230 Mr. Webster on the Strata lybig over the Chalk, 



Limneus corneus 



perhaps a large specimen of L. 



longiscatus 

 Gyrogonites 

 Striated seeds of a flattened oval form, with 



parts of coleopterous insects.* 



M. Brongniart has enumerated the following fossils as belonging 

 to this formation. 



Cyclostoma elegans antiquum Limneus inflatus 



Potamides Lamarckiif Bulimus pygmeus 

 Planorbis rotundatus - - terebra 



- - cornu Pupa Defrancii 



- - prevostinus Helix lemani 

 Limneus corneus - Desmarestina 

 ^' - ■ - fabulum Gyrogonites 



^ - ventricosus 

 '.'■ The last mentioned fossil, to which Lamarck has given the name 

 of Gyrogonites, is a small globular canellated body about the size 

 of a mustard seed. The specimens of the French fossils of this 

 species, in the possession of the Society, are extremely perfect, and 

 correspond exactly to those which I found. They are veiy nume- 

 rous in the freshwater stone at Gurnet point ; but they are there 



* These were found in some specimens cf clay containing also freshwater shells 

 which were dug out of a deep well at Newport. But as no distinct account was kept of 

 the strata passed through, it is not certain to which of tlie freshwater formations they 

 belong, 



+ It is proper to observe ihat the Potamides of Limarck is a Cerithium. But having 

 considered the cerithia as marine shells, he thought it projjcr, on finding a species among 

 the freshwater shells, to rcgnrd this as of a distinct genus ; founding the distinction not 

 on any diftercnce in its form, but on (he difference of the water in Mhich it had lived. 



