468 MESOZOIC TIME. 



saurs: Fig. 854 A, tooth of Mosasaurus pnnceps Mh., from New Jersey; M. maximus 

 Cope, from New Jersey; M. minor Gibbes, from Alabama. Fig. 854 D, form of jaw of 

 Edestosaurus dispar Mh., a species from Kansas, thirty feet long; Fig. 854 B, snout of 

 Tylosaurus micromus Mh., from Kansas; T. proriger Mh. (Leiodon proriyer Cope), 

 from Kansas; T. dyspelor Mh. {Leiodon dyspelor Cope), fifty to sixty feet long, from 

 Kansas, etc. ; Fig. 854 C, paddle of Lesfosam-us simus Mh., from Kansas, a short-nosed 

 kind; Clidastes iyuanavus Cope, from New Jersey; C- intermedins L., from Alabama; 

 C. pumilus Mh., from Kansas, twelve feet long; Baptosaurus jjlatyspondylus Mh. and 

 B. fraternus Mh., both from New Jersey. The Mosasaurs, according to Marsh, have 

 very short necks, like the Ichthyosaurs. The vertebrae, in the genera Clidastes and 

 Edestosaurus, are united by a zygosphene articulation, as in snakes and the Iguanas. 



Among Pterodactyls, Pterodactylus ingens Mh., Pt. occidentals Mh., Pt. velox Mh., 

 all from Kansas, severally about twenty-five, twenty, and fifteen feet in expanse of 

 wings. 



The birds, described by Marsh, comprise five Waders, of the genera Termatornis and 

 Palaotringa, all from New Jersey; six Natatores, of the genera Graculavus, Hesper- 

 ornis, and Laornis, from New Jersey and Kansas; and two birds with teeth (Odont- 

 ornithes), of the genera Ichthyornis and Apatornis, from the Upper Cretaceous shale of 

 Kansas. 



See, on Cretaceous Reptiles: Leidy, Smithsonian Contrib. No. 192, 1865, 4to, and 

 later papers in the Proc- Acad. Nat. Sci. Philad., Reports in connection with Hayden's 

 Explorations; Cope's Synopsis, 4to, 1869, Trans. Amer. Phil. Soc., and later papers 

 in the Proc. Am. Phil. Soc, and Acad. Nat. Sci., and Hayden's Rocky Mountain 

 Reports; Marsh, Am. Jour. Sci., vols. i. to v. of the 3d series. Also, on Birds, 

 Marsh, ib. The existence in Mosasaurs of the articulation in the lower jaw was first 

 made known by Cope; and that of hind paddles and scales, as well as the character 

 of the paddles, by Marsh. (Am. Jour. Sci., III. hi. 448.) 



TTT Fossils characteristic of the Subdivisions of the 

 Cretaceous. 



A. Earlier Cretaceous. — No. 1 (Dakota group). Upper Missouri: Pharella (?) 

 Dahotensis M. & H., Axinma Siouxensis Gabb., Cardium, Corbicula, Yoldia, Tellina, 

 Leptosolen Conradi M., Cyrena (Cyprina) arenaria M.. TInio Nebrascensis M., Leaves 

 of Angiosj)erms. Alabama: Ceratites (?) Americanus Harper, Leaves of Angiosperms. 

 New Jersey : Leaves of Angiosperms. 



No. 2 (Benton group). Upper Missouri: Inoceramus problematicus, I. umbonatus 

 Ostrea congesta, Pholadomya (Anatimya) papyracea Con.; Ammonites per ■carinatus H. 

 & M., A. vespertinus Mort. (—A. Texanus R. ), Scaphites larvaformis M. & H. Texas: 

 Ammonites percarinaf us, Inoceramus capidus Shum. New Jersey: none. 



No. 3 (Niobrara group). Upper Missouri : Ostrea congesta, Inoceramus problematicus f 

 I. aviculoides M. & H., /. pseudo-mytiloides Schiel. Arkansas: Toxaster elegans, Hol- 

 aster simplex, Cardium multistnatum Shum., Inoceramus problematicus, I. confertim- 

 annulalus R., GrypJma Pitcheri. Texas: Rqlaster simplex, Epiaster elegans, Cidark 

 hemigranosa, Gryphcea Pitcheri, Ostrea subovata Shum. (0. Marshii Marcou), Inocera- 

 mus problematicus, Turrilites Brazoensis R., Ammonites Texanus, Hamites Fremonti 

 Marcou. New Jersey: none. 



B. Later Cretaceous. — No. 4 (Pierre group). Upper Missouri : Nautilus Dekayi, 

 Ammonites phcenta, A complexus H. & M., Baculites ovatus, B. compressus, Hel'ico- 

 ceras Mortoni M. & H., Inoceramus sublevis H. & M., Mosasaurus Missouriensis L. 

 Alabama: in bed a, Teredo tibialis (?) Mort.; in bed b, Exogyra costata, Gryphwa vesic- 

 ularis, Inoceramus biformis, Pecten 5-costatus Mort., Nautilus DeJcayi Mort., Am- 

 monites placenta, A. Delawarensis Mort., Baculites ovatus; in bed c, Ostrea larva, 

 Gryphwa lateralis (G. vomer Mort.), Neithea Mortoni Gabb. New Jersey: Bed a, 

 Ammonites placenta, Bacidites ovatus ; bed b, Amm. Delawarensis, A. complexus, Bacu- 



