VII. On the Freshwater Formations in the Isle of Wight, with some 

 , Observations on the Strata over the Chalk in the South-east part 

 of England. 



By Thomas Webster, Member of the Geological Society. 



Ai 



INTRODUCTION. 



.MONG the geological researches which have lately been made 

 in various parts of the globe, none have been more interesting than 

 those of M. M. Cuvier and Brongniart in the environs of Paris. 



These naturalists have described a series of mineral strata differing 

 in many respects from all that w^ere formerly known, and particularly 

 distinguished by their numerous and singular organic remains. The 

 animals whose exuviae had hitherto been more commonly noticed 

 in regularly stratified rocks were the inhabitants of an ocean ; but 

 many of the Parisian fossils belonged to freshwater lakes and marshes, 

 thus developing new and unsuspected agents in the forming of mi- 

 neral beds. 



The strata described by the French naturalists are deposited in a 

 cavity in the chalk stratum which extends through a considerable 

 part of the north of France. The bottom of this hollow is extremely 

 irregular ; and before it was covered by the materials now found in 

 it, must have presented partial cavities and projections, the latter 

 appearing as so many islands piercing through the other strata j and 



Vol. ij. x 



