WHITE.] LARAMIE FOSSILS. 97 
Shell resembling Goniobasis in form and in some of its other charac- 
teristics; but, unlike that genus, it is distinctly umbilicated; volutions 
more or less convex or angulated; aperture more or less produced in 
front; subovate or rhomboidal in outline; outer lip sinuous; inner lip 
having a more or less distinct layer of callus. 
I have here placed this genus provisionally in the family Ceriphasiid:e 
of Gill; but I am not entirely satisfied that it really belongs in that 
family. Being umbilicated, it bears a similar relation to Goniobasis that 
Cassiope Coqnand does to Turritella; but of course it is not regarded 
as having any near affinities with Cassiope, which is a marine genus. 
CASSIOPELLA TURRICULA White. 
Plate 27, figs. 3 a, b, ¢, d, e, f, and g. 
Leioplax? turricula White, 1876, Powell’s Rep. Geol. Uinta Mts., p. 133. 
Cassiopella turricula White, 1877, Bull. U. 8. Geol. Sur. Terr., vol. iii, p. 606. 
Shell elongate conical; the apical portion slender, the sides being 
slightly concave; volutions nine or ten, gradually increasing in size, 
prominent, angulated, the angle being prominent or subcarinated, and 
situated a little in advance of the middle of the exposed portion of the 
volutions of the spire; suture slightly impressed, but appearing deep in 
Seance of the prominence of the volutions; last volution broadly 
rounded from the prominent revolving angle to the verge of the umbili- 
cus; umbilicus narrow, deep, and marked within by two or three re- 
volving lines. Surface, upon both sides of the prominent angle of the 
volutions, marked more or less distinctly by two or three revolving 
raised lines ; and the proximal surface of the last volution is also marked 
by similar lines. Aperture subrhombic in outline. 
Length, 34 millimeters ; diameter of the last volution, 15 millimeters. 
Position and locality.—This is the type, and only known species of the 
genus; and it has hitherto been found only at Black Buttes Station, 
Union Pacifie Railroad, Wyoming, in the upper portion of the Laramie 
Group. It is associated in the same layer with Viviparus plicapressus, 
Tulotoma thompsoni, Campeloma multistriata, Goniobasis gracilenta, and 
several species of Uino. It is therefore referred to a fresh-water habitat, 
although many young examples of Corbula subtrigonalis were also found 
immediately associated with it. . 
Genus HYDROBIA Hartmann. 
HYDROBIA ANTHONYI Meek & Hayden. 
HYDROBIA WARRENANA Meek & Hayden. 
HYDROBIA SUBCONICA Meek & Hayden. 
HYBROBIA ? ENLIMOIDES Meek & Hayden. 
These four species were obtained by Dr. Hayden from the Laramie 
Group of the Upper Missouri River region, and none of them have yet 
been elsewhere identified. They are described on pages 571-573, vol. ix, 
U.S. Geol. Sur. Terr. (4to ser.), the two former being figured on plate 43 
of that volume; but the two latter are illustrated by a wood-cut each, 
accompanying the descriptions. 
The genus Hydrobia has not been recognized elsewhere in the Lara- 
mie Group, if we except a species which was described by myself from 
the coal-bearing series near Evanston, Wyo., and another from certain 
of the strata exposed in the Caiion of Desclation, Green River, Utah. 
7H 
