92 
since its texture is such, as I have found almost constantly to charac- 
terize the fossil remains of any individual of this genus, which had 
been composed of a sponge-like substance. This substance has evi- 
dently, like sponge, been of a reticular texture ; but the disposition ot 
the meshes, if so they may be called, is in the spongy alcyonium much 
more uniform and determinate than in ordinary sponge, and though 
not to be described in words, the texture is so peculiar and character- 
istic, as directly to be known by those, who have been in the habit of 
examining these and similar substances, by the aid of magnifying 
glasses. The magnified appearance of its surface is shewn Plate VII. 
Fig. 7. 
The fossil represented Plate VII. Fig. 6, and which is also from 
Berkshire, appears to bear a tolerably close resemblance to alcyonium di- 
gitatum of Linnaeus ; or the dead mans hand, or dead mans toes of Ellis. 
Its texture evidently appears to be of that kind, being finely reticu- 
lated, which would correspond with the carneous spongy substance, 
of which the recent zoophyte is formed. Its surface also, thickly beset 
with minute openings, bearing somewhat of a stellated appearance to 
the naked eye, serves to confirm the resemblance. This fossil is now 
a carbonate of lime moderately hard, but friable. 
In the elegant work of Knorr, Mr. Walsh describes several fossil 
elongated alcyonia, by the silly term which the antients had adopted, of 
pi'iapolithi. One of these from Touraine is figured Plate VII. Fig. 1. 
It had, at its superior termination, that opening observable in many 
of these animals, which served for the reception of the sea-water, from 
which, it is probable, they derived their support. 
On rubbing down this substance on a sand-stone, at this termina- 
tion, for the purpose of examining its structure, its hardness and the 
partial polish it obtained, proved, that it had suffered an impregnation 
with silica: and an examination of this surface with a lens plainly 
shewed that the flinty part was regularly distributed in continuous 
meandering lines, bearing the peculiar and characteristic form of the 
