468 MESOZOIC TIME. 



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

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

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

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

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

 Kansas, etc. ; Fig. 854 C, paddle of Lestosaurus 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 platyspondylus 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 Pterosaurs, Pteranodon ingens Mh., Pt. occidentale Mh., Pt. velox Mh., all 

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

 wings. 



The birds comprise Waders, of the genera Termatornis and Palceotringa, from New 

 Jersey; Natatoree, of the genus Laornis, from New Jersey and Kansas ; and birds with 

 teeth, or Odontornithes, all from Kansas. 



Of the last, the Hesperornis group has been called by Marsh, in allusion to the teeth 

 in sockets, Odontolcce. The relations to the Ostrich are shown in the absence of a crest 

 from the sternum, and in other characters (Marsh, Amer. Jour. Sci., xiv. 85, 1877). 

 H. gracilis of Marsh is a second species. Lestornis crassipes Marsh, of the same family, 

 was somewhat larger than H. regalis. Bajrtornis advenus Marsh, is supposed to be near 

 Hesperornis; it was as large as the Loon. Graculavus anceps and G. agilis are two 

 species from Kansas related to Ichthyornis. 



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. 448, 1872.) 



III. Fossils characteristic of the Subdivisions of the 

 Cretaceous. 



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

 Ddkotensis M. & H., Axinwa Siovxensis Gabb., Cardium, Corbicula, Yoldia, Tellina, 

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

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

 New Jersey : Leaves of Angiosperms. 



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

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

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

 Ammonites percarinatus, Inoceramus capulus Shum. New Jersey : none. 



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

 I. aviculoides M. & H., /. pseudo-mytiloides Schiel. Arkansas: ToxasUr elegans, Hoi' 

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

 annulaius R., Grypliaia Pitcheri. Texas: Holaster simplex, Epiaster elegans, Cidarh 

 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 DeTcayi, 

 Ammonites placenta, A. complexus H. & M., Baculites ovntus, B. compressus, Helico- 

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

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

 ularis, Inoceramus biformis, Pecten b-costatus Mort., Nautilus Dehayi Mort., Am- 

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

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

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



