131 
ORTHOCERA econica, 
TAB. LX.—Figs. 1, 2, and 3. 
Sprc. Cuar. Shell long-conical, aperture oval, a 
hitle wider one way than the other, smooth, 
chambers numerous, increasing in depth by 
age; siphuncle nearly touching one of the 
sides, small, 
OST IG RE re 
Tur septa have even margins and regularly concave sure 
faces, they are very thin and twice as distant from each 
other at the broadest end of the shell; the siphuncle is oval, 
about half a line wide. 
These figures exhibit specimens from the Alum Clay at 
Whitby, presented to me by the Marchioness of Bath. 
Fig. 1 is a dark Iron clay stone, the shell chiefly Carbonate 
of Iron. ‘The edges of the septa have something like a 
double margin, or a little sulcus, which is occasionally 
apparent within the shell. Fig. 2 has the shell of a lighter 
tint with some signs of Pyrites and the remains of the 
pearly lustre in the division; it is also less conical, and I 
should consider it as the narrow continuance of the same 
species. Fig. 3 shows the convex side of one of the septa 
with the siphuncle near the edge. 
