Lorraine Faunas of New York and Quebec 271 
a short distance below the termination of the posterior lateral 
tooth. The impression is very shallow and usually but faintly 
outlined. The pallial line also is faint. No trace of an anterior 
muscular scar has been noticed so far. The location for this scar 
should be just below the anterior termination of the jugum. It 
should be noted that the posterior crural ridge, forming the pos- 
terior half of the jugum of the right valve is exactly opposite the 
posterior crural ridge of the left valve, in this respect not fitting 
the ordinary conception of a tooth among the pelecypods. 
The shell of the right valve frequently is as thick as that of the 
left valve, and it is similar structurally, but the valve is only 
slightly convex toward the beak, and becomes flattened, or even 
slightly oblique, toward the basal parts of the shell. 
The specimen here figured, from the Riviere des Hurons, near 
St. Jean Baptiste, was collected October, 1872, by Thomas Curry. 
It is associated in the same slab with Cymatonota recta, Ulrich, 
Byssonychia radiata, Hall, Cleidophorus praevolutus, Foerste, and 
Lophospira bowdeni-beatrice, Foerste. It is numbered 8429, and 
is preserved by the Geological Survey of Canada in the Victoria 
Memorial Museum, at Ottawa. A younger specimen. No. 8433, 
from the same locality is represented by Fig. 11 on plate III. 
The shell now known as Pterinea demissa was originally de- 
scribed by Conrad, Journal of Academy of National Sciences, Phila- 
delphia, 1842, p. 242, plate 13, Fig. 3.) from the Lower Silurian 
sandstone near Rome, in Oneida county. New York. Here it was 
found associated with Rafinesquina nasuta, Conrad, in the quarries 
exposing the lower part of the grey sandstone overlying the Lor- 
raine shales. The specimen figured by Conrad was a young indi- 
vidual, with a height from the ventral margin to the hinge-line 
of only 27 mm. 
Along the Nicolet River, in the province of Quebec, Pterinea 
demissa is very common at several horizons in the Richmond. It 
occurs also at various horizons in the upper 500 feet of the under- 
lying Lorraine section. It is found at Chambly, on the Richelieu 
river, and probably ranges throughout the Proetus division of the 
Lorraine in this part of Canada, although by no means as common 
in the Lorraine as in the Richmond. Small specimens occur half 
a mile south of the railroad station at St. Hilaire. 
Specimens of Pterinea demissa occur at numerous localities 
within 12 miles east of Ottawa. Three-quarters of a mile west of 
