Narrative and Critical History of America, Vol. 1 (of 8) / Aboriginal America

by Unknown

He then goes on to consider the bearings of the age of this gravel upon the question of the antiquity of man. “When we find that the Trenton gravel contains implements of human workmanship so placed with reference to it that it is evident that at or soon after the time of its deposition man had appeared on its borders, and when the question of the antiquity of man in America is thus before us, we are tempted to inquire still further into the age of the deposit under discussion. It has been clearly shown by several competent archæologists that the implements that have been found are a constituent part of the gravel, and not intrusive objects. It was of peculiar interest to find that it has been only within the limits of the Trenton gravel, precisely traced out by the writer, that Dr. Abbott, Professor F. W. Putnam, Mr. Lucien Carr, and others, have discovered these implements in situ.... At the localities on the Pennsylvania Railroad, where extensive exposures of these gravels have been made, the deposit is undoubtedly undisturbed. No implements could have come into this gravel except at a time when the river flowed upon it, and when they might have sunk through the loose and shifting material. All the evidence points to the conclusion that at the time of the Trenton gravel flood man ... lived upon the banks of the ancient Delaware, and lost his stone implements in the shifting sands and gravel of the bed of that stream.... The actual age of the Trenton gravel, and the consequent date to which the antiquity of man on the Delaware should be assigned, is a question which geological data alone are insufficient to solve. The only clew, and that a most unsatisfactory one, is afforded by calculations based upon the amount of erosion. This, like all geological considerations, is relative rather than absolute, yet several calculations have been made, which, based either upon the rate of erosion of river channels or the rate of accumulation of sediment, have attempted to fix the date of the close of the glacial epoch. By assuming that the Trenton gravel was deposited immediately after the close of this epoch, an account of such calculations may be of interest. If the Trenton gravel is post-glacial in the widest acceptation of the term, a yet later date must be assigned to it.”

After going carefully through them all, he concludes: “Thus we find that if any reliance is to be placed upon such calculations, even if we assume that the Trenton gravel is of glacial age, it is not necessary to make it more than ten thousand years old. The time necessary for the Delaware to cut through the gravel down to the rock is by no means great. When it is noted that the gravel cliff at Trenton was made by a side wearing away at a bank, and when it is remembered that the erosive power of the Delaware River was formerly greater than at present, it will be conceded that the presence of the cliff at Trenton will not necessarily infer its high antiquity; nor in the character of the gravel is there any evidence that the time of its deposition need have been long. It may be that, as investigations are carried further, it will result not so much in proving man of very great antiquity as in showing how much more recent than usually supposed was the final disappearance of the glacier.”

Professor Lewis’s studies of the great terminal moraine of the northern ice-sheet were still further prosecuted in conjunction with Professor George Frederick Wright, of Oberlin, Ohio, whose labors have been of the highest importance in shedding light upon the question of the antiquity of man in America.[1498] Together they traced the southern boundary of the glacial region across the State of Pennsylvania, and subsequently Professor Wright has continued his researches through the States of Ohio, Indiana, and Kentucky, as far as the Mississippi River and even beyond. He has found that glacial floods similar to those of the Delaware valley have deposited similar beds of drift gravel in the valleys of all the southerly flowing rivers, and he has called attention to the importance of searching in them for palæolithic implements. As early as March, 1883, he predicted that traces of early man would be found in the extensive terraces and gravel deposits of the southern portion of Ohio.[1499] This prediction was speedily fulfilled, and upon November 4, 1885, Professor Putnam reported to the Boston Society of Natural History that Dr. C. L. Metz, of Madisonville, Ohio, had found in the gravels of the valley of the Little Miami River, at that place, eight feet below the surface, a rude implement made of black flint, of about the same size and shape as one of the same material found by Dr. Abbott in the Trenton gravels. This was followed by the announcement from Dr. Metz that he had discovered another specimen (a chipped pebble) in the gravels at Loveland, in the same valley, at a depth of nearly thirty feet from the surface. Professor Wright has visited both localities, and given a detailed description of them, illustrated by a map. He finds that the deposit at Madisonville clearly belongs to the glacial-terrace epoch, and is underlain by “till,” while in that at Loveland it is known that the bones of the mastodon have been discovered. He closes his account with these words: “In the light of the exposition just given, these implements will at once be recognized as among the most important archæological discoveries yet made in America, ranking on a par with those of Dr. Abbott at Trenton, New Jersey. They show that in Ohio, as well as on the Atlantic coast, man was an inhabitant before the close of the glacial period.”[1500] Further confirmation of these predictions was received at the meeting of the American Association for the Advancement of Science, at Cleveland, Ohio, in August, 1888, when Mr. Hilborne T. Cresson reported his discovery of a large flint implement in the glacial gravels of Jackson County, Indiana, as well as of two chipped implements made of argillite, which he had found in place at a depth of several feet in the ancient terrace of the Delaware River, in Claymont, Newcastle County, Delaware.[1501]

This discovery of Mr. Cresson’s has assumed a great geological importance, and it is thus reported by him: “Toward midday of July 13, 1887, while lying upon the edge of the railroad cut, sketching the boulder line, my eye chanced to notice a piece of steel-gray substance, strongly relieved in the sunlight against the red-colored gravel, just above where it joined the lower grayish-red portion. It seemed to me like argillite, and being firmly imbedded in the gravel was decidedly interesting. Descending the steep bank as rapidly as possible, the specimen was secured.... Upon examining my specimen I found that it was unquestionably a chipped implement. There is no doubt about its being firmly imbedded in the gravel, for the delay I made in extricating it with my pocket-knife nearly caused me the unpleasant position of being covered by several tons of gravel.... Having duly reported my find to Professor Putnam, I began, at his request, a thorough examination of the locality, and on May 25, 1888, the year following, discovered another implement four feet below the surface, at a place about one eighth of a mile from the first discovery.... The geological formation in which the implement was found seems to be a reddish gravel mixed with schist.”[1502]

Professor Wright thus comments upon these discoveries and their geological situation: “The discovery of palæolithic implements, as described by Mr. Cresson, near Claymont, Del., unfolds a new chapter in the history of man in America. It was my privilege in November last to visit the spot with him, and to spend a day examining the various features of the locality.... The cut in the Baltimore and Ohio railroad in which this implement was found is about one mile and a half west of the Delaware River, and about one hundred and fifty feet above it. The river is here quite broad. Indeed, it has ceased to be a river, and is already merging into Delaware Bay; the New Jersey shore being about three miles distant from the Delaware side. The ascent from the bay at Claymont to the locality under consideration is by three or four well-marked benches. These probably are not terraces in the strict sense of the word, but shelves marking different periods of erosion when the land stood at these several levels, but now thinly covered with old river deposits. Upon reaching the locality of Mr. Cresson’s recent discovery, we find a well-marked superficial water deposit containing pebbles and small boulders up to two or three feet in diameter, and resting unconformably upon other deposits, different in character, and in some places directly upon the decomposed schists which characterize the locality. This is without question the Philadelphia Red Gravel and Brick Clay of Lewis. The implement submitted to us was found near the bottom of this upper deposit, and eight feet below the surface.... As Mr. Cresson was on the ground when the implement was uncovered, and took it out with his own hands, there would seem to be no reasonable doubt that it was originally a part of the deposit; for Mr. Cresson is no novice in these matters, but has had unusual opportunities, both in this country and in the old world, to study the localities where similar discoveries have heretofore been made. The absorbing question concerning the age of this deposit is therefore forced upon our attention as archæologists.... The determination of the age of these particular deposits at Claymont involves a discussion of the whole question of the Ice Age in North America, and especially that of the duality of the glacial epoch. At a meeting of this society on January 19, 1881, I discussed the age of the Trenton gravel, in which Dr. Abbott has found so many palæoliths, and was led also incidentally at the same time to discuss the relative age of what Professor Lewis called the Philadelphia Red Gravel. I had at that time recently made repeated trips to Trenton, and with Professor Lewis had been over considerable portions of the Delaware valley for the express purpose of determining these questions. The conclusions to which we—that is, Professor Lewis and myself—came were thus expressed in the paper above referred to (Proc. Boston Soc. of Nat. Hist., vol. xxi. pp. 137-145), namely, that the Philadelphia Brick Clay and Red Gravel (which are essentially one formation) marked the period when the ice had its greatest extension, and when there was a considerable depression of the land in that vicinity; perhaps, however, less than a hundred feet in the neighborhood of the moraine, though increasing towards the northwest. During this period of greatest extension and depression, the Philadelphia Red Gravel and Brick Clay were deposited by the ice-laden floods which annually poured down the valley in the summer seasons. As the ice retreated towards the headwaters of the valley, the period was marked also by a reëlevation of the land to about its present height, when the later deposits of gravel at Trenton took place. Dr. Abbott’s discoveries at Trenton prove the presence of man on the continent at that stage of the glacial epoch. Mr. Cresson’s discoveries prove the presence of man at a far earlier stage. How much earlier, will depend upon our interpretation of the general facts bearing on the question of the duality of the glacial epoch.

“Mr. McGee, of the United States Geological Survey, has recently published the results of extensive investigations carried on by him respecting the superficial deposits of the Atlantic coast. (See Amer. Jour. of Science, vol. xxxv., 1888.) He finds that on all the rivers south of the Delaware there are deposits corresponding in character to what Professor Lewis had denominated Philadelphia Red Gravel and Brick Clay.... From the extent to which this deposit is developed at Washington, in the District of Columbia, Mr. McGee prefers to designate it the Columbia formation. But the period is regarded by him as identical with that of the Philadelphia Red Gravel and Brick Clay, which Professor Lewis had attributed to the period of maximum glacial development on the Atlantic coast.

“It is observable that the boulders in this Columbia formation belong, so far as we know, in every case, to the valleys in which they are now found.... It is observable also that it is not necessary in any case to suppose that these deposits were the direct result of glacial ice. Mr. McGee does not suppose that glaciers extended down these valleys to any great distance. Indeed, so far as we are aware, there is no evidence of even local glaciers in the Alleghany Mountains south of Harrisburg. But it is easy to see that an incidental result of the glacial period was a great increase of ice and snow in the headwaters of all these streams, so as to add greatly to the extent of the deposits in which floating ice is concerned. And this Columbia formation is, as we understand it, supposed by Mr. McGee to be the result of this incidental effect of the glacial period in increasing the accumulations of snow and ice along the headwaters of all the streams that rise in the Alleghanies. In this we are probably agreed. But Mr. McGee differs from the interpretation of the facts given by Professor Lewis and myself, in that he postulates, largely, however, on the basis of facts outside of this region, two distinct glacial epochs, and attributes the Columbia formation to the first epoch, which he believes to be from three to ten times as remote as the period in which the Trenton gravels were deposited. If, therefore, Dr. Abbott’s implements are, as from the lowest estimate would seem to be the case, from ten thousand to fifteen thousand years old, the implements discovered by Mr. Cresson in the Baltimore and Ohio cut at Claymont, which is certainly in Mr. McGee’s Columbia formation, would be from thirty thousand to one hundred and fifty thousand years old.

“But as I review the evidence which has come to my knowledge since writing the paper in 1881, I do not yet see the necessity of making so complete a separation between the glacial epochs as Mr. McGee and others feel compelled to do. But, on the other hand, the unity of the epoch (with, however, a marked period of amelioration in climate accompanied by extensive recession of the ice, and followed by a subsequent re-advance over a portion of the territory) seems more and more evident. All the facts which Mr. McGee adduces from the eastern side of the Alleghanies comport, apparently, as readily with the idea of one glacial period as with that of two.... Until further examination of the district with these suggestions in view, or until a more specific statement of facts than we find in Mr. McGee’s papers, it would therefore seem unnecessary to postulate a distinct glacial period to account for the Columbia formation.... But no matter which view prevails, whether that of two distinct glacial epochs, or of one prolonged epoch with a mild period intervening, the Columbia deposits at Claymont, in which these discoveries of Mr. Cresson have been made, long antedate (perhaps by many thousand years) the deposits at Trenton, N. J., at Loveland and Madison, Ohio, at Little Falls, Minn., ... and at Medora, Ind.... Those all belong to the later portion of the glacial period, while these at Claymont belong to the earlier portion of that period, if they are not to be classed, according to Mr. McGee, as belonging to an entirely distinct epoch.”[1503]

The objects discovered by both Dr. Metz and Mr. Cresson have been deposited in the Peabody Museum at Cambridge, and their artificial character cannot be disputed.