by any sudden cataclysm, both on account of their regularity, and also of the fact, already mentioned, that the materials of one river-system are never mixed with those of another. To take an instance. The gravel of the Somme valley is entirely formed of débris from the chalk and tertiary strata occupying that area; but at a right angle to, and within a very few miles of, the headwaters of the Somme, comes the valley of the Oise. In this valley are other older strata, no fragments of which have found their way into the Somme valley, though they could not have failed to do so, had the gravels in question been the result of any great cataclysm, or had the Somme then drained a larger area than at present. The beds in question are found in some cases 200 feet above the present water-level, and the bottom of the valley is occupied by a bed of peat, which in some places is as much as 30 feet in thickness. We have no means of making an accurate calculation; but even if we allow, as we must, a good deal for the floods which would be produced by the melting of the snow, still it is evident that for the excavation of the valley by the river to a depth of more than 200 feet,1 and then for the formation of so thick a bed of peat, much time must have been required. If, moreover, we consider the alteration which has taken place in the climate, as well as in the fauna; and, finally, remember also that the last eighteen hundred years have produced scarcely any perceptible change, we cannot but come to the conclusion that many, very many, centuries have 1 Many persons find a difficulty in understanding how the river could have deposited gravel at so great a height, forgetting that the valley was not then excavated to anything like its present depth. elapsed since the river ran at a level so much higher than the present, and the country was occupied by a fauna so unlike that now in existence there. 1 6. The presence of man is proved by the discovery of stone implements 1 (Figs. 55 and 56). Strictly speaking, these only prove the presence of reasoning beings; but this being granted, few, if any, would doubt that the beings in question were men. Human bones, moreover, have been found in cave-deposits, which, in the opinion of the best judges, belonged to this period; and M. Boucher de Perthes considers that various fragments of human bone found at Moulin Quignon are also genuine. On this point long discussions have taken place, into which I will not now enter. The question before us is, whether men existed at all, not whether they had bones. On the latter point no dispute is likely to arise, and as regards the former, the works of man are as good evidence as his bones could be. Moreover, there seems to me nothing wonderful in the great scarcity of human bones. A country where the inhabitants subsist on the produce of the chase can never be otherwise than scantily peopled. If we admit that for each man there must be a thousand head of game existing at any one time—and this seems a moderate allowance; remembering also that most mammalia are less long-lived than men, we should naturally expect to find human remains very rare as compared with those of other animals. Among a people who burnt their dead, of course this disproportion would be immensely increased. That the flint implements found in these gravels are implements it is unnecessary 1 For a general account of stone implements I may refer to Mr. Evans's admirable work on that subject. to argue. Their regularity, and the care with which they have been worked to an edge, prove that they have FIG. 55.-Flint Implement from St. Acheul, near Amiens. Natural size. (In my collection.) been intentionally chipped into their present forms, and are not the result of accident. That they are not forgeries we may be certain: firstly, because they have been found in situ by many excellent observers-by all, in fact, who have looked perseveringly for them; and secondly, because, as the discolouration of their surface is quite superficial, and follows the existing outline, it has evidently been produced since the flints were brought to their present forms. This is clearly shown in Fig. 57, which represents a fractured surface of Fig. 56, and shows the dark natural flint surrounded by the altered surface. The forgeries for there are forgeries -are of a dull lead colour, like other freshly-broken surfaces of flint. The same evidence justifies us in concluding that the implements are coeval with the beds of gravel in which they are found. 7. Without counting flakes, several thousand flint implements of the Paleolithic Age have been discovered in north- FIG. 57.-Section of Fig. 56 showing discolouration of surface. ern France and southern Eng land. These are all of types which differ considerably from those which came subsequently into use, and they are none of them polished; we may therefore, I think, infer that the art of polishing stone implements was as yet unknown. 8 and 9. In the same manner, I think, we may safely conclude that the use of metal and of pottery |