DEVONIAN SPECIES. 47 



genvis Edmondia, I am by no means sure that I would not be nearer correct 

 to call it Palceoneilo Pinonensis, since it has much the general appearance, 

 and some indications of the oblique posterior basal sulcus, or slight con- 

 cavity, of some species of the latter genus. Still, as it shows no traces 

 of hinge-crenulations in any of the casts contained in the collection, while 

 some of them seem to show some appearance of an impression near the 

 hinge such as might have been made by a thin cartilage-process like that 

 seen in each valve of Edmondia, I have concluded to place it, for the present, 

 doubtfully in that genus. It may be found, however, when its generic 

 characters can be made out from better specimens, to belong to an unde- 

 scribed genus. 



Locality and position. — Three miles south of Piiion Pass, Pifion Range, 

 Central Nevada ; from a limestone containing Atryj^a reticularis, Spirifer 

 Pinonensis, a small Favosites, and an Avicula or Pferinea, and believed to 

 belong to the Lower Devonian. 



CEPHALOPODA. 



ORTHOCERATITID^. 



Genus ORTHOCERAS, Auct. 

 Orthoceras Kingii, Meek. 



Plate 2, fig. H, 



Shell attaining a rather large size, conical in general form, rather 

 rapidly tapering; section circular or a little oval; septa numerous and 

 closely arranged, the distance between being uniform, or very nearly so, 

 without regard to the increase in the size of the shell from the smaller to 

 the larger end; all deeply concave. (Surface and siphuncle unknown.) 



Entire length imknown ; length of a specimen imperfect at both ends 

 and septate throughout, 5.25 inches ; greatest diameter of same at the larger 

 end, about 3.20 inches; of smaller end, 2 inches; distance between the 

 septa throughout, 0.23 inch. 



The specimen of this species is quite imperfect ; but it seems desirable 

 to call attention to it as one of the fossils characterizing the silver-bearing 

 rocks of the White Pine District. It may be compared with such forms as 



