LAMELLIBRANCHIA TA. 
173 
In the volume of Plates and Explanations this species was referred to 
L. Dekayi in the absence of the original specimen, which has since been 
compared and found to belong to the Chemung group. 
Formation and locality. In a slaty sandstone of the Chemung group, eight 
miles north of Binghamton, N. Y. 
Leiopteria linguiformis. n. sp. 
PLATE LXXXVIII, FIG. 29. 
Shell above medium size, erect, sub-rhomboidal; body elongate-ovate, making 
an angle of about 60° with the hinge-line; length equal to three-fourths of 
the height; anterior margin nearly vertical from the byssal sinus to below 
the middle of the valve; basal margin broadly rounded; post-basal margin 
rapidly curving into the wing. 
Left valve convex above, depressed-convex below. Right valve unknown. 
Hinge-line straight, nearly equal to the length of the shell. 
Beak acute, erect, prominent, rising above the hinge-line. Umbonal 
region convex, subtending an acute angle. 
Ear small, triangular, bending slightly downward, limited by a well- 
defined byssal depression; margin nearly straight; extremity rounded. 
Byssal sinus shallow. Wing broad-triangular, joining the body below the 
middle of the post-cardinal slope, not strongly limited; margin concave; 
extremity acute. 
Surface marked by concentric striae which are strongly lamellose on the 
ear, the pallial margins and on the wing. 
Ligamental area narrow, marked by two or three longitudinal grooves. 
Muscular impression oval, situated near the middle of the post-cardinal 
slope. 
The specimen described has a length of 33 mm., height 42 mm., and 
hinge-line 32 mm. 
