In 1874, Dr. Samuel Aughey made known the existence in Nebraska of “hundreds of miles of similar lacustrine deposits, almost level or gently rolling.”[1512] To these the name of “loess” has also been given, as well as to the mud deposits derived from the northern drift. Aughey states that these beds are perfectly homogeneous throughout, and of almost uniform color, ranging in thickness from five to one hundred and fifty feet. Generally they lie above a true drift formation derived from glaciers in the Black Hills, and represent “the final retreat of the glaciers, and that era of depression of the surface of the State when the greater part of it constituted a great fresh-water lake, into which the Missouri, the Platte, and the Republican rivers poured their waters.” The Missouri and its tributaries, flowing for more than one thousand miles through these deposits, gradually filled up this great lake with sediment. The rising of the land by degrees converted the lake-bottom into marshes, through which the rivers began to cut new channels, and to form the bluffs which now bound them. “The Missouri, during the closing centuries of the lacustrine age, must have been from five to thirty miles in breadth, forming a stream which for size and majesty rivalled the Amazon.” Many remains of mastodons and elephants are found in this so-called loess, as well as those of the animals now living in that region, together with the fresh-water and land shells peculiar to it. In it Aughey has also discovered an arrow-point and a spear-head, of which he gives well-executed figures. Both are excellent examples of those well-chipped implements which are regarded as typical of the Neolithic age or the age of polished stone, and are absolutely different from the palæolithic implements of which we have hitherto spoken. They were both found in railroad cuttings on the Iowa side of the Missouri River, and within three miles of it. The first lay at a depth of fifteen feet below the top of the deposit. Of the second he says it was “twenty feet below the top of the loess, and at least six inches from the edge of the cut, so that it could not have slid into that place.... Thirteen inches above the point where it was found, and within three inches of being on a line with it, in undisturbed loess, there was a lumbar vertebra of an elephant.”[1513]
This intermingling in these deposits of the bones of extinct and living animals appears to have been brought about by the shifting of the beds of the vast rivers he has described, which have been flowing for ages through the slight and easily moved material. It seems to be analogous to what has taken place in recent times in the valley of the Mississippi and in its delta. The finding, therefore, of arrow-heads of recent Indian type, even in place under twenty feet of loess and below a fossil elephant-bone, cannot be considered as affording any stronger proof of the antiquity of man than the oft-cited instances of the discovery of basket-work and pottery underneath similar fossils at Petite Anse Island in Louisiana, or of pottery and mastodon-bones on the banks of the Ashley River in South Carolina. No such discovery can be considered of consequence as bearing upon the question of palæolithic man.
The late Thomas Belt wrote to Professor Putnam, in 1878, that he had discovered “a small human skull in an undisturbed loess in a railway cutting about two miles from Denver (Colorado). All the plains are covered with a drift deposit of granitic and quartzose pebbles overlaid by a sandy and calcareous loam closely resembling the diluvial clay and the loess of Europe. It was in the upper part of the drift series that I found the skull. Just the tip of it was visible in the cutting about three and one half feet below the surface.”[1514] Not long after this Mr. Belt died, and we are without further information in regard to the locality. It would seem, however, that the loess in which the skull occurred belongs to the latest in the lacustrine series, and consequently does not imply any very great antiquity for it.
OBSIDIAN SPEAR-HEAD
Found in the Lahontan sediments,—from a cut in Russell’s Lake Lahontan, monograph xi. of Powell’s U. S. Geological Survey, p. 247.
In 1882 Mr. W. J. McGee, of the U. S. Geological Survey, obtained from the upper lacustral clays of the basin of the ancient Lake Lahontan, where they are exposed in the walls of Walker River Cañon, a spear-head, made of obsidian, beautifully chipped, and perfectly resembling those found on the surface throughout the southwest. “It was discovered projecting point outwards from a vertical scarp of lacustral clays twenty-five feet below the top of the section, at a locality where there were no signs of recent disturbance.”[1515] This is said to have been “associated in such a manner with the bones of an elephant or mastodon as to leave no doubt of their having been buried at approximately the same time.” But we are also told that these lakes are of very recent date, and that they have “left the very latest of all the complete geological records to be observed in the Great Basin.”[1516] The fossil shells obtained from these deposits all belong to living species; while the mammalian remains, which have been found in only very limited numbers, and all, with a single exception, in the upper beds, “are the same as occur elsewhere in tertiary or quaternary strata.” Mr. McGee says: “If the obsidian implement ... was really in situ (as all appearances indicated), it must have been dropped in a shallow and quiet bay of the saline and alkaline Lake Lahontan, and gradually buried beneath its fine mechanical deposits and chemical precipitates.”[1517]
In Mr. Russell’s opinion, this single implement, although supported by no other finds of a similar character, is sufficient to prove that “man inhabited this continent during the last great rise of the former lake.” But if this last great rise occurred in recent times, the presence of the bones of tertiary mammals in the upper beds shows that great natural forces must have been in operation at that time to have washed these out of their original place of deposit. The principal organic remains found, we are told, are those of living shells, and the intermingling of these with the bones of tertiary mammals could scarcely have taken place in “shallow and quiet bays.” To the writer this discovery seems rather to prove that an Indian spear-head was in some manner washed down and buried in the clays of the Walker River Cañon than that man was the contemporary there of the tertiary or quaternary mammalia. This fairly seems to be a case where, in the language of Dr. Brinton, “Archæology may at times correct Geology.”[1518]