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scribed by Mr. Guettard, as found at Verest and Montrichard. This 
was selected in preference to a more perfect one, from its plainly 
shewing the structure of the fossil and the mode of its formation. Its 
external surface is covered, with irregular risings and depressions, and 
serves, as in the madreporite, Plate VII. Fig. 4, for the basement of 
the fabric, erected by myriads of hydrae. The tracks in which each has 
laboured being evident on the broad edge of the fossil, where a frac- 
ture, obviously before petrifaction, has well displayed the resulting 
structure. Even with the naked eye, the little grooves formed by 
these insects are discernible, and may be traced to the upper surface, 
which is very closely beset with their terminations in small foramina, 
with crenulated edges. 
In another remarkably fine and perfect specimen of this funnel- 
formed fossil, obtained by Mr. Strange, from France, the structure is 
also very manifest. The external ridges and depressions, as well as the 
internal numerous foramina, are exceedingly distinct, and the grooves, 
passing across the upper edge of the fossil from the external surface, 
and opening on the internal, are very numerous and plainly marked. 
This fossil is of an uncommon size, being seven inches in height, 
nearly eight inches in its widest diameter, and an inch and a half in 
thickness. The substance of both these fossils appears to be com- 
posed of an intermixture of lime and flint : the solid part of the original 
body having been silicified, and calcareous matter having filled 
up the interstices ; as has been remarked of several preceding speci- 
mens. The alcyonic appearance is, I think, still more evident in another 
most beautiful fossil, originally of a funnel form, but which has 
the appearance of having suffered compression, the sides of the cone 
being brought nearly within half an inch of each other. This was 
also in Mr. Strange’s collection, and marked as having been obtained 
from Italy. It is about four inches in height, about the same dimen- 
sions from one end of the upper part of the flattened cone to the 
other, and little more than half an inch in its thickness. Its edge, at its 
