102 
PALEONTOLOGY OF NEW-YORK. 
younger specimens are neat and well defined, preserving the carina and concentric folds which 
become obsolete in older specimens. The shell originally has been very convex, but, from 
pressure, it is often^flattened, and the form of the outline altered. 
The only shell in the Clinton group resembling this species is the Orthonota curia , from 
which it differs in its greater proportional height, and from the hinge-line being less straight. 
Fig. 3 a. A young individual of this species. 
Fig. 3 b, c. The right valves of trvo individuals of medium size. 
Fig. 3 d. The left valve of an older individual. 
Fig 4 a. This individual has nearly the same form as figs. 3 h and 3 c, but is more compressed, 
and the concentric folds are not at all conspicuous. I am unable to find any characters, 
however, indicating a specific distinction. 
Position and locality. In the upper gray sandstone of the Clinton group, south of Mohawk 
village, Herkimer county. 
499. 9. TELLINQMYA ELLIPTIC A (». S p.). 
Pl. XXX. Fig. 4 b. 
Elliptical; extremities nearly equal; beak scarcely prominent • surface convex, without any 
distinctive elevations, marked by fine concentric striae. 
This species approaches Tellinomya curta of the preceding plate 27 ; but the extremities 
are more nearly equal, and the beak more nearly central than in that species. The surface is 
similarly marked by fine concentric striae, though of these the species under consideration 
scarcely preserves any remains. 
Position and locality. In the upper gray sandstone of the group south of Mohawk village, 
Herkimer county. 
Pl. XXX. Fig. 5 a, b. 
Shell with both valves closed, elongate, sub-cordate ; umbones very prominent and some¬ 
what gibbous below, becoming narrow and thin towards the posterior extremity ; anterior 
extremity very short; surface of the cast preserving very slight traces of concentric striae. 
This species is readily recognized by its gibbous anterior below the beaks, and by its 
elongate-cordate form when both valves are closed. The specimen figured is somewhat crushed, 
so that its entire characters are not preserved. 
Fig. 5 a. View looking upon the cardinal line. 
Fig. 5 b. Lateral view of left valve, which is crushed, showing the outline of the right valve 
beyond. 
Position and locality. In the upper gray sandstone of the group, south of Mohawk village, 
Herkimer county. 
