5(1 
what resembles ; it is also smoother, and in many respects 
sufficiently different never to be confounded with that 
species. 
Lately discovered by Mr. G. B. Sowerby in the upper 
marine formation at Headon Hill : fragments have also 
been found in other parts of the same formation upon 
the Isle of Wight, by Prof. Sedgwick. 
