442 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [May 24, 



which they carried out into the valleys traversing the JS'orth Downs 

 and into the valley of the Thames. It is therefore possible that some- 

 where between Calais and Dover there may have been an old river 

 flowing eastward from the Weald en area, and debouching in this part 

 of the English Channel, into which it might have transported the 

 chert and other pebbles we find in the old beach at Sangatte. I am 

 disposed, however, to consider the transport by sea-action along a 

 channel open from west to east, as at present, although much 

 narrower, the more probable. 



Above the old beach is a mass, from twenty to eighty feet thick, of 

 angular flint and chalk-rubble, identical in general characters with 

 that in the same position at Brighton, in which Dr. Mantell dis- 

 covered the remains of the Elephant, Horse, &c., but presenting 

 some features of much interest, that have not yet been observed at 

 Brighton. At both places irregular seams of fine chalk-rubble and 

 marl are intercalated with the flint debris, but at Sangatte there 

 are in addition some beds which are not to be distinguished from 

 ordinary Loess. Not only do they resemble that deposit in general 

 characters, but I likewise discovered in some of these loams, as also 

 in some of the more marly beds, several species of land-shells common 

 in the Loess. I found also, what I before discovered in the Loess of 

 the Somme valley, numerous small, semitransparent, calcareous con- 

 cretions, the probable remains of land-slugs. The follovnng is a list 

 of the shells from the Sangatte eliif, revised by my friend Mr. 

 Gwyn Jeflreys : — 



Helix concinna. Pupa marginata. 



■ pulchella. Arion ater. 



Succinea oblonga. Limax agrestis. 



I found no freshwater shells, or Mammalian remains. 



There is no intercalation of sea-beach or sea-bed in this mass of 

 overlying rubble. The two beds are perfectly distinct, and the old 

 beach must have been raised so as to form dry land before the accu- 

 mulation of the land debris above it. It is an interesting problem 

 how it could have been formed in such a position — whether by the 

 mere melting of the winter snow on the adjacent range of chalk 

 hills, or by the flooding of some adjacent river. It is not, however, 

 my intention on this occasion to discuss this subject, but merely to 

 make known additional facts which I consider of importance in their 

 bearing on a very interesting theoretical question, and again to direct 

 attention to a remarkable section — one requii-ing further examination 

 — with the view especially better to determine the old rock -pebbles 

 and the organic remains that are to b§ found in it. 



