PLATE 15, 16. 
flat or concave; but it is generally so imbedded in the 
mass of stone usually constituting that side of the spe- 
cimen, that its true form can scarcely be ascertained; it 
sometimes indeed seems to be wanting. The surface of 
the large valve is most commonly shattered and imperfect. 
Fig. 1. Represents a specimen with the strias and fur- 
rows more regular than they usually are found. 
FIG. 2. 
CONCHYLIOLITHUS Anomites (crassus) sxibro- 
tundus, longitudinaliter sulcatus striatusquc; striis 
tuberculatis, valva altera subglobosa. S. p. 
Dift’ers from the foregoing in the sides not being dilated ; 
and in the beak, which is broader, more convex, and 
rarely curved so much over the hinge. The tubercles arc 
generally also less spine-like, smaller, and the striae more 
regular than in C. a. giganteus. 
A large species; but seldom attaining the size of the 
former. It is common In most parts of Derbyshire, where 
limestone strata prevail. I have met with some good speci- 
mens between Buxton and Fairfield, on the top of the hill 
called Stonebench. The larger valve is all that is commonly 
found of this fossil. 
