[12 NEW YORK STATE MUSEUM 
Diaphorostoma? niagarense (Hall) ? 
Poleumita scamnata Clarke and Ruedemann 
Streptomytilus? cf. eduliformis (Clarke and Ruedemann) 
Cuneamya cf. alveata Whitfield and Hovey 
Ctenodonta cf. salinensis Ruedemann 
C. ruedemanni nov. 
Pterinea cf. poststriata Ruedemann 
P. rotunda nov. 
P. jordani nov. 
172) SiO, 
Orthodesma? sp. 
Camarotoechia litchfieldensis (Schuchert) 
Lingula vernoni nov. 
Cornulites hopkinsi nov. 
Besides the above several unidentified ostracods, and forms re- 
sembling bryozoa occur. 
The fossils are sparingly distributed in the rock at best, and 
their fragmentary nature renders specific determination difficult 
in many cases. In general the fauna consists largely of pelecypods. 
Only two brachiopods were found, of which Camarotoechia 
litchfieldensis is quite abundant. No Salina eurypterids were 
observed. The fauna appears to be typically mid-Sherman with a 
mixture of Niagaran and Salinan forms. A majority of the old 
species occur through the Cayugan, two slightly later. Two were 
reported previously in the Niagaran (Guelph) only, and one in 
the lower Clinton. The fauna is marine, and flourished apparently 
in a solution concentrated enough to allow of the occasional crys- 
tallization of halite. This interesting fact may aid in the de- 
termination of the origin of the Vernon formation. 
Descriptions of Species 
vf Ctenodonta ruedemanni nov. 
Plate 1, figure 4 
Shell small, strongly inequilateral, with a length of about 1% 
times the height, flat. Beak prominent and mildly acute, set far 
forward with a resulting distinct apical angle. Dorsal line convex 
and sloping as in C. salinensis. Anterior margin rounded, 
posterior probably sharper. Surface covered with indistinct lines 
of growth. A single left valve only was found. 
This species resembles the Salina species C. salinensis, but 
its beak is slightly farther forward than that of the latter. 
