39 MOSASAURUS. 
or described by Mitchell,’ De Kay,’ Harlan,* Morton,* Gibbes,’ and Emmons.’ The 
1 Observations on the Geology of North America, by Samuel L. Mitchell, published in the 
American edition of the Essay on the Theory of the Earth, by Cuvier, New York, 1818. Prof. 
Mitchell was the first to indicate the existence of remains of Mosasauwrus in the United States. In 
Plate VIII, Fig. 4, he represents the tooth of a Mosasaurus from the foot of Neversink Hills, New 
Jersey, and refers to it, p. 384, as resembling the teeth of the famous fossil reptile of Maestricht. 
2 Annals Lyceum Nat. Hist. New York, Vol. III, p. 135, Pl. I1I, 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 4 tooth, p. 188, Pl. III, Figs. 8, 4, which he refers to 
Geosaurus, but which I am inclined to suspect also belongs to the former genus. 
3 Journal Acad. Nat. Sciences, Philadelphia, Vol. IV, p. 235, Pl. XIV, 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 Mosasaurus. 
+ Synopsis of Organic Remains, p. 27, 28, Pl. XI, Figs. 7, 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. Puiladelphia, Vol. 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 Mosasaurus, the author refers them to a distinct species 
under the name of MZ. occidentalis. 
5 Memoir on Mosasaurus and the allied Genera. By Robert W. Gibbes, M. D. Smithsonian 
Contributions, Vol. II. The author indicates, describes, and figures a number of specimens, which 
he refers to several distinct species of Mosasaurus. 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., 8. C., and Wilmington, N. C., but neither describes nor figures 
them. I have as yet seen no trace of Mosasawrus 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 Pl. I, Figs. 3, 4, 5, are referred by Dr. Gibbes to a species with the name of Mosasaurus 
minor. 
Two specimens, the summits of large teeth, represented in Pl. II, Figs. 4, 5, from the Cretaceous 
formation of the Chattahoochie R., Georgia, are referred to a species under the name of Mosasaurus 
Coupert. 
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, 8S. C. As observed by the author, “it was most probably derived from the 
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 Hocene 
deposit of Wilmington, N. C. 
The allied genera of the memoir are named Holcodus, Conosaurus, and Amphorosteus. The 
tooth, represented in Pl. III, 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 Pl. III, Figs. 1-5, from the Hocene deposit of the Ashley R., 8. C., referred to Cono- 
saurus, I have proved, through microscopic examination of the structure, to belong to a fish. The 
vertebra, represented in Pl. III, Figs. 10-16, from the Cretaceous deposit of Alabama, referred to 
Amphorosteus, may probably prove to be different from those of Mosasaurus, but at present I consider 
the matter doubtful. 
6 Report of the North Carolina Geological Survey, by E. Emmons, p. 217, Figs. 36a, 37. The 
