ANNIVERSARY ADDRESS OF THE PRESIDENT. xlv 



it first occupied, leaving more or less of a platform at that elevation, 

 bounded by a cliff of the aerial bed of shingle. 



(5.) The land was elevated to its present position. 



The marine bed mentioned in (1) consists of coarse marine gravels, 

 shingle, and sand. The author recognizes it on many parts of the 

 coast of Devon and Cornwall, and also considers the lower sand and 

 shingle extending from Brighton to Rottingdean, as belonging to it. 

 He also traces evidences of the other two beds at various points of 

 the south coast of this country, and of the Channel Islands. 



In developing his theoretical views, founded on the facts above 

 stated, the author assumes the deposition of the oldest of the marine 

 beds above mentioned as contemporaneous with that of the Norwich 

 or Mammaliferous Crag. After this came the aggregation of the 

 superincumbent bed of shingle above described as subaerial. But 

 for the disintegration in which he conceives this aggregation to have 

 originated, he considers a much greater intensity of cold to be neces- 

 sary than could consist with the present position of the land, and is 

 hence led to the opinion that those districts where the above beds 

 exist must at the time of their formation have had " an elevation of 

 great amount, such as would place the whole of the higher portions 

 of this country in regions of excessive cold.^^ The author also states 

 that ''his view is quite distinct from the popular one, subsequently 

 proposed by M. Agassiz, of a * period of cold ' or ' glacial period.' " 

 What relation he supposes it to have borne to that period he does not, 

 I think, distinctly explain. All the minor details of his views depend 

 on the conclusions that the shingle-bed is subaerial, and that it could 

 only be produced by a great elevation of the land above its present 

 level. 



The masses of sharp shingly stones described by Mr. Austen, and 

 their local character, entirely agree with his opinion as to their ori- 

 gin ; but it should be borne in mind that they might have these 

 characters without being subaerial. An example will be found in a 

 paper of which I shall have shortly to speak, by Mr. Prestwich, of an 

 aggregation very similar to the above-mentioned beds so far as regards 

 the character of its materials, but of which the origin is unquestion- 

 ably subaqueous. The first manifest test to be applied to such beds 

 to determine whether they are subaerial, is to compare the distance 

 to which they extend from the foot of the cliff or hill from which 

 they may have fallen, with the height of the cliff or hill itself. If 

 that distance should exceed two or three times the height of the cliff, 

 it would be, I conceive, extremely improbable that the general mass 

 could have been aggregated from the falling of disintegrated materials 

 by their own weight. No intensity of the disintegrating power could 

 meet this difficulty. Mr. Austen has not given us the means of ap- 

 plying this test ; but I am sure that he will feel that geologists have 

 a right to demand it before they adopt his conclusions on this point 

 as the foundation of the further theoretical views which he has made 

 to rest almost entirely upon them. I allude to his assumed enor- 

 mous elevation, at a former though recent geological epoch, of the 

 regions in which these beds are found, and of which their existence 



