The Age of the Earth, considered geologically and historically

Preface

. The following analysis of the prevailing geological opinions of the day would not have been attempted, had it not been thought that the question cannot long rest where it now stands. Neither would the author have set himself against an array of high authorities on the science, had he not been equally aware of the conflicting and unstable nature of opinion, even among those authorities, on the subject at issue. To any one who has watched the progress of theoretical geology for the last few years, — without even revert ing to the speculations of the last century, — where opinion has so often vacillated and changed on the subject, and where so many hasty conclusions have been formed, that scarcely has an author his speculations half through the press, when the last part must

PREFACE.

. be written as a caveat or contradiction of the first,— it will not be deemed a high degree of presumption to attempt an analysis of the points of discussion, and to place these in such a shape as may enable the general inquirer to comprehend the import and bearing of the whole question. In a work recently published for the use of students, where the facts of geology alone are given, I have endeavoured to illustrate the practicability of teaching all that is really important in the science, apart from theoretical views. That work having already had a rapid circulation, I have in the present endeavoured to complete my original plan, by giving an analysis of those facts as they bear upon theoretical and historical views of the past condition of the earth. I am well aware, however, that the execution of this task is very incomplete, and could have wished that some one, having more extensive means of information, and more leisure from the anxieties of daily avocations, had under taken it. I must also here, in the outset, state, that I may be reckoned by some not an unpreju-

PREFACE.

. V diced judge of the questions before me ; for, entertaining such a belief in the Sacred Writings as makes me confident that their general import was intended to be as readily understood by the mass of mankind as by the critical inquirer, I am disposed to give implicit credence to the narrative of creation, to the whole extent that it goes ; and whereever discrepancies present themselves, to await the issue of the approximation of geological knowledge to the sacred history, instead of attempting to torture this latter into a conformity with the former. I am not aware, however, that in these pages this bias has materially influenced the impartiality of my statements, or swayed, in any degree, my conclusions from facts. The few practical illustrations which I have appended in the Notes are necessarily of a local nature, consisting of those which come more immediately under my inspection ; and they are given more with a view of shewing, that if the labours of research were some times directed to illustrate how far the fossils of the great leading formations may coincide instead of differ, the results would perhaps VI

PREFACE.

. accumulate as much on the one side as they hitherto appear to have done on the other. I have also attempted to shew, that the diluvial covering of the different strata has not yet received from geologists that attention which its importance, in a theoretical view, deserves. To those who have ample leisure and other concomitant opportunities for such pur suits, there is not a field of greater interest presented to the exertions of the philosopher than some of these geological investigations afford ; and few where he can be more harm lessly, or, as regards the promotion of the arts and conveniences of life, perhaps more usefully employed. 21, Forth Street, January, 1838. CONTENTS.

Part I. Geological Phenomena Supposed To Indicate The Age Of The Earth

SacT- PAGi. I. General View of the Earth's Strata and their Aggregate Thickness, .... U II. Proofs of the Rapid Accumulation ofthe Sedimentary Matter at present forming, ... 20 III. Different Formations may be contemporary, . . 31 IV. Some Formations have been suddenly deposited, . 36 V. Successive Series of Organic Remains in the different Formations, .... A J VI. Change of Temperature, VII. Operations at present in progress, . gj

Part II. Geological Phenomena Compared With The Mosaical Record

I. The Mosaical and Geological views of Creation, . 71 II. Mosaical and Geological views of the Deluge, 87 III. General Summary, . . . j07

Part III. Sketch Of Geological Theories

I. Early History of Geology, .... 125 II. Later Geological Theories, .... CONTENTS. NOTES AND ILLUSTRATIONS. NOTK I'AO« I. Niddry Quarry near Edinburgh, . • . 1 53 II. Fossil Trees, Craigleith Quarry, . . • lfifi III. Theories of Igneous Rocks, .... 161 IV. Successive Creations of Animals, and Linnæan Theory, 1C2 V. Edinburgh and Wealden Strata, . . . 1CC V.* List of Fossil Mammalia, . . . 1 68 VI. Theory of Change of Temperature, . . 169 VII. Commencement of present Epoch, . . 170 VIII. Effects of River Currents, . . . .171 IX. Faber, &c. on Days of Creation, ... ib. X. Drs Chalmers, Buckland, &c. on a Pre- Adamite World, 180 Dr Powell on Figurative Interpretations of Moses, . 1118 XI. Nebular Cosmogony, . . . .1-0 XII. Ruins of Babylon and Nineveh, ... 193 XIII. Josephus and Philo on the Deluge, . . .ib.

XIV. Drs Fleming, Buckland, and Cuvier on do. . 194 XV. Ancient Chronology, . . . .197 Plate I. to face . . . Page 1 68 II. . . . . 1C7 III. .... 196 IV. .

Part I. Geological Phenomena Supposed To Indicate The Age Of The Earth

a • ' The great branches of the Comparative Geology and Comparative Palæontology, (or study of Fossil Remains,) of distant countries, much as they have recently advanced, have as yet even a still wider interval to pass over than that which they may liave already accomplished before they shall have obtained that degree of completeness which alone can qualify them to serve as sound bases in any geological theory."— Con ybe are — Geological Report of British Association. " While so large a portion ofthe globe is geologically unexplored— while all the general views which are to extend our classifications satisfactorily from one hemisphere to another, are still unformed— while the organic fossils of the tropic* are almost unknown, and their general relation to the existing state of things has not even been conjectured, — how can we expect to speculate rightly and securely respecting the history of tho whole of our globe ? and if geological classification and description are thus imperfect, the knowledge of geological causes is still more so."— Whew-ell's History ofthe Inductive Sciences, vol. iii. p. 621.

Section I. General View Of The Earth's Strata, And Their Aggregate Thickness

The creation of the world, and the planetary system of which it forms a part, is an exercise of the Divine power so utterly beyond the conception of man, that, in speculating upon it, he is glad to throw around the whole the envelopment of infinitude, and filling his imagination with ideas of boundless space and indefinite duration, he endeavours to bring up his mind in some degree commensurate with the subject. It is in this way, perhaps, as well as from that innate love of novelty implanted in the breast, that the prevailing opinions of the present time seem to tend so much to the idea of an extreme antiquity of the globe beyond that definite period within which tradition and common belief has hitherto confined it. Yet if it be pleasing for the mind to forego the trammels of authority, and, starting with a few striking phenomena, to track creation through a revolving series of worlds till it is lost in the vague and indistinct boundaries of time; it is a no less singular, and perhaps as sublime, speculation, to think that this earthly scene of things, involving so much that is vast and important both in the moral and physical world, and occupying but a brief moment and a mere point of space in the great theatre of eternity, should yet have these points and limits accurately defined and indicated to the mental intelligences, for whose aid and use they are declared to have been created.

The very nature of the study, too, is such as to have a continual tendency to carry the mind beyond the sober boundaries of facts into the airy regions of hypothesis. For, laying aside the speculations of the cosmogonists, — who have formed worlds out of red hot masses severed from the sun, or from fluid spheres of saturated water, or condensed nebulæ, which had hitherto floated as shapeless flocculi in space, — there is in the study of the visible phenomena of the earth's strata, sufficient of wonderful interest to excite and warm the imagination. The remains of unknown plants and animals, which have been entombed for ages in the hard rocks, and which present themselves only in fragments and disjointed members, yet sufficiently distinct to indicate many kinds of being which no longer have an existence on the earth — the exhumation of skeletons of unknown monsters, and the impressions of the footmarks of others, which have glided like ghosts from this visible scene, but left indelible marks in our sandstones of their actual existence, at a remote period, on our coasts and marshes, — form a species of exciting antiquarianism, compared to which the relics of Herculanæum and Pompeii are but as a tale of yesterday.

It is from these circumstances that perhaps somewhat exaggerated views have been adopted regarding the size, structure, and relative antiquity of these organic bodies, and from thence that many discordant deductions have been made respecting the formation of the strata in which they have been discovered. We must also recollect that another source of perplexity in investigating the history of these strata is, that only a part is nonvisible to us ; that, in the changes which have taken place on the earth's surface, much, if not the whole, of the original dry land has disappeared, and those portions which come under our inspection have evidently, for a considerable period, formed the bottom of the sea, and the successive layers have been accumulated, in a great measure, from the fragmentary portions or disintegration of earlier formed continents.

Thus a very important chain of evidence in determining the earth's antiquity is lost to us. We can only now extend our investi gations to — or, at least, geological investigations have only hitherto embraced — those portions of strata which have been formed successively from older existing strata ; the outskirts, as it were, of former continents, which had gradually gone on extending their boundaries into the surrounding ocean. Hence, facts connected with these circumstances early gave rise to theories of the successive appear ance of the various classes and genera of plants and animals on the earth, beginning with the simplest, and ascending gradually to the more complicated ; while more enlarged experience has shewn these theories to be quite unfounded. Indeed, reasoning a priori, and without regard to the indications presented in the fossiliferous strata, we would be inclined, on a review of the present system of things, to pronounce that the creation of all had been a coincident and simultaneous event.

Thus, a general and minute harmony appears to subsist among all parts of nature : the relative pro portion of land to water seems to be modified so as to produce the necessary amount of evaporation and rain ; the composition of the gases of the atmos phere seems to be regulated by the nice balance of interchange which subsists between the proportion of animal respiration and vegetable absorption, so that the necessary amount of oxygen is not dimi nished, nor carbonic acid too largely accumulated. Thus, too, every vegetable has its own insects and other animals that feed on it ; some peculiar to the root, others to the stem and leaves, while minute animalcules, mounting along with the juices through the porous vessels, make lodgments for their eggs and their young in the seeds ; thus completely identifying themselves with the germination and growth of the plants.

Every animal, too, has its own appropriate parasites, — entozoæ, which can live only within the bodies of larger animals, and whose origin and existence seem coeval with, and entirely dependent on, the bodies in which they are lodged. And if we look beyond our terrestrial globe, we shall find that other links of connection bind it to the great solar system of which it forms a part; where its position, its laws of rotation, and attrac tive forces, all so intimately adjusted to meet and accommodate those of the other spheres, lead us at once to conclude that all had a simultaneous origin. The opinions of those geologists who maintain the great antiquity of the earth, are formed from an inspection of its strata, which they find of such thickness as would indicate the lapse of millions of years in its accumulation ; and that, moreover, through the successive layers of these strata, are found the remains of plants and animals, in such positions as would shew that successive kinds of them had lived and become extinct during the long intervals between the deposition of the first and last orders of strata.

In the following treatise, then, we propose, I. To take a view of those facts and appearances which are supposed to indicate a great antiquity of the earth. II. To compare those facts and appearances with the Mosaical account of creation, the only historical record which has reached us of the age of the world. And, III. To give a brief sketch of geological theories, and the progress of opinion on the subject, to the present times. It has been computed, that the aggregate thick ness of the sedimentary stratified rocks, as far as they have been investigated in Europe, may amount to about thirty thousand feet, beginning at the primary schistose strata, and ascending in the order of their supposed successive depositions to the chalk and tertiary beds. The following table exhibits a view of those for mations, one or more of which are generally super imposed on each other, with an estimate of their medium aggregate thickness.

PRIMARY FORMATION. feet. feet. Gneiss, Thickness uncertain, but Mica slate, >■ in some situations cal- Clay slate, &c. } culated at 10,000 to 20,000 Grevwacke slates, ) Someti'°^ superimposed . Limestone, &c. )■ on the primary strata, Old red sandstone, s 0r helow the J**™** nnn J rous, 5000 to 10,000 15,000 7000 CARBONIFEROUS FORMATION. Mountain limestone varies from SO to 900"] onnf> Carboniferous sandstone varies from 1000 to £000 I SA1IFEROUS STRATA. 3» Magnesian limestone,. . . . 300 New red sandstone, . . . 900 " OOLITIC FORMATION. Lias, ..... 500 "I Oolite 1200 170° CHALK FORMATION. Greensand, .... 500 K Chalk, 600 I10° TERTIARY FORMATION Sand and clav, . . .1 „ Plastic clay, crag, &c. . . j"900 j 90° From this table, it appears that the aggregate thickness of those formations most usually super imposed on each other is, In the older series about 26,000 feet.

In the newer series about 5000 feet. The whole of these strata are not, however, found overlying each other. In England, where b2 the most accurate sections have been made, and where the most regular succession of these strata takes place, the primary rocks are found asso ciated on the north-western side of the island, the coal measures and new red sandstone in the middle, while the lias, oolite, chalk, and newer formations, form the eastern and southern boun daries.* It is also sufficiently ascertained that the aggregate thickness above mentioned does not extend throughout the whole space occupied by those strata. Indeed, it may be assumed as the maximum rather than the average thickness, for many of the strata are very unequal, deepening in some places so as to form hollow troughs, and thinning out in others so as entirely to disappear.

Yet, taking the most moderate computation, the mass of accumulated matter appears so enormous, that, in the opinion of many geologists, its gradual deposition, in layer after layer, must have occupied a vast period of time, which has been so far divided into epochs or eras from indications of change and revolution which the strata seem to have undergone. Now, it must be observed, that in many of the sedimentary formations, but especially in the primary strata, it is exceedingly difficult to ascer tain their actual thickness. A succession of stratified rocks may, on a general view, appear to S.e Section, Plate have a continuous inclination to each other for miles in extent, and thus seem of enormous thick ness, whereas it may only be a bed of very moderate dimensions, broken up by repeated wave-like erup tions of igneous rocks from below, which may not always make their appearance on the surface.

The sedimentary matter may have originally been deposited by a current of water flowing over a sloping channel, by which means a succession of inclined strata may have been formed, extending for a long space horizontally, although of no very considerable depth, — a mode of deposition which may be witnessed daily in many river currents, and which has been so well illustrated by M. de la Beche.* In the schistose strata, too, it is exceedingly diffi cult to form a probable guess at their thickness, from the extreme confusion and irregularity of their position, and frpm the lines of cleavage being often mistaken for those of stratification. If these slatey masses, too, owe their laminar, and perhaps their stratified, appearance, in a considerable degree, to a process of crystallization,! this will add to the difficulty of ascertaining the actual depth of the original deposition. * Theoretical Geology. t Vide Boase on Primary Strata.

Section II. Proofs Of The Rapid Accumulation Of Sedi- Mentary Matter At

PRESENT FORMING. As it is universally agreed, that almost all the sedimentary strata have been formed from the wearing down of older rocks, in a manner similar to tne processes of disintegration, which are taking place in the present land and ocean, we must first examine the amount of this, in order to com pare it with the operations of preceding ages. All our rivers are continually carrying down to the sea the matter of the rocks and soil over which their currents flow. This process is daily taking place, but in seasons of flood it is prodigiously augmented ; so that, the mouths of our smallest streams, basins, and harbours, are year after year filled up with the accumulated silt ; and in the larger rivers of the world, extensive deltas of solid matter are heaped up for hundreds of miles into the sea.

Pliny long ago remarked the extraordinary accu mulation of detritus in the Mediterranean Sea and ACCUMULATION OF SEDIMENTARY MATTER. 21 Persian Gulf, and the rapid advance of the land upon the sea. From more recent observations, it has been calculated that not less than one thousand square miles of solid land have been accumulated there within the last two thousand years. Celsius has also given details of the filling up of the Gulf of Bothnia, from which it appears that in many parts of this gulf, the process of accumulation had shallowed the water three feet in the course of fifty years. According to Linnæus, the annual increase of land on the eastern side of Gothland, near Hoburgh, had been for ninety years at the rate of from twelve to eighteen feet in extent. Sir George Staunton estimated the waters of the Yellow River in China to contain one part of earthy matter in two hundred ; and that the river carried down hourly two millions of cubic feet, or forty-eight millions daily.

From some recent experiments on the waters of the Ganges, Mr Everest has ascertained that, during the rainy season, the river holds suspended upwards of one four-hundredth part by weight of earthy matter, and he has calculated that, taking the average of the whole year, the enormous quantity of six thousand three hundred million cubic feet are discharged annually, — a mass equal in bulk and weight to sixty of the great Pyramids of Egypt. The delta forming at the mouth of this river, extends to a length of two hundred and twenty miles. Major Colebrook mentions the rapid filling up of some of the branches of the Ganges, and the excavation of new channels, where the mass of soil removed in the course of a few years amounted to forty square miles, or 25,600 acres. The immense transportation of earthy matter by the Ganges and Megna, is proved by the great magnitude of the islands formed in their channels, during a period far short of a man's life.* Similar accumulations are in the process of for mation at the mouths of all the great rivers of the world.

The Amazon carries the disintegrated rocks and soil of the South American continent into the Atlantic Ocean. Captain Sabine could distinguish the current of this immense river three hundred miles out at sea ; and, aided by an oceanic current flowing with the rapidity of four miles an hour, from south to north, the sedimentary mass is carried on as far as the mouth of the Orinoco, forming an extensive swamp along the coast of Guiana, and a long range of muddy shoals bordering the marshes. The sediment of the Orinoco is partly detained, and settles near its mouth, causing the shores of Trinidad to extend rapidly, and is partly swept into the Caribbean Sea by the equatorial current. The rivers which flow from the high lands of Mexico, especially when swollen by the tropical * Lyell's Geology.

Cuvier's Ossmens Fossiles. Playfair's Illustrations of Hutton. rains, carry down an enormous quantity of rocky debris and mud to the sea. But the oceanic current flowing rapidly across their mouths, prevents the formation of deltas, and preserves an almost uniform line of curve on that coast. The Mississippi, with its numerous tributary rivers, sweeps through many thousand miles of the North American continent. The alluvial plain of this great river is bounded on the east and west by great ranges of mountains, stretching along their respective oceans. Below the junction of the Ohio, the plain is from thirty to fifty miles broad ; and after that point, it goes on increasing in width till the expanse is perhaps three times as great. The river traverses the plain in a meandering course, describing immense and uniform curves.

After sweeping round the half of a circle, it is carried in a rapid current across its own channel, to another curve of the same — uniformity upon the opposite shore. The river is continually wearing down these curves, and when the bendings approach near to each other, high floods frequently burst the inter vening portion of land. At one spot, called the " grand cut off," vessels now pass from one point to another, in half a mile, to a distance which it formerly required a voyage of twenty miles to reach. After the flood season, when the river subsides within its channel, it acts with destructive force on the alluvial banks, rendered soft by the recent inundation. « Some years ago," says Captain Hall, " when the Mississippi was regularly surveyed, all its islands were numbered from the confluence of the Missouri to the sea; but every season makes such revolutions, not only in the number, but in the magnitude and situation of these islands, that this enumeration is now almost obsolete.

Some times large islands are entirely melted away, at other places they have attached themselves to the main shore, or, which is the more correct statement, the interval has been filled up by myriads of logs, cemented together by mud and rubbish. During floods, when the Mississippi and its tributaries overflow their banks, the waters being no longer borne down by the main current, and becoming impeded among the trees and bushes, deposit the sediment of mud and sand, with which they are abundantly charged. Islands arrest the progress of floating trees, and they become in this manner reunited to the land, the rafts of trees, together with mud, constituting at length a solid mass. The coarser portion subsides first, and the most copious deposition is found near the banks where the soil is most sandy.

Finer particles are found at the farthest distances from the river, where an impalpable mix ture is deposited, forming a stiff unctuous black soil. Thus, the river, by the continual shifting of its course, sweeps away during a great portion of the year considerable tracts of alluvium, which were. gradually accumulated by the overflow of former years.* Immense accumulations of trees and other vegetables are also taking place on these rivers — thus affording facts for the illustration of the origin of coal beds. Captain Hall thus describes the raft of the Atchafalaya. " This river flows out of the Mississippi, at a point about two hundred and fifty miles from the sea. Twenty seven miles from the efflux, a raft begins, and extends over a space of twenty miles ; but as the whole distance is not filled up with timber, the aggregate raft is only about ten miles long.

The width of the river is two hundred and twenty yards. The raft extends from bank to bank, and is supposed to be about eight feet thick. It has been accumulating for upwards of fifty years, and is annually increased. "f According to Darby, a section of the banks of this river, at low water, exhibits, first, an upper stratum, consisting of bluish clay, common to the banks of the Mississippi ; below this, a stratum of red ochreous earth, peculiar to Red River, under which the blue clay of the Mississippi again appears. And this arrangement, he says, is constant, proving that the waters of the Mississippi and the Red River occupied alternately, at some former periods, considerable tracts below their present point of union. * Flint's Geography of America. Lyell, vol. i. t Travels in America. But the waters of the ocean having an infinitely more extended surface to act upon, are also accumulating detritus to an enormous extent.

Not only do the tidal waves incessantly wear down and encroach upon the shores, but oceanic currents flowing over half the circumference of the globe, with considerable impetuosity, abrade the rocky depths and channels, and heap up and accumulate masses which, in many situations, are of very great magnitude. " So great," says Mr Lyell, " is the quantity of matter held in suspension by the tidal current on our shores, that the waters are in some places artificially introduced into certain lands below the level of the sea ; and by repeating this operation for two or three years, considerable tracts have been raised in the estuary of the Humber, to the height of about six feet. Large quantities of coarse sand and pebbles are also drifted along at the bottom, and where such a current meets with any deep depression in the bed of the ocean, it must necessarily fill it up, just as a river when it meets with a lake in its course, fills it gradually with sediment."

The bed of the German Ocean, according to the accurate survey of Mr Stevenson,* is traversed by several enormous banks, one of which, occupying a central position, extends from the Firth of Forth in a north-easterly direction, to a distance of one Edin. Phil. Journal, vol. v. hundred and ten miles. Others run from Denmark and Jutland, upwards of one hundred and five miles to the north-west ; while the greatest of all, the Dogger Bank, stretches for upwards of three hundred and fifty-four miles from north to south. The whole superfices of these shoals is equal to about one-fifth of the entire area of the German Ocean, or to about one-third of the whole extent of England and Scotland. The average height of the banks measures about seventy-eight feet; the upper portion consisting of fine and coarse silicious sand, mixed with shells and corals.

If such, then, be the ascertained rate a* which detrital matter is constantly accumulating by the action of rivers and the ocean, it ought to afford some data for ascertaining the period within which the ancient and now consolidated strata of the globe were formed. Thus, suppose that our largest rivers accumulated one foot in depth of solid strata annu ally, we would have, in two thousand years, a deposit of the same amount over the space which their waters covered. And suppose that the ocean, on an average, accumulated one-fifth of this quantity over its whole superfices annually, and that this matter was collected by tides and currents into numerous beds of unequal thickness, we can easily conceive, that over particular regions, the accumu lated collection of oceanic and fluviatile debris would amount, in the same period of time, to masses of strata of enormous thickness, silling up large hollow. and troughs in the bottom of the sea.

Suppose that in some of these situations, an accumulation of five to ten feet occurred annually, we should thus have, in two thousand years, a mass of strata, varying from ten to twenty thousand feet in thickness, thus equalling the depth of the thickest ancient accumulations yet discovered. " In certain parts of the globe," says Mr Lyell, " continuous formations are now accumulated over immense spaces along the bottom of the ocean. The materials undoubtedly must vary in different regions, yet for thousands of miles they may often retain some common characters, and be simultaneously in progress throughout a space, stretching thirty degrees of latitude from south-east to north-west, from the mouths of the Amazon, for example, to those of the Mississippi, as far as from the Straits of Gibraltar to Iceland.

At the same time, great coral reefs are growing around the West Indian islands, and in some part streams of lava are occasionally flowing into the sea, which become covered again in the intervals of eruptions with other beds of corals. The various rocks, therefore, stratified and unstratified, now forming in this part of the globe, may occupy, per haps, far greater areas than any group of our ancient secondary series which has yet been traced through Europe." * Principles of Geology, vol. Considering these circumstances, then, is it not reasonable to suppose, that, if the present ocean bed were elevated by subterranean forces above the level of its waters, and converted into dry land, we should find strata of the depth and magnitude which the present causes in action would lead us to calculate on.