Another remark which we make here, is respecting the power which a single fact may have in this investigation. It is not often that great questions in history, or social polity, or jurisprudence are determined by a single fact. The great results of history, economics, and law are effected by the converging power of many facts. So also in science. Its great results are determined by the accumulated power of multitudinous facts. Its final categories are fixed by abundant certainties and manifold inductions. And yet it may sometimes occur that a single fact may be of such a nature that there is no escaping the conclusion which it forces upon the mind. It may concentrate in itself all the elements of certainty usually obtained from many sources. It may be determinative in its very nature, and admit of scepticism only at the expense of rationality. A single human grave, with its entombed skeleton, discovered in some uninhabited waste, where it was never known the foot of man had trod, would prove conclusively that human footsteps had once trod there. The discovery of a single weapon of the quality and temper of the Damascus blade amid the ruins of a buried city, would prove as fully as would the discovery of a thousand that the people of that age of the world understood the methods of working steel. One canoe found moored to the bank of the Delaware, the Schuylkill, or the Susquehanna, when the white man began to penetrate this continent, would have been sufficient to prove that the aborigines understood, to that extent, the art of navigation. So in science, one fossil of a different species from any found heretofore in a certain deposit is sufficient to add another to the forms of life represented by that deposit. One fossil found lower in the geological scale than life was supposed to have begun on this planet, is sufficient to prove that it had a still earlier beginning. So with regard to contemporary forms of life, one fact may be sufficient to warrant or compel a conclusion. Hugh Miller cites the instance of fossil dung being found as proving to the anti-geologists that these fossils were once real living creatures, and not mere freaks of nature. The instance might not be thought conclusive, for if the Author of nature saw fit to amuse himself by making the semblances of huge iguanodons, elephants, and hippopotami, in the solid rocks, it might readily be supposed that He would extend His amusement to the making of fossil dung.[2] But now, if in the fossil entrails of the cave hyena the bones of a hare should be found, it would prove conclusively to any but an anti-geologist, that the hare lived contemporaneously with the hyena.
These remarks are not thrown in by way of apology for the paucity of facts adduced by Sir Charles Lyell to prove the antiquity of man, but merely to illustrate the force which it is possible, in certain circumstances, for a single fact to have. Thus, for instance, the Scotch fir is not now, nor ever has been in historic times, a native of the Danish isles, yet it has been indigenous there in the human period, for Steenstrup has taken out with his own hands a flint implement from beneath one the buried trunks of that species in the Danish peat bogs. Again, if an implement of human workmanship is found in close proximity to the leg of a bear, or the horn of a reindeer, of extinct species, in an ancient cavern, and all covered by a floor of stalagmite, we see not how the conclusion is to be avoided that they were introduced into the cave before the stalagmite was formed; and in that case the inference that they were contemporaneous, or nearly so, may well be left to take care of itself. The attempt has been made to treat with levity the whole subject of the antiquity of man because of the numerical meagreness of the facts adduced in support of it. But as to this, it need only be observed that as a new theme for investigation, its facts must necessarily be meagre, as must be the facts of any science in its inchoate condition, and that they are steadily growing in volume, so that it is not safe to venture a final verdict against it on that score. The facts in support of the globular form of the earth, or the Copernican theory of the heavens, or the great age of the earth, were at one time meagre—they are not so now. Sir Charles Lyell is a pioneer explorer in a new and mysterious realm: the time may come when, amid the abundance of the treasure gathered from it, the scanty hoard which he opens to his reader may seem meagre enough.
Nevertheless, Sir Charles Lyell is fully a believer in the doctrine of the high antiquity of man. His book is not merely a debating-club discussion of the pros and cons, the probabilities for and against the doctrine, but rather the earnest pleading of the advocate fully persuaded that the truth is on his side. Not that it displays any forensic heat;—it is calm, cautious, dispassionate; but it has the air of one governed by conviction, and he often assumes the entire truth of his conclusions with the quiet nonchalance of a man seemingly unconscious that what he regards as matters of established certainty will be viewed by the great majority of his fellow beings as startling novelties.
The main stream of the geological evidence of the antiquity of man tends to one point, viz., that man coexisted with the extinct animals. There are collateral branches of proof, but this is the main channel. The remains of man and of man's works and the remains of extinct races of animals lie side by side, and claim from the geologist the same meed of antiquity. This is the burden of the book before us. We offer the reader a brief outline of this evidence. In doing so, we will follow the order of Sir Charles Lyell's work, and merely state the leading facts which geological investigations have brought to light.
In the Danish islands there are deposits of peat from ten to thirty feet thick, formed in the hollows or depressions of the northern drift or bowlder formation. These beds of peat have been examined to the bottom, and they reveal the history of vegetation in those localities, and the contemporaneous history of human progress. Beginning at the top, the explorer finds the first layers to contain principally the trunks of the beech tree, along with implements and tools of wood and iron. Below these is a deposit of oak trunks, with implements mainly of bronze. Farther down still he finds the trunks of the Pinus sylvestris, or Scotch fir, together with implements of stone. This clearly indicates that in the lapse of centuries the pine was supplanted by the oak, and the oak by the beech, and that man advanced contemporaneously from the knowledge and use of stone implements to those of bronze and iron. Now the known fact is that in the time of the Romans, as now, the Danish isles were covered by magnificent beech forests, and that eighteen centuries have done little or nothing toward changing the character of the vegetation. How many centuries must have elapsed to enable the oak to supplant the pine, and the beech to supplant the oak, can only be vaguely conjectured. Yet the evidence is clear that man lived in those old pine forests—leaving his implements of stone behind him, as he did his tools of bronze and iron in the succeeding periods. Along the coast of Denmark, also, are found shell mounds mixed with flint knives, hatchets, etc., but never any tools of bronze or iron, showing that the rude hunters and fishers who fed on the oyster, cockle, and other mollusks, lived in the period of the Scotch fir, or, as it has been called, the 'age of stone.'
In many of the Swiss lakes are found ancient piles driven into the bottom, on which were once erected huts or villages, the lacustrine abodes of man. This use of them is proved by the abundance of flint implements and fragments of rude pottery, together with bones of animals, which have been dredged up from among the piles. The implements found belong to the 'age of stone,' or the period of the Scotch fir in Denmark, and the bones of animals are all, with one exception, those of living species.
Passing over the fossil human remains and works of art of the 'recent' period, as found in the delta and alluvial plain of the Nile, in the ancient mounds of the valley of the Ohio, in the mounds of Santos in Brazil, in the delta of the Mississippi, in which, at the depth of sixteen feet from the surface, under four buried forests, superimposed one upon the other, was found, a few years ago, a human skeleton, estimated by Dr. B. Dowler to have been buried at least fifty thousand years—in the coral reefs of Florida, in which fossil human remains were found, estimated by Professor Agassiz to have an antiquity of ten thousand years—in the recent deposits of seas and lakes, in the central district of Scotland, which bears clear traces of an upheaval since the human period, and in the raised beaches of Norway and Sweden—passing over these for want of space for minute detail, we go back to the post-pliocene period, and find the bones of man and works of art in juxtaposition with the fossil remains of extinct mammalia.
In the cavern of Bize, in the south of France, and in the caves of Engis, Engihoul, Chokier, and Goffontaine, near Liége, human bones and teeth, together with fragments of rude pottery, have been found enveloped in the same mud and breccia, and cemented by stalagmite, in which are found also the land shells of living species and the bones of mammalia, some of extinct, and others of recent species. The chemical condition of all the bones was found to be the same. Quite a full account is given of the researches of MM. Journal and Christol in the Bize cavern, and of Dr. Schmerling in the Liége caverns, and every effort made, apparently, by the author, to weigh candidly and honestly the evidence for and against the contemporaneous existence and deposition of the human and mammalian remains. And while he admits that at one time he was strongly inclined to suspect that they were not coeval[3], yet he has been compelled by subsequent evidence, especially in view of the fact that he has had convincing proofs in later years that the remains of the mammoth and many other extinct species, very common in caves, occur also in undisturbed alluvium, imbedded in such a manner with works of art as to leave no room for doubt that man and the extinct animals coexisted, to reconsider his former opinion, and to assign to the proofs derived from caves of the high antiquity of man a much more positive and emphatic character.
In chapter fifth we have a minute and interesting account of such fossil human skulls and skeletons as have been found in caves and ancient tumuli, and a careful endeavor made to estimate their approximate age. In 1857, in a cave situated in that part of the valley of the Düssel, near Düsseldorf, which is called the Neanderthal, a skull and skeleton were found, buried beneath five feet of loam, which were pronounced by Professor Huxley and others to be clearly human, though indicating small cerebral development and uncommon strength of corporeal frame. In the Engis caves, near Liége, portions of six or seven human skeletons were found, imbedded in the same matrix with the remains of the elephant, rhinoceros, bear, hyena, and other extinct quadrupeds. In an ancient tumulus near Borrely, in Denmark, a human skull was discovered which was adjudged by its surroundings to belong to the 'stone period' of Denmark, or the era of the Scotch fir. The careful anatomical examination and comparison to which these skulls have been subjected, have led to important discussions, not only as to their age, but also as to their relation to existing races.
Next comes an extended account of the flint implements and other works of art, found so abundantly in juxtaposition with the bones of extinct mammalia, in various localities—in a cave at Brixham, near Torquay, in Devonshire; in the alluvium of the Thames valley; in the gravel of the valley of the Ouse, near Bedford; in a fresh-water deposit at Hoxne in Suffolk; in the valley of the Lach at Icklingham; in a cavern in Somersetshire; in the caves of Gomer in Glamorganshire, in South Wales; and especially in the gravel beds of Abbeville and Amiens, in France, and various localities of the valley of the Somme. As to these flint implements, they are chiefly knives, hatchets, and instruments of that sort, and they have been found in such large numbers, and such diverse localities, and so uniformly in close proximity with the remains of the same species of extinct mammalia, that the evidence derived from them is, to say the least, of a very weighty character, and in the opinion of Sir Charles Lyell clearly establishes the fact that Elephas primigenius, Elephas antiquus, Rhinoceros tichorrhinus, Ursus spelœus, and other extinct species of the post-pliocene alluvium, coexisted with man.