Fig. 10. A portion of a Choanite in flint; from gravel, Islington.

Fig. 11. A perfect specimen of a small simple coral (Fungia), from Maestricht.

Fig. 12. A spongite in a pebble; similar to fig. 5. Such specimens are very common in the shingle along the sea-shore at Brighton, Dover, &c.

Fig. 13. A fossil coral in limestone, from Maestricht. It is too imperfectly defined to determine the species or genus; an enlarged sketch of the structure is given at c.

Plate XLVI.

PLATE XLVI.