541 



Orthoo. 



rthoceras aequale. Emmons Keport on the Geology of 



the Second 

 District of the 

 State of New 

 York, 1842, p. 

 404, fig. 113, 1. 

 Trenton iorm- 

 oiion^ II c. 



Orthoceras amycus, Hall. Trans. Alb. Inst. Vol. 10, 1879. 



Collett's Indiana Report of 1881, p. 324, pi. 38, fi^gs. 3, 4. Dif- 

 fers from 0. annulatum in taper, &c. Niagara^ Vb. 



Orthoceras anceps, Hall. Geology of Canada, 1863, p. 



1QS,\A 150, fig. 108 «, specimen showing the 

 siphuncle and septa separating the 

 chambers; J, cross section showing 

 the flattened shape of this ceph- 

 alopod shell, and the position of the 

 siphunclar channel of communica- 

 tion between the chambers. Tren- 

 ton limestone, II c. 



