182 Mr. WiLBSTETL on-tbe Strata lymg over the Chalk.. 



the nature and variety of their composition, from the great regu- 

 larity and numerous alternations of the layers, and the other 

 circumstances which have been already mentioned, no one who 

 has viewed them with attention can doubt, that. they have suffered 

 no change except that of having been moved with the chalk from 

 the horizontal to the vertical position. 



The whole of these strata have evidently been formed at the 

 bottom of an ocean, from the nature of the fossils contained in 

 them, which, although entirely different from those of the chalk, 

 are yet all of marine origin. 



The chalk, A, w4iich forms the side of Alum bay, (Plate 11. 

 Fig. 2.) is somewhat harder than usual, and the flints are shivered, 

 so as to come to pieces on being taken out.* 



Next to the chalk, on the north, stands the bed of chalk marl 

 a, which has been already mentioned. 



To this succeeds a thick bed of clay, b, of a dark red colour, 

 often streaked or mottled with yellow and white ; towards the 

 south side is a thin layer of greenish-grey sand. This is divided 

 by a bed of yellowish white sand, c, from a very thick bed of 

 dark blue clay, d, which contains much green earth ; and also 

 nodules of a dark coloured limestone, in which I found a few 

 fossil shells : this bed, however, I am inclined to think, is not con- 

 tinuous for a great extent, as in a part of the cliff farther inland 

 and in the line of its direction, it had almost -disappeared. 



Next follows a vast succession of beds of sand of different 

 colours, which, though not distinctly separable from each other, 

 yet may be considered as divided into the following : 



* See (lie pnper on tins Miliject, by Sir Henry Etiglefielil, in the Transactions of the 

 l.iniiean Soeicty. 



