36 
BULLETIN OF THE LABORATORIES 
thread-like strias and rather coarse folds which are most prominent as 
they cross the antero-umbonal slope. Length 30 mm., height 22 mm., 
convexity of one valve, 7-9 mm. 
This species is unusually short and Schizodus-like and may not be 
aGrammysia, thongh doubtless falling in the same group with theWav- 
erly species referred doubtfully to that genus by Meek. 
Shale below conglomerate I, Granville. 
SCHIZODUS (CHEMUMGENSIS, var.) PROLONGATUS, Sp. n. 
(Plate VI, Fig I, also Plate IX, Fig. 20, vol. iii.) 
It is only in deference to the opinion of able palaeontologists that 
this form is separated from the typical S. Chemungensis, from which 
it differs almost solely in being generally somewhat more extended at 
the postero-basal angle and hence having somewhat more oblique poster- 
ior margin. There may or may not be a faint sinus passing upward 
from a point slightly forward from the posterior angle. Length, 33 
mm., height, 24 mm. 
This form is not rare in shales below conglomerate I, at Gran- 
ville. 
SCHIZODUS NEWARKENSIS, Herrick. 
(Plate VI, Fig. 6.) 
A number of additional specimens of this our largest Schizodus 
afford opportunity for ascertaining the typical form. As supposed, 
the original specimen proves to have been considerably distorted, 
but the species is quite distinctly characterized by the uniformly curved 
anterior margin which forms nearly a segment of a circle and the con- 
vexity of the surface near it as well as the obliquely protruded postero- 
inferior angle and large size. In outline the species somewhat resem- 
bles certain forms of Sc. chemungensis, which, however, never attains 
anything like the size of the present species. Length, 80 mm., height, 
60 mm. Length, 82 mm., height, 64 mm. 
MACRODON NEWARKENSIS, Sp. n. 
(Plate IV, Fig. 19.) 
Shell of medium size, rather flat, sub-oblong, about twice as long 
as high, basal and cardinal margings parallel, the former gently con- 
