On the Remains of Extinct Reptiles of the genera Mosasaurus 

 and Geosaurus found in the secondary formation of New- 

 Jersey ; and on the occurrence of the substance recently named 

 Coprolite by Dr. BucJdand, in the same locality. By 

 J. E. De Kay. 



Read January 11 and 25, 1830, 



T H E investigation of the structure of those animals whose 

 existence dates beyond history or tradition, is among the most 

 interesting inquiries of the naturahst. From an isolated frag- 

 ment of bone, found buried deep in the earth, to be enabled 

 to verify to what animal it belonged, to trace its relations 

 with other animals who have likewise perished, and to deter- 

 mine with tolerable precision the nature of the catastrophe 

 which had thus concealed it from view, all these have 

 exercised the learning and labor and ingenuity of modern na- 

 turalists. The connexion between zoology and the history 

 of our globe thus becomes evident, and those who undervalue 

 the one must have but limited views of the importance of the 

 other. The illustrious Cuvier, alluding to one of the animals 

 upon which we are about to treat, says, " la determination pre- 

 cise du fameux animal de Maestricht, nous paroit surtout aussi 

 remarquable pour la theorie des lois zoologiques que pour 

 I'histoire du globe." 



It is proposed in the present paper to examine the remains 

 of several animals from New- Jersey, which are now in the 

 Cabinet of the Lyceum, and to determine to what genera they 

 belong, leaving to other and abler hands those geological de- 

 ductions which naturally arise from the subject. 



