Among the Veronese fossils which I possess, is one which, though 
somewhat mutilated about the aperture, bears not only sufficient proofs 
of its belonging to this genus, but strong marks of its species, C. inter- 
ruption. It is of a remarkable size, being nearly four inches long. 
In the stratum of fossil shells running through Plumsted and Wool- 
wich, and appearing at Bromley, in Kent, shells of this genus are 
frequently found, but in so brittle and so injured a state, as not often 
to allow of their species being made out. I have, however, I think, 
discovered C. turritellatum , C. denticulatum, C. serrcitum, C. clava- 
tulatum, C. mutabile, and C. cinctum. 
In the whetstone of Blackdown Hills, Devonshire, a turreted shell 
exists in considerable numbers ; but it is very difficult to extricate 
them from the matrix, with their mouth perfect. I think, however, 
that I am right in considering these as belonging to C. turritellatum. 
They are completely silicious ; and many of them, with their included 
matrix, are transparent. 
The most extraordinary shell of this genus is, C. giganteum. It is 
turreted, extremely long, and transversely striated : the turns, in their 
upper part, are tubercular, and the columella has one fold. These 
enormous shells are generally a foot in length. One of the specimens 
which I possess, and which has lost at least an inch or two of its length, 
still measures fourteen inches. They are found at Grignon, and are 
not very rare : they are however, in general, very much injured, very 
seldom indeed having the lip and sides of the opening perfect. Their 
form is that of a winding turriculated pyramid, with in general twenty 
turns, beset on their upper part with a row of nodular tubercles, and 
having the general surface lightly and transversely striated. The open- 
ing is oblong and oblique, and terminates in the lower part in a canal, 
the extremity of which is moderately recurved ; and the superior part, 
instead of forming a canal, is laterally extended, in the manner of an 
ear-like process. There is only one fold on the columella. This is, 
undoubtedly, the largest unilocular univalve shell that is known. 
