326 PALEONTOLOGY OF NEW YORK. 



truncate. Cardinal line nearly straight. Anterior end sloping I'apidly 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 fine concentric striaa 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 obsei'ved among extensive collec- 

 tions from the localities where it occurs. 



Formation and localiiks. In the shaly sandstones of the Hamilton group, at 

 Jefferson and Fultonham, Schoh.arie county ; and Oneonta, Otsego county, N. Y. 



NUCDLITES TRIQUETER. 



PLATE XLVU, CIGS. I7-2S ; AND PLATK XCIII, FIGS. S-10. 



NuculiteJi Iriqueter, Courad. Geol. Surv. N. Y., Ann. Rep., p. 50. 1841. 



" " " Hall. Prolini. Notice Lamellibranchiata, 2, p. 4. 1S70. 



" " " " Pal iV. Y., vol. V, pt. 1. Plates and Explanations : PI. 47, figs. 17- 



LM. 1S83. 



Shell of medium size, or larger, trigon.al, short; length from one-fourth to 

 one-third greater th.an the height ; ba.sal m.argin regularly curving, sometimes 

 straight on the posterior portion, abruptly rounded into both extremities ; 

 posterior margin obliquely 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. 



