26 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 134 
is about 3 times as wide as long but the cardinal extremities are not 
preserved. A short and very thin median septum is visible just 
anterior to the beak. According to Tschernyschew his figured speci- 
men was compared with Stuckenberg’s. The Tschernyschew specimen 
is from the Schwagerina zone on the Issin-jelga River. 
Suborder OLDHAMINOIDEA Williams, 1953 
Superfamily OLDHAMINACEA Williams, 1953 
Family OL.DHAMINIDAE Schuchert and LeVene, 1929 
LEPTODUS? sp. 1 
Plate 1J, figures 36-39 
Known from an impression of the pedicle interior which does not 
indicate any of the exterior details and does not show the usual form 
of the genus. The specimen is 28.7 mm. long by 33.7 mm. wide at 
the widest part which is slightly anterior to the middle. The septal 
apparatus is moderately simple, consisting of four lobes on each side 
of the median axial thickening. Axis thick, moderately elevated, 
bounded on each side by a narrow groove from which are given off 
the oblique lobes. Angle of divergence of lobes from lateral grooves 
50°. Ridges between lobes thick and rounded. Troughs between the 
lateral ridges marked by oblique striations on the sides but by a low, 
rounded ridge on their floor. 
Type.—Figured specimen, U.S.N.M. 125325. 
Locality —637. 
Discussion.—The specimen on which the foregoing description is 
based is an impression of the interior of the pedicle valve prepared 
by removing much of the shell from the grooves. Not sufficient of the 
specimen is preserved to make an accurate generic or specific deter- 
mination. It is referred to Leptodus, but without information on the 
exterior, especially the posterior attachment surface, the determina- 
tion cannot be regarded as positive. The specimen is suggestive of 
some of the small stout leptodids from the upper part of the Leonard 
formation in the Glass Mountains but these have not been described. 
The Oregon example is quite unlike the specimen from the Cache 
Creek fauna of British Columbia described by Kindle (1926). The 
Canadian specimen has the grooves nearly parallel and nearly at right 
angles to the axis of the shell, whereas the Oregon specimen has the 
grooves directed anterolaterally. 
