Lorraine Faunas of New York and Quebec 283 
basal outline. General convexity of the shell small. Concentric 
striations best defined anteriorly, along that part of the shell which 
is anterior to the oblique umbonal ridge. Anterior adductor 
depressions large and distinctly defined, although usually very 
shallow, owing to the thinness of the shell. The interior of one 
of the valves is faintly striated posteriorly, below the umbonal 
ridge, in a direction parallel to a line drawn from the posterior 
termination of the umbonal ridge to a point half way between the 
beak and the upper anterior margin of the shell. 
Locality. Pulaski, a short distance down stream from the 
railroad bridge, about a mile east of the town; also in the Trinu- 
cleus horizon, a short distance farther down stream; and still 
farther down stream, below the dam, at the southwestern margin 
of the town. Within the village of Barnes Corners; also a mile 
southward. At Worthville, and also half a mile eastward. At 
the school at the head of the road from Turin westward through the 
Gulf and then south westward up the hill. Half a mile down 
stream from the Salmon River Falls, a short distance below the 
level of the base of the falls. 
19. Modiolopsis concentrica, Hall and Whitfield 
Modiolopsis concentrica was described from the Waynesville 
beds near Waynesville, Ohio. 
In Canada, specimens occur which unquestionably belong to 
the same group and are closely related, but the latter may not 
prove identical. One of these specimens, collected at Chambly, 
presents the following characteristics. The curvature of the 
shell along the hinge-line passes gradually into that of the strongly 
deflected posterior outline, as in Modiolopsis concentrica, but the 
concentric plications along the post-umbonal parts of the shell are 
far less conspicuous, the umbonal ridge is flatter, the area which 
should be occupied by a mesial sinus is scarcely concave, and the 
basal margin of the shell is scarcely concave. 
Locality. Specimen numbered 1545 and labelled as coming 
from Chambly. Preserved in the Victoria Memorial Museum, at 
Ottawa, by the Geological Survey of Canada. 
Modiolopsis concentrica does not belong to the group of Modio- 
lopsis modiolaris. An examination of the types, in the Museum 
at Albany, New York, indicates that Modiolopsis modiolaris 
