Henry Dewey — Raised Beach of North Devon. 159 



deposit, which received its name from Dr. Mantell, who first described 

 its occurrence at Brighton. 



2. Underlying Coombe Rock at Selsea Promontory is an interesting 

 series of deposits described by Ileid.-^ First is a floor with stranded 

 erratic blocks, one deeply striated, and many of foreign origin, 

 apparently associated with a bed of clay containing a fauna and flora 

 of Arctic species, which in turn is covered by a loam with no Arctic 

 but many warm temperate forms. 



1. The raised beach platform is strewn over with boulders of 

 rock that have travelled far from their source. These include 

 granites, gneisses, porphyries, and many other varieties of igneous 

 rocks which have been described by Prestwich, Bonney, and others. 

 Prestwich considered that they were in part derived from Scandinavia, 

 Central Germany, and the Ardennes, and had been carried by ice 

 southwards and stranded on the shore of the South of England. He 

 therefore inferred that the Straits of Dover were then in existence. 



That this ice was not due to the advance of a glacial episode but 

 rather to the retreat of one is evident from the fauna of the raised 

 beach. Of this Prestwich says- : "Of the total of sixty-four species 

 (of mollusca) only thirty-nine are common to the glacial drifts of 

 the North of England and Wales. There is the absence also ... of 

 such northern shells as Astarte horealis, Leda pernula, Fusus islandicus, 

 Natica grcerilandia, and others common in the glacial drift. The 

 raised beach mollusca agree therefore pretty closely with the 

 molluscan fauna now living in the British seas." 



We are now in a position to compare the raised beach deposits 

 and their faunas of the several coasts described previously, and to 

 consider the sequence of events which led to their formation. To 

 make the comparison readily intelligible the following tables are 

 arranged : — 



Erom an examination of this table we may say that there can be 

 no doubt as to the identity of the sequence over the whole of the 

 southern parts of Great Britain and Ireland. Granting this, tlien, 

 there remains to be considered the relation of Palaeolithic man to the 

 several episodes indicated by the deposits. The evidence given so 



Quart. Journ. Geol. Soc, vol. xlviii, p. 344, 1892. 



Ibid., p. 263. 



