780 THE PALEONTOLOGY OF MINNESOTA. 



[Ounerooeraa, *ji. 



This species is readily distinguished by its close air-chambers, regular sutures 

 and the subcentral position of the sipho. 



Formation and locality. Thz larger of the specimens here figured is from the Galena horizon, two 

 miles northeast of Spring Valley, Minnesota. The smaller specimen is probably from the same horizon, 

 but its precise locality has been lost. 



Museum Register, No. 340. 



GAMEROCERAS, sp. 



PLATE XLIX, FIG. 1. 



A single long fragment of a slender sipho, 378 mm. in length, 45 mm. in its 

 circular cross-section at the larger end, has very broad septal funnels, and these make 

 but slightly oblique or undulating ridges about the sipho. These are characters in which 

 the specimen is quite unlike anything heretofore described. The directness of the 

 septal funnels indicates a subcentral position of the sipho, while the length of the 

 funnels is much greater than observed in other species. The length of these 

 funnels is from 18 to 20 mm. and they are seen to very considerably overlap each 

 other. 



The specimen indicates a distinct species of large size, though this example of 

 the sipho constitutes our present knowledge of it. 



Formation and locality, ID the Trenton limestone at Cannon Falls, Minnesota. Collection of W. 

 H. Scofleld. 



CAMEROCEBAS, sp. nov. 



PLATE Ll, FIGS. 5-7. 



Among the figures given by Bigsby in his work on the Geography and Geology 

 of Lake Huron* is one which shows in section a Camerocems with large marginal 

 subtriangular sipho. No name has been applied to this American species, though 

 the peculiar shape of the sipho indicates a form unlike any which bear names with 

 us. Holm has described a species of this character from the Lower Silurian of 

 Esthland (Endoceras gladius.)-\ 



The specimen figured upon plate LI, figs. 5 7, is a very characteristic example 

 of one of these bodies, having one side broad and flat and the other broadly rounded. 

 The siphonal funnels on this cast are broad and distant, distinctly curved 

 upward on the fiat side, but regularly transverse on the rounded surface. From 

 Higsby's figure we infer that in their normal position in the shell these siphones 

 were submarginal, had their curved surface towards the conch and their flat side 

 inwards. 



Formation and locality. The specimen here figured is from the Trenton limestone at Zurnbrota 

 Ooodhuc county, Minnesota. 



Muneum Register, No. 3391). 



Trans. Goolog. Boo. London, vol. i, pi. 2, fig. 1. 1K24. 

 t IMC. cU., p. 13, pi. 2. 



