56 CANADIAN PERIOD. 



very small ; apertiu-e expanded, greatest expansion at the sides, giving it a 

 reniform outline; oiiter volution abruptly convex transversely; lip having 

 a moderately large deep notch in front, of uniform width, the sides being 

 parallel, and rounded at the bottom ; of equal width, and continuous with 

 this notch, there is a slightly-elevated, rounded, dorsal band extending along 

 the center of the volution until it enters the aperture. Surface-markings 

 not preserved in any of the specimens of the collection. 



Extreme w^idth across the aperture, eighteen millimeters ; postero- 

 anterior diameter of the shell, seventeen millimeters. 



Although the specimens are imperfect in some respects, they ai'e suf- 

 ficently well preserved to show that they represent a species quite unlike 

 any other known to me from any of the older Paleozoic rocks. 



Position and locality. — Strata of the age of the Quebec group of Canada; 

 Fish Spring, House range, Utah. 



Class CEPHALOPODA. 



Oedek TETKAEIiANCHlATA. 

 Family 0ETH0CEEATIDJ5. 



Genus OETHOCEEAS Breynius, 1732. 



Subgenus CAMAEOCEEAS Conrad, 1842. 



Orthoceras (Camaroceras) colon White. 



Plate III, fig. .5 a, b, a, and d. 



Orthoceras colon White, 1874, Expl. & Surv. west 100th Merid., Prelim. Eep. Invert. 

 Foss., 10. 



Shell annulated, very slightly tapering ; ti-ansverse section oval ; 

 siphuncle large, perij)heral, in contact Avith one of the broadly-rounded 

 sides, its diameter equal to about one-thu-d the short diameter of the shell ; 

 septa smooth ; convexity nearly uniform, reacliing farther forward at the 

 naiTower sides than at the broader ones ; annulations broadly rounded, 

 passing sinuously around the shell, the sinuosity being gi-eater upon one of 

 the broad sides than it is upon the other ; interspaces nearly corresponding 

 in width and curvature with the annulations. Surface-markings unknown. 



Long diameter, eighteen millimeters ; short diameter, fifteen millime- 

 ters ; distance from center to center of the annulations, six millimeters. 



