FOSSILS OF THE CARBONIFEROUS. 245 
Grammysia arcuata Conrad (Sp.) 
Plate xx, fig. 5. 
Posidonia ? arcuata Conrad, 1841. Ann. Rep. Geol. Surv. New York, p. 53. 
Grammysia arcuata Hall, 1870. Prelim. Notice Lam. Shells, p. 56. 
(Leptodomus ?) arcuata Hall, 1883. Pal. N. Y., vol. v, pt. 1; Plates and 
Explanations, pl. 1xi, figs. 1-9. 
Although this species is confined to the Hamilton Group of New York 
and Virginia, as far as heretofore known, we are unable to separate the Car- 
boniferous shell from it on good specific grounds. Its occurrence at this 
locality and horizon is not surprising, as we have in the Devonian, and also 
at this same locality, examples of as great a range of supposed limited 
species, ¢. g., Pleurotomaria nodomarginata, Schizodus cuneatus, ete. 
Formation and locality —Lower portion of the Carboniferous Group on 
the east slope of a small conical hill on the east side of Secret-cafion-road 
Canon, Eureka District, Nevada. 
Genus EDMONDIA De Koninck. 
Edmondia Medon, b. sp. 
Plate xxiii, fig. 6. 
Shell transversely subelliptical, moderately convex, equivalve. Hinge- 
line slightly arcuate; beaks depressed, situated on the anterior third of the 
shell. 
Surface marked by concentric lines and unduiations of growth. 
Interior characters unknown. 
Dimensions : height, 15™; width, 2.5; convexity of single valve, 0.5%. 
The specimen illustrated is the only well-preserved one we have of this 
species. In some respects it approaches H. Burlingtonensis W. and W. 
(See Pal. N. Y., vol. v, pt. 1; Plates and Explanations, pl. Ixiv, figs. 19-29, 
1883), of the Burlington limestone of Iowa, and the Chemung Group of 
New York, differing in its more elliptical form and depressed beak. 
Formation and locality—Lower portion of Lower Carboniferous lime- 
stone on east slope of a small conical hill on the east side of Secret-canon- 
road Cation, Eureka District, Nevada. 
