Page:Transactions of the Geological Society, 1st series, vol. 1.djvu/355

 specimens of Calyptræa trochiformis, Lam. Trochus apertus, Brander. Arcæ glycemeres, Arcæ Naticæ, and many minute shells in good preservation. All these shells appear to have entirely lost their animal matter, and not having become imbued with any connecting impregnation, they are extremely brittle. On examination with a lens it also appears that in most of the specimens nothing of their original surface remains, it having been every where indented with impressions of the surrounding minute sand, made whilst the shells were in a softened state. This circumstance is particularly evinced in the Cyclades, in which a particular character in the hinge was thus concealed; in a mass of these shells from the Isle of Wight, it appears that the lateral teeth are crenelated, somewhat similar to those of the Mactra solida in the gravel stratum; but in the Cyclades of Plumstead, this was not discoverable from the injuries which their surface had sustained from the sand.

The fossils of this stratum evidently agree with those found by Lamarck and M. De France, above the chalk at Grignon, Courtagnon, &c. and they have been just shewn, incidentally, to exist in the Isle of Wight. In an eastern and southern direction from London this stratum with its fossils is frequently discovered.

On the heath near Crayford, about four miles eastward of Charlton, long vaulted oysters are found similar to those already mentioned. About two miles further in the parish of Stone, is Cockle-shell-bank, so called, as Mr. Thorpe, the author of Custumale Roffesnse, says, p. 254 of that work, “ from the great number of small shells there observable.” These are the Cyclades already spoken of, and which Mr. John Latham, author of The general Synopsis of Birds, thought bore some resemblance to Tellina Cornea, Linn. ''Histor. Conchyl.'' of Lister, tab. 159. fig. 14. Mr. Latham here also met with a species of Cerithium, and another of Turitella. Fragments of these shells are