Ch. XVIII.] PARIS BASIN GYPSUM. 253 



of them belonging to a division of the order Pachydermata, 

 which is now only represented by four living species, namely 

 by three tapirs and the daman of the Cape. A few carni- 

 vorous animals are associated, among which are a species of 

 fox and gennet. Of the Rodentia, a dormouse and a squirrel ; 

 of the Insectivora, a bat ; and of the Marsupialia, (an order 

 now confined to America, Australia, and some contiguous 

 islands,) an opossum, have been discovered. 



Of birds about ten species have been ascertained, the ske- 

 letons of some of which are entire. None of them are referrible 

 to existing species *. The same remark applies to the fish, 

 according to MM. Cuvier and Agassiz, as also to the reptiles. 

 Among the last are crocodiles and tortoises of the genera 

 Emys and Trionix. 



The tribe of land quadrupeds most abundant in this forma- 

 tion is such as now inhabits alluvial plains and marshes and 

 the banks of rivers and lakes, a class most exposed to suffer by 

 river inundations. Whether the disproportion of carnivorous 

 animals can be ascribed to this cause, or whether they were 

 comparatively small in number and dimensions, as in the indi- 

 genous fauna of Australia, when first known to Europeans, is 

 a point on which it would be rash perhaps to offer an opinion 

 in the present state of our knowledge. 



We have no reason to be surprised that all the species of ver- 

 tebrated animals hitherto observed are extinct, when we recollect 

 that out of 1122 species of fossil testacea obtained from the Paris 

 basin, 38 only can be identified with species now living. We 

 have more than once adverted to the fact that extinct mam- 

 malia are often found associated with assemblages of recent 

 shells, a fact from which we have inferred the inferior duration 

 of species in mammalia as compared to the testacea ; and it is 

 not improbable that the higher order of animals in general may 

 more readily become extinct than the marine molluscs. Some 

 of the thirty-eight species of testacea above alluded to, as having 

 survived from the Eocene period to our own times, have now a 

 * Cuvier, Oss. Foss. torn. iii. p. 255. 



