54 



specimens himself; but from the experience of M. de Perthes, and 

 the evidence of the workmen, as well as from the condition of the 

 specimens themselves, he is fully satisfied of the correctness of that 

 gentleman's opinion, that they there also occur in beds of undisturbed 

 sand and gravel. 



At Moulin Quignon, and at St. Gilles, to the S.E. of Abbeville, 

 the deposit occurs, as at St. Acheul, on the top of a low hill, and 

 consists of a subangular, ochreous and ferruginous flint-gravel, with 

 a few irregular seams of sand, 12 to 15 feet thick, reposing upon an 

 uneven surface of chalk. It contains no shells, and very few bones. 

 M. de Perthes states that he has found fragments of the teeth of the 

 elephant here. The worked flints and the bones occur generally in 

 the lower part of the gravel. 



In the bed of gravel also on which Abbeville stands, a number of 

 flint-implements have been found, together with several teeth of the 

 Elephas primigenius, and, at places, fragments of freshwater shells. 



The section, however, of greatest interest is that at Menchecourt, 

 a suburb to the N.W. of Abbeville. The deposit there is very 

 distinct in its character ; it occurs patched on the side of a chalk 

 hill, which commands it to the northward ; and it slopes down under 

 the peat-beds of the valley of the Somme to the southward. The 

 deposit consists, in descending order, of 



Average thickness. 



1. A mass of brown sandy clay, with angular fragments of 

 flints and chalk rubble. No organic remains. Base very 



irregular and indented into bed No. 2 2 to 12 ft. 



2. A light-coloured sandy clay (" sable gras " of the work- 

 men), analogous to the loess, containing land shells, 

 Pupa, Helix, Clawilia of recent species. Flint-axes and 

 mammalian remains are said to occur occasionally in 



this bed 8 to 25 ft. 



3. White sand (" sable aigre"), with 1 to 2 feet of subangular 

 flint-gravel at base. This bed abounds in land and fresh- 

 water shells of recent species of the genera Helix, Succinea, 

 Cyclas, Pisidium, Valvata, Bithynia, and Planorbis, to- 

 gether with the marine Buccinum undatum, Cardium 

 edule, Tellina solidula, and Purpura lapillus. The author 

 has also found the Cyrena consobrina and Littorina rudis. 

 With them are associated numerous mammalian remains, 



and, it is said, flint-implements 2 to 6ft. 



4. Light-coloured sandy marl, in places very hard, with 

 Helix, Zonites, Succinea, and Pupa. Not traversed 3 + 



