PLATE 86. 



Fig. ]. 373. 27. Okthoceras coralliferum. (Pag- 312.) 



1 a. A small fragment from the altered shales near Waterford, Saratoga county. The septa are represented too 



distant in the figure. A portion of the coral covering the surface is magnified in 1 b. 

 1 c. A fragment from tlie green shales of Lewis county. 



1 d. A fragment from the sandstone of the Hudson-river grou]>. 



Fig. 2. 374. 28. Okthoceras lamellosum, (Pag. 312.) 



•J b, c. Fragments near the smaller extremity ; the septa being indistinctly preserved. 



2 d. A fragment showing the comparative distance of the septa, in which it varies slightly from 2 c. 

 2 e. Section of the last, showing the position of the siphuncle. 



Fig. 2 a. 375. 2. Ormoceras crebriseptum. (Pag. 313.) 



A fragment of this species, the siphuncle being distinctly moniliforin. 



