THE PALEONTOLOGY OF MINNESOTA. 



LBucania elliptlca. 



width of the last volution increases from 5 mm. to about 17.5 mm. The hight of the 

 aperture is about 10 mm. 



.Formation and locality.' 1 Central limestone" of the Stones River group, near Murfreesboro, Ten- 

 nessee. Vanuxemia bed, Cannon Falls, Minnesota. Black River group (VCtenodonta bed), near Fountain, 

 Minnesota. 



Collection. E. O. Ulrich. 



BCCANIA ELLIPTICA, . Sp. 

 PLATE LXVI. FIGS. 11 and 12. 



Of this species we have only three casts of the interior, and all are more or less 

 incomplete. The best is figured on plate LXVI. In this, as in the others, the 

 apertural portion is broken away quite to the posterior end of the slit. In the 

 figured example the last volution appears as though it had been free and possibly 

 expanded at the aperture, in which case we would have to call it a Salpingostoma. But 

 the slight expansion shown by the specimen is most probably the result of crushing. 

 The volutions, as far a sobserved, are elliptical in cross section and enlarge slowly, 

 the last in width from 6 mm. to 14 mm. On the whole the cast of the interior 

 resembles B. halli U. & S., B. emmonsi U. & S., and B. intexta Hall, the last in partic- 

 ular, but a distinct species is indicated by the rounded instead of angular sides of 

 the whorls. Detailed comparisons with the species named will bring out several 

 other differences. 



In the Kentucky specimens the volutions are less convex in the back than the 

 Minnesota type of the species, and it is possible that more perfect material will 

 prove them to belong to a distinct species. 



Formation and locality. Lower part of Fusispira bed, Trenton group, three miles south of Cannon 

 Falls, Minnesota; base of Trenton or top of Black River group, Mercer county, Kentucky. 



Collection. E. O. Ulrich. 



BUOANIA 8UBLATA, tt. Sp. 

 PLATE LXVI, FIGS. 16-10. 



This is a small subglobose shell, with wide volutions, broadly rounded on the 

 back, flatly sloping in the umbilicus; and sharply angular on the sides. The umbil- 

 icus is sharply defined and deep, but comparatively small, its greatest diameter 

 equalling only about half of the hight of the shell. The volutions increase gradually 

 in size to the aperture, are acutely subelliptical in section, about twice as wide as 

 high, and two and a half or three in number; the width of the aperture equals the 

 hight of the shell. The surface markings are preserved on only a very small part 

 of the shell. As near as can be determined they appear to have been about as in B. 

 halli. The slit-band lies between two thin elevated lines and is a trifle wider, and 



