30 MOSASAURUS. 
Mortoni, which would indicate the fossils as appertaining to the Cretaccous 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 crown, though such may have existed. The 
enamel towards the apex is smooth, but at rather moye 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 cight lines, The interior of the tooth is hollow as in the teeth 
of living Crocodiles. 
MOSASAURUWS. 
vaurian animal, resembling the famous fossil reptile of Maestricht, MircuEtn, Observ. Geol. N. America, 1818, 384, 
385, pl. viii, fig. 4. 
Saurian reptile, resembling the Maestricht Monitor, Hannay, Journ. Acad. Nat. Sci. 1825, Vol. IV, 235, pl. xiv, figs. 
2, 3,4; Med. and Phys. Researches, 1835, 384. 
Mosasaurus, De Kay, Ann. Lye. Nat. Hist, 1828-36, Vol. III, 135, pl. iii, figs. 1, 2.—Morroy, Am. Jour. Sci. 1830, 
Vol. XVIII, 246; Synop. Org. Rem. 1834, 27, pl. xi, figs. 7, 9.—Haran, Trans. Geol. Soc. 1835, 81; Med. and 
Phys. Res. 1835, 285.—Emmons, North Carolina Geol. Survey, 1858, 217. 
Geosaurus Mitchelli, Dk Kay, An. Lye. Nat. Hist. 1828-36, Vol. III, 138; Zool. New York, 1842, Part III, 28, pl. 22, 
figs. 55, 56.—Hanruan, Trans. Geol. Soc. 1835, 82; Med. and Phys. Res. 1835, 285; Edinb. Phil. Journ. 1834, 
Vol. XVIII, 32.—Picrer, Palcontologie, 1853, Vol. I, 506. 
Geosaurus, Morton, Am. Jour. Sci. 1830, Vol. XVIII, 246; Syn. Org. Rem. 1834, 28. 
Ichthyosaurus missouriensis, HARLAN, Trans. Am. Phil. Soc. 1834, Vol. IV, 405, pl. xx, figs. 3-8; Trans. Geol. Soc. 
1835, 80; Med. and Phys. Res. 1835, 284, 348, figs. 1-6. 
Mosasaurus Dekayi, Bronn, Lethea Geog. 1838, Vol. Il, 760.—Gispes, Mem. on Mosasaurus; Smithsonian Contribu- 
tions, 1851, Vol. II, 8, pl. i, figs. 2, 6. 
Batrachtosaurus, Hannan, Lond. and Edinb. Philos. Mag. 1839, Vol. XIX, 302. 
Batrachiotherium, Haxtan, Bul. Soc. Geol. 1839, Vol. X, 90. 
Mosasaurus major, De Kay, Zool. New York, 1842, Pt. III, 28, pl. 22, figs. 57, 58. 
Mosasaurus occidentalis, Morton, Proc. Acad. Nat. Sci. 1844, 133. 
Batrachiosaurus missouriensis, MEYER, Jahrb. Min. 1845, 312. 
Mosasaurus neovidii, Meyer, Jahrb. Min. 1845, 312. 
Mosasaurus Maximiliani, Gotpruss, Nov. Act. Acad. K. L. C. Nat. Cur. 1845, Vol. XXI, 179, pl. vi, vii, viii, ix, figs. 
1-3.—Meyenr, Jahrb. Min. 1845, 312; 1847, 122.—Owen, Jour. Geol. Soc. Lond. 1849, Vol. V, 382, pl. x, fig. 5.— 
Gipses, Mem. on Mosasaurus; Smithsonian Contributions, 1851, Vol. II, 6, pl. I, fig. 7.—Picrer, Paléontologie, 
1853, Vol. I, 505.—Emmoys, North Carolina Geol. Surv. 1858, 217, figs. 36a, 37. 
Mosasaurus Camperi, Pictrr, in part, Paléontologie, 1845, Vol. II, 64. 
Mosasaurus Hofmanni, Picret, in part, ibidem. 
Allantochelys Mortoni, Acassiz, Proc. Acad. Nat. Sci. 1849, 169. 
Mosasaurus minor, Gispes, Mem. on Mos. ; Smithsonian Contributions, 1851, Vol. II, 7, pl. i, figs. 3, 4, 5. 
Mosasaurus Couperi, Gisnes, ibidem, pl. ii, figs. 4, 5. 
Mosasaurus carolinensis, GisBEs, ibidem, 8, pl. ii, figs. 1, 2, 3. 
Holcodus acutidens, Gispes, in part, ibidem, 9, pl. iii, figs. 6-9. 
2? Amphorosteus Brumbyi, Gisses, ibidem. 
Mosasaurus Mitchelli, Lewy, Proc. Acad. Nat. Sci. 1859, 92. 
Mosasaurus missouriensis, Levy, ibidem, 1857, 90; 1859, 92. 
Elliptonodon compressus, Emmons, North Carolina Geol. Surv. 1858, 222, figs. 41, 42. 
Drepanodon impar, Lerpy, Proc. Acad. Nat. Sci. 1856, 255.—Esmons, North Carol. Geol. Surv., 1855, 224, figs. 45, 46. 
Lesticodus impar, Leiy, Proc. Amer. Philos. Soc. 1859, VII, 10. 
