980. THE PALEONTOLOGY OF MINNESOTA. 
[Lophospira oweni. 
is sharply angular. The basal part of the last turn is decidedly ventricose, turning 
more or less abruptly into the deep though small umbilicus. On the flattened and 
nearly vertical sides, about midway between the peripheral angle and the basal 
outline, a faintly raised line (lower carina) is usually distinguishable. The suture 
is deep and the upper edge of the last whorl is flattened, and forms a shoulder-like 
prominence, between which and the peripheral angle the surface is strongly concave. 
Aperture obliquely subquadrate, rounded below. Surface markings only in rare 
cases leaving any traces upon the casts, consisting on the shell itself of lamellar 
lines of growth, .5 to 1.0 mm. apart, with much finer lines between them. They 
curve rather strongly backward from above and below to the peripheral angle. 
Compared with species described in this report, L. conradana is distinguished 
by its strongly ventricose base. The general appearance of the shell might be 
considered to indicate close affinities with L. bicincta and L. obliqua, but the character 
and strong retral curve of the lines of growth prove that the species belongs to the 
L. perangulata section of the genus. 
The Wisconsin specimen figured by Prof. Whitfield (Joc. cit.) looks like an 
unusually large example of EL. conradana that has been shortened by pressure, 
causing the apical angle to be abnormally wide. Still, the angle in the figure is 
only about 68°, while in his description Prof. Whitfield gives it at “about ninety 
degrees.” Whatever the specimens described by him may turn out to be, we are 
satisfied that they are distinct from L. ventricosa Hall sp. Ina more recent publi- 
cation* Prof. Whitfield expresses himself as though he had arrived at a similar 
conclusion. - 
Formation and locality —A frequent fossil of the Vanuxemia bed of the Stones River group at 
Minneapolis and St. Paul, Minnesota; occurs also, though rarely, in equivalent strata at Beloit, Wisconsin. 
Collections.—Geological and Natural History Survey of Minnesota; H. O. Ulrich. 
Museum Register, No. 5036. 
LopHOSPIRA OWENI, 7”. Sp. 
PLATE LXXIII, FIGS. 41—45. 
Hight, of Black River specimens, 25 to 36 mm., of Utica specimens, 18 to 27 mm.; 
apical angle 59° to 62°. Volutions six or seven, the first very minute, decidedly 
angular. Peripheral band prominent, thick and rounded, sometimes margined by a 
delicate line on each side. Upper slope concave, except near the suture where 
there is usually a broad rounded ridge or carina; this ridge, however, becomes quite 
obsolete on the sixth or seventh volution. Lower side sloping inward, scarcely 
ventricose, the outline being first concave, next convex, then straight or concave 
and finally convex again, there being a peculiar swelling just behind the minute 
* Bull. Amer. Mus. Nat. Hist., vol.i, no. 8, p. 318, 1886. 
