The fauna to which Elephas meridionalis and its associates belong, can be shown to be of anterior date, in the north of France, to the flint implements of St. Acheul, by the following train of reasoning. The valley of the Seine is not only geographically contiguous to the valley of the Somme, but its ancient alluvium contains the same mammoth and other fossil species. The Eure, one of the tributaries of the Seine, in its way to join that river, flows in a valley which follows a line of fault in the Chalk; and this valley is seen to be comparatively modern, because it intersects at St. Prest, 4 miles below Chartres, an older valley belonging to an anterior system of drainage, which has been filled by a more ancient fluviatile alluvium, consisting of sand and gravel, 90 feet thick. I have examined the site of this older drift, and the fossils have been determined by Dr. Falconer. They comprise Elephas meridionalis, a species of rhinoceros (not R. tichorhinus), and other mammalia differing from those of the implement-bearing gravels of the Seine and Somme. The latter, belonging to the period of the mammoth, might very well have been contemporary with the modern volcanic eruptions of Central France; and we may presume, even without the aid of the Denise fossil, that Man may have witnessed these. But the tuffs and gravels in which the Elephas meridionalis are embedded were synchronous with an older epoch of volcanic action, to which the cone of St. Anne, near Le Puy, and many other mountains of M. Bertrand de Doue's middle period belong, having cones and craters, which have undergone much waste by aqueous erosion. We have as yet no proof that Man witnessed the origin of these hills of lava and scoriae of the middle phase of volcanic action.
Some surprise was expressed in 1856, by several of the assembled naturalists at Le Puy, that the skull of the "fossil man of Denise," although contemporary with the mammoth, and coeval with the last eruptions of the Le Puy volcanoes [Note 18], should be of the ordinary Caucasian or European type; but the observations of Professor Huxley on the Engis skull, cited in the fifth chapter, showing the near approach of that ancient cranium to the European standard, will help to remove this source of perplexity.
HUMAN FOSSIL OF NATCHEZ ON THE MISSISSIPPI.
I have already alluded to Dr. Dowler's attempt to calculate, in years, the antiquity of the human skeleton said to have been buried under four cypress forests in the delta of the Mississippi, near New Orleans (see above, Chapter 3). In that case no remains of extinct animals were found associated with those of Man: but in another part of the basin of the Mississippi, a human bone, accompanied by bones of Mastodon and Megalonyx, is supposed to have been washed out of a more ancient alluvial deposit.
After visiting the spot in 1846, I described the geological position of the bones, and discussed their probable age, with a stronger bias, I must confess, as to the antecedent improbability of the contemporaneous entombment of Man and the mastodon than any geologist would now be justified in entertaining.
(FIGURE 26. SECTION THROUGH THE ALLUVIAL PLAIN OF THE MISSISSIPPI.
1. Modern alluvium of the Mississippi.
2. Loam or loess.
3. f. Eocene.
4. Cretaceous.)
In the latitude of Vicksburg, 32 degrees 50 minutes north, the broad, flat, alluvial plain of the Mississippi, a b, Figure 26, is bounded on its eastern side by a table-land d e, about 200 feet higher than the river, and extending 12 miles eastward with a gentle upward slope. This elevated platform ends abruptly at d, in a line of perpendicular cliffs or bluffs, the base of which is continually undermined by the great river.
The table-land d-e consists at Vicksburg, through which the annexed section, Figure 26, passes, of loam, overlying the Tertiary strata f-f. Between the loam and the Tertiary formation there is usually a deposit of stratified sand and gravel, containing large fragments of silicified corals and the wreck of older Palaeozoic rocks. The age of this underlying drift, which is 140 feet thick at Natchez, has not yet been determined; but it may possibly belong to the glacial period. Natchez is about 80 miles in a straight line south of Vicksburg, on the same left bank of the Mississippi. Here there is a bluff, the upper 60 feet of which consists of a continuous portion of the same calcareous loam as at Vicksburg, equally resembling the Rhenish loess in mineral character and in being sometimes barren of fossils, sometimes so full of them that bleached land-shells stand out conspicuously in relief in the vertical and weathered face of cliffs which form the banks of streams, everywhere intersecting the loam.