992 THE PALEONTOLOGY OF MINNESOTA. 



[Schizolopha textllis. 



SCHIZOLOPHA TEXTILIS, W. Sp., (Ulfich.) 

 PLATE LXV, FIG. 30. 



Hight 30mm., width 27mm.; apical angle about 80. Shell turbinifonn, volutions about five, 

 ventricose below, with a subcentral and only moderately prominent peripheral angle; above this a slightly 

 concave space to the summit of a ridge which lies somewhat less than midway to the suture, then a wider 

 and more deeply concave space to a scarcely perceptible shoulder at the suture; immediately above the 

 last lies the slit-band of the preceding whorl; umbilicus very small; aperture subovate, higher than wide, 

 the inner lip not very thick and curving outward in the lower half; slit about 0.6 mm. in width and 15.0 in 

 length. Entire surface very delicately cancellated, the revolving lines much the finer of the two sets, the 

 lines of growth rather regular, raised, just about visible to the unassisted eye, moderately recurved to the 

 slit-band. 



Formation and locality, Upper part of Trenton group, Nashville. Tennessee. 

 Collection. E. O. Ulrich. 



SCHIZOLOPHA MOOREI, n. sp. (Ulrich.) 



PLATE LXV, FIGS. 3137. 



Hight of Richmond group form 28 to 38 mm., width 27 to 41 mm.; apical angle of same 75 to 82; 

 higbt of Lorraine group form 20 to 29 mm., width variable, usually about the same as the hight; apical 

 angle 65 in one instance, 83 in another, usually about 75. Of whorls there are at least six in the shell, 

 but casts of the interior, in which form the species occurs almost invariably, rarely if ever preserve more 

 than three or four, the first two or three having been rilled with shelly matter. In casts it is only the 

 last whorl that is strongly carinate on the periphery, the upper ones being more or less rounded. The 

 umbilicus is variable, being as a rule relatively larger and less steep in the Richmond group form, which 

 we regard as the typical one for the species, than it Is in the Lorraine group variety. On the shell of the 

 latter the edge of the narrow umbilicus is angular. That a similar angle surrounds the umbilicus in the 

 typical form is doubtful, though we have seen no specimens showing this part of the shell. Very few 

 casts give any idea whatever of the surface markings. As seen on gutta percha impressions of natural 

 molds of the exterior, they appear as rather coarsely lamellose and strongly recurved lines of growth. The 

 convexity of the slit-band seems to grow less with age, the elevated line on each side of it stronger. 



Formation and locality. Lorraine group at numerous localities in the vicinity of Cincinnati, Ohio; 

 reappears in the upper part of the Richmond group, of which it is one of the most characteristic fossils, 

 at many localities in Indiana and Ohio, being perhaps the most abundant at Richmond in the former 

 state and Oxford in the latter. 



Colkction. E. O. Ulrich. 



Genus LIOSPIRA, n. gep. 



In part Pkurotomaria and Raphistoma of many authors. 



For generic characters see page 953. 



We doubt that any one can, after a thorough investigation, deny that this is 

 not only a very convenient but also a most natural division of the Pleurotomariida-. 

 The lenticular form of shell which pertains to the majority of the species is of 

 course shared by other types, notably Raphistomina and Trepospira, and in a lesser 

 degree by Eotomaria; but who will say that the differences which exist between 

 these various types of shells, and which have in part been pointed out on preceding 



