490 PALAEONTOLOGY OF NEW YORK. 



PALiEANATINA ANGDSTA, n. sp. 



PLATE LXXIX, FIGS. 21KJ4. 



In part Patttanatina typo. Hall. Pal. N. Y., vol. v, pt. 1. Plates and Explanations: PI. 79, figB. 26-39. 



1883. 



Shell small, elongate, narrowly elliptical or sub-cylindrical ; length from two 

 and a halt" to three times the height ; basal margin straight or slightly sinu- 

 ate. Posterior extremity obliquely truncate or regularly rounded. Cardinal 

 line straight or slightly declining posteriorly. Anterior end narrow, rounded. 



Left valve gibbous in the umbonal region. Right valve less gibbous and 

 more depressed below the umbonal ridge. 



Beaks between the anterior third and fourth, small, scarcely rising above 

 the hinge. Umbonal slope obtusely sub-angular, extending to the post- 

 inferior extremity. Post-cardinal slope flat or concave, with a fold in the 

 left valve, a feature not observed in the right valve. There is a shallow 

 undefined depression extending from the umbo to the base, scarcely affecting 

 the margin. 



Surface marked by fine concentric striae, which become fasciculate on the 

 posterior end of the shell. 



Five specimens measure respectively 21, 24, 26.5, 30 and 32 mm. in 

 length, and 9, 10, 10, 10 and 10 mm. in height. 



Compared with either of the preceding species this shell is comparatively 

 smaller, more elongate, and the difference in the convexity of the valves is less 

 conspicuous. 



Farther collections may show the necessity of separating such specimens as 

 are represented in figure 30 of plate Ixxix. 



Formation and locality. In a conglomerate of the Chemung group, near Port- 

 ville, Alleghany county, N. Y. 



