151, 155 
 
 Garnet, ...... 95 
 
 " in volcanic rocks, . . .192 
 
 Gaseous, ..... 50 
 
 Geography, . . . . .13 
 
 Geologists, European, ''.'-: . . . 252 
 
 French, .... 252 
 
 German, . 252 
 
 " American, .... 252 
 
 Geology, . . . . 14, 31 
 
 " agrees with the Mosaic account, . 31 
 
 " consistency of with the Bible, . 33, 38 
 
 " foundation of, s . . . . 25 
 
 " history of, . . . . 244 
 
 Geological alphabet, . ,' . 16,62 
 
 " equivalents, , . * . 85 
 
 maps, v 219, 224, 230, 234, 249 
 
 Geysers, .';. .' . ,.-. . 182 
 
 Glass, ;* V . . . 52 
 
 Glacier, fall of, . , . . 152, 153 
 
 Glucinum, - *-* 58 
 
 Gneiss rock, ^ . . ' , -. , . 93, 94 
 
 Gneissoid, hornblende, ^ . . 94 
 
 Gold, . V . . . 60 
 
 Granite, . < ..- , + ^ ^ . 90 
 
 " porphyritic, , * . . 91 
 
 * graphic, .... 93 
 
 protogine, . . . . 91 
 
 " sienitic, ..... 91 
 
 veins, . . ... .92 
 
 Granular structure, , . . . 17 
 
274 
 
 INDEX. 
 
 Greenough, 
 Greenstone, 
 Graywacke, 
 
 Grindstones, 
 Ground, swell, 
 Guettard, 
 Gypsum described, 
 
 H. 
 
 Hall's experiment on basalt, 
 
 " limestone, 
 
 Hayden, . . . 
 
 Heat, . ; .J fe... 
 
 Herculaneum, . '/'' 
 Herschell's views of geology, 
 Himmalaya mountains, 
 Hitchcock, .. ; 
 
 Hollo way, 
 
 Hooke, -.;, 
 
 Hornblende, ; ; . + . 
 " rock, ' 
 
 " slate, . 
 
 Hornstone, ! - 4 * 
 
 Human bones, . * 
 
 Hutton, | '*'.-"'. 
 
 Huttonian theory, s 
 
 Hydraulic cement, * 
 
 Hydrogen, . r >' 
 
 I. 
 
 Icebergs, ,;. ^ . 
 
 Iguanodon, . - 
 
 Inclined strata, 
 Independent coal formation, 
 Inferior rocks, . . 
 
 Insects imbedded in amber, 
 Iodine, . .' ' f * 
 
INDEX. 
 
 275 
 
 Iridium, 
 Iron, cast, 
 
 ores, 
 
 " in volcanic rocks, 
 generally diffused 
 pyrites, 
 
 James, Dr., 
 
 Jasper, 
 
 Jet, a kind of wood coal, 
 
 Jorullo, volcano of, 
 
 Kaolin, or porcelain clay, 
 Kefferstein, 
 
 J. 
 
 K. 
 
 L. 
 
 Lake Huron, 
 
 retreat of, 
 Laminar, 
 Lava, 
 
 " quantities erupted, 
 Lead, 
 
 " ores, 
 Lehman, 
 Lias limestone, 
 
 " clay, 
 
 Light, evidence of, in ancient times of the earth, 
 Lignite, a kind of wood coal, 
 Lime, its uses on soils, 
 Limestone described, ^ 
 
 " encrinal, 
 " how distinguished, 
 magnesian, 
 ** metalliferous, 
 " mountain, 
 
 61 
 
 52 
 
 53, 105 
 
 192 
 53 
 
 192 
 
 25S 
 
 52 
 
 113 
 
 176 
 
 93 
 252 
 
 27 
 
 27 
 
 64 
 183 
 184 
 
 59 
 
 17, 102 
 
 25, 249 
 
 121 
 
 121 
 
 44 
 
 112, 113 
 227 
 
 69 
 102 
 
 70 
 115 
 102 
 108 
 
276 INDEX. 
 
 Limestone transition, . . . .101 
 
 '* caves in, . . . .103 
 
 " springs in, . . . .103 
 
 Liquidity of earth, .... 18 
 
 Llwydd, 248 
 
 Lister, ..... 248 
 
 Lithium, . . ' ^ . v . . 57 
 
 Lithography, . & . ''" ; , '; 121 
 
 London chalk basin, , A . * , . ' 132 
 
 Lunar irregularities .'./ '*.-'-. . ..,' < 20 
 
 M. 
 
 Maclure, American geologist, , . ' M * . 253 
 
 Madrepores, . . . ^ . . 124 
 
 Magnesia, composition of, , - V ';, ; ;l 49 
 
 '* injurious to vegetation, . . 115 
 
 Magnesian limestone, . . . .115 
 
 Magnesium. . . 49 
 
 Man, latest tenant of globe, . ~\ " 32 
 
 Manganese, . v . . . . ' 58 
 
 Maps, geological, . . 219, 224, 230, 234, 249 
 
 Marbles, . . , ,- f,, ,, **" * " 70 
 
 " white, . . t . ' .' :. St ^. 96 
 
 " variegated, * "' , 104 
 
 " verd antique, . . . *, 71 
 
 " " of New Haven, .\ ; 96 
 
 Marine and fresh water remains, . . 132 
 
 Marl, . . . .' , 70,227 
 
 Massive, . ** .. . 63,67 
 
 Mastodon, ., . V , ,' . ' 119 
 
 " extinct, . . . .119 
 
 McCulloch, , ^ , .^ . ,, 252 
 
 Mean density of the earth, . , F ,-. . 
 
 Medial rocks, ? ; > ( . :. ,. - 
 
 Megalosaurus, , * -'-.(. ^27 
 
 Mercury, . -^ t ; ^ 
 
 Metals, . ;-.'. . :^;v l *,* 
 
 ' earthy and alkaline, . . . . 206 
 
 Metalliferous limestone, . . & **- ^^ 
 
INDEX. 
 
 277 
 
 Mica, description of, 
 
 " slate, 
 Millepores, 
 Mineral, definition of, 
 Minerals associated, 
 
 " composed of, 
 
 " number of, 
 Mining, 
 Mississippi, . 
 
 " delta of, 
 
 " earthquakes of, 
 Mitchell, 
 
 Molybdenum . . 
 
 Monte Bolca, .^ 
 
 Morton, Dr., American geologist, 
 Mosaic account of the creation, 
 Mountain limestone, 
 Mount Holyoke, 
 Moving power of water, 
 Moya, 
 
 Murchinson, ,*" . ^P 
 
 Muscovy glass or mica, .. ,* 
 
 Newcastle coal mines, 
 
 New Haven marble, 
 
 Nickel, 
 
 Nitrogen, , 
 
 Objects of geology, 
 Ocean, mean depth of, 
 
 N. 
 
 O. 
 
 and land have chang d their 
 
 Oil contains carbon, 
 
 " of vitriol, 
 Olivine, 
 Olmsted, 
 Oolitic rocks, 
 
 relative levels, 
 
 64 
 
 94 
 
 124 
 
 16 
 
 17 
 
 48 
 
 48 
 
 238 
 
 151, 155 
 
 151, 155 
 
 177 
 
 249 
 
 57 
 
 134 
 
 127, 252 
 
 31 
 
 101 
 
 164 
 
 156 
 
 181 
 
 252 
 
 65 
 
 109 
 96 
 58 
 
 55 
 
 15 
 51 
 
 26 
 52 
 
 49,53 
 192 
 252 
 123 
 
 24 
 
278 
 
 INDEX. 
 
 Oolitic rocks, organic remains of, 
 Opake, definition of, 
 Ores of copper and lead, 
 
 iron, 
 
 clay iron stone, 
 
 in transition rocks, 
 
 of lead and silver, 
 
 in volcanic rocks, 
 Organic remains defined, 
 Osmium, . ', 
 
 Outcrop of strata, ' , , 
 
 Ovid, .*, 
 
 Owen, . Hf ., 
 
 Oxides, definition of, * , 
 
 Oxygen, > *?, . 
 
 P. 
 
 Packe, 
 
 Palisades of the Hudson, 
 
 Pallas, 
 
 Parkinson, <,;"' 
 
 Paris chalk basin, 
 
 Peat bogs, 
 
 " origin of, 
 
 " uses and qualities 
 
 Petrifactions, 
 
 Petrified forest, 
 
 Phenomena, indicating cent al heat 
 
 Phillips, 
 
 Phosphorus, . 
 
 Pitchstone, . 
 
 Platinum, 
 
 Pliny, _> 
 
 Plumbago, 
 
 Polygon, 
 
 Pompeii, destruction of, 
 
 Porcelain clay, * . : 
 
 Porphyritic structure, 
 
 Porphyry, 
 
INDEX. 
 
 279 
 
 Porphyry of Andes and Cordilleras, . 164, 192 
 
 Potassa, composition of, ... 49 
 
 Potassium, ..... 49 
 
 Primitive forms of crystals, ... 69 
 
 " limestone, ... 96 
 
 " rocks, . . 26, 89 
 
 Prism, . . . . .169 
 
 Protogine, . . . . .91 
 
 Padding stone, ..... 100 
 Pumice, ..... 193 
 
 Pussey, Professor, on interpretation, . . 42 
 
 Q. 
 
 Quartz, composition of, . . 52, 62 
 
 " constituents of rocks, ... 63 
 
 " description of, ... 62 
 
 " rock, . . 97 
 
 R. 
 
 Radiant heat of earth, .... 20 
 
 Rag coral, ..... 124 
 
 Rapidity of motion in earthquakes, . . 20 
 
 Raumer, ..... 253 
 
 Ray, . ; . / . . 248 
 
 Recapitulation of geological facts, . . 194 
 
 Red marl, \ . . . .115 
 
 " sandstone, . . . 100, 115 
 
 new, . . 100, 115 
 
 old, .. - . . 100 
 
 Reeds, impressions of in shale, . .110 
 
 Refraction, . . ' . . . 69 
 
 " double, V . .70 
 
 Rhodium, . ... . . . 61 
 
 Rhomboid, . , ... 69 
 
 Rivers engulphed, .... 103 
 
 " elevate their beds in some places, . 155 
 
 Roads, expense of construction, . . 229 
 
 " cuttings of, . . . 230,232 
 
'280 
 
 INDEX. 
 
 Roads, drainage of, .... 230 
 
 durability of, .... 232 
 
 macadamized, .... 230 
 
 materials for, 231 
 
 planned, .*! . . . . 230 
 
 stoning of, *.' . . ' . . . 230 
 
 in stratified rocks, jfl ^*V . 230 
 
 Rock crystal, . '*"' V ' ' * ' 52 
 
 " salt, . ' v *>;: 116,118,120 
 
 Rocks, definition of, . . t, . 16,17 
 
 " have the same relative situations, , . . / 72 
 
 Roe stone, or oolite, . . . . 123 
 
 Roof slate, . V ' . J .' " . * ! 98 
 
 s. 
 
 Safety lamp, . . V L* 178 
 
 Salammoniac, a volcanic product, ,..' 193 
 
 Salt, composition of, . 51 
 
 in the ocean, . <i . , 51 
 
 lakes, . . . . 117 
 
 licks, . . >. , .. 119 
 
 " big bone lickj . . 119 
 
 mines, . .^,, .,, ,*-,, 117,118 
 
 reservoir of, . ' ' ' '"' "; 121 
 
 rock, ' "'' . . 116,118 
 
 springs, . ;? . , , .. _ _, % . 118 
 
 " origin of, ,'^ tr -;' J . 119 
 
 Sand, composition of, *. . 52 
 
 " drifting of, . . 157 
 
 Sandstone, . . *^ 100, 105, 115, 128 
 
 " old red, . 100 
 
 " new red, . "** H . . 115 
 
 Saurian animals, . 116, 122, 125, 127 
 
 Saussure, . -. . . 252 
 
 Screw stones, or encrinites, . . 102 
 
 Secondary rocks, . ( + , ' . 26 
 
 " described, , : > s ' 104 
 
 Sedgwick, Professor, . V-V 252 
 
 Selenium, . *^ ' * " , ' 56 
 
. NDEX. 281 
 
 Serpentine described, . . . .71 
 
 rock, ... 96 
 
 * with limestone, forms a rare and valuable 
 
 marble, . . . 71, 96 
 
 Shale, . .... 105 
 
 " distinguished from slate, ... 98 
 
 " bituminous, .... 135 
 
 " contains impressions of plants . . 105 
 
 fish, . . 135 
 
 Shells of the tertiary, . . . 131, 132, 133 
 
 Shoals, 159 
 
 Sienite, 91 
 
 Sienitic greenstone, . . . .164 
 
 Silex, or silica, . . , 48, 52 
 
 Silicon, ..... 52 
 
 Silliman, Professor, . . . 206, 252 
 
 Silver, . ... . .60 
 
 Simple or elementary bodies, . - . 48, 54 
 
 Sink holes in limestone, .... 103 
 
 Skapta Jokul, of Iceland, . . 184, 188 
 
 " lava currents of, . . .184 
 
 Tjlate, description of, ... 71, 98 
 
 " alum, . . . .123 
 
 " argillaceous, .... 98 
 
 * 4 clay, or shale, "'.. . 105 
 
 " composition of, .71 
 
 " graywacke, ', . . . 99 
 
 " roof, > *. . . . 99 
 
 " stratification of, .... . 99 
 
 Slaty structure, . . . . ' 18 
 
 Smith, William, English geologist, . . 252 
 
 Soda and sodium, .... 49 
 
 Soils, alluvial, V" * ; ~ 223 
 
 " argillaceous, t V . . 214 
 
 " composition of, .' . . 214, 226 
 
 " drainage of, # ; . 215, 219, 222 
 
 " formation of, .... 213 
 
 " improvement of, . . 215, 220, 226 
 
 " light, . . . .216 
 
 permanency of, . . . .217 
 
 24* 
 
282 
 
 INDEX. 
 
 Soils, stimulants for, . . . .216 
 
 " substratum of, ... 215, 220 
 
 " texture of, . . . 214,218 
 
 " varieties of, . . . .214 
 
 Specific gravity, . ' . 18 
 
 Sponges, fossil, : ' ? 124 
 
 Spongiform, . >. .vV"' . . 63 
 
 Springs, boiling, of Iceland, . . . 182 
 
 " " of Arkansas, . & . , * 182 
 
 " and streams from limestone, . < . 103 
 
 Stalactical, . '-.. . , , ^ 63 
 
 Stalactites, . .' %/ . V. . 148 
 
 Staurotide in mica slate, '. . . 95 
 
 Steel, composition of, f . , . 52 
 
 Strabo, ''\ ;.' , ' > ' * . 244 
 
 Strachey, . ; . . . 248 
 
 Strata, . . . ; ;v . 26, 27 
 
 " not always level, . . , <! *V 73 
 
 Stratification, .... 72 
 
 " conformable, ... 76 
 
 " unconformable, , . * ; 76 
 
 " contorted, . . .^ % 77 
 
 " of slate, ' . . . 76 
 
 " of gneiss, ,;,?*,, k 'I'* ; - 94 
 
 Strontium, , ' ..;*' . 58 
 
 Structure, columnar, . 162, 166, 169 
 
 " compact, ... 17 
 
 " crystalline, . , ;'*-' 18 
 
 " granular, . . ' i; - 18 
 
 " porphyritic, . y^ -i 91 
 
 " slaty, . v ;.;Yv f\w t 18 
 
 St. Vincens, eruption of, * ' ' t ',' . 177 
 
 Sulphur, . . . :,-iifr 53 
 
 " in volcanos, .?<, ; * 193 
 
 Sulphuric acid, . ';. * 49 
 
 Sulphurous acid, . > - * t &;v ;*?-:>. 49 
 
 Sumbawa, eruption in, . \* , v . 184 
 
 Superior rocks, . !.,*.. ^gj? 88 
 
 Supermedial rocks, ... 88 
 
 Swallow holes, > w w,; 103 
 
INDEX. 283 
 
 T. 
 
 Talc described, . . 67 
 
 Talcose slate, . . 95 
 
 " granite, . 91 
 
 Taylor, . . 252 
 
 Tellurium, . . 57 
 
 Temperature of the earth . 19 
 
 " of interior of the earth explained, 21 
 
 " increases with the depth, . 21 
 
 " variable near the surface, . 21 
 
 Teneriffe, peak of, . . . 191 
 
 Tertiary rocks, . , 86, 128 
 
 confounded with alluvial, . 129 
 
 rarely intersected by dykes, . 132 
 
 fossils, mammalia, . . " 130 
 
 fossil shells, ... .131 
 
 fossil birds, fish, and animals, 130, 134 
 
 Testaceous animals, . .102 
 
 Thales, 
 
 Theories, geological, 
 
 Huttonian theory 
 " Wernerian theory 
 Thorium, 
 
 Tides of the Amazon, 
 Nova Scotia, 
 
 244 
 199 
 
 199, 203 
 
 199, 200 
 
 58 
 
 140 
 
 141 
 
 " the bay of Fundy, . . 141 
 
 " transporting power of, . ,156 
 
 Time required to produce changes on the ear h's surface, 30 
 
 Tin ores, . . . 17,59,93 
 
 Titanium, ... .57 
 
 Topaz associated with tin, . ,17 
 
 Torrents, * . . 150, 156 
 
 Trachyte, .'. . ~ 142, 193 
 
 Transition rocks, , . 86, 97 
 
 " " metalliferous, * 
 
 " limestone, 
 Trap rocks described, 
 
 " composition of, . 95, 162 
 
 * experiments on, . 167 
 
284 
 
 INDEX. 
 
 Trilobites, eyes of, 
 Tropical fossils, 
 Tuchsel, 
 Tungsten, 
 
 u. 
 
 Unconformable rocks, '.* ., , 
 " stratifications, 
 
 Upper secondary rocks, 
 Uranium, :*' *i ..u > 
 
 V. 
 
 Valleys, .^ 
 
 44 of denudation, 
 Vanadium, 
 Van Renseelaer, 
 Variegated sandstone, 
 Veins, 
 
 " metallic, .V 
 " walls, floor and roof of, 
 Velocity of rotation of earth 
 Verd antique marble, 
 
 " of New Haven, 
 
 Volcanic islands, formation of, 
 
 " often sink, 
 
 " rocks, 
 
 " " constituents of, 
 " mountains, conical, 
 " mountains sometimes engulfed, 
 Volcano, ^Etna, . 
 Jorullo, 
 Papandayang, 
 Peak of Teneriffe, 
 Pic, 
 
 Skapta Jokul, 
 Sumbawa, 
 Vesuvius, 
 [ description of, 
 
 45 
 
 19 
 
 249 
 
 57 
 
 162 
 76 
 
 114 
 57 
 
 27 
 
 29,81 
 57 
 253 
 115 
 86 
 247 
 17,86 
 19 
 71 
 96 
 188, 189 
 188, 189 
 162, 181, 192 
 192 
 180 
 190 
 
 176, 183 
 176 
 190 
 190 
 190 
 
 184; 188 
 184 
 
 181, 185 
 179 
 
INDEX. 
 
 285 
 
 Volcanos, fish from, 
 
 floods of ashes from, 
 long repose of, 
 often in groups, 
 submarine, 
 simultaneous action of, 
 
 Voltaire 
 
 w. 
 
 Wacke, . 
 
 Warmth variable below the surface, 
 
 Water, boring for, 
 
 " composition of, . , 
 
 Watt, Gregory, experiments of, 
 Waves, power of, . . 
 
 Webster, English geologist, , 
 
 " American geologist, 
 Welielska salt mine, . . 
 
 Wells ..... 
 Werner, , 
 
 Werner and Hutton compared, 
 Wernerian theory, . 
 
 West rock of New Haven, 
 
 Wheel whirls, . . . , 
 
 Whetstones, * * , 
 
 Whetstone slate, , , 
 
 Whiston, , 4' 4 
 
 Whitehurst, f 
 
 Wind, action of in transport, < 
 
 Wood contains carbon, . , 
 
 14 coal, . * . , 
 
 Woodward, ..'; , 
 
 Y. 
 
 Yellow-stone river, 
 Youth, influence of, 
 Yttrium, , 
 
 180 
 180 
 187 
 190 
 188 
 21 
 246 
 
 163 
 
 21 
 133 
 
 49 
 168 
 142 
 252 
 252 
 117 
 236 
 250 
 254 
 200 
 163 
 102 
 105 
 
 99 
 248 
 249 
 157 
 
 52 
 113 
 248 
 
 158 
 
 255 
 
 58 
 
286 INDEX. 
 
 Z. 
 
 Zeno, . . ..'.A. . 244 
 
 Zinc, , . . .. / 59 
 
 " ores, . . 17 
 
 Zirconium, . *. ^ J/ ^ 5g 
 

 
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