Elements of Geology; including fossil botany and palæontology. A popular treatise ... designed for the use of schools and general readers

Introduction

TO BOTANY, ELEMENTS OF CHEMISTRY, ELEMENTS OF MINERALOGY, A TREATISE ON PHYSICAL GEOGRAPHY, OUTLINES OF PHYSIOLOGY, AND NATURAL HISTORY OF BIRDS AND BEASTS. Zamia spiralia. NEW-YORK PUBLISHED BY PRATT, WOODFORD, AND CO 1847. Entered, according to Act of Congress, in the year 1847, By J. L. COM3TOCK, M. D. in the Clerk's Office of the District Court of Connecticut- STEREOTYPED BY PRINTED BY RICHARD H. HOBBS, CASE, TIFFANY, AND CO, HARTFORD, CONN. HARTFORD, CONN.

Preface

. When comparing the last stereotype impression of my "Outlines of Geology," published in 1834, with the most recent geological works of the present day, with the intention of reforming it into a new edition, I have found that such had been the progress of the science during the last few years, that a considerable portion ofthe work would require an entire change. Instead, therefore, of presenting my friends and the public, with a new edition, I herewith offer them a new book; and which, I cannot but think, contains much more interesting and important matter, than the old one did, even when it was new. The subjects of Fossil Botany and Animal Re mains, have received particular attention; these being not only the most popular and instructive branches of Geology, but those on which naturalists, both at home and abroad, have lately bestowed the most laborious and profound investigations.

Some of the old Lignographs, with their descriptions, on points where no improvements had been made, and also some of my speculations on the "Mosaic System of Botany," and on the "Days of Creation," have been retained. In other respects, the work is made of new matter, and has a new name.

PREFACE.

. With respect to the illustrations, the engravings were executed by Mr. Seth H. Clark, and stereotyped by Mr. R. H. Hobbs, both of this city; and I have much pleasure in believing that, in works of this description, our country can show no better specimens of either art. Hartford, (Conn.) March, 1847. AUTHORITIES. The following is a list of books which have been consulted, and most of them quoted in the progress of this work : De la Beche's Geological Manual. Ures' System of Geology, London. Bakewell's Geology. Macculloch's Geology, 2 vols., London. Penn's Comparative Estimate, 2 vols., London. Parkinson's Organic Remains, London. Buckland's Bridgewater Treatise. Buckland's Reliquiæ Diluvianæ. Mantell's Wonders of Geology, 2 vols., London. Mantell's Medals of Creation, 2 vols., London. Lyell's Principles of Geology, 3 vols. Lyell's Elements of Geology, 2 vols. Lyell's Travels in North America, 2 vols. Cuvier's Animal Kingdom, 5 vols. Cuvier's Ossemes Fossiles.

Cuvier's Revolutions of the Globe. Hitchcock's Report on the Geology of Massachusetts. Brande's Outlines of Geology. Mawes' Conchology, London. Richardson's Geology, London. United States Exploring Expedition, 5 vols. Conybeare and Phillips' Geology, London. Various Geological Reports. Silliman's Journal. Edinburgh Philosophical Journal. 1* EXPLANATIONS. M. C. means Medals of Creation. Wond. " Wonders of Geology. Bd. " Buckland's Bridgewater Treatise Rd. " Richardson's Geology. Ly. P. " Lyell's Principles of Geology. Ly. E. " Lyell's Elements of Geology. Lign. " Lignograph, wood cut. Dr. Mantell's Works contain some of the most beautiful geological engravings, extant ; and to these I am chiefly in debted for the ornamental part of my book. LIST OF LIGNOGRAPHS. Lign. Pa-re. 1 Endogenous structure, 33 2 Endogenous leaf, . . 33 3 Exogenous wood ... 34 4 Exogenousseedandleaf,35 5 Coniferous structure, 36 6 Cycas structure, ... 38 7 Zamia spiralis, .... 38 8 Zamia leaf, 39 9 Section of fern, ... 41 10 Fossil fuci, 57 11 Hypnum.

Equisetum, 58 12 Equisetum Lyelli. Catamites radiata, ... 59 13 Calamites nodosus, . . 60 Leaves illustrating forms, 62 14 Thick fern 63 15 Round fern, 64 16 Toothed fern, .... 64 17 Anomalous fern, ... 65 18 Embroidered fern . . 66 19 Spear-leafed fern, . • 66 20 Laticed fern, .... 67 21 Fern stem, 68 22 Sigillaria 70 23 Stigmaria, 71 24 Scaly-tree, 72 25 Fossil seeds, 73 26 Exogenous leaves, . . 77 27 Infusoria 84 28 Infusoria, 86 29 Polythalamia, 88 30 Xanthidia, 89 31 Fossil corals, 93 32 Encrinites, 96 33 Galerites, 100 34 Barnacle. Cardium, . 106 Lign. Page. 35 Mya hinge. Cardium hinge, 107 36 Univalve. Spiral shell, 109 37 Patella. Pholas, . . 110 38 Mytilus. Scallop, . . Ill 39 Argonauta. Patella, 112 40 Dentalium. Cypræa, 113 41 Bulla. Voluta, ... 114 42 Buccinum. Strombus, 115 43 Murex.

Turbo, ... 116 44 Conus. Trochus, . 117 45 Helix. Nerita, ... 118 46 Terebratula 120 47 Spirifera. Trigonia. . 121 48 Teredo navalis, . . . 122 49 Fossil Gasteropoda, . 123 Paludina. Limnea, " Cerithium. Fusus, . " 50 Belemnites, .... 126 51 Fossil Ammonites . . 129 52 Fossil Trilobites, . . 130 53 Fossil fishes 133 54 Scales of fishes, . . 134 55 Scales of fishes, ... " 56 Sharks' teeth, .... 137 57 Winged-fish, .... * 138 58 Lizard's head, ... 139 59 Ichthyosaurus' head . 142 60 Ichthyosaurus' skeleton, 144 61 Plesiosaurus' skeleton, 145 62 Megalosaurus' tooth, 146 63 Pterodactylus, .... 148 64 Bird-tracks and Rain-drops, 154 65 Elephant's jaws, . . . 174 66 Elephant's head, . . LIST OF LIGNOGRAPHS. Lign. P*,S° 97 Intrusion of granite into limestone. . . 247 98 Porphyritic granite, . 248 99 Gneiss rock 253 100 Eruption of Vesuvius, 267 101 Obelisks of St. Bruno, 279 102 Radiated fissures, . . 281 103 Tunnel-shaped cavity, 282 104 Puzzuoli and ruins of Serapis, 287 105 Temple of Serapis, . 289 106 Tubular shells, .... 304 107 Pebbles in oblique strata, 305 108 Running water, . . . 311 109 Geysers of Iceland, . 329 110 Flustra.

Coral polypi, 345 111 Coral island, 349 112 Rocking-stone, East Lyme, 355 113 Coal strata, 361 114 Searching for coal, . 362 115 Metallic veins, ... 366 116 Metallic veins, .... 367 117 Theory of veins, . . 370 118 Common springs, . . 375 119 Artesian wells, . . . 377 120 Overflowing wells, . . " 121 Deep well at Hunter's hall, 379 122 Hydrostatic springs, 381 123 Human skeleton at Guadaloupe, .... 393 124 Impressions of human feet in sandstone, . 396 Lign. Page. 67 Mastodon's grinder, . 180 Mastodon Maximus, 181 68 Hippopotamus' tooth, 186 69 Skeleton of Megatherium, 187 70 Gaylenreuth cavern, 193 71 Hvpogene rocks, • . • 204 72 Strata in Ohio, ... 206 73 Horizontal strata, . • 212 74 False stratification, • 66 75 Ripple-marks, .... 213 76 Dip of strata, .... 214 77 Taking angles, .... 215 76 Outlier, 216 79 Conformable strata, • " 80 Fault and Dike, . . . 217 81 Slaty structure, . . . 219 82 Concentric balls, ... 222 83 Contorted strata, . . 223 84 Contorted strata at Lyme, 224 85 Denuding effects of water, 226 86 Monte Nuovo, ... 231 87 Angular basalt, .... 233 88 Basaltic columns, . 234 89 Fingal's cave, StafTa, 235 90 Protrusion of greenstone, 236 91 Protrusion of basalt, 240 92 Veins of basalt, ...

" 93 Basaltic veins from above, 241 94 Protrusion of granite, 244 95 Protrusion of granite into hornblend, . . . 245 96 Granite passing in mica slate, ELEMENTS OF GEOLOGY.

Chapter I. Preliminary Explanations

1. Definition. The term Geology is derived from Greek, ge, the " earth," and logos, " reason," or " discourse," and therefore signifies the doctrine or science of the earth. It is the physical history ofthe globe, and has for its object, the investigation of the causes which have produced the phenomena exhibited both by the external and interior portions of the planet on which we live. 2. More extensive view of Geology. — As the student proceeds in the study of this science, he will find that it includes within its inquiries nearly every natural subject which the mind of man has ever investigated. In close connection with it, and indeed forming portions of its legitimate inquiries, are the sciences of Mineralogy, Botany, Conchology, and Zoology. 3. Zoology being the science of animals generally, in cludes the different departments of Ichthyology, or the study of fishes; Ornithology, that of birds; Entomology, that of insects ; Malacology, that of soft animals, as the clam and oyster, and Mammalogy, that of milk-giving animals. 4.

Besides the above named sciences, Geology has given rise to a new science called Palæontology, or the study of the fossil, organic remains of animals. 5. Now, lest the student should be discouraged at the onset with the idea that an intimate knowledge of all these sciences is necessary in order to proceed with that of Geology, we deem it proper to state here that so much of each of these subjects as is required for his present What is the meaning of the term Geology ? What does the science of Geology include? What are the sciences most nearly connected with it? What does the science of Zoology include ? What is Palæontology ? MINERALS. purpose will be so explained as to be readily understood. It must not, however, be concealed that the student who begins the study of Geology with a good knowledge of Botany, Mineralogy, Conchology, and indeed of natural history generally, has a great advantage over him who knows little or nothing of these subjects. 6.

The objects embraced by Palæontology, as the petrified or fossil remains of fish, animals, and shells, have been appropriately and eloquently called the Medals of Creation; for, says Mr. Mantell, "as an accomplished nu mismatist, (or reader of coins.) even when the inscription of an ancient and unknown coin is illegible, can, from the half obliterated characters, and from the style of art, de termine with precision the people by whom, and the period when it was struck ; in like manner the geologist can decipher these natural memorials, interpret the hieroglyph ics with which they are inscribed, and from apparently the most insignificant relics trace the history of beings of whom no other records are extant, and restore anew those forms of organization which lived and died, and whose races were swept from the face of the earth, ere man and the creatures which are his contemporaries became its denizens."

M. C. p. 23. ARRANGEMENT or STRATA and their contents. 7. The solid materials composing the earth, so far as man has observed, consist of Minerals and Fossils. The depth, or perpendicular distance to which geolo gists have been able to extend their observations is estimated at about fifteen miles. This distance includes the highest mountains, and the deepest valleys. MINERALS. 8. Minerals are inorganic substances formed by nat ural causes, some by heat, and some by water. They form the great body of which the earth is composed, as granite, gneiss, trap, limestone, and sandstone. The great ranges of mountains in every part of the globe, are chiefly composed of these materials. It will be shown hereafter which class owes their origin to fire, and which to water. What sciences are considered important in the study of Geology?

What are the objects embraced by Palæontology? Why are fossils called the Medals of Creation ? What are the solid materials of the earth ? What are minerals ? How have minerals been formed? FOSSILS. 11 I FOSSILS. 9. Fossils are remains of animals and vegetables, which, at unknown periods of time have been entombed in the strata of the earth by natural causes. Most of these remains though they may still maintain their original shapes, are found to have lost all their animal or vegetable matter, being petrified, or turned into stone, as the common expres sion is. This idea is, however, far from conveying the truth, for although the fossil may, and does often retain the exact form of the animal or vegetable body from which it was moulded, still there has been no transformation from one to the other, but only a deposition of the stony particles, as those of the organic matter decayed, and evapo rated, or were washed away.

Thus the stone imitates the organic relic. 10. In many instances such have been the immense depositions of animal remains, particularly of shells, and the silicious cases of animalcules called infusoria, that entire strata, of great thickness and extent, appear to have been formed of these materials, to the exclusion of all others. 1 1. As examples of the great extent to which the solid materials of the earth are owing to animal origin, we tran scribe the following from Mr. Mantell's Medals of Creation. 12. These formations include hundreds of miles in ex tent, and are, some of them, several hundred feet in thickness ; and when we consider the comparatively small portions of the earth which have been examined for such purposes, and that none of them are on this side of the Atlantic, we may, perhaps, form some idea of the great extent to which the solid portions of the globe are owing to organic materials. 13.

Rocks composed chiefly of animal remains. Strata. Prevailing Fossils. Formations. Trilobite schist. Trilobites and shells. Silurian Dudley limestone. Corals, shells, trilobites, crinoidea. system. Shelly limestone. Productæ, spiriseræ. t: Mountain limestone. Corals and shells. Corboni- Encrinital marble. Lily-shaped animals and shells. serous Mussel-band. Fresh water mussels. system. Ironstone nodules. Trilobites, insects, and shells. " What are fossils? How are petrifactions formed? What is said of the vast amount of animal depositions? What is said of the extent of the formations composed of animal remains ? vegetable remains. gTRATA. prevailing Fossils. Formations. Lias-shales and clays. Pentacrinites, reptiles, and fishes. Lias. Limestone. Terebratulæ and other sheUs. Lias conglomerates.

Fishes, shells, corals. Gryphite limestone. Shells, principally gryphites. Limestone. Terebratulæ and other sheUs. Inferior Stonesfield slate. Shells, reptiles, fishes, insects. Pappenheim schist. Crustacea, reptiles, fishes, insects. Oolite. Bath-stone, Shells, corals, crinoidea. reptiles. Limestone. Cephalopoda, principally ammonites. Coral-ra" Corals, shells, echini, ammonites. Bradford' limestone. Crinoidea, shells, corals, cephalopoda. Portland oolite. Ammonites, trigoni-c, and other shells. Porbeck and Sussex marb'.e. Fresh-water shells, reptiles, fishes. Wealden. Wealdea limestone. Cvclades, Crustacea, reptiles, fishes. Tilgate grit. Reptiles, fishes, shells. Farringdon gravel. Sponges, corals, echini, shells. Shankhn Jasper and chert. Shells, sponges, animalcules. sand. Greensand. Fibrous zoophytes.

" Chalk. Corals, infusoria, echini, shell** Chalk. Maestricht limestone. Corals, ammonites, belemnites, reptiles. " Hippurite limestone. Shells, principals hippuriles. Hard chalk, Echini and belemnites. Flints. Infusoria, echini, corals, shells, &c. Limestone. Fresh-water shells. Tertiary. Nummulite rock. Nummulites. Septaria. Nautili, turritellæ, shells. " Calcaire grosser. Shells and corals. Gypseous limestone. Mammalia, birds, reptiles, fishes. Siliceous limestone. Shells, Lacustrine marls. Cyprides, fresh-water shells. Monle Bolca sandstone. Fishes in abundance. " Bone breccia. Mammalia and land-shells. Sub-Himalaya limestone. Elephant. Mastodon, reptiles. " Tripoli. Infusoria, nearly entire. " Richmond marl. Animalcules and infusoria. " Semiopal. Infusoria. " Mountain meal. Infusoria.

" Guadaloupe limestone. Human bones, shells, and corals. Human BermuJalimeslone. Corals, shells, serpulæ. epoch. Bermuda chalk Comminuted corals, shells. " Bog-iron ochre. Infusoria. M. C. p. 21. * Chalk. Flints. VEGETABLE REMAINS. 14. The solid parts ofthe earth which have been derived from vegetables, though probably not so great as those above described, are still of vast extent in different parts of the world. These formations, known at the present What is said of the existence as coal, where climate renders it necessary for the comfort of man PROCESS OF NATURE IN THE FORMATION OF COAL. 13 day under the name of coalfields, exist, probably, in most parts of the world where the climate renders large quan tities of fuel necessary for the comfort of man ; a signal interposition of the Creator for his benefit, and clearly proving that it emanated from design, since coal has rarely, if ever, been discovered in any quantities in hot climates.

VEGETABLE origin of coal. 15. Among the early geologists, the origin of coal was for a long time a matter of dispute ; but at the present day it is universally admitted that all its varieties are of vegetable origin. 16. Proofs of the origin of Coal.— The experiments of Prof. Goppert, of Breslau, on the transformation of vegetables into coal, and which were afterwards followed in England, appear to have left no doubt on this subject in the mind of any philosopher ; though perhaps they only served to confirm opinions formed on less certain grounds. 17. This philosopher endeavored to imitate the agency of nature in producing the results in question, and he did so with perfect success. Having observed that the leaf, (that of the fern) in iron-stone nodules, might occasion ally be separated, in the form of a carbonaceous film, he placed such leaves in clay, dried them in the shade, and then exposing the clay to a red heat, he thus obtained striking resemblances to the fossil plants.

According to the degree of heat, the plant was found to have become either brown, shining black, or to be entirely lost, the im pression only remaining ; but, in the latter case, the sur rounding clay was stained black, thus indicating that the color of the coal-shales is derived from the carbon of the plants which they include, or once included. PROCESS OF NATURE IN THE FORMATION OF COAL. 18. It might be supposed from the results of the above experiments, that the action of volcanic heat on vegetables was required to produce coal ; this supposition is, however, by no means entertained: the application of artificial heat being the only means by which the long processes of What has been the origin of mineral coal ? What were Gdppert's ex periments to show the vegetable origin of coal ? PROCESS OF NATURE nature, consisting of fermentation and pressure, could be imitated. 19.

Changes produced on hay and other vegetables. — If hay be stacked in a moist condition, and closely packed, it is well known that fermentation will be the result, especially, during the hot season, and that the heat pro duced is sometimes so great as to produce spontaneous combustion, by which the mass is consumed. But if care be taken to confine the mass from contact of the air, and thus prevent ignition, the hay will be found to have ac quired a dark brown color, a glazed or oily appearance, and a bituminous smell, resembling that of coal. The same result will be produced if flax, hemp, ferns, the twigs of trees or other small vegetables, capable of being pressed into a close mass, be treated in the same manner. 20. Now this is considered an illustration, on a small scale, of what was once performed by natural means, to such a vast extent as to produce large coal fields, by throwing into masses whole forests, instead of a few pounds of hay, and then subjecting such accumulations to the pressure, perhaps, of hundreds of feet of incumbent earth. 21.

Structure of bituminous coal. — Although the vege table origin of all coal will not admit of question, yet, says Mr. Mantell, evidence of the original structure is not always attainable. The most perfect bituminous coal has undergone (apparently) a complete liquefaction, and if any portions of organization remain, they appear as if imbedded in a pure bituminous mass. The slaty coal generally preserves traces of cellular or vascular tissue, and the spiral vessels, (Lign. 2, 68.) and the dotted cells, indicating the coniferous structure, may readily be detected by the aid of the microscope, in chips or slices. In many examples, the cells are filled with an amber-colored resin ous substance ; in others, the organization is so well pre served, that on the surface exposed by cracking from heat, the vascular tissue, spiral vessels and cells, studded with glands, may be detected.

Even in the white ashes left after the combustion of coal, traces of the spiral vessels are discernible by a high magnifying power. Some What is said of the fermentation of hay, and its appearance when the air is excluded ? How does this illustrate the origin of coal ? What is said of the structure of slaty, bituminous coal ? IN THE FORMATION OF COAL. 15 beds of coal appear to be composed wholly of minute leaves, or partially decomposed foliage ; for if a mass re cently taken from the mine be split asunder, the exposed surfaces are found covered with delicate pellicles of carbonized leaves and fibres matted together ; and flake after flake may be peeled off through a thickness of many inches, and the same structure be apparent. 22. The above experiments and circumstances being deemed sufficient to show that coal is of vegetable origin, and this being our main object at this place, we shall now turn our attention to other subjects, to resume that of coal more particularly in its proper place.

Part I Chapter II

FOSSIL REMAINS OF ANIMALS AND PLANTS. 23. Having made the foregoing explanations and re marks, we are prepared to take a more extended view of the subject of organic remains, taking the Medals of Creation and Dr. Buckland's Bridgewater Treatise as our guides. 24. The study of organic remains, says Dr. Buckland, forms the peculiar feature and basis of modern geology, and is the main cause of the progress of this science since the commencement of the present century. We find certain families of organic remains pervading strata of every age, under nearly the same generic forms which they present among existing organizations. Such are the Nautilus, Echinus. Terebratula, and various forms of corals ; and among plants, the Ferns, Lycopodians, and Palms. 25. Some families peculiar to given formations. — Other families, both of plants and animals, are limited to particular formations, there being certain points where entire groups ceased to exist, and were replaced bv others of a different character.

The changes of genera and species are still more frequent, and hence it has been well observed, that to attempt an investigation of the structure and revolutions of the earth without applying minute attention to the evidences afforded by organic remains, would be no less absurd than to undertake to write the history of any ancient people without reference to docu ments afforded by their medals and inscriptions, their monuments, and the ruins of their cities and temples. 26. Zoology and Botany required. — The study of Zool- What is said of the importance of the study of organic remains ? What is said of Zoology and Botany as preparatory to the study of Geology ? FOSSIL REMAINS OF ANIMALS AND PLANTS. 17 ogy and Botany has therefore become as indispensable to the progress of Geology as a knowledge of Mineralogy.

Indeed, the mineral character of the inorganic matter of which the earth's strata are composed, presents so similar a succession of beds of sandstone, clay, and limestone, repeated irregularly, not only in different, but in the same formations, that similarity of mineral composition is but an uncertain proof of contemporaneous origin, while the surest test of identity of time is afforded by the corres pondence of the organic remains ; in fact, without these, the proofs of the lapse of long periods as Geology shows to have been occupied in the formation of the strata of the earth, would have been comparatively indecisive. 27. Secrets of nature revealed by organic remains. — -The secrets of nature that are revealed to us by the history of fossil organic remains, form, perhaps, the most striking results at which we arrive from the study of Geology.

It appears almost incredible to those who have not mi nutely examined natural phenomena, that the microscopic examination of a mass of rude and lifeless limestone should often disclose the curious fact, that large proportions of its substance have once formed parts of living bodies. 28. Large portions of the earth's surface derived from animals. — The study of these remains has also fully demonstrated that no small part of the present surface of the earth has been derived from the remains of animals that constituted the population ofthe ancient seas. Many extensive plains, and massive mountains form, as it were, the great charnel-houses of preceding generations, in which the petrified exuviæ of extinct races of animals and vegetables are piled into stupendous monuments of the operations of life and death, during unknown periods of past time. 29.

The deeper we descend, the more ancient the remains. — The deeper we descend into the strata of the earth, the higher do we ascend into the ancient history of the past ages of creation. We here find successive stages marked by the varying forms of animal and vegetable life, and these generally differ more and more widely from existing What secrets of nature are revealed by the study of fossil remains ? Whence is a large proportion of the surface of the earth said to be de rived ' Are the remains at, and below the surface, the same ? 2* FOSSIL REMAINS OF species as we go further downwards into the receptacles of the wreck of more ancient creations. 30. Similar remains exist in similar strata. — When we discover a constant and regular assemblage of organic remains commencing with one series of strata, and end inoin another, which contains a different assemblage, we have herein the surest grounds whereon to establish those divisions which are called geological formations, and we find many such divisions succeeding each other when we investigate the mineral deposites on the surface of the earth.

As examples, if we find strata containing the remains of trilobites, whether they occur in the northern or southern quarters of the globe, we may conclude that the formations where they exist are of the same age, and have been formed under similar circumstances and of the same materials ; and so, also, of the nautili, echini, or other organic exuviæ. 31. Most of these remains are extinct. — The study of these remains presents to the zoologist a large amount of species and genera which are extinct ; that is. not known to exist any where in the living state at the present day, but which, at the same time, bear important relations to existing forms of animals and vegetables, and often sup plying links, which had hitherto been unknown, in the great chain whereby all animated beings are held to gether, in a series of gradual connections. 3vi.

Bearing on natural theology. — The discovery, amid the relics of past creations, of the links that seemed wanting in the present system of organic nature, affords to natural theology an important argument, in proving the unity and universal agency of a common great first cause ; since every individual in such a uniform and closely connected series, is thus shown to be an integral part of one grand, original design. It is true, that the non-discovery of such links would form but a negative and feeble argument against the common origin of organic beings, because, for aught we know, the existence of in tervals may, in themselves, have formed a part of the original design ; but the existence of such links shows a Are similar remains found in similar strata, or not? Isa trilobite is found in America, and another in Asia, what do they indicate with respect to the age of the strata?

Are these remains of extinct or living <renera ' How does this subject relate to natural theology ? ANIMALS AND PLANTS. 19 unity of design, which very clearly proves the unity of intelligence in which it originated. 33. The lowest orders chiefly prevail in the lowest strata. — It is indeed true, that animals and vegetables of the low est orders, prevailed chiefly at the apparent commence ment of organic life. Thus we find in the deepest strata, chiefly, the remains of animals of the most simple con struction, as the sponges, star-fishes, and corals. And of vegetables, those are rarely found, other than such as belong to the class Cryptogamia, as the ferns, mosses, and fuci, or sea-weeds. In a few instances, however, the bones of fishes, of reptiles, and more rarely of birds and whales have been discovered among the early formations, proving the existence of these tribes at very remote periods. 34.

More recent strata inclose more perfect animals. — As we ascend towards the surface, and examine more re cent formations, we find that remains of the more perfect animals gradually become more abundant, until we arrive at the perfect structures of the saurians, or lizards, the elephants, mastodons, and other Mammalia, some of which belong to existing genera, and all to existing orders. 35. Shells the most common remains. — The most prolific source of organic remains is the accumulation of the shelly coverings of animals which occupied the bottom of the sea, apparently during a long series of succeeding generations. A large proportion of the entire substance of many strata is composed of myriads of these shells reduced to small fragments by the long continued movement of the water. In other strata, the presence of count less multitudes of unbroken corallines, and of fragile shells, having their most delicate spines still attached and unbroken, shows that the animals which formed and in habited them, lived and died undisturbed where these remains are found. 36.

Such strata prove the lapse of time. — Strata thus formed of the exuviæ of innumerable generations of or ganic beings, afford strong proof of the lapse of long periods of time, wherein the animals from which they have been derived, lived and multiplied and died, at the bottom Where do the lowest orders of animal and vegetable fossils chiefly prevail ? What remains are found in the more recent formations ? What is said of strata formed entirely of shells ? FOSSIL REMAINS OF ANIMALS AND PLANTS. of the seas, which to all appearance once occupied the places of our present continents and islands. Kepeated changes of species, both of animals and vegetables, as their "remains show, in the succeeding members of the different formations, give further evidence, not only of the lapse of time, but also of important changes in the phy sical condition, and climate of the ancient world. 37.