FOSSIL MAMMALIA. 31 



by Mr. Mantell, of Lewes, which seems to have been herbivio- 

 rous, and to have inhabited the fresh water. This is the igua- 

 noddn, and it is supposed to have been sixty feet long. 



In the chalk, according to Cuvier, there are only reptiles, the 

 remains of crocodiles and tortoises. In the tufa of Mount St. 

 Pierre, near Maestricht, which is of the chalk formation, has 

 been found, amidst marine tortoises, shells and zoophytes, 

 another gigantic member of the saurian family, a distinct 

 genus, for which Mr. Conybeare has proposed the name of 

 mosasaurus. 



In the argilla and lignites, covering the superior portion 

 of the chalk, the Baron declares that he has discovered nothing 

 but crocodiles ; and thinks that the lignites of Switzerland, in 

 which are bones of the beaver and mastodon, must be assigned 

 to a more recent era. He adds, that it was only in what the 

 French call the calcaire grassier, surmounting the argilla, 

 that he commenced to discover mammiferous remains, and that 

 they belonged to marine mammalia. But Dr. Buckland men- 

 tions the occurrence of these in the stratum of Cuckfield, in 

 Sussex, much anterior to the formation of which we now 

 speak ; and they are also declared to have been found in the 

 calcareous slate of Stonesfield, and in the corn-brash limestone 

 in Oxfordshire. 



These marine mammalia are dolphins, lamantins, and morses, 

 apparently of an unknown species. The lamantin is at pre- 

 sent confined to the torrid zone, and the morse to the Icy Sea ; 

 still those two genera are found together in the coarse limestone, 

 in the midst of France. This union of species, whose consimi- 

 lars are now allocated in opposite zones, is by no means un- 

 common. 



In the strata succeeding this coarse limestone, or in the an- 

 cient contemporaneous fresh- water depositions, the class of ter- 

 restrial mammifera first begins to appear in tolerable abundance. 

 Belonging to the same age are the animal remains buried in 

 the molasse and ancient gravel-beds in the south of France ; 



