314 
Aug. F. Foerste 
sides attached to the main body of the shell along straight or 
moderately curved divergent lines^ forming an angle of about 75 
degrees with each other, this angle becoming more acute near the 
apex. The lines of attachment are about 20 mm. long, equalling 
from two-thirds to three-fourths the length of the shell from the 
apex to the antero-lateral angles. The striae upon the inner 
surface of this septum indicate that its anterior edge was moder- 
ately convex. Seen from the lower side of the shell, the septum 
was moderately concave; at the apex the shell is only moderate- 
ly incurved. Convexity, aside from the dorsum, estimated at 
5 to 7 mm., but the shell may be more or less vertically compressed 
as it lies in the rock. 
Type. Richelieu River, near Chambly, collected 1881 by A. 
H. Foord. No. 2155, Paleontological collections. Geological 
Survey of Canada, Victoria Memorial Museum, Ottawa, Canada. 
Fig. 1, on plate II. 
Another specimen, plate II, Fig. 2, referred to Pterotheca penta- 
gona, was found by the writer on the Nicolet River, southwest of 
Ste. Monique. This specimen occurred associated with a variety of 
Leptaena rhomboidalis, Rafinesquina mucronata, Catazyga erratica, 
Proetus, and numerous other species, at a horizon 820 feet below 
the lowest strata in this section in which Strophomena planumhona 
and Rhynchotrema perlamellosa are found. Trinucleus and Triar- 
thus occur 730 feet below this Pterotheca pentagona horizon. This 
second specimen also is preserved in the Victoria Memorial 
Museum, and is numbered 8409. 
Pterotheca transversa was described in 1852 by Salter, under the 
term Cleodora transversa, in the Report of the British Association 
for 1851, on page 64, from Desertcreat, Tyrone, in Ireland.^ With 
this species the Canadian form has been erroneously identified. 
47. Cornulites, sp. 
At the Strophomen nasuta and Trinucleus horizons, between 
the railroad bridge, about a mile east of Pulaski, and a point 
several hundred yards westward, down the stream, there is a form 
of Cornulites with a free habit of growth, and practically straight 
or only slightly curved. These straight forms are known usually 
as Tentaculites. At the initial tip it probably was attached to 
some other organism, but no evidence of such attachment was 
