93 
dorsal margin. Beaks small. All of posterior ear not preserved; fairly 
long, wide anteriorly, and separated from body of shell by a fairly deep 
sinus. Anterior ear small, not well preserved, but appears to be convex 
and separated from body of shell by a narrow sulcus. 
Body of shell ornamented with about fourteen radiating, narrow, 
rounded (umbrella-like) ribs, separated by shallow, broadly concave 
interspaces in which are numerous radiating striae. Some of these striae 
are a little coarser than the others; these, however, do not increase in 
size much ventrally and do not become radii of higher order. The ears 
are covered with radiating striae. 
Length 63 mm.; height 55 mm.; thickness (of left valve) 9 mm. 
This species is very close to Oxytoma mcconnelli Whiteaves 1 from the 
Fernie formation of Minnewanka lake, Alberta, in size, outline, and in 
general character of ornament. The Minnewanka Lake species, however, 
has more ribs on the body of the valve, the striae are coarser and more 
uneven, and the sinus below the posterior ear is more shallow. 
Horizon and Locality. From talus of the middle sedimentary division 
of the Hazelton group, exposed in a cliff about 1 mile southeast of Silver 
lake, Hudson Bay mountain, B.C. 
Type: Victoria Memorial Museum; holotype, Cat. No. 7703. 
Perna weelaupensis n. sp. 
{Weelaup, a big stone mountain) 
Plate XIX, figures 1, 2 
A curved, semiovate species, produced in the antero-dorsal angle and 
expanded ventrally. The dorsal margin is fairly long and almost straight, 
the anterior margin deeply concave, the ventral margin long and rounded, 
and the posterior margin gently rounded, long, and inclined to the dorsal 
margin. The valves are flattened and are narrowly inflected along the 
anterior margin. The umbo is triangular and produced forward consider- 
ably in advance of the main body of the shell. The surface is not well 
preserved, but apparently has irregular lines of growth. Serial multi- 
vincular ligament preserved, but is not distinct. 
Height 39 mm.; length 43 mm.; thickness 8 mm. 
The shell from the Great Oolite of Minchinhampton, Yorkshire, 
England, identified by Morris and Lycett 2 as Perna rugosa Munst., is 
similar, but is larger, the umbo is not produced forward so much, the post- 
erior margin is not so much inclined, and the outline does not widen so 
much ventrally. 
Horizon and Locality . In talus of the middle sedimentary division 
of the Hazelton group, exposed in a cliff about 1 mile southeast of Silver 
lake, Hudson Bay mountain, B.C. 
Type: Victoria Memorial Museum; holotype, Cat. No. 7704. 
i Whiteaves, J. F.: Geol. Surv., Canada, Mes. Foss., vol. I, pt 4, p. 300 (1900). 
Whiteaves, J. F.: Geol. Surv., Canada, Contr. Can. Pal., vol. I, pt. 2, p. 106, PI. 23, figs. 1 to lb (1899). 
* Mon. Mollusea Great Oolite, pt. 2, Pal. Soe., p. 26, PI. 3, fig. 1 (1863). 
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