scribed by Mr. Guettard, as found at Verest and Montrichard. 

 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 miriadsof 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 lirne and flint : the solid part of the ori- 

 ginal body having been silicified, and calcareous matter having filled 

 tip the interstices ; as has been remarked of several preceding speci- 

 mens. The alcyonic appearance is, I think, still more evident in an- 

 other 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. Strangers 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 



