82 
distinguished by a small protuberance that perhaps makes 
it more perfect and certain than any before seen, if it be not 
a specific difference. They are said to be found along 
with the Turrilites, at Mount St. Catherine, near Rouen. It 
is not a little remarkable that it is not found in Sussex or 
Wiltshire with our Turrilites, for the shell figured by 
Mr. Parkinson, plate 9, f. 6, which at first sight a little 
resembles it, and which is found in the same stratum with 
the Turrilites, is certainly oval or elliptical by distortion, 
and is of a different species ; when most perfect the speci- 
mens have a round contour. I have specimens variously 
distorted. I do not know that any Turrilites have yet 
been discovered in Ireland : there are however two or more 
truly elliptical shells. 
Those found at St. Catherine are said to be argillaceo- 
calcareous, ours are a very foetid Limestone, which is very 
apparent when scraped. 
