894 THE PALEONTOLOGY OF MINNESOTA. 



[Bucania slngularis. 



The shell in this and the species with which we have compared it is unusually 

 thick for the genus, especially on the ventral side of the volutions, and casts of the 

 interior must look very different from the shells themselves. We have not, how- 

 ever, seen any casts which seemed at all likely to belong to either. 



Formation and locality. From the uppermost beds of the Richmond group, near Richmond, 

 Indiana. 



Collection. E. O. Ulrich. 



BUCANIA SINGULARIS, . Sp. (Ulfick.) 

 PLATE LXVI, FIG. 47. 



This species is remarkable for the prominence of the transverse lamellae and 

 for the unusual length of the intervals between them. They appear to be especially 

 thick and prominent on the lateral portions of the back. The slit-band is elevated 

 and, like the lamellaB, shows rather distinctly on the cast of the interior. Aside 

 from the lamellae the whorls are rather broadly rounded on the back, and narrowly 

 rounded on the sides, leaving an umbilicus, the greatest width of which equals about 

 one-third of the entire hight of the shell. The mouth is transverse and somewhat 

 elliptical in outline, the inner lip thick, cut out in the middle and with a compara- 

 tively narrow prominence immediately above the excision, the outer lip with a very 

 wide angular sinus and a narrow open slit at least 15 mm. long in a specimen 30 mm. in 

 hight. The surface markings are obscured by a delicate bryozoan which we failed to 

 remove satisfactorily. As near as we can make them out they appear to consist of (1) 

 lines of growth, and (2) of elevated points arranged in decussating series or of lines 

 running rectangularly across the spaces between the elevated edges of the lamella). 

 Similar variations of sculpture have been observed in B, lindsleyi. 



Though clearly a Bucania, we are in doubt about the specific alliances of this 

 shell. Selecting from the species described in this work, B. crassa and B. lindsleyi 

 (Safford) appear to be the nearest. Still, the differences are so manifest that com- 

 parisons are deemed quite unnecessary. 



Formation and locality. Upper beds of Trenton group, Nashville, Tenn. 

 Colkction. E. O. Ulrich. 



BUCANIA PUNCTIB'RONS Emmons. 



PLATE LXVIl, FIGS. 41-44. 



Bellerophon puncliff,,^ KMMUN-S 1842, Geol. Rept. 2nd Dist. New York, p. 392. 

 liucrtnia pitnctifrons HALL, 1847, Pal. New York, vol. 1, p. 187. 



Shell rather small, probably not exceeding 20 mm. in hight. Volutions three 

 or three and a half, rounded on the back, subangular on the sides; umbilicus large, 



