B48 PALEOZOIC PALEONTOLOGY. 
mm. wide bearing from eighty to ninety cost at the margin. Cardi- 
nal margin marked by two or three spines on each side of the beak, of 
which the outermost ones are directed more obliquely outward than 
the second ones. Brachial valve not observed. 
The dimensions of a nearly-perfect pedicle valve are: length, 7.5 
mm.; width, 11 mm. 
Remarks.—This species is one of the rarest in the New Jersey 
Oriskany fauna, and has been observed only as a member of the 
Orbiculoidea jervensis fauna. It seems to be identical with the little 
shell from New York described by Clarke as C. hudsonicus. 
CHONOSTROPHIA COMPLANATA (Hall). 
Plate XLVI., Wig. 12. 
1859. Chonetes complanata Hall, Pal. N. Y., vol. III., p. 418, pl. 93, 
figs. 1 a—d. 
Description.—Shell semi-circular to semi-elliptical in outline, 
broader than long, greatest width along the hinge-line; cardinal ex- 
tremities usually nearly rectangular. Pedicle valve depressed-convex 
on the umbo, nearly flat or concave toward the lateral and front mar- 
gins; the cardinal margin with three or four tubular spines, directed 
obliquely outward, on each side of the beak; cardinal area narrowly 
linear. Brachial valve depressed-convex, flattened toward the cardinal 
extremities, most prominent near the middle. Surface of both valves 
marked by fine, radiating, irregularly-bifurcating strie, of which 
about four occupy the space of 1 mm. near the margin. Internally 
the valves are finely papillose, the papille being arranged radially 
along the lines of the external radiate markings. 
The dimensions of a rather large pedicle valve are: length, 16.5 
mm.; width, 28 mm. 
