WHITE.] LARAMIE FOSSILS. 93 
appearance under the lens. In addition to these, there are usually from 
four to six much larger, nearly equidistant, revolving raised lines of 
nearly equal size upon the visible portion of the volutions of the Spire, 
and ten or twelve of them upon the body volution. These larger revolv- 
ing raised lines are sometimes absent or obsolete, but the smaller mark- 
ings first mentioned are always present. 
Length, about 22 millimeters; diameter of body volution, 11 milli- 
meters. 
This species is evidently nearly related to G. nebrascensis Meek & 
Hayden, and ought, perhaps, to be referred to Pachycheilus Lea, but the 
difficulty of learning the exact character of the outer lip leaves the mat- 
ter in some doubt. 
Position and locality.—Bear River series of the Laramie Group, seven 
miles northward from Evanston, in the valley of Bear River, where it 
is associated with many of the characteristic species of that series. 
GONIOBASIS MACILENTA White. 
Plate 30, fig. 10 a. 
Goniobasis arcta White (not Meek), 1879, An. Rep. U.S. Geol. Sur. Terr. for 1877, p. 244. 
Shell small, slender, terete; test thin; sides of the spire straight ora 
little concave; volutions, apparently ten or more, gradually increasing 
in size, their sides flat and forming the continuous surface of the straight 
sides of the shell; suture linear; surface marked by lines of growth, 
which cross the volutions with a slightly sinuous course, but nearly in 
line with the axis of the shell. Near the distal border of the volutions 
there is a revolving depressed line, which has the appearance of a 
second suture. There appears to be no tendency to form longitudinal 
varices such as mark G. cleburni, G. chrysallis, and other species, nor 
have other revolving lines than the one already mentioned been detected. 
The length of the type specimen, when perfect, was about 12 millime- 
ters; diameter of the last volution, a little more than 2 millimeters. A 
less perfect example, the largest in the collection, indicates about double 
that size. 
Upon the first discovery of this species I supposed it to be identical 
with G. arcta Meek, which he described in Simpson’s Report on the Great 
Basin of Utah, p. 366, as from the Tertiary strata of the valley of Ham/’s 
Fork, a tributary of Green River. That form is closely like the one in 
question in general aspect, and I was led to believe a mistake had 
occurred in giving its location similar to one made in regard to Limneea 
mitidula in the same connection, and which he afterward corrected. 
A careful study of our examples shows that they cannot be referred to 
that species, and I therefore apply to it a new specific name. The per- 
fectly flattened sides of all the volutions of the spire, with the linear 
suture and its companion impressed line, distinguish it from all other 
known species. 
The companion line of the suture of this species seems to have more 
Significance than as a mere specific character, from the fact that it is 
more or less distinctly represented in both G. chrysallis and G. chrysal- 
loides, both of which species are from the same series of strata and from 
the same locality that furnished the type specimens of this species. 
Position and locality—Bear River series of the Laramie Group, near 
the mouth of Sulphur Creek, valley of Bear River, Wyoming. 
