Lorraine Faunas of New York and Quebec 289 
margin, and above this ridge, toward the cardinal outline, are not 
flattened, but have a more evenlyconvex appearance. The general 
aspect is that of a Cymatonota but there are no oblique wrinkles 
along the hinge-line. 
If Cymatonota parallela, Hall, {Paleontology of New York, vol. 
i, plate 82, Fig. 7c) did not show the oblique folds along the 
cardinal line, which are characteristic of Cymatonota, the Barnes 
Corners species might have been compared with that form, al- 
though the latter is figured as somewhat shorter. It is evident 
from the descriptive text that Hall included both forms with and 
without an oblique carina, and both with and without oblique 
folds on the cardinal margin in his species, but he placed special 
emphasis on the presence of the oblique folds along the hinge- 
line, and only forms possessing these folds can be regarded as 
typical. 
The Barnes Corners specimen resembles most closely the 
Orthodesma parallelum, from Rome, used for Fig. 712, on page 
511 of Dana’s Manual of Geology, which may be a Cymatonota. 
24. Orthodesma prolatum, sp. nov. 
{Plate I, Fig. 15) 
Hinge-line posterior to the beak apparently straight, meeting 
the upper part of the oblique posterior margin at an angle of about 
120 degrees. Umbonal ridge rather angular, especially toward 
the beak. The postumbonal slope, between the umbonal ridge 
and the cardinal margin, is flattened, or, rather, it consists of two 
flattened areas meeting each other at an angle of about 170 degrees. 
At the posterior extremity of the shell, this second line of angula- 
tion is about 5 or 6 mm. distant from the crest of the umbonal 
ridge and 4 mm. distant from the cardinal margin. It is not 
known whether this second line of angulation is a constant char- 
acteristic of the species, but, in the single individual at hand, it is 
noticed that the concentric striae ornamenting the shell become 
conspicuously more prominent, broader, and more regular, be- 
tween this second line of angulation and the cardinal margin, 
than elsewhere on the shell. Of these prominent striae along the 
cardinal margin there are about 8 in a length of 5 mm. measured 
transversely to the striae. Elsewhere on the shell the concentric 
striae are finer and closer, and are accompanied by obscure con- 
