496 PALEONTOLOGY OF NEW YORK. 



become almost parallel to the cardinal border, while in that species the stria3 

 terminate abruptly at the cardinal linf.. 



Formation and locality. In the central portion of the Hamilton group, near 

 Geneva, N. Y. 



Glossites depressus, n. sp. 



PLATE XL, FIGS. 15, 17 ; AND PLATE XCVI, FIG. 12. 



In part Modwmorpha t amygdalina (Winchbli,), Hall. Prelim. Notice Lamellibranchiata, 2, p. 78. 1870. 



" Pal. N. Y., vol. V, pt. 1. Plates and Explana- 

 tions : PI. 40, figs. 12-20 1883. 

 Not SanfftiinolUes amygdalinus, 'WiifcuKi,!,. Proc. Acad. Nat. Sci., Phila., p. 13. 18B3. 



Shell above the medium size, sub-elliptical, wider behind ; length about twice 

 the height ; basal margin gently curved to near the extremities, where it 

 rapidly recurves. Posterior extremity abruptly rounded, obliquely sub- 

 truncated on its upper portion. Cardinal margin gently arcuate for its 

 entire length. Anterior end slightly produced, rapidly declining from the 

 beak and narrowly rounded below. 



Valves depressed-convex in the posterior and basal portions, becoming 

 moderately convex in the umbonal region. 



Beaks sub-anterior, small and closely appressed, scarcely rising above the 

 hinge-line. Umbonal slope not defined. 



Surface marked by fine concentric striae, which are fasciculate upon the 

 middle and posterior portions of the shell, producing undulations of the sur- 

 face which are sometimes strongly marked in the cast. 



Anterior muscular impression shallow, close to the anterior margin. 



One of the specimens described has a length of 50 mm. and a height of 26 

 mm. A smaller individual measures 47 mm. in length and 24 mm. in height. 



This species closely resembles G. lingualis, but the anterior end is propor- 

 tionally shorter and the vjilves are more expanded posteriorly. 



Formation and localities. In the shaly sandstones of the middle portion of the 

 Chemung group, at Buck's quarry, north-west of Elmira, associated with Orthis 

 impressa ; and near Elmira, associated with Orthis Tioga and Leptodesma protextum. 



