344 PALAEONTOLOGY OF NEW YORK. 



PaljEoneilo angusta, n. sp. 



PLATE XCm, FIG. II. 



Shell below the raedium size, elongate, sub-elliptical; length about twice the 

 height; basal margin regularly curving. Posterior extremity produced, 

 obliquely sub-truncate and doubly emarginate. Cardinal line straight and 

 long. Anterior end comparatively large and broadly rounded. 



Valves very moderately convex below, scarcely gibbous in the middle and 

 above. 



Beaks at about the anterior third, low, closely appressed, rising but little 

 above the hinge-line. Umbonal slope defined, sub-angular, extending to the 

 post-inferior extremity. Post-cardinal slope broad, and marked longitudinally 

 by a distinct angular fold reaching to the posterior margin. 



Surface marked by fine concentric striae ; and on the upper anterior por- 

 tion, the umbo and post-cardinal slope, by regular somewhat distant lamellose 

 elevations. 



Two specimens measure respectively 20 and 26 mm. in length, and 10 and 

 13 mm. in height. 



In its elongate form it bears some resemblance to P. muta, but the post-car- 

 dinal slope is narrower, the ridge along this slope is stronger and more nearly 

 central and the posterior extremity is doubly sinuate. 



Formation and locality. In the Chemung group, near Elmira, N. Y. 



PALiEONEILO BISULCATA. 

 PLATE L, FIGS. 12-14. 



PalcBojieilo bisulcata. Hall. Pi-elim. Notice Lamellibranchiata, 2, p. 10. 1870. 



" " " Pill. N. Y., vol. V, lit. 1. Plat«8an<l ExplanatioiiH: PI. 50,tijf8. 13, 14. 1883. 



Shell small, broadly sub-ovate ; length nearly one-half greater than the height ; 

 basal margin regularly curving to the post-inferior extremity. Posterior mar- 

 gin sinuate, obliquely sub-truncate. Cardinal line arcuate. Anterior end 

 regularly rounded. 



