Page:Geological Evidences of the Antiquity of Man.djvu/139

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N the section of the valley of the Somme, given at p. 106 (fig. 7), the successive formations newer than the chalk are numbered in chronological order, beginning with the most modern, or the peat, which is marked No. 1, and which has been treated of in the last chapter. Next in the order of antiquity are the lower-level gravels No. 2, which we have now to describe; after which the alluvium, No. 3, found at higher levels, or about eighty and one hundred feet above the river-plain, will remain to be considered.

I have selected, as illustrating the old alluvium of the Somme occurring at levels slightly elevated above the present river, the sand and gravel-pits of Menchecourt, in the northwest suburbs of Abbeville, to which, as before stated, p. 94, attention was first drawn by M. Boucher de Perthes, in his work on Celtic antiquities. Here, although in every