LAMELLIBRANCHIA TA. 
499 
Yalves depressed-convex in the lower and posterior portion, becoming con¬ 
vex in the umbonal region. 
Beaks at about the anterior fifth, small and appressed, rising but little 
above the hinge-line. Umbonal slope convex above, not defined toward the 
post-inferior extremity. 
Surface marked by fine concentric striae, which are fasciculate, and pro¬ 
duce undulations of the surface at irregular intervals, and are more con¬ 
spicuous on the posterior half of the shell. Anterior muscular scar situated 
just below the lunule, near the anterior extremity. Cardinal margin flat¬ 
tened as in other species of this genus. 
Two specimens measure respectively 40 and 51 mm. in length, and 17 and 
22 mm. in height. 
This species resembles G. depressus, but is distinguished by its greater con¬ 
vexity, more elongate form, and much more extended anterior end. 
Formation and locality. In a red sandstone of the Chemung group, at Nelson, 
Tioga county, Pa. 
Glossites procerus, n. sp. 
PLATE XCVI, FIG. 13. 
Shell above the medium size, elongate-sub-elliptical, narrower in front; length 
two and one-half times the height; basal margin gently curved, abruptly 
rounded into both extremities. Posterior margin recurved to the hinge¬ 
line. Cardinal line gently arcuate. Anterior end produced, declining from 
the beaks and narrowly rounded in the lower part. 
Yalves depressed-convex in the lower and posterior portions, becoming 
moderately convex along the middle and in the umbonal region. 
Beaks at about the anterior fifth, small and closely appressed. Umbonal 
slope not strongly defined, but the convexity continues to the post-inferior 
extremity. 
Surface marked by fine strise of growth, which are sometimes fasciculate, 
forming concentric undulations. Anterior muscular scar strongly developed. 
