MEMOIR 



MOSASAURUS 



THREE ALLIED NE¥ GENERA. 



The great fossil of Maestricht has been a subject of much interest as well as 

 difference of opinion among naturalists ; but, after long discussion, the researches 

 of the younger Camper determined its saurian character, and it was by Cuvier 

 referred to a distinct genus, called by Conybeare Mosasaurus : The Saurian of the 

 Meuse. Since its discovery, occasional announcements have appeared of other 

 remains having been found in various localities, chiefly in the United States ; — in 

 fact, with the exception of two vertebrae reported by Dr. Mantell as found near 

 Lewes,* and of portions of a large jaw from the Norfolk Chalk,-)- they are entirely 

 confined to our country. 



The first notice of such relics in our palaeontology is by Dr. Samuel L. Mitchell, J 

 who mentions, as found in the Cretaceous strata of Monmouth, New Jersey, and 

 has figured, " a tooth and part of the jaw of a lizard monster or saurian 

 animal, resembling the famous reptile of Maestricht." 



In the fourth volume of the Journal of the Academy of Natural Sciences, Dr. 

 Harlan described a tooth as resembling, " in every respect," those of the " Maes- 

 tricht Monitor." This was found in the Marl of New Jersey, near Woodbury. 



Dr. J. E. Dekay read before the Lyceum of Natural History of New York, in 

 1830, an account of the remains " of Extinct Reptiles of the Genera Mosasaurus 

 and Geosaurus found in the Secondary of New Jersey." § He described the tooth 

 alluded to by Mitchell, and referred it unequivocally to Mosasaurus.\\ He also 

 reported the fact of the existence, in the New Jersey Marl, of the subgenus Geo- 

 saurus, Cuv., from a specimen in the cabinet of the Lyceum, and called it Geo- 

 saurus Mitchelli. 



* Geology of Southeast of England. + Wonders of Geology. 



I Observations on the Geology of North America. § Annals of the Lyceum, Vol. IIL 



II Mosasaurus Dekayi, Bronn, Lethsea Geogn., 1837. 



