182 PROCEEDINGS OF THE ACADEMY OP 



I have sometimes been inclined to think Prof. Hall's Turbo 

 paludinseformia^ of Fremont's Report, might have been founded 

 upon a young or imperfect specimen of this species, but the fact 

 that that shell occurs in a yellowish-gra}' limestone showing 

 sometimes an oolitic structure, and also containing Prof. Hall's 

 Cerithium nochdosum (a true Goniobasis), shows that it must 

 belong to a different horizon from the shell here under considera- 

 tiou, "which comes from the oldest tertiary beds of the Bear River 

 country, holding, according to Dr. Haj^den's examinations, a 

 position below the yellowish-gray limestone beds of that region. 



Locality and position. Gilmore, Wyoming (Mr. Durkee) ; Bear 

 River near the mouth of Sulphur Creek, Utah (Col. Simpson); 

 and at various localities in the Bear River countrj^ (Dr. Hayden). 

 It is always associated with Corbula pryriformis, PyrguUfera 

 humerosa^ Corbicula Durkei^ and Unio prisons ; none of which 

 have been identified among the specimens from the higher beds 

 of that district. 



VIVIPAEIJS? WYOMINGENSIS, Meek. 



Shell obliquely conoid-subovate; spire conical, with slightly 

 convex slopes; apex rather pointed; volutions six, those of the 

 spire obliquely compressed convex, last one large, a little com- 

 pressed on the upper slope, but rounding over the middle, and 

 somewhat produced below; suture Avell defined, but not deep; 

 aperture ovate; lip not thickened on the inner side below, and 

 apparently very faintl}" dilated around the outer side, at the 

 immediate margin. Surface with rather regular, distinct, oblique 

 lines of growth, that are crossed, near the upper margins of the 

 volutions, by fine, regular, revolving stria?. Axis apparently 

 sometimes very slightly perforated. 



Length, 1.45 inches; breadth, 1.15 inches; height of aperture, 

 about 0.90 inch; breadth of do., about O.GO inch; divergence of 

 slopes of the spire, 0.72°. 



The specimens of this shell in the collection are mainly broken 

 or distorted casts. One of the latter, however, is very nearly 

 perfect, while some of the other specimens retain more or less of 

 the shell itself. From the strong, regularly arranged strife of 

 o-i'owth, seen on some of the latter, and apparently some indica- 

 tions of a slight reflection of the outer lip, 1 was led to think it a 

 land shell, probably belonging to some of the elevated types 



[August 15, 



