ware. ] TERTIARY FOSSILS. 45 
surface being regularly rounded and without revolving angles or lines. 
Surface smooth, or marked only by the ordinary striz of erowth. 
Diameter of the coil of the largest example discovered, 8 millimeters: 
transverse diameter of the last volution, 1} millimeters. 
This species is remarkable for its numerous slender and plain volu- 
tions and small size. It differs materially from any other species known 
to me, either fossil or recent, in the slenderness of the volutions and the 
almost exact plane of its coil. The aperture is apparently without any 
thickening or reflexure of the peristome, even when fully adult. 
Position and locality—It has been found only in strata belonging to 
the basal portion of the Green River Group, or to the upper portion of 
the Wahsatch Group, about three miles east of Table Rock Station, 
Union Paciiic Railroad, Wyoming. 
Genus PHYSA Draparnaud. 
PHYSA BRIDGERENSIS Meek. 
Plate 19, figs. 10 a and b. 
Physa bridgerensis Meek, 1873, An. Rep. U. 8. Geol. Sur. Terr. for 1872, p. 516. 
The specimens from which Mr. Meek drew his description of this 
species having been lost or mislaid, the figures illustrating it on plate 
19 have been drawn from opposite views of two specimens which were 
obtained from the Bridger Group in the valley of Henry’s Fork, a few 
miles east of Fort Bridger, by one of Professor Powell’s parties in 1875, 
They do not strictly agree in all particulars with Mr. Meek’s descrip- 
tion, but the discrepancy is probably due to the fact that his types were 
less perfect than our examples are. He, however, recognized the identity 
of the latter with his species upon an examination which he gave them 
at my solicitation a short time before his death, and there is probably 
no reason to question it. The fact that both, his types and our examples 
are from the same formation and the same region, also favors this view. 
The following is Mr. Meek’s description : 
“Shell attaining a large size, subovate in form; spire prominent, coni- 
cal; volutions four and a half to five, moder ately convex, last one large 
but not very ventricose; suture well defined; aperture narrow- subovate, 
arcuate, acutely angular above, and about twice as long as the spire; 
columella twisted into a rather prominent fold. Surface with fine sharp 
lines of growth. 
“Length about 1.15 inches; breadth, 0.66 inch. 
ce This i is a fine large species, with a ‘more prominent spire than any 
of our recent species ‘Tesemblin g it in other respects. None of the speci- 
mens found are perfectly preserved. 
“Locality and position—Church Buttes, fourteen miles from I ort 
Bridger, Wyoming Territory. Tertiary.” 
Genus SUCCINEA Draparnaud. 
Subgenus BRACHYSPIRA Pfeiffer. 
SUCCINBA (BRACHYSPIRA) PAPILLISPIRA White. 
Plate 19, fig. 4 a. 
Succinea papillispira White, 1876, Powell’s Rep. Geol. Uinta Mts., p. 129. 
Shell rather small, ovate or subelliptical in lateral outline; spire 
minute but prominent; last volution expanded and broadly convex ; 
