582 UNITED STATES GEOLOGICAL SDEVEY OF THE TERRITORIES. 



In Dr. Hayden's Annual Report of the United States Geological Survey 

 of the Territories for 1872 (published in 1873), I mentioned on page 476, 

 that I had found at Black Butte station on the Union Pacific Railroad, in 

 Wyoming Territory, associated with the bones of a large Dinosaurian, speci- 

 mens consisting of the upper turns of the spire, as I believed, of examples of 

 this species. The specimens are mere distorted casts, but certainly closely 

 resemble the corresponding part of this shell. Since that time, Professor 

 Powell and Dr. White have found much better specimens of the Black Butte 

 shell at that locality, which show that it develops nodes on the lower or 

 body-volution (which part I had not seen), and is therefore quite decidedly 

 different specifically, if not even a member of the distinct group Fulotonia. 



A single distorted specimen, found by Professor Lesquereux at the 

 Carbon coal-mines on the Union Pacific Railroad in Wyoming, is evidently 

 more nearly allied to this ; but it is not well enough preserved to show its 

 surface-markings. It has the same trochiform outline, but appears to have 

 its spire a little more pointed, and the angle of its body-volution less defined. 

 If distinct, it may be called Viviparus carbonarius. 



Locality and position. — Fort Union group, ten miles below Fort Union, 

 Montana. There are also casts of it among collections marked one hundred 

 and fifty miles below Fort Union (probably Eocene). 



Viviparus Lcirtyi, M. &H. 



Plate 44, iig. 4. 



Pahidiua Lehlyi, Meek and Hayden (1856), Proceed. Acad. Nat. Sci. Philad., VIII, 123. 

 Yimpara Leidyi, Meek aud Haydeu (1860), ib., XII, 185. 



Viviparus Leidyi, Meek and Hayden (1H63), in Professor Gill's Syst. Arrang. of the Yiviparidw, 6 (Proceed. 

 Acad.). 



Shell attaining a large size, thin, subovate ; spire rather prominent, con- 

 ical, about equaling the length of the aperture ; volutions six to six and a 

 half, flattened near the summit of the spire, and becoming convex below ; 

 last one angular around the middle in young shells, but rounded aud pro- 

 duced below in the adult; suture well defined between the lower whorls, 

 and merely linear above; aperture ovate, rather angular above, somewhat 

 produced and rounded below; inner lip thin, and more or less reflexed ; 

 umbilical perforation small, somewhat spiral ; surface marked with small 

 obscure lines of growth, which are crossed on the upper flattened whorls by 

 • two nearly obsolete, equidistant, revolving ridges and minute revolving stria?. 



