Mr. J. C. Delametherie, Journal de Physique, fyc. Tome lxv. 
Nov. 180 7, says, “ I have a gigantic fossil cerite, cerites gigas, Lam. 
which Mr. Maclure, of the Philosophical Society of Philadelphia, 
found at Grignon, in a mineralogical tour which we made there in 
the month of July. It is the largest which is known. Its circum- 
ference, near the mouth, is from twenty-two to twenty-three inches, 
or about seven inches and a half in diameter. The thickness of the 
lip is about seven lines. Its complete length should be about thirty 
inches ; but it is broken, and the piece which I have is but about ten 
or twelve inches long. 
In addition to this statement of the learned author of La Theoi'ie 
de la Terre, I have the pleasure to state, that I am in possession of a 
nearly corresponding specimen, a cast, which I purchased out of the 
Leverian collection, and which in all probability was obtained from 
Grignon. It is a lime-stone cast, in which six turns, with the mouth, 
is so well preserved, as decidedly to determine it to have derived its 
form from a shell of this genus. This shell must have exceeded in 
size that of M. Delametherie ; since, independent of the thickness of 
the shell, its greatest circumference, near to the mouth, is nearly 
twenty-four inches ; its diameter being, of course, about eight inches. 
This specimen is about sixteen inches in length ; and its weight, there 
being no externally adhering matrix, is full twenty-one pounds and a 
half. M. Delametherie concludes, from his fragment, which is from 
ten to twelve inches in length, that the shell must have been thirty 
inches in length ; but I think, from the proportions of my fragment, 
which, being nearly six inches longer than that of M. Delametherie, 
gives better grounds of calculation, that he may have over calculated 
the original length of the shell ; since I cannot believe that my 
specimen, if perfect, although larger than his, would have attained 
more than twenty-eight inches. 
Different species of this genus are found, in delicately beautiful 
calcareous masses, in the neighbourhood of Courtagnon. But among 
