182 PALEOZOIC PALEONTOLOGY. 
proceeds it becomes more and more obtuse. Aperture straight at the 
inner margin, somewhat narrowly produced at the lower angle. Sur- 
face markings rarely preserved; whenever preserved, they consist of 
rather distant, delicate, sublamellose striew, with very fine lines be- 
tween them, all curving backward strongly to the peripheral band.”— 
Ulrich and Scofield. 
Remarks.—This species is rare in the Black River horizon of the 
Trenton formation at Jacksonburg, and has not been observed in a 
satisfactory condition of preservation to exhibit all its characteristics. 
There seems to be no doubt, however, that the New Jersey shell is 
identical with the species which has been described as L. owent from 
Minnesota. 
LIOSPIRA MICULA (Hall). 
Plate XII., Figs. 24-25. 
1862. Pleurotomaria micula Hall, Geol. Rep. Wis., vol. I; p-. 55, 
fig. 4 (no description). 
189%. Inospwra micula U. & S., Pal. Minn., pt. II., p. 994, pl 68; 
figs. 24-29. 
Description—Shell small, discoidal-lenticular, consisting of about 
four volutions. The winbilicus filled by a perfectly-smooth, rather 
distinctly outlined, concave, reflexed callosity of the inner lip. The 
sutures very shallow; the spire forming an almost continuous, even 
slope from the apex to the periphery, the apical angle being from 
120° to 127°. The periphery of the outer volution is sharply angular 
in the casts, but is more rounded when the shell is preserved. The 
volutions subrhomboidal in cross-section. The aperture irregulary 
triangular in outline, wider than high, the inner hp nearly vertical. 
Diameter of shell usually from 9 to 12 mm. 
Remarks.—In 1847 Hall* described Pleurotomaria subtilistriata 
from the Trenton limestone at Watertown, New York. ‘The size of 
the species was described as follows: “Most of the specimens being 
scarcely visible to the naked eye.” The specimens illustrated, how- 
ever, said to be the largest seen, are 10°mm. and 11.5 mm. in diameter, 
respectively, and, so far as can be judged from the figures, are not 
Palo Na Volpe 72. 
