Upper Greensand. 



225 



&c.). In Lamellibranchiate molluscs it is even richer 

 than the Lower Greensand, abounding especially in 

 species of the genera Inoceramus, Gryphcea (lcevigata\ 

 Lima, Pecten asper, Astarte, Trigonia, Cucullcea, 

 Cyprina, and Cytherea. It is also rich in Gasteropoda, 

 such as Turritella, Pleurotomaria, Natica (N. Gentii), 

 &c., and yields many species of Ammonites, Nautili, 



FIG. 44. 



Rhynchonella latissima. Selenia personata. Siphonia pyriformis. 



Group of Upper Greensand Fossils. 



Hamites, Baculites, Scaphites, and Belemnites. Crus- 

 tacea, Hoploparia longimana, Necrocarcinus Bechii, 

 &c. Probably three species of Eeptilia belong to 

 this formation, Plesiosaurus pachycomus, a Crocodile, 

 and a Turtle. 



THE CHALK, from its familiar characters and general 

 uniformity of structure, is the most easily recognisable 



Q 



