Mr. Webster on the Strata lying over the Chalk* 253 



But I shall now venture with less hesitation to draw an important 

 conclusion from the section of the Isle of Wight, which has been 

 already described, and which of itself forms a volume in which we 

 may read the geological history of several of the latest revolutions 

 which our earth has experienced. 



The idea I allude to is, that the last freshwater formation, as 

 well as all the other strata which we have been considering, Is 

 anterior to the great event which gave the last shape and surface to 

 our land. 



In the highly Inclined and vertical positions of the strata of 

 Alum bay, we see the effects of some great convulsion of nature, 

 previous to the formation of the last strata. 



In the horizontal deposits of the North side, we see strata of 

 great extent and antiquity yet formed at a later period. But in the 

 outline exhibited by the surface of the island, and which has no 

 reference whatever to that of the strata, is plainly to be perceived 

 the effect of a general and powerful agent, which has subsequently 

 formed the whole of the contour by one bold and sweeping outline. 



It may be interesting to see how the same result can be obtained 

 by a careful survey of different portions of the globe. 



Messrs. Cuvier and Brongniart have laid considerable stress on 

 the observation, that the outline of the present surface has no re- 

 semblance whatever to the undulations of the strata derived from 

 the irregularity of the bottom of the basin. But how much more 

 striking is this in the Isle of Wight ? By no ingenuity of reasoning 

 can the present form of its surface be derived from the bottom of 

 that ocean which deposited the chalk ; nor would it be produced 

 by any of the causes now acting ; and nothing remains for us but 

 to admit that it has been the effect of an extraordinary and an ex- 

 tensively aeting cause. 



