The Antiquity of Man

of Chalk, covered with gravel, topped as usual with loam or fine sediment, the surface of the loam being 100 feet above the Somme, and about 150 above the sea.

Many stone coffins of the Gallo-Roman period have been dug out of the upper portion of this alluvial mass. The trenches made for burying them sometimes penetrate to the depth of 8 or 9 feet from the surface, entering the upper part of Number 3 of the sections Figures 21 and 22. They prove that when the Romans were in Gaul they found this terrace in the same condition as it is now, or rather as it was before the removal of so much gravel, sand, clay, and loam, for repairing roads, and for making bricks and pottery.

(FIGURE 21. SECTION OF GRAVEL PIT CONTAINING FLINT IMPLEMENTS AT ST. ACHEUL, NEAR AMIENS, OBSERVED IN JULY 1860.

1. Vegetable soil and made ground, 2 to 3 feet thick.
2. Brown loam with some angular flints, in parts passing into ochreous gravel, filling up indentations on the surface of Number 3, 3 feet thick.
3. White siliceous sand with layers of chalky marl, and included fragments of Chalk, for the most part unstratified, 9 feet.
4. Flint-gravel, and whitish chalky sand, flints subangular, average size of fragments, 3 inches diameter, but with some large unbroken Chalk flints intermixed, cross stratification in parts. Bones of mammalia, grinder of elephant at b, and flint implement at c, 10 to 14 feet.
5. Chalk with flints. a. Part of elephant's molar, 11 feet from the surface. b. Entire molar of Elephas primigenius, 17 feet from the surface. c. Position of flint hatchet, 18 feet from the surface.)

In the annexed section (Figure 21), which I observed during my last visit in 1860, it will be seen that a fragment of an elephant's tooth is noticed as having been dug out of unstratified sandy loam at the point a, 11 feet from the surface. This was found at the time of my visit; and at a lower point, at b, 18 feet from the surface, a large nearly entire and unrolled molar of the same species was obtained, which is now in my possession. It has been pronounced by Dr. Falconer to belong to Elephas primigenius.

A stone hatchet of an oval form, like that represented at Figure 9, was discovered at the same time, about one foot lower down, at c, in densely compressed gravel. The surface of the fundamental Chalk is uneven in this pit, and slopes towards the valley-plain of the Somme. In a horizontal distance of 20 feet, I found a difference in vertical height of 7 feet. In the chalky sand, sometimes occurring in interstices between the separate fragments of flint, constituting the coarse gravel Number 4, entire as well as broken freshwater shells are often met with. To some it may appear enigmatical how such fragile objects could have escaped annihilation in a river-bed, when flint tools and much gravel were shoved along the bottom; but I have seen the dredging instrument employed in the Thames, above and below London Bridge, to deepen the river, and worked by steam power, scoop up gravel and sand from the bottom, and then pour the contents pell-mell into the boat, and still many specimens of Limnaea, Planorbis, Paludina, Cyclas, and other shells might be taken out uninjured from the gravel.

It will be observed that the gravel Number 4 is obliquely stratified, and that its surface had undergone denudation before the white sandy loam Number 3 was superimposed. The materials of the gravel at d must have been cemented or frozen together into a somewhat coherent mass to allow the projecting ridge, d, to stand up 5 feet above the general surface, the sides being in some places perpendicular. In Number 3 we probably behold an example of a passage from river-silt to inundation mud. In some parts of it, land shells occur.