380 PALEONTOLOGY OF NEW YORK. 



curving upward to about the middle of its height, above which it is obUquely 

 sub-truncate. Cardinal line straight, more than two-thirds the length of the 

 shell, slightly declining posteriorly. Anterior end short, regularly rounded. 



Valves regularly convex in the lower and posterior portion, becoming 

 gibbous in the middle and above. 



Beaks at about the anterior third or fourth, rather prominent. Umbonal 

 slope sub-anguljir above, and sometimes continued obscurely to the post-inferior 

 extremity. Cincture broad, undefined, extending from the beaks to the base 

 anterior to the middle, and producing a flattening of the valve and a slight 

 constriction of the basal margin. 



Surface marked by fine concentric striaa, with a few, more or less distinct, 

 concentric undulations, which become obsolete at about the umbonal angle. 

 Interior unknown. 



Three specimens measure respectively 21, 25 and 30 mm. in length, and 

 14, 16 and 21 mm. in height. 



This species resembles G. communis, but the concentric undulations are not so 

 numerous, the umbonal slope less defined, the posterior end broader and not 

 so obliquely truncate above the middle, and the cincture more nearly vertical. 



Formation and localities. In the conglomerate of the Chemung group, at 

 Panama, and four miles north of Panama, N. Y. ; in the same horizon, at Alle- 

 ghany Springs, Warren county. Pa. ; also in some shaly sandstones, near Sala- 

 manca, and in the conglomerate, at Portville, N. Y. 



Grammysia duplicata, n. sp. 



PLATE XCin, FIG. 2S. 



Shell small, ovate, abruptly depressed and cuneate behind ; length more than 

 one-third greater than the height ; basal margin regularly curved with a 

 scarcely perceptible sinus anterior to the middle. Posterior extremity 

 abruptly rounded below and shortly truncate above. Cardinal line straight, 

 margined by a narrow escutcheon. Anterior end about one-third the length 

 of the shell, pointed, truncate below the lunule. Margin of the lunule nearly 

 straight and slightly declining. 



