LAMELLIBRANCHIATA. 325 



concentric strioe of growth, which are sometimes scarcely fasciculate on the 

 lower portion of the shell. 



Hinge furnished with numerous transverse teeth, as represented in figs. 

 7-9, plate xlvii. 



There is a strong vertical clavicular ridge just anterior to the beaks which 

 extends for more than half the height of the shell. Anterior muscular scar 

 sub-circular, distinct, situated within the cavity of the anterior end. 

 Posterior scar narrow-ovate, very close to the post-cardinal margin. Umbo 

 marked by three or four strong muscular pits. Pallial line distinct, distant 

 from the margin of the valve. 



Four specimens measure respectively 35, 33, 26 and 24 mm. in length and 

 20, 15, 12 and 11 mm. in height. 



This species more nearly resembles N. cuneiformis than any other, but is 

 readily distinguished by its shorter anterior end, wider post-cardinal slope and 

 rounded urabonal ridge. It also resembles Nucula [Nuculites] ovata, Sowerbv, as 

 identified by Phillips, but is somewhat more elongate in form, with the post- 

 cardinal line less oblique. 



Formation and localities. In the shales of the Hamilton groujj, in Schoharie 

 and Otsego counties ; on the shores of Skaneateles, Cayuga, Seneca and Canan- 

 daigua lakes, and numerous localities in Western New York ; also in the same 

 horizon at Patterson's creek, Va. 



Nuculites cuneiformis. 



I'l-ATK XLVII, FI(!S, IS-IC. 



Nucidifes cuneiformU, Conrad. Geol Surv N. Y., Ann. Rep., p. 50, plate, fijf. 7. 1.S41. 

 " " " Hall. Prelim. Notice Lamellibranoliiata, 2, p. 4. 1S70. 



« «< " " Pal. N. Y., vol. V, pt. 1. Plates and Explanations ; PI. 47, figs. 



13-1(;. 1883. 



Shell of medium size, elongate-ovate, cuneiform, widest in front and pointed 



behind; length usually more than twice the height; basal margin gently 



curving in the anterior part, becoming nearly straight behind, and abruptly 



rounded into both extremities. Posterior extremity narrow, pointed, obliquely 



42 



