248 



THE AGE OF MAMMALS 



in western Europe we know only the mammals adapted to moister and 

 better forested conditions. 



In the Upper Miocene of Europe this contrast no longer obtains, for 

 there is suddenly revealed a great fauna of dry plains and uplands; this 

 fauna is similar to that of the drier parts of Africa and Asia of the 

 present day, and to that of North America in Upper Miocene times. 



Comparison between the Old and New Worlds in the Lower and Middle 

 Miocene, or before this great upland element in Europe appears, is as 

 follows : 



Mammals of the Lower and Middle Miocene 



Peculiar to Europe 



Dinotheres 



Anthracotheres 



Tragulids 



(water chevrotains) 

 Horned cervuline deer 

 True horned antelopes 

 Cricetines, or hamsters 

 Picas, or tailless hares 

 Leptictids or erinaceids 

 Dicerorhine rhinoceroses 

 Bears 

 Viverrids 

 True suillines 

 Siren ians 

 — {Haliiherium, 



Metaxytherium) 



Peculiar to North America 



Camelids 



Protohippine horses 

 Antilocaprids, primitive 

 Oreodonts 



Dicotylids, peccaries 

 Haplodontids, sewellels 

 Geomyids, gophers 

 Heteromyids 

 Leporids, hares 

 ?Cricetines 

 Mylagaulids 

 Procyonids 



Common to Europe and 



North America 

 Mastodons 



(trilophodont) 

 Anchitheres 

 Tapirs 

 Rhinoceroses 



(aceratherine and tele- 



ocerine) 

 Chalicotheres 

 Primitive hornless deer 

 Mustelids 

 True felids 

 Machserodonts 

 Typical canids 

 Canids 



(short faced) 

 Amphicyonids 

 Castorids, beavers 

 Talpids, moles 

 Murids, mice 



A very marked difference is seen in the prevalence of Amphicyon and 

 the early appearance of the bears in Europe, and rarity of true canids of 

 the wolf and fox type; while in America the canids abound and are widely 

 varied, the bears are altogether absent and the amphicyons appear gradually. 



America still has many of its own rodents, such as the sewellels (hap- 

 lodontids), gophers (geomyids), and especially hares (leporids). The 

 greatest diversity between Europe and America, however, is among the 

 Artiodactyla; America is seen to be developing its own pigs or dicotylids, 

 its highly diversified oreodonts and camels, its peculiar hypertragulids, in- 

 cluding the ancestors of the American deer, and its o^vn antelopes (antilo- 

 caprids), which are widely different from the true or bovine antelopes of 

 Europe. The evolution of a distinctive plains fauna of North America is 

 witnessed especially in the long-limbed and long-toothed varieties of the 



