152 BOULDER CLAY, [i860. 



Gower caves and occupies higher ground. The caves I believe 

 to be subsequent to that period in fact [the bones] subsequent 

 to the raised beaches. This is a point Falconer will go more fully 

 into. I have found a capital raised beach in very close relation to 

 the caves. I do not think Devon and Cornwall were submerged 

 during the Boulder Clay period yet even here is a difficulty, 

 for I have in one place a raised beach under land which clearly 

 is covered in part with B. Clay. I do not in fact see where the 

 break is that would ensue upon a very great difference in the 

 submergence. Yet I have evidence of shallowing of the sea 

 but the subject is so vast and complicated that I should require a 

 volume rather than a note to say all I should like about it. 



With regard to South Wales more especially, I must return 

 there, as with the exceptions of Carmarthen and Gower I dwelt 

 nowhere. However, on the one important point of the relative 

 age of the raised beaches of South Wales, Devon, and Cornwall, 

 I hope we shall be able to decide. [S. P.] Woodward pronounces 

 the Menchecourt shell decidedly Cyrena fluminalis. I am, my 

 dear Sir Charles, very truly yours, J. PRESTWICH. 



H. Falconer to J. Prestwich. 



31 SACKVILLE STREET, W., 2nd Jtme 1860. 



MY DEAR PRESTWICH, You know what a fierce onslaught was 

 made on me by Lyell and Austen. I thought the latter was 

 going to eat me up. The whole subject will be up again at the 

 next meeting, when the main brunt of the battle will fall on you. 

 There is no wavering in the aspect of the mammalian evidence 

 it is coming out stronger than ever, as I can show you when you 

 happen to pass this way. 



But we must be prepared for every aspect, and there is one 

 point I specially wish to ask you about, namely, the Cefn Cave. 

 I know all about the contained mammalia, having had the 

 collection up here. 



But Trimmer, in his paper on the Erratics of the " Norfolk 

 Areas" (Geol. Proceedings, November 20, 1850, p. 20), states 

 that "Britain sank as well as rose during that [the Glacial] 

 period. These proofs consist in the forest of Happisburgh and 

 Cromer . . . and in the circumstance that on the western 

 coast the northern Drift, with its marine remains, has penetrated 



