PLATE 22, 23. 
P.23. — FIG. J, 2. 
CONCHYLIOLITHUS Anomites (siriatus) semlor- 
blculatis obsolete undatus longitudinaliter undique 
striatiis : striis approximatis elevatis subaequalibus, 
S. p. 
A fossil shell. The original an Anomia. Perforate ; the 
perforation large, triangular, between the beaks. Hinge 
straight, extended, patulous. Valves convex, semicircular, 
and longitudinally striated on every side. The strias close, 
nearly equal, and prominent. In the smaller valve, a con- 
vex wave, which is answered by a concave one (scarcely 
distinguishable) in the larger valve ; both terminating in a 
small wave at the margin. The beak of the perforated 
valve, large, curved, and somewhat pointed. 
Not uncommon about Castleton, and other parts of Der- 
byshire, where the limestone strata occur. 
Fig. ]. 2. Two different views of the same specimen — 
The outside consists of grey limestone, which has displaced 
the original shell — The inside is filled with spar — visible at 
ff. a. where the limestone is broken. 
In this specimen, the aperture, which divides the hinge 
between the beaks, is hidden by a small portion of the 
matrix (a hard limestone) remaining in that part. Since 
our drawing was made, we have met with more perfect 
specimens, in which the perforation is sufficiently evident. 
L 
