of the fluvio-marine sands. From the same beds, and in marls alternating with the sands, remains of the elephant, rhinoceros, and other mammalia, have been exhumed.
Above the fluvio-marine strata are those designated No. 2 in the section (fig. 16), which are almost devoid of stratification, and probably formed of mud or sediment thrown down by the waters of the river when they overflowed the ancient alluvial plain of that day. Some land shells, a few river shells, and bones of mammalia, some of them extinct, occur in No. 2. Its upper surface has been deeply furrowed and cut into by the action of water, at the time when the earthy matter of No. 1 was superimposed. The materials of this uppermost deposit are arranged as if they had been the result of land floods, taking place after the formations 2 and 3 had been raised, or had become exposed to denudation.
The fluvio-marine strata and overlying loam of Menchecourt recur on the opposite or left bank of the alluvial plain of the Somme, at a distance of two or three miles. They are found at Mautort, among other places, and I obtained there the flint hatchet figured at p. 115 (fig. 9), of an oval form. It was extracted from gravel, above which were strata containing a mixture of marine and freshwater shells, precisely like those of Menchecourt. In the alluvium of all parts of the valley, both at high and low levels, rolled bones are sometimes met with in the gravel. Some of the flint tools in the gravel of Abbeville have their angles very perfect, others have been much triturated, as if in the bed of the main river or some of its tributaries.
The mammalia most frequently cited as having been found in the deposits Nos. 2 and 3 at Menchecourt, are the following:—
Elephas primigenius.
Rhinoceros tichorhinus.
Equus fossilis Owen.
