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 L 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, whicli 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. 
Bagshot 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, 
