32 M O S A S A U R U S . 



or described by Mitchell,' De Kay,- Harlan,^ Morton,^ Gibbes,^ and Emmons.^ The 



' Observations ou the Geologj' of Xorth America, by Samuel L. Mitchell, published in the 

 American edition of the Essay on the Theory of the Earth, by Cuvier, New Tork, 1818. Prof. 

 Mitchell was the first to indicate the existence of remains of 3Iogasau?-us in the United States. In 

 Plate YIII, Fig. 4, he represents the tooth of a IIoHasaurus from the foot of Nevershik Hills, New 

 Jersey, and refers to it, p. 384, as resembling the teeth of the famous fossil reptile of Maestricht. 



» Annals Lyceum Nat. Hist. New York, Yol. Ill, p. 135, PI. Ill, Figs. 1, 2. Dr. De Kay, besides 

 describing and figuring a tooth, from Monmouth County, New Jersey, which he refers to Mosasaurus, 

 also gives a description and representation of a tooth, p. 138, PI. Ill, Figs. 3, 4, which he refers to 

 Geosaurus, but which I am inclined to suspect also belongs to the former genus. 



' Journal Acad. Nat. Sciences, Philadelphia, Yol. lY, p. 235, PI. XIY, Figs. 2-4. Dr. Harlan 

 represents a tooth from the vicinity of Woodbury, New Jersey, which he says resembles in every 

 respect the teeth of the Maestricht Monitor. In his Med. and Phys. Researches, p. 285, he refers 

 the same specimen to the genus Moaaxaurus. 



* Synopsis of Organic Remains, p. 27, 28, PI. XI, Figs. T, 9, 10. In this work Dr. Morton 

 simply refers to and reproduces the specimens described by Drs. De Kay and Harlan. In the Proc. 

 Acad. Nat. Sci. Philadelphia, Yol. II, p. 132, Dr. Morton refers to a collection of remains of Mosa- 

 saurus from New Jersey, forming part of the material of the above memoir. From differences 

 observed in comparison with the European llosasaurus, the author refers them to a distinct species 

 under the name of 31. occidentalis. 



5 Memoir on Mosasaurus and the allied Genera. By Robert W. Gibbes, M. D. Smithsonian 

 Contributions, Yol. II. The author indicates, describes, and figures a number of specimens, which 

 he refers to several distinct species of llosasaurus. Most of the specimens were found in the Cre- 

 taceous deposits, or are readily referred thereto, but several he mentions as having been derived from 

 the Eocene formations of Ashley R., S. C, and Wilmington, N. C, but neither describes nor figures 

 them. I have as yet seen no trace of llosasaurus remains from any of the Tertiary deposits of the 

 United States. 



A small vertebra, with an attached portion of another, from the Cretaceous formation of Alabama, 

 together with fragments of two small teeth, from unknown localities of Alabama and Georgia, repre- 

 sented in PI. I, Figs. 3, 4, 5, are referred by Dr. Gibbes to a species with the name of llosasaurus 

 minor. 



Two specimens, the summits of large teeth, represented in PI. II, Figs. 4, 5, from the Cretaceous 

 formation of the Chattahoochie R., Georgia, are referred to a species under the name of ilosasaurus 

 Couperi. 



An uncharacteristic fragment of a large jaw, represented in PI. II, Figs. 1, 2, 3, is referred to a 

 species with the name of Mosasaurus carolinensis. The specimen is stated to have been found in 

 association with Cetacean remains in the Pliocene deposit overlying the Cretaceous formation in the 

 vicinity of Darlington, S. C. As observed by the author, " it was most probably derived from Hhe 

 atter formation ;" and he adds, " its appearance and the mineralization of its structure render it 

 probable that it came originally from the Cretaceous." The same explanation, I am inclined to 

 believe, would apply to the vertebra which Dr. Gibbes mentions as having been found in the Eocene 

 deposit of Wilmington, N. C. 



The allied genera of the memoir are named Holcodus, Conosaurus, and Amphorosteus. The 

 tooth, represented in PI. Ill, Fig. 13, from the Cretaceous formation of New Jersey, referred to 

 Holcodus, belongs to the Crocodilian Hyposaurus. The tooth, represented in Figs. 6-9, from the 

 Cretaceous of Alabama, also referred to Holcodus, I suspect belongs to Mosasaurus. The teeth, 

 represented in PI. Ill, Figs. 1-5, from the Eocene deposit of the Ashley R., S. C, referred to Cono- 

 saurus, I have proved, through microscopic examination of the structure, to belong to a fish. The 

 vertebra, represented in PI. Ill, Figs. 10-16, from the Cretaceous deposit of Alabama, referred to 

 Amphorosteus, may probably prove to be different from those of Mo.sasaurus, but at present I consider 

 tlie matter doubtful. 



" Report of the North Carolina Geological Survey, by E. Emmons, p. 21 Y, Figs. 36a, 31. The 



