Lorraine Faunas of New York and Quebec 281 
toward the umbonal ridge, as well as the concentric markings 
which sometimes are strongly developed here I regard the 
drawing of this form in the Ohio Palaeontology as misinterpreted 
and would not be surprised to learn that the details had been too 
strongly accentuated. 
17. Pholadomorpha chambliensis, sp. nov. 
{Plate I, Fig. 8) 
Shell transversely oblong, the cardinal and basal margins 
diverging scarcely 10 degrees. The anterior margin is more 
broadly rounded and the posterior margin is less oblique than in 
typical Modiolopsis pholadiformis. The low transverse plications 
can be detected only on the posterior half of the shell, on the slope 
beneath the umbonal ridge, but they may be more distinctly indi- 
cated in other individuals. Umbonal ridge angulate along its 
upper outline for a distance of about 15 mm. from the beak, 
rounding rapidly posteriorly, merging into the general convexity 
of the shell. 
Length 68 mm., height posteriorly 28 mm., height at beak 24 
mm., extension of shell anterior to beak about 12 mm., convexity 
of the single valve about 3 mm. 
Locality. Apparently from Chambly, from a siliceous limestone 
containing Byssonychia radiata, Bafinesquina alternata, and 
apparently also Catazyga headi. Specimen No. 2069, Geological 
Survey of Canada, in the Victoria Memorial Museum, Ottawa, 
Canada. 
18. Modiolopsis modiolaris, Conrad 
{Plate III, Fig. 1; Plate V, Figs. 1 A, B, C, 2 A, B, C) 
In the Second Annual Report of the New York Geological Survey, 
1838, Conrad described this species as follows: 
Shell ovate oblong, compressed; surface with coarse concentric lines, 
obsolete on the posterior side; posterior extremity obliquely truncated. 
Length, nearly 3 inches. Locality, Pulaski, Oswego county, with the 
preceding {Cymatonota pholadis). 
The writer has recently collected Modiolopsis modiolaris in the 
same slab with Cymatonota pholadis, a short distance down 
