80 
MELANIA Heddingtonensis. 
TAB, XXXIX.* — Right and left hand figures • 
Spec. Char. About three times as long as the 
diameter; whorls eight or more; surface of 
each whorl concave near the middle,, with an 
obtuse angled rising near the upper part. 
A. thick rugged shell, four or five inches long; the lines 
of growth are deep. The upper part of the whorl is 
angular. 
I have received this from Heddington, near Caine in 
Wiltshire, and have found specimens about Shotover hill 
in Oxfordshire, where I have also found the inside cast. 
Casts of these and other spiral shells are commonly called 
screws, and are often found with little or no remains of the 
shells in solid masses of stone, and sometimes have the 
impression so perfect around them, that the outer pattern of 
the shells is very distinct, and may therefore often be 
convenient in a geological point of view to assist us to 
recognize these casts, for in some places we very seldom 
find any thing else. I think it desirable here to figure the 
cast of this shell, as likely to be instructive; besides it 
makes us acquainted w ith the particulars of the inside of 
the shell, and is an assurance of its not being chambered as 
a Turrilites; see Tab. 36 . 
