CHAP. IX. EXTINCT MAMMALIA IN VALLEY OF THE OISE. 153 Valley of the Oise. A flint hatchet, of the old Abbeville and Amiens type, was found lately by M. Peigné Delacourt at Précy near Creil, on the Oise, in gravel, resembling, in its geological position, the lower-level gravels of Montiers near Amiens, already described. I visited these extensive gravel-pits in 1861, in company with Mr. Prestwich; but we remained there too short a time to entitle us to expect to find a flint implement, even if they had been as abundant as at St. Acheul. In 1859, I examined, in a higher part of the same valley of the Oise, near Chauny and Noyon, some fine railway cuttings, which passed continuously through alluvium of the post-pliocene period for half a mile. All this alluvium was evidently of fluviatile origin, for, in the interstices between the pebbles, the Ancylus fluviatilis and other freshwater shells were abundant. My companion, the Abbé E. Lambert, had collected from the gravel a great many fossil bones, among which M. Lartet has recognised both Elephas primigenius and E. antiquus, besides a species of hippopotamus (H. major ?), also the rein-deer, horse, and the musk buffalo (Bubalus moschatus). The latter seems never to have been seen before in the old alluvium of France.* Over the gravel above mentioned, near Chauny, are seen dense masses of loam like the loess of the Rhine, containing shells of the genera Helix and Succinea. We may suppose that the gravel containing the flint hatchet at Précy is of the same age as that of Chauny, with which it is continuous, and that both of them are coeval with the tool-bearing beds of Amiens, for the basins of the Oise and the Somme are only separated by a narrow water-shed, and the same fossil quadrupeds occur in both. * Lartet, Annales des Sciences Naturelles Zoologiques, tom. xv. p. 224. 154 POST-PLIOCENE ALLUVIUM OF ENGLAND. CHAP. IX. The alluvium of the Seine and its tributaries, like that of the Somme, contains no fragments of rocks brought from any other hydrographical basin; yet the shape of the land, or fall of the river, or the climate, or all these conditions, must have been very different when the grey alluvium in which the flint tools occur at Paris was formed. The great size of some of the blocks of granite, and the distance which they have travelled, imply a power in the river which it no longer possesses. We can hardly doubt that river-ice once played a much more active part than now in the transportation of such blocks, one of which may be seen in the Museum of the Ecole des Mines at Paris, three or four feet in diameter. Post-pliocene Alluvium of England, containing Works of Art. In the ancient alluvium of the basin of the Thames, at moderate heights above the main river, and its tributaries, we find fossil bones of the same species of extinct and living mammalia, accompanied by recent species of land and freshwater shells, as we have shown to be characteristic of the basins of the Somme and the Seine. We can scarcely therefore doubt that these quadrupeds, during some part of the postpliocene period, ranged freely from the continent of Europe to England, at a time when there was an uninterrupted communication by land between the two countries. The reader will not therefore be surprised to learn that flint implements of the same antique type as those of the valley of the Somme have been detected in British alluvium. The most marked feature of this alluvium in the Thames valley is that great bed of ochreous gravel, composed chiefly of broken and slightly worn chalk flints, on which a great part of London is built. It extends from above Maidenhead through the metropolis to the sea, a distance from west to east CHAP. IX. POST-PLIOCENE ALLUVIUM OF ENGLAND. 155 of fifty miles, having a width varying from two to nine miles. Its thickness ranges commonly from five to fifteen feet.* Interstratified with this gravel, in many places, are beds of sand, loam, and clay, the whole containing occasionally remains of the mammoth and other extinct quadrupeds. Fine sections have been exposed to view, at different periods, at Brentford and Kew Bridge, others in London itself, and below it at Erith in Kent, on the right bank of the Thames, and at Ilford and Gray's Thurrock in Essex, on the left bank. The united thickness of the beds of sand, gravel, and loam amounts sometimes to forty or even sixty feet. They are for the most part elevated above, but in some cases they descend below, the present level of the overflowed plain of the Thames. If the reader will refer to the section of the post-pliocene sands and gravels of Menchecourt, near Abbeville, given at p. 122, he will perfectly understand the relations of the ancient Thames alluvium to the modern channel and plain of the river, and their relation, on the other hand, to the boundary formations of older date, whether tertiary or cretaceous. So far as they are known, the fossil mollusca and mammalia of the two districts also agree very closely, the Cyrena fluminalis being common to both, and being the only extra-European shell, this and all the species of testacea being recent. Of this agreement with the living fauna there is a fine illustration in Essex; for the determination of which we are indebted to the late Mr. John Brown, F.G.S., who collected at Copford, in Essex, from a deposit containing bones of the mammoth, a large bear (probably Ursus spelaus), a beaver, stag, and aurochs, no less than sixty-nine species of land and fresh-water shells. Forty-eight of these were terrestrial, and two of them, Helix incarnata and H. ruderata, no longer inhabit the British Isles, but are still living on the continent, * Prestwich, Geological Quarterly Journal, vol. xii. p. 131. 156 MEETING OF NORTHERN AND SOUTHERN FAUNA. CHAP. IX. ruderata in high northern latitudes.* The Cyrena fluminalis and the Unio littoralis, to which last I shall presently allude, were not among the number. I long ago suggested the hypothesis, that in the basin of the Thames there are indications of a meeting in the postpliocene period of a northern and southern fauna. To the northern group may have belonged the mammoth (Elephas primigenius) and the Rhinoceros tichorhinus, both of which Pallas found in Siberia, preserved with their flesh in the ice. With these are occasionally associated the rein-deer. In 1855 the skull of the musk-ox (Bubalus moschatus) was also found in the ochreous gravel of Maidenhead, by the Rev. C. Kingsley and Mr. Lubbock; the identification of this fossil with the living species being made by Professor Owen. A second fossil skull of the same arctic animal was afterwards found by Mr. Lubbock near Bromley, in the valley of a small tributary of the Thames; and two other skulls, those of a bull and a cow were dug up near Bath Easton from the gravel of the valley of the Avon by Mr. Charles Moore. Professor Owen has truly said, that, as this quadruped has a constitution fitting it at present to inhabit the high northern regions of America, we can hardly doubt that its former companions, the warmly-clad mammoth and the two-horned woolly rhinoceros (R. tichorhinus), were in like manner capable of supporting life in a cold climate.' t 6 I have alluded at p. 153 to the recent discovery of this same buffalo near Chauny, in the valley of the Oise, in France; and in 1856 I found a skull of it preserved in the museum at Berlin, which Professor Quenstedt, the curator, had correctly named so long ago as 1836, when the fossil was dug out of drift, in the hill called the Kreuzberg, in the southern * Quarterly Geological Journal, vol. viii. p. 190, 1852. Mr. Brown calls them extinct species, which may mislead some readers, but he merely meant extinct in England. See also Jeffreys, Brit. Conch. p. 174. Geological Quarterly Journal vol. xii. p. 124. CHAP. IX. MIGRATIONS OF QUADRUPEDS. 157 suburbs of that city. By an account published at the time, we find that the mammalia which accompanied the musk buffalo were the mammoth and tichorhine rhinoceros, with the horse and ox;' * but I can find no record of the occurrence of a hippopotamus, nor of Elephas antiquus or Rhinoceros leptorhinus, in the drift of the north of Germany, bordering the Baltic. On the other hand, in another locality in the same drift of North Germany, Dr. Hensel, of Berlin, detected, near Quedlinburg, the Norwegian Lemming (Myodes Lemmus), and another species of the same family called by Pallas Myodes torquatus (by Hensel, Misothermus torquatus)-a still more arctic quadruped, found by Parry in latitude 82°, and which never strays farther south than the northern borders of the woody region. Professor Beyrich also informs me that the remains of the Rhinoceros tichorhinus were obtained at the same place.† As an example of what may possibly have constituted a more southern fauna in the valley of the Thames, I may allude to the fossil remains found in the fluviatile alluvium of Gray's Thurrock, in Essex, situated on the left bank of the river, twenty-one miles below London. The strata of brickearth, loam, and gravel exposed to view in artificial excavations in that spot, are precisely such as would be formed by the silting up of an old river channel. Among the mammalia are Elephas antiquus, Rhinoceros leptorhinus (R. megarhinus, Christol), Hippopotamus major, species of horse, bear, ox, stag, &c., and, among the accompanying shells, Cyrena fluminalis, which is extremely abundant, instead of being scarce, as at Abbeville. It is associated with Unio littoralis, fig. 22, also in great numbers, and with both valves united. This conspicuous fresh-water mussel is no longer an inhabitant of * Leonhard and Bronn's Jahrbuch, 1836, p. 215. † Zeitschrift der Deutschen Geolo gischen Gesellschaft, vol. vii. 1855, p. 497, &c. |
