81 
Remarks. This form is rather abundant. It occurs in a dense quartz- 
ite from which we did not succeed in extracting an identifiable specimen. 
It is large, with probably five or six regularly enlarging whorls; these have 
a slightly angular shoulder. Umbilicus prominent. Surface markings 
unknown, as all our specimens are internal moulds. These specimens may 
possibly be very large representatives of this species. 
Locality and Horizon. In the Minnewanka region in the Permian 
of section 1-10 (c). 
Genus, Strophostylus Hall 
Strophostylus carleyanus (Hall) var. 
1856. Natica carleyana Hall, Trans. Albany Inst., vol. 4, p. 31; Naiicopsis 
carleyana Hall, 1883, 12th Rept. Geol. Surv., Indiana, p. 369, PI. 
31, figs. 26, 27. 
Remarks. Our single specimen is rather poorly preserved but appears 
to fall within the limits of this species, except that it is double the size. 
Locality and Horizon . Mississippian (St. Louis) of Mississippi valley. 
In the Minnewanka region in the Lower Mississippian of section 2-? 22 (R). 
Strophostylus sp. 7 
Description. Shell small, consisting of three volutions. Apex of spire 
depressed and minute, rising little above the final volution. Surface 
ornamented by fine growth lines. Height 10 mm., breadth 7 mm. 
Remarks. The preservation of our single specimen is such that the 
columellar grooves, if present, do not show. There is some resemblance to 
the widespread Pennsylvanian species, S. nanus , but the aperture of our 
form is more elongate and the whorls more rounded. 
Locality and Horizon. In the Minnewanka region in the Mississippian 
of section 2-24 (R). 
Genus, Loxonema Phillips 
Loxonema rockymontanum n. sp. 
Plate IV, figures 9 a, b; 10 
Description . Shell of medium size. Whorls seven or eight, slowly 
enlarging, convex exteriorly, somewhat flattened on the base; the smaller 
whorls have the outer surface also flattened, with the result that the 
suture is shallow. The last two or three whorls are more rounded on the 
outer surface and hence produce a more prominent suture. Aperture 
broadly ovate-cuneate antero-posteriorly; a shallow anterior canal is 
present. Surface of shell ornamented with numerous, low, faint, revolving 
lines (20 to 30 upon a whorl 4 mm. wide), and with fine, slightly S-shaped 
growth lines paralleling the aperture; the latter markings become 
rather strong upon the last whorl. Height of shell about 30 mm., height 
of last whorl 11 mm., length of aperture 11 mm., its greatest width 9 mm. 
Apical angle about 32 degrees. 
