90 THE CHICAGO ACADEMY OF SCIENCES. 
fold, and showing by the side of the inner lip below, appearances of 
a small umbilical indentation. Surface marked by fine, rather obscure 
lines of growth, with (on some specimens) exceedingly faint traces 
of microscopical revolving striz. 
“Length, 0.40 inch; breadth, 0.20 inch; apical angle convex, di- 
vergence 40°” (Meek). 
Type: U.S. Nat. Mus. no. 685; no. 23116; plesiotypes no. 12500. 
Horizon: Bear River formation,! Cretaceous Period. 
Locatity: Bear River, near mouth of Sulphur Creek, Uinta 
County, Wyoming; Mellis Station, Bear River Valley ; 20 miles north 
of Cokeville, Uinta County, southwestern Wyoming, embedded in thin 
layers of impure limestone. 
RemArKs: “Among recent species, this may be compared with 
L. humilis and the several forms regarded by Mr. Binney as varieties 
of this species. It is a decidedly more slender shell, with a less ex- 
panded aperture and less developed inner lip than Mr. Binney’s figure 
(p. 63, fig. 99, Land and Fresh-Water Shells) of an authentic specimen 
of that species. It agrees, however, more nearly in form with some 
of those figured by Mr. Binney as varieties of L. humilis, but still 
differs from them all in other details” (Meek). 
As stated by Meek, this species bears a close resemblance to the 
recent Galba humilis (Say),? and it undoubtedly groups with that 
species. There seems to be some confusion regarding this species. 
In his discussion of the Bear River formation, Dr. White remarks as 
follows :* 
“Ever since the first publication of this species, more or less doubt 
has prevailed as regards its specific and generic characters, the locality 
and formation from which it was first obtained, and the identity of 
the type specimens. I have hitherto been somewhat disposed to regard 
it as identical with the form which is described on a following page 
under the name of Charydrobia stachei, and I should, therefore, have 
rejected it from this summary of the fauna of the Bear River for- 
mation if it were not that a considerable number of specimens have 
lately been obtained which conform well to the original description 
as published by Mr. Meek. The specimens believed to be those which 
were thus originally used by him are figured on plate VI. They are 
preserved in the collections of the United States National Museum, 
River formation te sufficiently distinet from that of the Laramie to Justify. its 
SL fae eat ay apa Ie Cae even though its stratigraphical relations may not 
The resemblance to G, humilis modicella is remarkable. 
*Bull. 128, U. S. Geol. Surv., p. 45: 
, 
Te 
