Relics of the kinds above cited have been found at intervals for many years past, but their age and significance were doubted, and only within some forty years has the great antiquity of man upon the earth been generally acknowledged by scientists. The most important early find of ancient implements was made by Boucher de Perthes in 1841 and subsequently, in the high level gravels of the valley of the Somme, in Picardy, France. In deep layers of these gravels, which were deposited at a period when the river occupied a wider and higher channel than at present, he found rude flint weapons and tools, bearing plain evidences of human workmanship, and mingled with the teeth and bones of animals, both of living and extinct species. Among the bones were those of the mammoth and the hairy rhinoceros, species evidently contemporary with man, though they have long since vanished from the earth. At a somewhat earlier date, implements of men, mingled with bones of the cave-bear, cave-lion, hyena, and other species, had been found in the caves of France and Belgium. These were frequently buried beneath deposits of stalagmite and other materials that must have taken a long time to accumulate.
The significance of these discoveries was long in forcing itself upon the attention of scientific men. Nearly twenty years passed before Boucher de Perthes could get the noted geologists of France and England to investigate the Somme gravels. When they did so they were quickly convinced of the genuine antiquity of these relics, and announced it as a fact beyond question that man had lived in the Somme valley and fashioned rude implements out of flint during what was known as the Quaternary or Drift Period of geology.
The discoveries here made set men actively at work investigating elsewhere. Excavations were made in other high level gravels, caverns were carefully and minutely examined, Kent's Cavern, England, was dug out to its rock bottom, dozens of important finds resulted, and the antiquity of man was proved to extend back from thousands to tens of thousands, if not to hundreds of thousands, of years. And the coexistence of man with the animals whose bones accompanied his relics was proved by unquestionable evidence, for drawings and carved forms of these animals were found, proving incontestably that man had gazed upon their living forms. Thus the sketch of a mammoth, showing the long hair which served to protect this animal from the cold, was found engraved upon a piece of mammoth ivory, and one of a group of reindeer on a piece of reindeer horn. There were also drawings of the cave-bear, the seal, etc., and one very interesting group showing the aurochs, a number of trees, and a man with a snake apparently biting his heel. The carvings consisted of the horn handle of a dagger, cut into the shape of a reindeer, and other forms.
That these relics belong to a far distant age is proved by the strongest evidence. It must suffice here to give some of the more striking of these proofs of antiquity. The flint hatchets found at St. Acheul, France, were obtained from a gravel bed which lay below twelve feet of sand and marl. On the surface was a layer of soil, in which were graves of the Gallo-Roman period, showing that it had been there for at least fifteen hundred years. The time needed for the slow accumulation of the whole series of deposits must have been very considerable.
A much more decisive proof of antiquity is given by the position in which this and similar gravel beds lie. They are found along the sides of rivers at a height often of a hundred or two hundred feet above the flood level of the streams. When they were deposited, the rivers must have run at this elevation, so that time has since elapsed sufficient for the streams to cut down their valleys to the present depths. The streams may have formerly been of greater volume, and had superior cutting powers, and they may have been aided by the ice of the Glacial Age, yet, however we estimate, the conclusion is inevitable that the men who dropped their implements into those gravels must have lived upon the earth ages before the beginning of historical times.
The presence there of remains of animals which ages ago perished from the earth is another circumstance indicative of high antiquity. These embrace the mammoth,—the great hairy elephant of prehistoric times,—an extinct hair-clad rhinoceros, the large and powerful cave-bear and cave-lion, the great Irish elk, and still other animals of whose existence we know only by their bones. Others, which existed in common with men of later date, are the reindeer and the musk-ox, species of which now inhabit the coldest regions of the north, and whose presence in southern Europe at that era seems to indicate a much colder climate than that of historic times.
The evidences of human antiquity here briefly presented are accompanied by indications of a gradual development of the human intellect. If man has "fallen from his high estate," he has left no traces of this high estate on his downward path. We possess abundant indications of his upward climb, we find none of a preceding descent. If we base our opinions on known facts, the theory of development is the only one that can be sustained; the doctrine of a fall is absolutely without warrant outside the pages of Genesis.
The successive stages of man's mental development, as indicated in the work of his hands, are well and clearly marked. At the lowest level we find tools and weapons of the palæolithic or old stone age, made of roughly chipped stone, rude in form, and never ground or polished. These present some evidence of gradual improvement, but we must go to a higher level to find implements of a decidedly higher order, the neatly shaped and polished stone implements of the neolithic or new stone age. With the coming of these appears a much greater diversity in tools and weapons, and evidences of a growing skill in manufacture and a considerably greater power of invention. Still higher lie the deposits of the bronze age, in which metal replaces stone in human implements. Finally appears the age of iron, that in which we still remain. We need merely refer in passing to the lake-dwellings of Switzerland, with their many interesting relics of man during the later stone, the bronze, and the early iron eras; and the kitchen-middens, or refuse-heaps, of the Danish islands and elsewhere, which extend from the old stone age far down toward the historic period.
These are but a portion of the evidences of man's antiquity and his gradual progress in the arts of manufacture. Others have been found in many parts of the earth. Many of them exist in America, proving that man resided on this continent at a very distant era. When we consider that late discoveries in Babylonia appear to carry back the age of civilization and historical relics to some ten thousand years, and that semi-civilization must have extended very considerably beyond that time, the vista of man's gradual progress seems to recede interminably and the era of primitive man to stretch backward to an enormously remote period. In truth, discoveries have been made which are claimed to carry man back beyond the Quaternary and into the Tertiary Period of geology, since cut and scratched bones have been found in Pliocene deposits, which some geologists of experience believe to have been the work of human hands. Still more remote are some seemingly chipped flints and bones cut in a way that suggests human action, which have been found in deposits of the very far-distant Miocene Age. The immense remoteness of this epoch and the rudeness of the work have cast much doubt on the human origin of these remains, though their authenticity as the work of man has been accepted by several competent observers, among them the able anthropologist, Quatrefages.
If we confine ourselves, however, to the conclusions regarding ancient man which are generally accepted, we must say that he has not been clearly traced back beyond the Glacial Period, though some of the relics found in the older river gravels and in the lowest cave accumulations may well be of pre-glacial age. Many geologists believe that he reached Europe as early as the extinct mammals with which he was contemporaneous there, but how far back in time this would carry his advent it is impossible to say.