92 



since its texture is such, as I have found almost constantly to charac- 

 terise 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 of 

 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. (5, 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 man's 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 priapolithi. One of these from Touraine is figured, Plate VII. Fig. 1. 

 It had at its superior termination that opening, observable in many 

 to 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 



