CRHPHALOPODA. 789 
Orthoceras sociule.] 
interrupt the surface sculpture, but have the appearance of opaque or dull lines 
upon the shining surface of the shell. These I presume to be traces of color lines. 
Formation and locality.—In the Trenton limestone, Cannon Falls, Minnesota. Collection of W. H. 
Scofield. 
OrTHOCERAS soctALE Hall, 1877. 
PLATE LY, FIG. 7. 
Orthoceras gregarium HALL, 1861. Rept. Supt. Geol. Surv. Wisconsin, p. 46. 
Orthoceras sociale HALL, 1877. In Miller’s North American Palxozoic Fossils, 2d ed., p. 245. 
Original description: “Sheil of medium size, gradually expanding from the 
apex, transverse section circular. Septa deeply concave, not very distant, varying 
from six to nine in the space of an inch, according to age. Siphuncle central in 
young specimens, often becoming subcentral or quite excentric in old individuals.” 
This species which is better known from the general diffusion in collections of 
the fine specimens occurring in rocks of the Hudson River horizon in the Maquoketa 
region of Iowa than from any published accounts or illustration, is represented in 
the collections of the Minnesota survey by excellent representatives from Graf, 
Iowa. There are also a few examples from the Trenton and Galena horizons at 
Cannon Falls which bear very much the same proportions, symmetrical form and 
general aspect of 0. sociale and hence suggest the presence of that species in these 
rocks. 
ORTHOCERAS BELTRAMII, Sp. nov. 
PLATE LY, FIG. 10. 
Shell very small, straight, very gradually expanding; cross-section subelliptical; 
external surface smooth, so far as known. Sutures direct, without lobes or undula- 
tions. Air-chambers very deep. The specimen upon which the species is 
founded is imperfect at the apical end, but retains most of the body-chamber. Its 
length is 29 mm.; its lower diameter 2 mm.; its apertural diameter, 3.5 mm. It 
bears fourteen air-chambers in a length of 21 mm., the body-chamber being 8 mm. 
in length. 
Formation and locality—In the Galena shales at Wykoff, Minnesota. Collection of Dr. C. H. 
Robbins. 
ORTHOCERAS MULTICAMERATUM Emmons, 1842. 
Orthoceras multicameratus EMMONS, 1842. Geology of New York, Rept. Second Dist., p. 382, fig. 93. 
Orthaceras multicameratum HALL, 1847. Palxontology of New York, vol. i, p. 45, pl. x1, figs. la-c. 
Original description: “Vixtremely elongate, slender, very gradually tapering to 
an acute point; surface apparently smooth or girt with slight undulations; septa 
