LAMELLIBRANCHIA TA. 
405 
The specimen described has a length of 34 mm., a height in the middle of 
16 mm., and the depth of both valves is 9 mm. 
This species is the only one of the genus yet noticed in the Upper Helderberg 
group. It somewhat resembles G. lingualis, from the Chemung group, but the 
anterior end is much shorter and more rapidly declining from the beaks, which 
are more elevated, the umbonal slope is more convex, and the cardinal slope 
is comparatively narrower. 
Formation and locality. In the Corniferous limestone at Littleville, near 
Avon, Livingston county, N. Y. 
Glossites subtenuis, n. sp. 
PLATE XL, FIGS. 12, 20. 
In part Modiomorplta ? amijf/dalina (Winchell), Hali.. Prelim. Notice Lamellibranchiata, 2, p 78. 1870. 
“ “ “ “ “ Pal. N. Y., vol. v, pt. 1. Plates and Explanations : 
PL 40, figs. 12-20. 1883. 
Not Sangubidlites amygdalinus, Winchell. Proc. Acad. Nat. Sci., Phila., p. 13. 1863. 
Shell small, elongate-elliptical; length twice the height; basal margin very 
gently curved, turning abruptly to the anterior and posterior. Posterior 
extremity regularly rounded. Cardinal margin nearly straight. Anterior 
end short, without limitation, gently declining from the beak and abruptly 
rounded at the extremity. 
Valves depressed-convex in the basal and posterior portions of the shell, 
becoming moderately convex in the umbonal region. 
Beaks sub-anterior, small, closely -appressed. Umbonal slope not defined. 
Test thin, marked by fine concentric striae, which are fasciculate upon the 
umbonal slope and posterior region, giving prominent undulations to the 
surface. Interior unknown. 
One of the specimens described has a length of 32 mm. and a height of 15 
mm. A comparatively broader specimen measures 30 mm. in length and 15 
mm. in height. 
Compared with G. amygdalina, this species has a narrower shell with a 
shorter anterior end; the posterior end is narrower and the striae curve and 
