ARCHIBALD GEIKIE, LL. D., F.R.S., Professor of Geology, University of Edinburgh, spoken of by the New York Independent as “an author who is surpassed by none of his compeers in scientific attainment, and hardly equaled by any of them for his gifts in the imparting of knowledge,” has lately issued a “Text Book of Geology;” and he is also the author of the treatise on geology in the latest edition of the Encyclopedia Britannica; therefore we shall doubtless be justified in accepting his work as the latest, the ablest, and the best contribution in favor of geological science as it is at the present day. And after reading and studying it through three times, the impression left upon my mind by it was that expressed by the title which I have placed at the head of this article.ARSH August 7, 1883, page 497.1

Geology is defined as “the science which investigates the history of the earth.” “Its object,” as stated, “is to trace the progress of our planet from the earliest beginning of its separate existence, through its various stages of growth, down to the present condition of things.” “It seeks to determine the manner in which the evolution of the earth’s great surface features has been effected.”ARSH August 7, 1883, page 497.2

But it is only by a proper understanding of the present order of things, that the past can be made out. He says: “Only in proportion as we understand the present, where everything is open on all sides to the fullest investigation, can we expect to decipher the past, where so much is obscure, imperfectly preserved, or not preserved at all. A study of the existing economy of nature ought thus to be the foundation of the geologist’s training.”ARSH August 7, 1883, page 497.3

So, then, here we have properly, at the very beginning, laid down the foundation of geological deduction. And we may, properly enough, inquire, is this foundation secure, is it a foundation upon which we can finally stand and safely build? Let Mr. Geikie anser. In the very next paragraph he says:—ARSH August 7, 1883, page 497.4

“While, however, the present condition of things is thus employed, we must obviously be on our guard against the danger of unconsciously assuming that the phase of nature’s operations which we now witness has been the same in all past time, that geological changes have taken place in former ages in the manner and on the scale which we behold to-day, and that at the present time all the great geological processes, which have produced changes in the past eras of the earth’s history, are still extant and active. Of course we may assume this uniformity of action, and use the assumption as a working hypothesis. But it ought not to be allowed any firmer footing, nor on any account be suffered to blind us to the obvious truth that the few centuries where in man has been observing nature, form much too brief an interval by which to measure the intensity of geological action in all past time. For aught we can tell, the present is an era of quietude and slow change, compared with some of the eras which have preceded it. nor can we be sure that, when we have explored every geological process now in progress, we have exhausted all the causes of change which even in comparatively recent times have been at work.” And in another place (No. I, under the Age of the Earth) he says plainly that this assumption “may be entirely erroneous.”ARSH August 7, 1883, page 497.5

According to this, “the foundation of a geologist’s training” is an “assumption;” and this assumption must not be allowed a “firm footing” because it may “blind us to an obvious truth,” and because it also may be “entirely erroneous.”ARSH August 7, 1883, page 497.6

And here, after laying a—yes, the—foundation, he has certainly destroyed it, and we might exclaim, not exactly with the psalmist, “if the foundations be destroyed, what shall the “geologists “do”? If, therefore, the foundation be assumption, the superstructure can be nothing more, and this also is just as plainly stated as is the foregoing, as follows:—ARSH August 7, 1883, page 497.7

“In dealing with the Geological Record, as the accessible solid part of the globe is called, we cannot too vividly realize that at the best it forms but an imperfect chronicle. Geological history cannot be compiled from a full and continuous serious of documents. From the very nature of its origin, the record is necessarily fragmentary, ad it has been further mutilated and obscured by the revolutions of successive ages.” “Enormous gaps occur where no record has been preserved at all. It is as if whole chapters and books were missing from an historical work.”—See Part V., Gaps in the Geological Record; also in the Introduction.ARSH August 7, 1883, page 497.8

Geology reveals no beginning:—ARSH August 7, 1883, page 497.9

“It is still true that in the data with which they are accustomed to deal, as comprising the sum of geological evidence, there can be found no trace of a beginning. The oldest rocks which have been discovered on any part of the globe have probably been derived from other rocks older than themselves. Geology, by itself, has not yet revealed, and is little likely ever to reveal, a trace of the first solid crust of our globe. If, then, geological history is to be compiled from direct evidence furnished by the rocks of the earth, it cannot begin at the beginning of things, but must be content to date its first chapter from the earliest period of which any record has been preserved among the rocks.”—Part I., Cosmical Aspects. If, then, it begins at an uncertain place, and follows an uncertain course, and sometimes no course al all, how can the ending be anything else but uncertain?ARSH August 7, 1883, page 497.10

In Part II., Geognosy, he discusses the Age of the Earth, and Measures of Geological Time, from which we extract the following. He says that the age of the earth may be attacked from either the geological or the physical side. First the geological:—ARSH August 7, 1883, page 497.11

“The geological argument rests chiefly upon the observed rates at which geological changes are being effected at the present time, and is open to the obvious preliminary objection that it assumes the existing rate of change as the measure of past revolutions,—an assumption which may be entirely erroneous, for the present may be a period when all geological events march forward more slowly than they used to do.” “If we assume that the land has been worn away, and that stratified deposits have been laid down nearly at the same rate as at present, when we must admit that the stratified portion of the crust of the earth must represent a very vast period of time. Dr. Crall puts this period at not less, but much more, than sixty million years.” “On any supposition, it must be admitted that these vicissitudes in the organic world can only have been effected with the lapse of vast periods of time, though no reliable standard seems to be available whereby these periods are to be measured. The argument from geological evidence is strongly in favor of an interval of probably not less than one hundred million years since the earliest form of life appeared upon the earth, and the oldest stratified rocks began to be laid down.”ARSH August 7, 1883, page 497.12

Yes, no doubt, “if we assume” that such an such is the case, “probably” the balance will follow. But why are we called upon to “assume” an “erroneous assumption” only for the purpose of reaching an indefinite conclusion? This “argument from geological evidence,” is like the famous essay on “Snakes in Ireland;” viz., “There are no snakes in Ireland.” So, likewise, there is no geological evidence, and he says so. Why may we not just as rightfully assume that these changes and revolutions have been wrought in short periods, or even suddenly, as many of them have certainly been made violently?ARSH August 7, 1883, page 497.13

And the argument from physics is just about as inconclusive as that from “geological evidence.” He says:—ARSH August 7, 1883, page 498.1

1. “Sir William Thompson, applying Fourier’s theory* of thermal conductivity, pointed out some years ago (1862) that in the known rate of increase of temperature downward and beneath the surface, and the rate of loss of heat from the earth, we have a limit to the antiquity of the planet. He showed, from the data available at the time, that the superficial consolidation of the globe could not have occurred less than twenty million years ago.... nor more than four hundred million years ago; ... he inclines rather toward the lower than the higher antiquity, but concludes that the limit, from a consideration of all the evidence, must be placed within some such period of past time as one hundred million of years.ARSH August 7, 1883, page 498.2

2. “The argument from tidal retardation proceeds on the admitted fact that, owing to the friction of the tide-wave, the rotation of the earth is retarded, and is therefore much slower now than it must have been at one time. Sir William Thompson contends that had the globe become solid ten thousand million years ago, or indeed any high antiquity above one hundred million years, the centrifugal force due to the more rapid rotation must have given the planet a very much greater polar flattening than it actually possesses. He admits, however, that, though one hundred million years ago that force must have been about three per cent greater than now, yet ‘nothing we know regarding the figure of the earth and the disposition of land and water would justify us in saying that a body consolidated when there was more centrifugal force by three per cent than now, might not now be in all respects like the earth, so far as we know it at present.’” Thus, first, he contends that if the earth had become solid one hundred million years ago, it would have been much flatter at the poles than it is, yet is willing to admit that had it become solid then, we do not know but that it would have been now just as it is. Then if the result is the same in either case, where is the use of going back one hundred million years, or ten thousand million years for the start? And so “Professor Tait concludes that this argument, taken in connection with the previous one, probably reduces the possible period which can be allowed to geologists to something less than ten millions of years.” “What a falling off is there, my countrymen!!” From ten thousand million to simply ten million! May we hope from this that they will finally reach the reasonable limit? But, Mr. Geikie has not yet exhausted his “argument” on the age of the earth; he presents his third from physics, thus:—ARSH August 7, 1883, page 498.3

3. “The third argument, based upon the age of the sun’s heat, is confessedly less reliable than the two previous ones.” But the “two previous ones” themselves are confessedly unreliable and if the third be admitted as “confessedly less reliable” than they, how much reliability has geological science for the age of the earth?ARSH August 7, 1883, page 498.4

The secret, however, of the whole matter is exposed in his last remark on this subject; viz., “One hundred million years is probably amply sufficient for all the requirements of geology.” Yes, the geological ship has been launched upon the sea of speculation, and nothing less than one hundred million years will give her searoom.ARSH August 7, 1883, page 498.5

(To be continued.)

February 13, 1883

August 14, 1883