262 
Aug. F. Foerste 
valves show a convexity of about 7 or 8 mm., their greatest con- 
vexity being anteriorly, where the shell is deflected toward the 
anterior and antero-lateral margins. The radiating striae vary 
in size, three finer striae being intercalated between each pair of 
more conspicuous striae over the greater part of the valve, but 
along the anterior margin the intermediate striae become more 
conspicuous so that the difference in size is less noticeable. Here 
about 16 striae are seen in a width of 5 mm. Very fine concen- 
tric striae, seen only under a lens, are clearly indicated. Along 
the hinge-line there is a tendency toward wrinkling, the wrinkles 
being more perpendicular toward the beak and more oblique 
toward the postero-lateral angles. The wrinkling does not ex- 
tend over the middle parts of the shell as in Strophomena flue- 
tuosa. Interiorly, the central parts of the shell present a few 
vascular markings, rather inconspicuously developed, while 
laterally there are numerous radiating lines suggesting relationship 
to the so-called ovarian markings more conspicuously developed 
in other shells. The entire inner surface is covered with a fine 
shagreen, or by numerous minute granules seen only under a lens. 
The occurrence of these specimens of Strophomena in the 
Lorraine areas east of Montreal is especially* interesting in view 
of the entire absence of the planumhona group of Strophomena in 
the Maysville beds of the Cincinnatian province. 
All of the specimens here described are preserved in the Vic- 
toria Memorial Museum, at Ottawa, by the Geological Survey of 
Canada. The original of Fig. 4A is numbered 8404, and that 
of Fig. 4B, 8405. 
It is scarcely necessary to state that this occurrence of Stro- 
phomena of the planumhona type on the Richelieu River, at Cham- 
bly village is regarded as belonging more than 500 feet below the 
lowest horizon at which Strophomena planumhona occurs asso- 
ciated with Rhynchotrema perlamellosa, in the Richmond along 
the Nicolet River. A brachial valve of Strophomena was found 
also along the Nicolet River, at the highest Leptaena rhomhoi- 
dalis horizon, in the lower part of the Proetus zone. Here it was 
associated with Pterotheca pentagona, a form described from Cham- 
bly. These occurrences of Proetus, Leptaena, Strophomena, 
and Pterotheca are noteworthy, since none of these genera are 
known in the Lorraine of New York. 
