242 University Geological Survey of Kansas. 



Ptychodus occidentalis. Plate XXIX, fig. 4; plate XXX, fig. 13. 



Ptychodus occidentalis Leidy, Proc. Acad. Nat. Sci. Phil. 1868, p. 207; 

 Ext. Vert. Fauna West. Terr., p. 308, pi. xvn, ff. 7, 8, pi. xvm, ff. 15-18: 

 Cope, Cret. Vert., p. 244; Williston, cf. cit. 33 — Niobrara, Benton of 

 Kansas. 



Two teeth, one from the same conglomerate that yielded the 

 teeth referred to P. janewayii, the other, without locality, from 

 Mr. Joseph Savage's collection, I refer to this species. The 

 species differs from the following in having the transverse 

 ridges continued to the lateral rims, and not separated by an 

 area of fine reticulation. The anterior surface has finer, elon- 

 gated, nearly straight ridges and grooves in this species, while 

 in the others the markings are reticulate or vermiculate. 



Ptychodus janewayii. Plate XXX, figs. 9, 10, 11. 



Sporetodus janewayii Cope, Hayden's Bull. U. S. Geol. Surv. No. 2, 



(1874). pi. xlvii. 

 Ptychodus janewayii Cope, Cret. Vert., p. 244; Williston, cf. cit. 33. 



"Surface irregularly convex, covered with a dense layer, 

 which does not exhibit pores, and is thrown into transverse or 

 oblique ridges. Surface with four folds, which traverse it 

 obliquely from border to border. At the base of the outer, at 

 one end, is a series of adherent tubercles ; at the basis of that, 

 at the opposite end, is a broken fold, with tubercles at its outer 

 base. Length, 0.0045 m. ; width, 0.0025 m. A portion of a 

 larger and more central tooth has the surface with an unsym- 

 metrical convexity, and is crossed transversely by five folds, 

 from border to border." 2 



Three small teeth, shown enlarged in plate XXX, fF. 9-11, 

 from the conglomerate containing specimens of Corax curvatus, 

 appear to belong to this species. The horizon of the conglom- 

 erate is near the line of contact between the Dakota and Ben- 

 ton, in Ellsworth county. Cope's type was from a bed of 

 conglomerate containing Lamna and Isurus teeth of small size 

 near Stockton. It is probable that the horizon is the same in 

 both. 



2. Cope, 1. c. 



