CHAP. Tin. MAMMALIA FOUND AT MENCHECOURT. 125 



of the fluvio-marine sands. From the same beds, and in 

 marls alternating with the sands, remains of the elejihant, 

 rhinoceros, and other mammalia, have been exhumed. 



Above the fluvio-marine strata ure those designated No. 2 

 in the section (fig. 16), which are almost devoid* of strati- 

 fication, 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 cat 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 Menche- 

 court 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 ob- 

 tained 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 fresh- water shells, 

 precisely like those of Menchecourt. In the alluvium of all 

 parts of the vallej^, 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 per- 

 fect, 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 : — 



Mephas primigenius. 

 Mliinoceros tichorhinus. 

 Equus fossilis Owen. 



