280 EOCENE PERIOD. [Ch. XX. 



A great number of the marine shells of this clay have been 

 identified with those of the Paris basin, and are mentioned by 

 name in Appendix I. It is quite evident, therefore, that these 

 two formations belong to the same epoch. 



No remains of terrestrial mammalia have as yet been found 

 in this clay, but the occurrence of bones and skeletons of cro- 

 codiles and turtles prove, as Mr. Conybeare justly remarks, 

 the existence of neighbouring dry land. The shores, at least, 

 of some islands were accessible, whither these creatures may 

 have resorted to lay their eggs. In like manner, we may infer 

 the contiguity of land from the immense number of ligneous 

 seed-vessels of plants, some of them resembling the cocoa-nut, 

 and other spices of tropical regions, which have been found 

 fossil in great profusion in the Isle of Sheppey. Such is the 

 abundance of these fruits, that they have been supposed to 

 belong to several hundred distinct species of plants, 



Bag shot sand. The third and uppermost group, usually 

 termed the Bagshot sand, rests conformably upon the London 

 clay, and consists of siliceous sand and sandstone devoid of 

 organic remains, with some thin deposits of marl associated. 

 From these marls a few marine shells have been obtained which 

 are in an imperfect state, but appear to belong to Eocene 

 species common to the Paris basin *. 



Fresh-water strata of the Hampshire basin. In the northern 

 part of the Isle of Wight, and part of the opposite coast of 

 Hampshire, fresh-water strata occur resting on the London 

 clay. They are composed chiefly of calcareous and argilla- 

 ceous marls, interstratified with some thick beds of siliceous 

 sand, and a few layers of limestone sometimes slightly siliceous. 

 The marls are often green, and bear a considerable resemblance 

 to the green marls of Auvergne and the Paris basin. The 

 shells and gyrogonites also agree specifically with some of those 

 most common in the French deposits. Mr. Webster, who first 

 described the fresh-water formation of Hampshire, divided it into 

 an upper and lower series separated by intervening beds of marine 



* Warburton, Geol. Trans., vol. i. Second Series. 



