83 SYSTEMATIC PALEONTOLOGY 



SO determined by him appear to be young examples of 0. silUmani and 

 0. desorii, together with some that are clearly referable to Carcliarias. 



Genus OTODUS Agassiz. 



Otodus obliquus Agassiz. 

 Plate XXX, Figs. 8, 9. 



Otodus obliquus Agassiz, 1843, Poiss. Foss., Tol. iii, p. 367, pi. xxxi, pi. xxxvi, figs. 



22-27. 

 Otodus obliquus Eastman, 1901, Md. Geol. Survey, Eocene, p. 106, pi. xv. 



This species, so abundant in the Eocene, occurs very sparingly in the 

 Miocene of this State, the few examples known having been obtained 

 from Charles county, and forming part of the Thomas Collection. 



Occurrence. — Calvert Foemation. Charles county near the Patux- 

 ent river. 



Collection. — Philadelphia Academy of Natural Sciences. 



Genus CARCHARODON Agassiz. 



Carchaeodon" megalodon" (Chaiiesworth). 

 Plate XXXI, Figs, la, lb, Ic, 2, 3, 4a, 4b. 



Carcliarias megalodon Cbarleswortb, 1837 (ex Agassiz MS.), Mag. Nat. Hist. n. s., 



vol. i, p. 225, woodc. fig. 24. 

 Carcharodon megalodo7i Agassiz, 1843, Poiss. Foss., vol. iii, p. 247, pi. xxix. 

 Carcharodon megalodoti Gibbes, 1849, Jour. Acad. Nat. Sci. Phila., 2nd sen, vol. i, 



p. 143, pi. xviii, pi. xix, figs. 8, 9. 

 Carcharodon rectus Agassiz, 1856, Kept. Pac. R. R. Explor. and Surv., vol. v, p. 314, 



pi. i, figs. 29-31. 

 Carcharodon rectus Agassiz, 1856, Amer. Jour. Sci., ser. ii, vol. xxi, p. 274. 

 Carcharodon megalodon Emmons, 1858, Rept. N. Car. Geol. Survey, p. 227, fig. 50. 

 Carcharodon ferox Emmons, 1858, Rept. N. Car. Geol. Survey, p. 229, figs. 52-54. 

 Carcharodon triangularis Emmons, 1858, Rept. N. Car. Geol. Survey, p. 232, fig. .59. 

 Carcharodon inegalodo7i Leidy, 1877, Jour. Acad. Nat. Sci. Pbila., 2nd ser., vol. viii, 



p. 253. 



Description. — Teeth attaining a very large size, comparatively broad 

 and robust, the outer coronal face flat or slightly convex, the apex 

 sometimes gently curved outwards; distinct lateral denticles absent. 



The teeth of Carcharodon, which are such a conspicuous feature in 

 the Eocene of South Carolina and other states, appear to diminish in 

 abundance proceeding northward, and ascending in the geological series. 



