30 MOSASAURUS. 



Morton!, which would indicate the fossils as appertaining to the Cretaceous era. 

 The reptilian tooth, and several of those of the fishes, are partially imbedded in 

 hard iron pyrites. 



The Crocodilian tooth, represented in Fig. 8, Plate XIX, presents the ordinary 

 form of the teeth of recent Crocodiles and Alligators, being curved conical. The 

 crown, or enamelled portion of the tooth, worn away at the point, in its present state 

 measures seventeen lines long, and the remaining portion of the somewhat gibbous 

 fang is half an inch long, I can detect no appearance of acute ridges separating 

 the inner and outer faces of the cro^vn, though such may have existed. The 

 enamel towards the apex is smooth, but at rather more than the basal half of the 

 crown it is thrown into well-defined, slightly tortuous, longitudinal folds or ridges, 

 reminding one of the appearance of those in the teeth of Polyptichodon. Between 

 the folds the surface exhibits shallow punctures. The diameter of the tooth at the 

 base of the crown is eight lines. The interior of the tooth is hollow as in the teeth 

 of living Crocodiles. 



]nOISA8AlJRVS. 



oaurian animal, resembling the famous fossil reptile of Maestriclit, Mitchell, Observ. Geol. N. America, 1818, 384, 



385, pi. viii, fig. 4. 

 Saurian reptile, resembling the Maeatricht Monitor, Haklan, Journ. Acad. Nat. Sci. 1825, Vol. IV, 235, pi. xiv, figs. 



2, 3, 4 ; Med. and Phys. Researches, 1835, 384. 

 Mosasaurus, De Kay, Ann. Lye. Nat. Hist, 1828-3(j, Vol. Ill, 135, pi. iii, figs. 1, 2. — Morton, Am. Jour. Sci. 1830, 



Vol. XVIII, 246 ; Synop. Org. Rem. 1834, 27, pi. xi, figs. 7, 9.— Haklan, Trans. Geol. Soo. 1S35, 81 ; Med. and 



Phys. Res. 1835, 285.— Emmons, North Carolina Geol. Survey, 1858, 217. 

 GeosauTus Mitchelli, De Kay, An. Lye. Nat. Hist. 1828-36, Vol. Ill, 138 ; Zool. New York, 1842, Part III, 28, pi. 22, 



figs. 65, 56.— Harlan, Trans. Geol. Soo. 1835, 82; Med. and Phys. Res. 1835, 285; Edinb. Phil. Journ. 1834, 



Vol. XVIII, 32.— PicTET, Paleontologie, 1853, Vol. I, 506. 

 Geosaurus, Morton, Am. Jour. Sci. 1830, Vol. XVIII, 246 ; Syn. Org. Rem. 1834, 28. 

 Ichthyosaurus missouriensis, Haklan, Trans. Am. Phil. Soc. 1834, Vol. IV, 405, pi. xx, figs. 3-8 ; Trans. Geol. Soc. 



1835, 80; Med. and Phya. Res. 1835, 284, 348, figs. 1-6. 

 Mosasaurus Dekayi, Bronn, Lethaea Geog. 1838, Vol. II, 760. — Gibbes, Mem. on Mosasaurus ; Smithsonian Contribu- 

 tions, 1851, Vol. II, 8, pl. i, figs. 2, 6. 

 Batrachlosuurus, Harlan, Lond. and Edinb. Philos. Mag. 1839, Vol. XIX, 302. 

 Butrachiotherium, Haklan, Bui. Soc. Geol. 1839, Vol. X, 90. 

 Mosasaurus major, De Kay, Zool. New York, 1842, Pt. Ill, 28, pl. 22, figs. 57, 58. 

 Mosasaurus occidentalis, Morton, Proc. Acad. Nat. Sci. 1844, 133. 

 Batrachiosaurus missouriensis, Meyer, Jahrb. Min. 1845, 312. 

 Mosasaurus neovtdii, Meyer, Jahrb. Min. 1845, 312. 

 Mosasaurus Maximi/iaiii, GoLDFDSS, Nov. Act. Acad. K. L. C. Nat. Cur. 1845, Vol. XXI, 179, pl. vi, vii, viii, ix, figs. 



1-3.— Meyer, Jahrb. "Min. 1845, 312 ; 1847, 122.— Owen, Jour. Geol. Soc. Lond. 1849, Vol. V, 382, pl. x, fig. 5.— 



Gibbes, Mem. on Mosasaurus; Smithsonian Contributions, 1851, Vol. II, 6, pi. I, fig. 7. — Pictet, Paleontologie, 



1853, Vol. I, 505.— Emmons, North Carolina Geol. Surv. 1858, 217, figs. 36a, 37. 

 Mosasaurus Camperi, Pictet, in part, Paleontologie, 1845, Vol. 11, 64. 

 Mosasaurus Hofmanni, Pictet, in part, ibidem. 

 Atlantocheli/s Mortoni, Agassiz, Proc. Acad. Nat. Sci. 1849, 169. 



Mosasaurus minor, Gibbes, Mem. on Mos. ; Smithsonian Contributions, 1851, Vol. II, 7, pl. i, figs. 3, 4, 5. 

 Mosasaurus Coupari, Gibbes, ibidem, pl. ii, figs. 4, 5. 

 Mosasaurus caroliuensis, Gibbes, ibidem, 8, pl. ii, figs. 1, 2, 3. 

 Hulcodus acuiidens, Gibbes, in part, ibidem, 9, pl. iii, figs. 6-9. 

 1 Amphorosteus Brumhyi, Gibbes, ibidem. 

 Mosasaurus Mitchelli, Leidy, Proc. Acad. Nat. Sci. 1859, 92. 

 Mosasaurus missouriensis, Leidy, ibidem, 1857, 90 ; 1859, 92. 



ElUptonodon compressus, Emmons, North Carolina Geol. Surv. 1858, 222, figs. 41, 42. 



Drepanodon impar, Leidy, Proc. Acad. Nat. Sci. 1856, 255.— Emmon.s, North Carol. Geol. Surv., 1858, 224, figs. 45, 46. 

 Lesticodus impar, Leidy, Proc. Amer. Philos. Soc. 1859, VII, 10. 



