874 THE PALEONTOLOGY OF MINNESOTA. 



LProtowarthia conclnna. 



Formation and locality. Richmond group of the Cincinnati period, Versailles, Indiana, and Butler 

 county, Ohio. 



Collection. E. O. Ulrich. 



PROTOWARTHIA CONCINNA, . sp. 



PLATE LX1II, FIGS. 36-39. 



Comp. Bellerophon mori-owensis MILLER and DYEK, 1878, Contr. to Pal., no. 2, p. 8. 



The specimen upon which this species is founded has, although it is much 

 smaller, relatively nearly the same dimensions and form as P. subcompressa. The 

 dorsum however is narrowly rounded instead of broadly, the aperture is triangular 

 rather than semi-ovate, and the sinus is narrower, while the thickened base of the 

 lip forms a small sharply defined and shallow umbilical depression which is not 

 seen in that species. The surface of the specimen is without markings of any kind 

 save on the small end of the visible volution where some traces of minutely granu- 

 lose lines are to be detected. Greatest diameter 18 mm.; transverse diameter 13 

 mm.; width of aperture 11.5 mm.; central bight of same 8 mm. 



It is possible that this is not distinct from the Bellerophon morrowensis described 

 by Miller and Dyer from about the same horizon in Ohio. If they prove to be the 

 same then their type specimen must be considerably crushed since it is described as 

 "lenticular in form" and with the "dorsal side sharply angular." Under the 

 circumstances we are obliged to consider our species as distinct. 



Formation and locality. Richmond groups of the Cincinnati period, near Spring Vailey, Minnesota. 

 Collection. E. O. Ulrich. 



PROTOWARTHIA OBESA, n. sp. (Ulrich.) 



PLATE LXIII, FIGS. 45-47. 



Shell rather large, obese, the greatest diameter between 30 mm. and 45 mm., 

 the greatest width of the aperture usually about one-tenth less; volutions ventricose, 

 almost uniformly rounded, the center of the dorsum just appreciably elevated; 

 umbilicus covered by the reflexed or thickened lip, small in the cast; aperture 

 transverse, the central hight somewhat greater than half the width; apertural lobes 

 rounded, sinus very broad and comparatively shallow, but the depth seems to be 

 somewhat variable; test thick. The specimens are all casts of the interior and 

 exhibit merely obscure traces of the lines of growth. A small patch of the shell on 

 one of the specimens shows that the growth lines are fine and unequal, and that 

 revolving lines are wanting. Two or three broad transverse furrows cross the back 

 of each of the five specimens before us. These furrows were produced by 

 thickened bands upon the inner side of the shell, passing almost directly from side 



