Page:Transactions of the Geological Society, 1st series, vol. 2.djvu/240

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230
Mr. Webster on the Strata lying 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. [1]

M. Brongniart has enumerated the following fossils as belonging to this formation.

Cyclostoma elegans antiquum Limneus inflatus
Potamides Lamarckii[2] 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 very numerous

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

  1. These were found in some specimens of 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 the freshwater formations they belong.
  2. It is proper to observe that the Potamides of Lamarck is a Cerithium. But having considered the cerithia as marine shells, he thought it proper, on finding a species among the freshwater shells, to regard this as of a distinct genus; founding the distinction not on any difference in its form, but on the difference of the water in which it had lived.