100 SKETCH OF THE HISTORY OF MAMMALIA. 



they lived and died ; their dead carcases drifted to the 

 bottom of the lake, swept off from the shore in seasons 

 of flood, when the swollen rivers cleared the adjacent 

 lowlands of hosts of dead, and perhaps also of the living, 

 hurrying them to destruction, and depositing their relics, 

 to he in other ages brought to light, the "reliquia vetus- 

 tioris sevi." 



The Lophiodon. 



Another fossil genus allied to the tapirs is termed by 

 Cuvier Lophiodon : not less than fifteen species are de- 

 termined ; and they are found in the same fresh-water 

 formation as the Palaeotheria. The dentition of the 

 Lophiodon differs from that of the last-named animals, 

 the lower jaw having only six molars. The teeth in 

 character approach those of the rhinoceros. Fig. 57 

 represents a lower back molar of the gigantic Lophiodon 

 of Argenton ; Fig. 58, an upper back molar ; Fig. 59, 

 a canine tooth ; Fig. 60, two incisor teeth : all of the same 

 species. With many essential parts of the osteology of 

 these extinct animals naturalists are as yet unacquainted ; 

 the bones of the nose, for example, and those of the feet, 

 are not recovered. The remains of the Lophiodons 

 found at Issel, Argenton, Bucksweiler, Montpellier, 

 Montabusard, &c., occur in beds of fresh-water forma- 

 tion, but below those superficial strata containing the 

 bones of the mammoth and mastodon. They are as- 

 sociated with the relics of forms of terrestrial animals of 

 which we have no living prototypes, and with those of 

 crocodiles and fresh-water tortoises. The antiquity of 

 these beds may be inferred from the fact that in most 

 places they are covered by strata of decidedly marine 

 formation, so that the Lophiodon existed and passed 

 away not only before the races had commenced whose 

 remains are found (and found only) in the alluvial strata 

 of the earth, but before the extinction of ptill older races ; 

 they belong in fact to strata of our continent over which,, 

 after becoming consolidated, the sea has rolled, and re- 

 mained long enough to cover them with rocks of a new 

 origin. 



