148 ABSENCE OF HUMAN BONES EXPLAINED. CHAP. VIII. specimens of fresh-water and brackish-water shells, such as Unio and Dreissena, of living species; and in clay brought up from below the sand, shells of Tellina, Lutraria, and Cardium, all of species now inhabiting the adjoining sea. As the Dreissena is believed by conchologists to have been introduced into Western Europe in very modern times, brought with foreign timber in the holds of vessels from the Wolga and other rivers flowing into the Black Sea, the layer of sand containing it in the Haarlem lake is probably not more than a hundred years old. One or two wrecked Spanish vessels, and arms of the same period, have rewarded the antiquaries who had been watching the draining operations in the hope of a richer harvest, and who were not a little disappointed at the result. In a peaty tract on the margin of one part of the lake a few coins were dug up; but if history had been silent, and if there had been a controversy whether Man was already a denizen of this planet at the time when the area of the Haarlem lake was under water, the archæologist, in order to answer this question, must have appealed, as in the case of the valley of the Somme, not to fossil bones, but to works of art embedded in the superficial strata. Mr. Staring, in his valuable memoir on the Geological Map of Holland,' has attributed the general scarcity of human bones in Dutch peat, notwithstanding the many works of art preserved in it, to the power of the humic and sulphuric acids to dissolve bones, the peat in question being plentifully impregnated with such acids. His theory may be correct, but it is not applicable to the gravel of the Valley of the Somme, in which the bones of fossil mammalia are frequent, nor to the uppermost fresh-water strata forming the bottom of a large part of the Haarlem Lake, in which it is aot pretended that such acids occur. The primitive inhabitants of the Valley of the Somme CHAP. VIII. SCARCITY OF HUMAN BONES. 149 may have been too wary and sagacious to be often surprised and drowned by floods, which swept away many an incautious elephant or rhinoceros, horse and ox. But even if those rude hunters had cherished a superstitious veneration for the Somme, and had regarded it as a sacred river (as the modern Hindoos revere the Ganges), and had been in the habit of committing the bodies of their dead or dying to its waters even had such funeral rites prevailed, it by no means follows that the bones of many individuals would have been preserved to our time. A corpse cast into the stream first sinks, and must then be almost immediately overspread with sediment of a certain weight, or it will rise again when distended with gases, and float perhaps to the sea before it sinks again. It may then be attacked by fish of marine species, some of which are capable of digesting bones. If, before being carried into the sea and devoured, it is enveloped with fluviatile mud and sand, the next flood, if it lie in mid channel, may tear it out again, scatter all the bones, roll some of them into pebbles, and leave others exposed to destroying agencies; and this may be repeated annually, till all vestiges of the skeleton may disappear. On the other hand, a bone washed through a rent into a subterranean cavity, even though a rarer contingency, may have a greater chance of escaping destruction, especially if there be stalactite dropping from the roof of the cave or walls of a rent, and if the cave be not constantly traversed by too strong a current of engulfed water. 150 FLINT IMPLEMENTS IN BASIN OF THE SEINE. CHAP. IX. CHAPTER IX. WORKS OF ART IN POST-PLIOCENE ALLUVIUM OF FRANCE AND ENGLAND. FLINT IMPLEMENTS IN ANCIENT ALLUVIUM OF THE BASIN OF THE TION OF THE OLDER ALLUVIUM OF THE THAMES TO THE GLACIAL Flint Implements in Post-pliocene Alluvium in the Basin of the Seine. IN the ancient alluvium of the valleys of the Seine and its principal tributaries, the same assemblage of fossil animals, which has been alluded to in the last chapter as characterising the gravel of Picardy, has long been known; but it was not till the year 1860, and when diligent search had been expressly made for them, that flint implements of the Amiens type were discovered in this part of France. In the neighbourhood of Paris, deposits of drift occur answering both to those of the higher and lower levels of the basin of the Somme before described. In both are found, mingled with the wreck of the tertiary and cretaceous rocks of the vicinity, a large quantity of granitic sand, and pebbles, and occasionally large blocks of granite, from a few inches * Prestwich, Proceedings of Roy. Soc. 1862. CHAP. IX. BASIN OF THE SEINE. 151 to a foot or more in diameter. These blocks are peculiarly abundant in the lower drift commonly called the 'diluvium gris.' The granitic materials are traceable to a chain of hills called the Morvan, where the head waters of the Yonne take their rise, 150 miles to the SSE. of Paris. It was in this lowest gravel that M. H. T. Gosse, of Geneva, found, in April 1860, in the suburbs of Paris, at La Motte Piquet, on the left bank of the Seine, one or two wellformed flint implements of the Amiens type, accompanied by a great number of ruder tools or attempts at tools. I visited the spot in 1861 with M. Hébert, and saw the stratum from which the worked flints had been extracted, twenty feet below the surface, and near the bottom of the 'grey diluvium,' a bed of gravel from which I have myself, in and near Paris, frequently collected the bones of the elephant, horse, and other mammalia. More recently, M. Lartet has discovered at Clichy, in the environs of Paris, in the same lower gravel, a well-shaped flint implement of the Amiens type, together with remains both of Elephas primigenius and E. antiquus. No tools have yet been met with in any of the gravel occurring at the higher levels of the valley of the Seine; but no importance can be attached to this negative fact, as so little search has yet been made for them. Mr. Prestwich has observed contortions indicative of iceaction, of the same kind as those near Amiens (see p. 138), in the higher level drift at Charonne, near Paris; but as yet no similar derangement has been seen in the lower gravels—a fact, so far as it goes, in unison with the phenomena observed in Picardy. In the cavern of Arcy-sur-Yonne a series of deposits have lately been investigated by the Marquis de Vibraye, who discovered human bones in the lowest of them, mixed with remains of quadrupeds of extinct and recent species. This 152 BONES IN THE CAVE OF ARCY. CHAP. IX. cavern occurs in Jurassic limestone, at a slight elevation above the Cure, a small tributary of the Yonne, which last joins the Seine near Fontainebleau, about forty miles south of Paris. The lowest formation in the cavern resembles the 'diluvium gris' of Paris, being composed of granitic materials, and like it derived chiefly from the waste of the crystalline rocks of the Morvan. In it have been found the two branches of a human lower jaw with teeth well-preserved, and the bones of the Elephas primigenius, Rhinoceros tichorhinus, Ursus spelaus, Hyena spelaa, and Cervus Tarandus, all specifically determined by M. Lartet. I have been shown this collection of fossils by M. de Vibraye, and remarked that the human and other remains were in the same condition and of the same colour. Above the grey gravel is a bed of red alluvium, made up of fragments of Jura limestone, in a red argillaceous matrix, in which were embedded several flint knives, with bones of the reindeer and horse, but no extinct mammalia. Over this, in a higher bed of alluvium, were several polished hatchets of the more modern type called 'celts,' and above all loam or cave-mud, in which were Gallo-Roman antiquities.* The French geologists have made as yet too little progress in identifying the age of the successive deposits of ancient alluvium of various parts of the basin of the Seine, to enable us to speculate with confidence as to the coincidence in date of the granitic gravel with human bones of the Grotte d'Arcy and the stone-hatchets buried in 'grey diluvium' of La Motte Piquet, before mentioned; but as the associated extinct mammalia are of the same species in both localities, I feel strongly inclined to believe that the stone hatchets found by M. Gosse at Paris, and the human bones discovered by M. de Vibraye, may be referable to the same period. *Bulletin de la Société Géologique de France, 1860. |