To Thomas Pennant, Esquire

The fossil-shells of this district, and sorts of stone, such as have
fallen within my observation, must not be passed over in silence.
And first I must mention, as a great curiosity, a specimen that was
ploughed up in the chalky fields, near the side of the down, and
given to me for the singularity of its appearance, which, to an
incurious eye, seems like a petrified fish of about four inches long,
the cardo passing for an head and mouth. It is in reality a bivalve of
the Linnaean genus of Mytilus, and the species of Crista Galli;
called by Lister, Rastellum; by Rumphius, Ostreum plicatum
minus; by D'Argenville, Auris Porci, s. Crista Galli, and by those
who make collections cock's comb. Though I applied to several
such in London, I could never meet with an entire specimen; nor
could I ever find in books any engraving from a perfect one. In the
superb museum at Leicester-house, permission was given me to
examine for this article; and though I was disappointed as to the
fossil, I was highly gratified with the sight of several of the shells
themselves in high preservation. This bivalve is only known to
inhabit the Indian Ocean, where it fixes itself to a zoophyte, known
by the name Gorgonia. The curious foldings of the suture, the one
into the other, the alternate flutings or grooves, and the curved
form of my specimen being much easier expressed by the pencil
than by words, I have caused it to be drawn and engraved.

Cornua Ammonis are very common about this village. As we were
cutting an inclining path up the Hanger, the labourers found them
frequently on that steep, just under the soil, in the chalk, and of a
considerable size. In the lane above Well-head, in the way to
Emshot, they abound in the bank, in a darkish sort of marl; and are