584 CENOZOIC ERA— AGE OF MAMMALS. 



North America from the Gulf to arctic regions. Of the two species of 

 elephant, however, the primigenius was mostly confined to the higher 

 latitudes, and the Americanus to the southern portions. The latter is 

 distinguished from the former by less crowded enamel plates in the 

 grinders and less curved tusks. According to Cope, about fifty species 

 of Proboscidians are known. Of these five are Dinotheres, twenty-five 

 Mastodons, six Elephants, and five of uncertain place. The Dino- 

 therium appeared first, then the Mastodon, and last the Elephant. 

 This is also the order of specialization of teeth-structure. The order 

 of appearance and of extinction of these three forms are shown in di- 

 agram (Fig. 953). 



r^G* ^m*^. 



MIOCENE PLIOCENE QUATERNARY* PRESENT 



Fig. 953.— Diagram showing Distribution in Time of Proboscidians. 



Among Edentates, a Megatherium, a Megalonyx, and several Mylo- 

 dons, have been found in North America ; but, as their principal home 

 was in South America, we will describe them under that head. 



River-Gravels. — In many portions of the United States, but espe- 

 cially in California, remains of mastodon and elephant, and bison, etc., 

 are found in great numbers in river-gravels. The river-gravels of Cali- 

 fornia are spoken of again further on. 



Quaternary in South America. — A large number (more than 100) of 

 species of mammals have been found in the soil of the pampas and in the 

 caves of Brazil. They are mastodons (different species from the North 

 American), llamas, horses, tapirs, rodents, many species of panther- like 

 carnivores, large saber- toothed tigers (Machairodus neogceus and neca- 

 tor), with curved, saber-like tusks twelve inches long and eight inches 

 beyond the gums (Fig. 954), and especially a large number of Edentates 

 allied to the sloths and armadillos, but of gigantic size. 



Of the Edentates, the most remarkable, in fact, one of the most 

 remarkable animals which have ever existed, is the Megatherium (great 

 beast) Cuvieri. The genus Megatherium ranged in Quaternary times 

 through South America, and into North America, as far as the shores 

 of Georgia and South Carolina. At the mouth of the Savannah Eiver 

 the remains of several individuals of a species of this genus (M. mira- 

 bilis) have been found. But the largest species and the most perfect 

 specimens have been found in South America. 



The Magatherium Cuvieri, of which we give a figure (Fig. 955), was 

 larger than a rhinoceros, but was still more remarkable for the clumsy 

 massiveness of its skeleton than for its size. This is especially true of 

 its hind-legs, hip-bones, and tail. For this reason, it is supposed to 



