300 



MAMMALIA OF PAKIS GYPSUM. 



[Ch. XVL 



Cheiroptera, a bat ; while the Marsupialia (an order now confined to 

 America, Australia, and some contiguous islands) are represented by 

 an opposum. 



Of birds, about ten species have been ascertained, the skeletons of 

 some of which are entire. None of them are referable 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 croc- 

 odiles and tortoises of the genera Emys and Trionyx. 



The tribe of land quadrupeds most abundant in this formation is 

 such as now inhabits alluvial plains and marshes, and the banks of 

 rivers and lakes, a class most exposed to suffer by ri^er inundations. 

 Among these were several species of Paleotherium, a genus before 

 alluded to (p. 283). These were associated with the Anoplotherium, 

 a tribe intermediate between pachyderms and ruminants. One of 

 the three divisions of this family was called by Cuvier Xiphodon. 

 Their forms were slender and elegant, and one, named Xiphodon 

 gracile (fig. 264), was about the size of the chamois ; and Cuvier in- 



Fig. 264. 



Xiphodon gracile, or Anoplotherium gracile, Cuvier. Eestored outline. 



ferred from the skeleton that it was as light, graceful, and agile as the 

 gazelle. 



When the French osteologist declared, in the early part of the 

 present century, that all the fossil quadrupeds of the gypsum of Paris 

 were extinct, the announcement of so startling a fact, on such high 

 authority, created a powerful sensation, and from that time a new im- 

 pulse was given throughout Europe to the progress of geological in- 

 vestigation. Eminent nuturalists, it is true, had long before main- 

 tained that the shells and zoophytes met with in many ancient Euro- 

 pean rocks had ceased to be inhabitants of the earth, but the majority 

 even of the educated classes continued to believe that the species of 

 animals and plants, now contemporary with man, were the same as 

 those which been called into being when the planet itself was created 



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



