52 



Average thickness. 



and fresh water shells (Lymnea, Succinea, Helix, Bithynia, 

 Planorbis, Pupa, Pisidium, and Ancylus> all of recent 

 species) are common, and mammalian bones and teeth are 

 occasionally found ................................................ 2 to 8ft. 



26. Coarse subangular flint-gravel, white with irregular 

 ochreous and ferruginous seams, with tertiary flint peb- 

 bles and small sandstone blocks. Remains of shells 

 as above, in patches of sand. Teeth and bones of the ele- 

 phant, and of a species of horse, ox, and deer, generally 

 near base. This bed is further remarkable for containing 

 worked flints (" Haches " of M. de Perthes, and " Langues 

 de Chat" of the workmen) .................................... 6 to 12 ft. 



Uneven surface of chalk. 



The flint-implements are found in considerable numbers in 26. 

 On his first visit, the author obtained several specimens from the 

 workmen, but he was not successful in finding any himself. On his 

 arrival, however, at Abbeville, he received a message from M. Pinsard 

 of Amiens, to whose cooperation he expresses himself much indebted, 

 to inform him that one had been discovered the following day, and 

 was left 2/1 situ for his inspection. On returning to the spot, this 

 time with his friend Mr. Evans, he satisfied himself that it was 

 truly in situ, 1 7 feet from the surface, in undisturbed ground, and 

 he had a photographic sketch of the section taken*. 



Dr. Rigollot also mentions the occurrence in the gravel of round 

 pieces of hard chalk, pierced through with a hole, which he considers 

 were used as beads. The author found several, and recognized in 

 them a small fossil sponge, the Coscinopora ylobularis, D'Orb., from 

 the chalk, but does not feel quite satisfied about their artificial 

 dressing. Some specimens do certainly appear as though the hole 

 had been enlarged and completed. 



The only mammalian remains the author here obtained, were 

 some specimens of the teeth of a horse, but whether recent or ex- 

 tinct, the specimens were too imperfect to determine ; and part of 

 the tooth of an elephant (Elephas primigeniusl). In the gravel-pit 

 of St. Roch, 1| ile distant, and on a lower level, mammalian 



* On revisiting the pit, since the reading of this paper, in company with 

 several geological friends, the author was fortunate to witness the discovery and 

 extraction by one of them, Mr. J. W. Flower, of a very perfect and fine specimen 

 of flint-implement, in a seam of ochreous gravel, 20 feet beneath the surface. 

 They besides obtained thirty-six specimens from the workmen. June, 1859. 



