162 
INOCERAMUS vetustus. 
TAB. DLXXXIV.—jig. 2. 
Spec, Cuar. Ovate, convex, smooth, regularly un- 
dulated ; valves nearly equal; beaks short, 
pointed, curved ; a concave space in the ante- 
rior side resembling a large lunette; hinge 
line short. 
Very regularly arched and gradually rising undula- 
tions of a smooth surface distinguish this from I. Bron- 
gniarti, independently of the difference in the anterior 
side. I have not seen the hinge, but the line to which 
it is attached is short ; the front is very round. 
Occurs in the Mountain Limestone at Castleton in 
Derbyshire, and near Settle in Yorkshire. 
enema 
INOCERAMUS dubius. 
TAB. DLXXXIV.—ig. 3. 
Spec. Cuar. Ovate pointed, concentrically striated 
and indistinctly waved ; valves unequal, both 
convex ; beaks short, pointed. 
Srronatry resembling I. concentricus. The convexity 
of the valves is variable; one valve is sometimes flat : 
it is then more strongly marked by the strie formed of 
the edges of the laminz, so characteristic of shells of the 
genus Inoceramus. I have not seen the hinge. 
A mass of indurated Alum Shale, containing brilliant 
casts in Pyrites of this shell and a portion of Ammo- 
nites elegans? was collected by that indefatigable geo- 
logist, R. I. Murchison, Esq. on the Whitby coast in 
1826. A portion of it is the subject of this figure. 
