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LECTURE 5 NOTE G.—P. 185
THE ANTIQUITY OF MAN AND GEOLOGICAL TIME.
In illustration of the tendency in recent science greatly to restrict the period formerly claimed for man’s antiquity, the following passages may be cited from an able article on the Ice Age in The Edinburgh Review for April 1892, based on Dr. Wright’s Ice Age in North America, and its bearings on the Antiquity of Man (1890).903903Dr. Wright’s conclusions are reproduced in his Man and the Glacial Period, in the International Scientific Series, published since this note was written (1892).
“The Falls of Niagara,” says this writer, “indeed constitute of themselves in Dr. Wright’s apt phrase, a glacial chronometer.’ Much trouble has been bestowed upon its accurate rating; and repeated trigonometrical surveys since 1842 afford so sure a basis for calculation, that serious error in estimating, from the amount of work done, the time consumed in doing it need no longer be 445apprehended....The average rate of recession, arrived at through careful weighing of these and other analogous facts, is five feet per annum, or nearly a mile in a thousand years. Hence from seven to eight thousand years have elapsed since the foam of Niagara rose through the air at Queenston; and the interval might even be shortened by taking into account some evidences of pre-glacial erosion by a local stream, making it probable that from the whirlpool downward the cutting of the gorge proceeded more rapidly than it does now. The date of the close of the Glacial Epoch in the United States can scarcely then be placed earlier than 6000 B.C. . . .
“Their testimony does not stand alone. . . . Pre-glacially, it [the Mississippi] followed a wide bend from Minneapolis to Fort Snelling; now it flows straight across the intervening eight miles to its junction with the Minnesota. On its way it leaps the Falls of St. Anthony; and the rate of their retreat since 1680, exactly determined from the observation of Father Hennequin, proves them to be about eight thousand three hundred years old. This second glacial timepiece accordingly, which, owing to Its more southerly position was started earlier than the first, gives substantially the same reading. . . . The ravines and cascades of Ohio, studied by Dr. Wright, agree with the two great Falls in giving a comparatively recent overthrow of the ice regime. The unworn condition of the glacial deposits, the sharpness of glacial groovings, above all, the insignificant progress made by the silting up of glacial lakes, testify as well, and in some cases quite definitely, to a short lapse of time.
“But if the Ice Age in America terminated—as we seem bound to admit—less than ten thousand years ago, so, beyond question, did the Ice Age in Europe. There is no possibility of separating the course of glacial events in each continent. The points of agreement are too many; the phenomena too nearly identical in themselves and in their sequence. Elevation and depression of continents, the formation, retreat, and second advance of the ice-sheet, the accompaniment of its melting by tremendous floods, the extermination of the same varieties of animals, the appearance and obliteration of Palaeolithic man, all preserved identical mutual relations in the Old and New Worlds. . . . The point has an important bearing upon the vexed question of the antiquity of man,” etc. —Edinburgh Review, April 1892, pp. 315–319.
The same view was advocated by Mr. P. F. Kendall in a paper prepared by Mr. Gray and himself on “The. Cause of the Ice-Age,” read in the Geological Section of the British Association, August 4, 1892. He said: “Another fact of great importance bearing upon this question was the exceedingly recent date of the glacial period. It was the custom of geologists not long ago to talk about the glacial period as perhaps a quarter of a million years ago, or, at all events, to make a very liberal use of thousands and hundreds of thousands of years. But now it was found that all the physical evidence was in favour of a very recent departure of the ice. They could, for instance, put the date of the commencement of the great cut of the Niagara Falls at the close of the glacial period, and other 446like evidence in America pointed clearly to the recency of the departure of the ice.”—Scotsman Report, August 5. The remainder of the paper was an examination of the theories of the late Dr. Croll, Dr. Wall, and Mr. Warren Upham, and the exposition by the authors of a theory of their own connected with the variability in the heat of the sun. Sir Archibald Geikie, in his President’s Address at the same meeting of the British Association, while himself putting in a plea for longer periods on the ground of the geological record, grants that the recent drift of physical science has been enormously to reduce the unlimited drafts on time formerly made by geologists. Lord Kelvin “was inclined, when first dealing with the subject, to believe that, from a review of all the evidence then available, some such period as one hundred million years would embrace the whole of the geological history of the globe. . . . But physical inquiry continued to be pushed forward with regard to the early history and antiquity of the earth. Further consideration of the influence of tidal rotation in retarding the earth’s rotation, and of the sun’s rate of cooling, led to sweeping reductions of the time allowable for the evolution of the planet. The geologist found himself in the plight of Lear when his bodyguard of one hundred knights was cut down. ‘What need you five-and-twenty, ten, or five? demands the inexorable physicist, as he remorselessly strikes slice after slice from his allowance of geological time. Lord Kelvin, I believe, is willing to grant us some twenty millions of years, but Professor Tait would have us content with less than ten millions.”—Report of Address. One argument of Professor Geikie for lengthening the time is the extreme slowness with which, on the evolution hypothesis, the changes in species have been brought about—a very distinct petitio principii. It is worth while in this connection to note his admission: “So too with the plants and the higher animals which still survive. Some forms have become extinct, but few or none which remain display any transitional gradations into new species.”
Professor Tait’s own words are: “I daresay many of you are acquainted with the speculations of Lyell and others, especially of Darwin, who tell us that even for a comparatively brief portion of recent geological history three hundred millions of years will not suffice.—Origin of Species, 1859, p. 287. We say: So much the worse for geology as at present understood by its chief authorities; for, as you will presently see, physical considerations from independent points of view render it utterly impossible that more than ten or fifteen millions of years can be granted.”—Recent Advances in Physical Science, pp. 167, 168. “From this point of view we are led to a limit of something like ten millions of years as the utmost we can give to geologists for their speculations as to the history even of the lowest orders of fossils” (p. 167).
See further on this subject Dawson’s Origin of the World, and Fossil Men and their Modern Representatives; Reusch’s Nature and the Bible, ii. pp. 265–366; and Wright’s Man and the Glacial Period, in the International Scientific Series.447
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