290 
PALAEONTOLOGY OF NEW YORK. 
Test thin, finely striated concentrically, with rarely any evidence of 
fascicolation. 
Anterior muscular impression large, situated just within the anterior 
margin of the shell. Posterior scar superficial. 
A specimen of medium size has a length of 20 mm., and a height of 14 
mm. A more elongate form has a length of 20 mm., and a height of 12 
mm. A large symmetrical specimen has a length of 30 mm., and a height 
of 20 mm. 
This is a small species of quadrangular form, but subject to much varia¬ 
tion in its proportions, depending chiefly on the manner in which the lateral 
compression has been directed, whether in the line of the longitudinal or 
vertical axis of the shell; those lying in one direction on the surface of the 
shale being lengthened, and those at the right angles being considerably 
widened and shortened. 
This species differs from any of the foregoing in its small size, quadrangular 
form, well-defined, straight, sub-angular umbonal ridge. The specimens, although 
imbedded in a fine micaceous sandy shale, have had their surface characters 
almost entirely destroyed by the deposition of sand, which has become incorpo¬ 
rated with the shell, giving the surface a roughly granulose texture. 
Formation and localities. In the micaceous sandy shales of the Chemung 
group, at Belmont and Rockville, in Alleghany county; and in Cattaraugus 
county, N. Y. 
Modiomorpiia neglecta. 
PLATE XLI, FIG. 13. 
Modiomorpiia neglecta. Hall. Pal. N. Y., vol. v, pt. 1. Plates and Explanations : PI. 41, figs. 12, 13. 1SS3. 
(Fig. 12 in error.) 
Shell small, ovate, wider behind; length and height as 3 to 2; basal margin 
straight in the middle, curving abruptly both at the anterior and posterior 
extremities; posterior margin regularly rounded, curving into the cardinal 
margin, which is gently arcuate. Anterior end very short, declining abruptly 
from the beaks, and regularly rounded below; obscurely limited by a depres¬ 
sion extending from the beaks to the basal margin. 
