Part 4 (1/2)

To give a popular view of the evidence sustaining the affirmative of this question is no easy task. It needs a full and accurate acquaintance with the multiplied facts of geology, and, what is still more rare, a familiarity with geological reasoning, in order to feel the full force of the arguments that prove the high antiquity of the globe. Yet I know that I have a right to presume upon a high degree of scientific knowledge, and an accurate acquaintance with geology, among those whom I address.

In the first place, I must recur to a principle already briefly stated in a former lecture, viz., that a careful examination of the rocks presents irresistible evidence, that, in their present condition, they are all the result of second causes; in other words, they are not now in the condition in which they were originally created. Some of them have been melted and reconsolidated, and crowded in between others, or spread over them. Others have been worn down into mud, sand, and gravel, by water and other agents, and again cemented together, after having enveloped mult.i.tudes of animals and plants, which are now imbedded as organic remains. In short, all known rocks appear to have been brought into their present state by chemical or mechanical agencies. It is indeed easy to say that these appearances are deceptive, and that these rocks may, with perfect ease, have been created just as we now find them. But it is not easy to retain this opinion, after having carefully examined them. For the evidence that they are of secondary origin is nearly as strong, and of the same kind too, as it is that the remains of edifices lately discovered in Central America are the work of man, and were not created in their present condition.

In the second place, processes are going on by which rocks are formed on a small scale, of the same character as those which const.i.tute the great ma.s.s of the earth. Hence it is fair to infer, that all the rocks were formed in a similar manner. Beds of gravel, for instance, are sometimes cemented together by heat, or iron, or lime, so as to resemble exactly the conglomerates found in mountain ma.s.ses among the ancient rocks. Clay is sometimes converted into slate by heat, as is soft marl into limestone, by the same cause. In fact, we find causes now in operation that produce all the varieties of known rocks, except some of the oldest, which seem to need only a greater intensity in some of the causes now at work to produce them. By ascertaining the rate at which rocks are now forming, therefore, we can form some opinion as to the time requisite to produce those const.i.tuting the crust of the globe. If, for instance, we can determine how fast ponds, lakes, and oceans are filling up with mud, sand, and gravel, conveyed to their bottoms, we can judge of the period necessary to produce those rocks which appear to have been formed in a similar manner; and if there is any evidence that the process was more rapid in early times, we can make due allowance.

In the third place, all the stratified rocks appear to have been formed out of the fragments of other rocks, worn down by the action of water and atmospheric agencies. This is particularly true of that large proportion of these rocks which contain the remains of animals and plants. The mud, sand, and gravel of which these are mostly composed, must have been worn from rocks previously existing, and have been transported into lakes, and the ocean, as the same process is now going on. There the animals and plants, which died in the waters, and were transported thither by rivers, must have been buried; next, the rocks must have been hardened into stone, by admixture with lime, or iron, or by internal heat; and, finally, have been raised above the waters, so as to become dry land. Beds of limestone are interstratified with those of shale, sandstone, and conglomerate; but these form only a small proportion of the whole, and, besides, were mostly formed in an a.n.a.logous manner, though by agencies more decidedly chemical.

Now, for the most part, this process of forming rocks by the acc.u.mulation of mud, sand, and gravel is very slow. In general, such acc.u.mulations, at the bottom of lakes and the ocean, do not increase more than a few inches in a century. During violent floods, indeed, and in a few limited spots, the acc.u.mulation is much more rapid; as in the Lake of Geneva, through which the Rhone, loaded with detritus from the Alps, pa.s.ses, where a delta has been formed two miles long and nine hundred feet thick, within eight hundred years.[7] And occasionally such rapid depositions probably took place while the older rocks were in the course of formation. But in general, the work seems to have gone on as slowly as it usually does at present.

Yet, in the fourth place, there must have been time enough since the creation to deposit at least ten miles of rocks in perpendicular thickness, in the manner that has been described. For the stratified rocks are at least of that thickness in Europe, and in this country much thicker; or, if we regard only the fossiliferous strata as thus deposited, (since some geologists might hesitate to admit that the non-fossiliferous rocks were thus produced,) these are six and a half miles thick in Europe, and still thicker in this country. How immense a period was requisite for such a work! Some do, indeed, contend that the work, in all cases, as we have allowed it in a few, may have been vastly more rapid than at the present day. But the manner in which the materials are arranged, and especially the preservation of the most delicate parts of the organic remains, often in the very position in which the animals died, show the quiet and slow manner in which the process went on.

In the fifth place, it is certain that, since man existed on the globe, materials for the production of rocks have not acc.u.mulated to the average thickness of more than one hundred or two hundred feet; although in particular places, as already mentioned, the acc.u.mulations are thicker.

The evidence of this position is, that neither the works nor the remains of man have been found any deeper in the earth than in the upper part of that superficial deposit called _alluvium_. But had man existed while the other deposits were going on, no possible reason can be given why his bones and the fruits of his labors should not be found mixed with those of other animals, so abundant in the rocks, to the depth of six or seven miles. In the last six thousand years, then, only one five hundredth part of the stratified rocks has been acc.u.mulated. I mention this fact, not as by any means an exact, but only an approximate, measure of the time in which the older rocks were deposited; for the precise age of the world is probably a problem which science never can solve. All the means of comparison within our reach enable us to say, only, that its duration must have been immense.

In the sixth place, during the deposition of the stratified rocks, a great number of changes must have occurred in the matter of which they are composed. Hundreds of such changes can be easily counted, and they often imply great changes in the waters holding the materials in solution or suspension; such changes, indeed, as must have required different oceans over the same spot. Such events could not have taken place without extensive elevations and subsidences of the earth's crust; nor could such vertical movements have happened without much intervening time, as many facts, too technical to be here detailed, show. Here, then, we have another evidence of vast periods of time occupied in the secondary production and arrangements of the earth's crust.

In the seventh place, numerous races of animals and plants must have occupied the globe previous to those which now inhabit it, and have successively pa.s.sed away, as catastrophes occurred, or the climate became unfit for their residence. Not less than thirty thousand species have already been dug out of the rocks; and excepting a few hundred species, mostly of sea sh.e.l.ls, occurring in the uppermost rocks, none of them correspond to those now living on the globe. In Europe, they are found to the depth of about six and a half miles; and in this country, deeper; and no living species is found more than one twelfth of this depth. All the rest are specifically and often generically unlike living species; and the conclusion seems irresistible, that they must have lived and died before the creation of the present species. Indeed, so different was the climate in those early times,--it having been much warmer than at present in most parts of the world,--that but few of the present races could have lived then. Still further: it appears that, during the whole period since organized beings first appeared on the globe, not less than four, or five, and probably more--some think as many as ten or twelve--entire races have pa.s.sed away, and been succeeded by recent ones; so that the globe has actually changed all its inhabitants half a dozen times. Yet each of the successive groups occupied it long enough to leave immense quant.i.ties of their remains, which sometimes const.i.tute almost entire mountains. And in general, these groups became extinct in consequence of a change of climate; which, if imputed to any known cause, must have been an extremely slow process.

Now, these results are no longer to be regarded as the dreams of fancy, but the legitimate deductions from long and careful observation of facts.

And can any reasonable man conceive how such changes can have taken place since the six days of creation, or within the last six thousand years? In order to reconcile them with such a supposition, we must admit of hypotheses and absurdities more wild and extravagant than have ever been charged upon geology. But admit of a long period between the first creative act and the six days, and all difficulties vanish.

In the eighth place, the denudations and erosions that have taken place on the earth's surface indicate a far higher antiquity to the globe, even since it a.s.sumed essentially its present condition, than the common interpretation of Genesis admits. The geologist can prove that in many cases the rocks have been worn away, by the slow action of the ocean, more than two miles in depth in some regions, and those very wide; as in South Wales, in England. As the continents rose from the ocean, the slow drainage by the rivers has excavated numerous long and deep gorges, requiring periods incalculably extended.

I do not wonder that, when the sceptic stands upon the banks of Niagara River, and sees how obviously the splendid cataract has worn out the deep gorge extending to Lake Ontario, he should feel that there is a standing proof that the common opinion, as to the age of the world, cannot be true; and hence be led to discard the Bible, if he supposes that to be a true interpretation.

But the Niagara gorge is only one among a mult.i.tude of examples of erosion that might be quoted; and some of them far more striking to a geologist.

On Oak Orchard Creek, and the Genesee River, between Rochester and Lake Ontario, are similar erosions, seven miles long. On the latter river, south of Rochester, we find a cut from Mount Morris to Portage, sometimes four hundred feet deep. On many of our south-western rivers we have what are called _canons_, or gorges, often two hundred and fifty feet deep, and several miles long. Near the source of Missouri River are what are called the Gates of the Rocky Mountains, where there is a gorge six miles long and twelve hundred feet deep. Similar cuts occur on the Columbia River, hundreds of feet deep, through the hard trap rock, for hundreds of miles, between the American Falls and the Dalles. At St. Anthony's Falls, on the Mississippi, that river has worn a pa.s.sage in limestone seven miles long, which distance the cataract has receded. On the Potomac, ten miles west of Was.h.i.+ngton, the Great Falls have worn back a pa.s.sage sixty to sixty-five feet deep, four miles, continuously--a greater work, considering the nature of the rock, than has been done by the Niagara. The pa.s.sage for the Hudson, through the highlands, is probably an example of river erosion; as is also that of the Connecticut at Brattleboro' and Bellows Falls. In these places, it can be proved that the river was once at least seven hundred feet above its present bed. On the Deerfield River, a tributary of the Connecticut, we have a gulf called the _Ghor_, eight miles long and several hundred feet deep, cut crosswise through the mica slate and gneiss by the stream.

On the eastern continent I might quote a mult.i.tude of a.n.a.logous cases.

There is, for instance, the Wady el Jeib, in soft limestone, within the Wady Arabah, south of the Dead Sea. The defile is one hundred and fifty feet deep, half a mile wide, and forty miles long. In Mount Lebanon, several remarkable chasms in limestone have been described by American missionaries, as that on Dog River, (Lycus of the ancients,) six miles long, seventy or eighty feet deep, and from one hundred and twenty to one hundred and sixty feet wide; also, Wady Barida, whose walls are six hundred to eight hundred feet high. On the River Ravendoor, in Kurdistan, is a gorge, described in a letter from Dr. Perkins, one thousand feet deep. Another on the Euphrates, near Diadeen, is seventy feet deep, and is spanned by a natural bridge one hundred feet long. On the River Terek, in the Dariel Caucasus, is a pa.s.s one hundred and twenty miles long, whose walls rise from one thousand to three thousand feet high. In Africa, the River Zaire has cut a pa.s.sage, forty miles long, through mica slate, quartz, and syenite; and in New South Wales, c.o.x River pa.s.ses through a gorge twenty-two hundred yards wide and eight hundred feet high.

Ninthly. Since the geological period now pa.s.sing commenced, called the _alluvial_, or pleistocene period, certain changes have been going on, which indicate a very great antiquity to the drift period, which was the commencement of the alluvial period, and has been considered among the most recent of geological events. I refer to the formation of deltas and of terraces.

Of the deltas I will mention but a single example, to which, however, many others correspond. The Mississippi carries down to its mouth 28,188,803,892 cubic feet of sediment yearly, which it deposits; or one cubic mile in five years and eighty-one days. Now, as the whole delta contains twenty-seven hundred and twenty cubic miles, it must have required fourteen thousand two hundred and four years to form it in this manner.

Terraces occur along some of the rivers of our country from four hundred to five hundred feet above their present beds, and around our lakes to the height of nearly one thousand feet. They are composed of gravel, sand, clay, and loam, that have been comminuted, and sorted, and deposited, by water chiefly. At a height two or three times greater, on the same rivers and lakes, we find what seem to be ancient sea beaches, of the same materials, deposited earlier, and less comminuted. The same facts also occur in Europe, and probably in Asia.

Now, it seems quite certain, that these beaches and terraces were formed as the continents were being drained of the waters of the ocean, and the rivers were cutting down their beds; which last process has been going on in many places to the present day. Yet scarcely nowhere, since the memory of man, have even the lowest of these terraces and beaches been formed, save on a very limited scale, and of a few feet in height. The lowest of them have been the sites of towns and cities, ever since the settlement of our country, and on the eastern continent much longer. Yet we see the processes by which they have been formed now in operation; but they have scarcely made any progress during the period of human history. How vast the period, then, since the work was first commenced! Yet even its commencement seems to have been no farther back than the drift epoch, since that deposit lies beneath the terraces. But the drift period was comparatively a very recent one on the geological scale. How do such facts impress us with the vast duration of the globe since the first series of changes commenced!

Finally. There is no little reason to believe that, previous to the formation of the stratified rocks, the earth pa.s.sed through changes that required vast periods of time, by which it was gradually brought into a habitable state. It is even believed that one of its earliest conditions was that of vapor; that, gradually condensing, it became a melted globe of fire, and then, as it gradually cooled, a crust formed over its surface; and so at last it became habitable. All this is indeed hypothesis; and, therefore, I do not place it in the same rank as the other proofs of the earth's antiquity, already adduced. Still this hypothesis has so much evidence in its favor, that not a few of the ablest and most cautious philosophers of the present day have adopted it. And if it be indeed true, it throws back the creation of the universe to a period remote beyond calculation or conception.

Now, let this imperfect summary of evidence in favor of the earth's high antiquity be candidly weighed, and can any one think it strange that every man, who has carefully and extensively examined the rocks in their native beds, is entirely convinced of its validity? Men of all professions, and of diverse opinions concerning the Bible, have been geologists; but on this point they are unanimous, however they may differ as to other points in the science. Must we not, then, regard this fact as one of the settled principles of science? If so, who will hesitate to say that it ought to settle the interpretation of the first verse of Genesis, in favor of that meaning which allows an intervening period between the creation of matter and the creation of light? This is the grand point which I have aimed to establish; and, in conclusion, I beg leave to make a few remarks by way of inference.

First. This interpretation of Genesis is entirely sufficient to remove all apparent collision between geology and revelation. It gives the geologist full scope for his largest speculations concerning the age of the world.

It permits him to maintain that its first condition was as unlike to the present as possible, and allows him time enough for all the changes of mineral const.i.tution and organic life which its strata reveal. It supposes that all these are pa.s.sed over in silence by the sacred writers, because irrelevant to the object of revelation, but full of interest and instruction to the men of science, who should afterwards take pleasure in exploring the works of G.o.d.

It supposes the six days' work of creation to have been confined entirely to the fitting up the world in its present condition, and furnis.h.i.+ng it with its present inhabitants. Thus, while it gives the widest scope to the geologist, it does not encroach upon the literalities of the Bible; and hence it is not strange that it should be almost universally adopted by geologists as well as by many eminent divines.

I would not forget to notice in this connection, however, a recent proposed extension of this interpretation by Dr. John Pye Smith, founded on the principle already ill.u.s.trated, that the sacred writers adapted their language to the state of knowledge among the Jews. By the term _earth_, in Genesis, he supposes, was designed not the whole terraqueous globe, but ”the part of our world which G.o.d was adapting for the dwelling-place of man and animals connected with him.” And the narrative of the six days' work is a description adapted to the ideas and capacities of mankind in the earliest ages, of a series of operations, by which the Being of omnipotent wisdom and goodness adjusted and furnished, not the earth generally, but, as the particular subject under consideration here, a PORTION of its surface for most glorious purposes.

This portion of the earth he conceives to have been a large part of Asia, lying between the Caucasian ridge, the Caspian Sea and Tartary on the north, the Persian and Indian Seas on the south, and the high mountain ridges which run at considerable distance on their eastern and western flanks. This region was first, by atmospheric and geological causes of previous operation, under the will of the Almighty, brought into a condition of superficial ruin, or some kind of general disorder, probably by volcanic agency; it was submerged, covered with fogs and clouds, and subsequently elevated, and the atmosphere, by the fourth day, rendered pellucid.--_Script. and Geol._ p. 275, 2d edit.