Xlvi PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



is alleged as the principal proof. To many geologists the founda- 

 tion will possibly appear small for the superstructure raised upon it. 



Mr. Austen has not stated the height to which he supposes the 

 south coast of this country to have been elevated during his cold 

 period, but he appears, I think, to intimate by a reference to the 

 soundings of 200 fathoms' which are found at no great distance in 

 the Atlantic, that an elevation not much exceeding that amount might 

 give us in this country a permanent snow-line. I have shown, how- 

 ever, in a memoir lately read, that a very much greater elevation 

 would be necessary for that purpose, and I have there fully explained 

 my reasons for believing that the cold of the Pleistocene period was 

 not produced by an elevation of the land, but by entirely different 

 causes. The author, therefore, will not be surprised to find me un- 

 prepared to accept many of the theoretical views put forward in this 

 paper, and for which I must refer you to the paper itself. The 

 questions arising from changes of climatal conditions, and the physi- 

 cal causes of those changes, are of great difficulty, and, however im- 

 perfectly I may have discussed the subject myself, I have shown at 

 least that there are many essential considerations connected with it, 

 to which the author of the present paper makes no allusion. At the 

 same time the facts brought forward are entitled to the same con- 

 sideration as other facts, so far as they bear upon the subject ; and 

 for the careful observation and arrangement of those facts, we must 

 all feel our obligation to Mr. Austen. 



I have already alluded to an accumulation of angular materials 

 observed by Mr. Prestwich, and very similar in character to those 

 described by Mr. Austen. It is described in his paper "On the 

 Drift of Sangatte Cliffs near Calais." It resembles also the similar 

 accumulation at Brighton, described long since by Dr. Mantell. The 

 whole mass abuts against an old chalk cliff 80 feet high, rising to the 

 same height on the face of the cliff, and thinning off in receding from 

 it. The lowest part consists of a bed of rolled water-worn flints, 

 marking the former existence of a sea-beach exactly analogous to that 

 at Brighton beneath the Elephant-bed. The mass immediately 

 superincumbent on this bed consists of a coarse mixture of sand, clay, 

 and chalk, containing a few unrolled flints, and some irregular patches 

 and layers of flint-gravel. The whole of this part of the mass is about 

 50 or 60 feet thick, and above it, but without any distinct separation, 

 is a mass of angular flint-gravel, 20 or 25 feet in thickness. It con- 

 tains also a small quantity of materials derived from the ruins of the 

 former tertiary strata of the district. The whole appears to be chiefly 

 of local origin. 



The author considers this accumulation of Drift to have been com- 

 paratively rapid and tumultuous, nor can I recognize the slightest 

 ground of dissent from this opinion. The distance to which the mass 

 extends from the old chalk cliff against which it abuts, excludes the 

 possibility of its being referred to the cause to which Mr. Austen, as 

 already stated, refers certain smaller accumulations of similar mate- 

 rials on the south coast of this country. The analogy between this 

 case and that of the Elephant-bed and subjacent pebble-bed at Brigh- 



