974 THE PALEONTOLOGY OF MINNESOTA. 
[Lophospira medialis. 
Nearly intermediate between L. perangulata Hall and L. sororcula Billings sp., 
having a small umbilicus and depressed volutions like the former and a hight of 
spire and general appearance more like the latter. The convexity or obscure 
angulation of the upper part of the volutions, as well as the lesser development of 
the lower carina, distinguishes it from both and suggests relationship with L. oweni 
and L. ampla. 
Formation and locality.—Rare in the Trenton group of Minnesota, in the Clitambonites bed at St. 
Paul, and the Fusispira bed at Wykoff; common in the upper beds of the Trenton between Burgin and 
Danville and at other localities in Kentucky; occurs also in middle Tennessee and in Lincoln county, 
Missouri. 
Collection.—E. O. Ulrich. (45 specimens.) 
LoPHOSPIRA MEDIALIS, Var. BURGINENSIS, ». var. (Ulrich.) 
PLATE LXXIII, FIGS, 30 and 31. 
Hight 10 to 14 mm., apical angle almost constantly 60°; volutions six. 
Agrees in all respects with M. medialis excepting that the average size is less, 
and the lower carina much stronger and more prominent. The lower carina causes 
also a flattening of the base that does not occur in the typical variety. 
Var. burginensis, having a small umbilicus, must still remain separate from the 
Quebec group ZL. sororcula Billings. It resembles very greatly also L. pulchella, but 
has a wider apical angle, while the subsutural or upper carina is never well defined 
as it isin that species. In ZL. perangulata the apical angle is somewhat narrower, 
the slope of the upper side of the whorls less steep, and the space between the 
peripheral and lower carinz more nearly vertical and less concave. 
Formation and locality.—Upper part of the Trenton group, Burgin, Danville, Lexington and other 
localities in Kentucky. 
Collection.—E. O. Ulrich. (35 specimens.) 
LopHosPIRA ABNORMIS, ”, sp. (Ulrich.) 
PLATE LXXIII, FIGS, 36—40. 
Hight 15 to 20 mm.; apical angle increasing with growth from 42° to 53°; 
volutions six or seven. 
The size, surface markings, umbilicus and form of the volutions is almost 
exactly as in L. medialis, and if the last two whorls only were compared it would 
be most difficult to distinguish them, Still, a comparison of interior casts, the 
condition in which L. abnormis is usually found, will show that in the present 
species the umbilicus is less abrupt and the peripheral angle of the whorls more 
prominent and situated lower down, causing the upper slope to be slightly wider, 
‘higher and more convex. Besides the casts show an obscure revolving line or ridge 
