234 Royal Society : — 



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, Clausilia 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 feetofsubangular 

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

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

 Cyc/as, Pisidium, Valvata, Bithynia, and Planorbis, to- 

 gether with the marine Buccinum undatum, Cardium 

 edule, Tellium solidula, and Purpura lapil/uft. The author 

 has also found the Cyrena comobrina and Littorina rudis. 

 With them are associated numerous mammalian remains, 



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



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

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



The Mammalian remains enumerated by M. Buteux from this pit 

 are Elepltas primigenius, Rhinoceros tichorhinus, Cervus so?no- 

 nensis?, Cervus tarandus prisons, Ursus spe/ceus, Hyaena spelcea, 

 Bos primigenius, Equus adamaticus, and a Felis. It would be 

 essential to determine how these fossils are distributed — which occur 

 in bed No. 2, and which in bed No. 3. This has not hitherto been 

 done. Tbe few marine shells occur mixed indiscriminately with the 

 freshwater species, chiefly amongst the flints at the base of No. 3. 

 They are very friable and somewhat scarce. It is on the top of this 

 bed of flints that the greater number of bones are found, and also, 

 it is said, the greater number of flint-implements. The author, 

 however, only saw some long flint flakes (considered by M. de 

 Perthes as flint knives) turned out of this bed in his presence ; but 

 the workmanship was not very clear or apparent ; still it was as 

 much so as in some of the so-called flint knives from the peat -beds 

 and barrows. There are specimens, however, of true implements 

 ("baches") in M. de Perthes' collection from Menchecourt ; one 

 noticed by the author was from a depth of 5, and another of 7 

 metres. This would take them out from bed No. I, but would 

 leave it uncertain whether they came from No. 2 or No. 3. From 

 their general appearance, and traces of the matrix, the author would 

 be disposed to place them in bed No. 2, but M. de Perthes believes 

 them to be from No. 3 ; if so, it must have been in some of the sub- 

 ordinate clay seams occasionally intercalated in the white sand. 



Besides the concurrent testimony of all the workmen at the dif- 

 ferent pits, which the author after careful examination saw no 

 reason to doubt, the flint-implements ("baches") bear upon them- 

 selves internal evidence of the truth of M. de Perthes' opinion. It 

 is a peculiarity of fractured chalk flints to become deeply and per- 

 manently stained and coloured, or to be left unchanged, according to 

 the nature of the matrix in which thev are imbedded. In most clay 



