262 PALEONTOLOGY OP THE EUREKA DISTRICT. 



described from them, namely: Pupa vetusta, P. Bigsbyi Dawson, Zonites 

 (Conulus) prisons Carpenter, from the Coal Measures of the South Joggins, 

 Nova Scotia; Pupa Vermillionensis, Dawsonella Meeld Bradley, from the 

 Upper Coal Measures of Vermillion River, Illinois, and Strophites grandczva 

 Dawson, from, the Devonian plant beds of St. John, New Brunswick (Amer. 

 Journ. Sci., 3d ser., vol. xx, p. 403, 1880). Subsequently Prof. R. P. Whit- 

 field gave the results of his study of 'Dawsonella Meeki, showing that it was 

 probably an operculate shell, and he also described Antliraco-pupa Ohioensis 

 from the higher beds of the Coal Measures at Marietta, Ohio (Ibid., xxi, 

 p. 125, -881). All of the species are true land shells, the aquatic division 

 of the Pulmonifera being unrepresented up to the time of the discovery in 

 Nevada of the species to be described. The geologic horizon at which the 

 latter occur is intermediate in position to the Devonian plant beds of New 

 Brunswick and the localities in the Coal Measures of Nova Scotia, Illinois, 

 and Ohio. 



A brief notice of these shells was published in Science, vol. ii, p. 808, 

 1883. 



Genus PHYSA Draparnaud. 



Physa prisca Walcott. 

 Physa prisca Walcott, 1883. Science, vol. ii, p. 808, fig. 2. 



Shell small, oblong, sinistrally spiral, and with about four volutions, 

 the last one expanded, ventricose, with the short, small spire 

 above less than one-fourth its length ; aperture more than three- 

 fourths of the length of the body volution, broadly rounded 

 anteriorly, becoming more pointed at the opposite end; outer 

 lip thin, inner lip slightly reflected on the last whorl. 



Surface smooth or marked by fine lines of growth. 



FIG. 6. Outline 



The shell is apparently that of a true Physa, although ofaheii.xs. 

 thicker than in most species of the genus. It may belong to a subgeneric 

 group, but of this we have little evidence in the specimens before us. 



The largest specimen has a length of 9 1 1 , and the smallest of 4 mm . 



Formation and localities. Lower portion of the Carboniferous Group, 

 in a chocolate-colored limestone, on the western slope of New York and 

 Richmond Mountains, Eureka District, Nevada. 



