DEVONIAN FAUNAS. B47 
and front margins; beak obtuse, not incurved; cardinal area of 
moderate height, flat; delthyrium broadly triangular, closed by a del- 
tidium. Brachial valve regularly convex, the greatest elevation near 
the middle. Surface of both valves marked by rather coarse, radiating 
strie, which increase by bifurcation and which become stronger toward 
the margin of the shell. Toward the cardinal margin the radiating 
striz curve posteriorly as they approach the margin. 
The approximate dimensions of an imperfect cast of the brachial 
valve are: length, 32 mm.; width, 32 mm. 
Remarks.—This is a rare species in the Oriskany fauna of New Jer- 
sey, and no specimens attaining the great size of some of those from 
’ New York have been observed. The New Jersey specimens studied 
are all imperfect casts of the brachial valve, and do not at all fairly 
represent the species. 
ORTHOTHETES sp. undet. 
Plate XLV., Fig. 9. 
Several imperfect specimens of a species of Orthothetes have been 
observed associated with the Orbiculoidea jervensis fauna of the 
Oriskany formation, but they are too imperfect for identification. 
The dimensions of one of the best ones are: length, 12 mm.; width, 
16.5 mm. 
CHONETES HUDSONICA Clarke. 
Plate XLVI., Fig. 11. 
1900. Chonetes hudsonica Clarke, Mem. N. Y. St. Mus., No. 3, vol. 
III., p. 49, pl. 7, figs. 1-6. 
Description.—Shell of medium or small size, hinge-line equaling 
the greatest width; cardinal extremities angular, lateral margins sub- 
parallel for a short distance, then curving rather abruptly into the 
broadly-rounded anterior margin. Greatest convexity of the pedicle 
valve posterior to the middle, slightly flattened toward the cardinal 
extremities. Surface marked by fine, rounded coste, with rounded 
interspaces, increasing by bifurcation and implantation, a shell 11 
