438 Dr. Nils Olof Hoist — The Ice Age in England. 



higher than now. The Cromer River to the north, and the Hurd 

 Deep River to the south, of the Straits of Dover are sufficient and 

 clear proofs of this. Men and beasts had then no difficulty in 

 ■wandering from the continent to England. But it is equally clear 

 that when the former river disembogued to the east of the present 

 coast of Norfolk a sinking of the land was begun. A later, more 

 advanced stage of this sinking has been proved by some borings in the 

 coast district of Belgium : at Ostend, at Leffinghe, south-west of 

 Ostend, and at Petit Crocodile, north of Middelkerke. So long ago 

 as 1884 Gustave F. Dollfus * drew attention to the Ostend boring, as 

 indeed it well deserved. Briefly stated, at Ostend at a depth of 22-45- 

 33-5 metres 2 below the surface, which lies only a few metres above 

 the level of the sea, there has been found a rich marine fauna, which, 

 however, is entirely devoid of southern species. From this Dollfus 

 draws the obviously correct conclusion that the North Sea was not 

 yet in connexion with the English Channel. The Straits of Dover 

 did not then exist. 



The same was the case at least at the beginning of that considerably 

 later stage of depression to which the so-called ' raised beach ' on the 

 south coasts of England and "Wales and on the French coast (at 

 Selsey, at Brighton, on Gower, at Sangatte, etc.) bears witness. In 

 the Selsey Beach, for instance, the lower layer yields a marine 

 molluscan fauna with forms of so southern a character that they have 

 now to be sought as far down as the coast of Portugal. 3 This ' raised 

 beach ' depression is clearly pre - glacial, while the succeeding 

 depression may be called glacial, since it was during it that the 

 glaciation reached the maximum, while it came to a close with the 

 deposition of the 'late-glacial' loam. 



It was during the succeeding glacial depression that the marine 

 North Sea fauna, more like the present one, first came down to the 

 south coast of England, where it is observed in the Chichester district, 

 at Oving, and at Goodwood Park. The Straits of Dover are now 

 open, and England is no longer connected by land with the continent. 

 J. Prestwich, however, who came, to the same conclusion as long ago 

 as 1865, 4 though by quite a different road, has shown that they were 

 open when the sand that covers the ' raised beach ' at Sangatte was 

 deposited ; and in so far as this sand really belongs to the older stage, 

 the opening of the Straits must have already been effected during its 

 latter portion. This chronological discrepancy is not great, and 

 entirely disappears if it can be shown that the North Sea fauna 

 migrated to the south coast already during the last stage of the 

 'raised beach'. Here, nevertheless, we may recall the fact that 

 R. A. C. Godwin-Austen observed "a black band", or, in other 

 words, "an old terrestrial surface," between the pre-glacial 'raised 



1 G. F. Dollfus, 1884.' " Le terrain quaternaire d'Ostende et le Corbicula 

 fluminalis" : Ann. Soc. malac. Belgique, tome 19, pp. 28-54. 



2 The depth in the other localities is less : 12-2-24-9 and 14-8-21-5 metres. 



3 E. Godwin- Austen, 1857. " On the Newer Tertiary Deposits of the Sussex 

 Coast" : Quart. Journ. Geol. Soc, vol. 13, pp. 40-72, see p. 54. 



4 J. Prestwich, 1865. "Additional Observations on the Eaised Beach of 

 Sangatte, etc. " : Quart. Journ. Geol. Soc, vol. 21, pp. 440-2. 



