326 
PALAEONTOLOGY OF NEW YORK. 
truncate. Cardinal line nearly straight. Anterior end sloping rapidly in a 
straight line from the beaks, and abruptly rounded below. 
Valves depressed-convex below, becoming convex and sometimes gibbous 
in the umbonal region. 
Beaks at about the anterior fourth, slightly incurved and rising above the 
hinge. Umbonal ridge angular, extending from the beak to the posterior 
extremity ; post-cardinal slope abrupt. 
Test marked by tine concentric striae which are sometimes fasciculate on 
the lower portions of the shell. 
Internal characters similar to those of the preceding species. 
Two specimens measure respectively 32 and 29 mm. in length and 15 and 
14 mm. in height. 
This species is distinguished by its elongate cuneate form. It appears to be 
a rare species, as but few specimens have been observed among extensive collec¬ 
tions from the localities where it occurs. 
Formuiion and localities. In the shaly sandstones of the Hamilton group, at 
Jefferson and Fultonham, Schoharie county ; and Oneonta, Otsego county, N. Y. 
Nuculites triqueter. 
PLATE XLVII, FIGS. 17-28 ; AND PLATE XCHI, FIGS. 8-10. 
Nuculites triqueter , Conrad. Geol. Surv. N. Y., Ann. Rep., p. 50. 1841. 
“ “ “ Hall. Prelim. Notice Lamellibrancliiata, 2, p. 4. 1S70. 
“ “ “ “ Pal N. Y., vol. v, pt. 1. Plates and Explanations: PI. 47, figs. 17- 
24. 1SS3. 
Shell of medium size, or larger, trigonal, short; length from one-fourth to 
one-third greater than the height; basal margin regularly curving, sometimes 
straight on the posterior portion, abruptly rounded into both extremities; 
posterior margin oblicpiely truncate; cardinal margin arcuate. Anterior 
end short, rounded. 
Valves convex, gibbous in the middle and above. 
Beaks at the anterior third or fourth, very prominent, incurved, arching 
over the hinge. Umbo prominent and gibbous. Umbonal ridge distinct, 
