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Mr. Webster on the Strata lying over the Chalk.
221
M. Brongniart mentions the following as being found in the
various beds of the upper marine marls.
| Cytherea (bom-bees) | Ostrea Hippopus |
| – – – – – plana | – – – – Pseudochama |
| – – – – – elegans | – – – – longirostris |
| – – – – – semisulcata | – – – – canalis |
| Cerithium plicatum | – – – – cochlearia |
| – – – – – cinctum | – – – – cyathella |
| Ampullaria patula | – – – – spatulata |
| Cardium obliquum | – – – – linguatula |
| Nucula margaritacea | Bones and parts of Fishes |
| Patella spirorostris—Cuv. p. 187. | |
| In the upper marine sand stones. | |
| Oliva mitreola | Pectunculus pulvinatus |
| Fusus, resembling longævus | Crassatella compressa? |
| Cerithium cristatum | Donax retusa? |
| – – – – – – lamellosum | Cytherea nitidula |
| – – – – – – mutabile? | – – – – – lævigata |
| Solarium? | – – – – – elegans? |
| Melania costellata? | Corbula rugosa |
| Melania? | Ostrea flabellula |
I have already mentioned that considerable difficulties appear to me to exist in assigning a place to the Woolwich beds. The actual lowness of their level, appearing to dip under the London clay, and their situation near the chalk without the intervention of that bed, at first seem to determine their geognostic position. Whilst the circumstances of their not being seen in any part covered by
