PECTEN obscura. 
TAB. CCV.--- Fig. 1. 
Srrc. Cuar. Sub-orbicular, depressed, with ob- 
secure arched longitudinal ruge# upon the 
surface ; ears large. 
Somewnat longer than wide: the surface is dull, almost 
smooth ; but it has some indications of diverging furrows. 
The edge is thick. 
Occurs upon the sandy Limestone slate of Stonesfield, 
near Oxford. My specimen was forwarded to me long 
since by Dr. Williams. 
PECTEN lens. 
TAB. CCV.—Figs. 2 and 3. 
Spec. Cuar. Orbicular, convex; surface marked 
with diverging arched strie;  stric deeply 
punctured. 
Neary lenticular, but thickest near the beaks; the 
shell seems to be tender, as its remains are much broken: 
the ears are not perfect in either of my specimens. 
A produce of the forest marble near Oxford. 
