BAISED BEAOHEa. 423 



ADDENDA. 



Extract from the Report of Sir Henry De la Beche, on the 

 Greology of Devon and Cornwall, pp. 399, 400. 



"Though Mr. Carne, sometime since, called attention to the 

 general facts connected with the stream tin of Cornwall as 

 furnishing strong evidence in favour of a sweeping inundation 

 having passed over the land, the effects produced by which have 

 never been repeated by any subsequent flood," less attention 

 seems to have been paid to this evidence, whilst the distributing 

 causes of various superficial gravels of England have been under 

 consideration, than the relative importance of the subject 

 appears to demand. The evidence of a considerable drift from 

 the north, in many parts of England is well-known ; and being 

 conspicuous upon parts of the South Wales coal field, particularly 

 in Glamorganshire, we should anticipate that it might be visible 



also in the district under consideration On the opposite of 



the Bristol Channel the drift from the north is readily seen, 

 rounded portions of marked rocks, well-known to occur on the 

 north, being found not alone in valleys, but on hills, and on their 

 flanks, where no rivers, such as would flow from that land from 

 the present inequalities of its surface, could produce the deposits 

 of gravel and boulders there seen. A great mass of detritus 

 seems to have been swept into the Bristol Channel from the 

 northward, and this we could scarcely suppose would happen 

 without a great body of water passing onwards to the southward 

 carrying before it, when it struck the opposite shores of the 

 Bristol Channel, a large proportion of the disintegrated or 

 decomposed surfaces of rock." 



Professor Prestwich expresses the opinion that — " The Isle 

 of Portland, together with the whole line of coast from the 

 Laud's End to the Straits of Dover, as well as the opposite coast 

 of Erance was gradually submerged ; and adds, .... A review of 

 the extent of the submergence is beyond the limits of the 

 present paper ; but from the fact that at Ohesilton the great mass 

 of the debris and the large blocks of Portland flint come from 

 beds now from 350 to 450 feot above the sea in that part of the 



