ORISKANY SANDSTONE. 
419 
Leptsena? liucleata. 
Plate XCIY. Fig. 1 a, b, c, d. 
Leptana nuclcata : Hall, Regents’ Report of 1856, p. 47; Palaeozoic Fossils, 1857, p. 7. 
Shell semicircular. Ventral valve extremely gibbous, abruptly depressed 
or flattened towards the lateral extremities : beak (internal cast) very 
abruptly incurved, and divided by a central groove which extends 
downwards nearly to the middle of the valve. Dorsal valve unknown i 
hinge-line equal to the greatest width of the shell, terminating in 
minute triangular extensions; area sublinear, incurved beyond the 
plane of the valves. Surface unknown. 
Internal casts of the ventral valve of this little shell are common in the Oriskany 
sandstone; but I have seen no specimens showing the external characters, nor have 
any specimens of the dorsal valve yet been recognized. I have referred it provisio¬ 
nally to the Genus Lept;ena, but with much doubt as to its true generic relations. 
Fig. 1 a, b. Ventral and profile views of the cast. 
Fig. 1 c. Cardinal view. 
Fig. 1 d. Profile view enlarged. 
Geological position and locality. In the Oriskany sandstone : Albany county. 
Spirifer suhmucronatiis. 
Plate XCVI. Fig. 7 a-f. 
Spirifer submucronatus : Hall, Regents’Report of 1856, p. 62; Palaeozoic Fossils, 1857, p. 22. 
Shell semicircular, with the extremities mucronate : valves equally and 
moderately convex. Ventral valve regularly convex, a little flattened 
at the lateral extremities : beak little elevated above the area line, 
and slightly incurved; mesial sinus shallow, and flat in the middle ; 
area of moderate height; foramen somewhat large, often partially 
closed. Dorsal valve depresso-convex in the middle and flattened 
laterally, often a little concave towards the extremities : mesial fold 
distinctly defined, equal in width to the two adjoining costas, somewhat 
