Page:Transactions of the Geological Society, 1st series, vol. 1.djvu/359



A Muscle. No instance appears in which any shell of this genus has been found in our chalk.

Two Oysters. The Kentish chalk-pits yield at least three species of this genus. One of them bearing very much the form and appearance of Ostra edulis, but being only about a fourth of its size; one smaller, the serrated edge of which places it in the family of Cristæ galli; and the third still smaller, not half an inch in length, crenelated on each side of the hinge.

A species of Pecten. There are two or three small species of pecten in the English chalk; besides a shell, with long slender spines, which may be safely classed with the pecten.

A Crania (Anomia Craniolaris, Linn. Crania personata, Lam.) This fossil is not known in the English chalk; nor indeed could it be easily ascertained, unless the inferior valve happened to be well displayed.

Three Terebratulæ. T. sulcata and a terebratula agreeing with Anomia terebratula Linn. are frequently found in our chalk; and sometimes another species, hardly half an inch in length, with remarkably acute and well defined ribs.

A Spirorbis. Traces of these shells are frequently found on the surface of the echinitæ.

Ananchitæ, (Echinus ovatus.) The crustaceous covering of which, it is remarked by M. Cuvier and Brongniart, remains calcareous, and has assumed a sparry texture, whilst the middle alone is changed into silex. No actual change has however taken place, as far as respects the flinty part of the fossil, the flint having merely filled up the hollow of the sparry crustaceous covering. This fossil is frequently found in the English chalk.

Porpitæ. These also occur in the English chalk.

Five or six different fossil bodies called by the French oryctologistt, Polypiers, one appearing to belong to the genus Caryophyllæa. Several