72 THE AGE OF MAMMALS 



or Leptodon, a very large member of the Hyracoidea, probably aquatic in its habits, 

 indicating that this order enjoyed an extensive adaptive radiation in Tertiary 

 times." 



"It thus appears that the Proboscidia, Hj'raeoidea, certain Edentata, the 

 antelopes, the giraffes, the hippopotami, the most specialized ruminants, and 

 among the rodents, the anomalures, dormice, and jerboas, among monkeys the 

 baboons, may all have enjoyed their original adaptive radiation in Africa; that 

 they survived after the glaciial period, only in the Oriental or Indo-Malayan region, 

 and that this accounts for the marked community of fauna between this region 

 and the Ethiopian as observed by Blanford and Allen." 



Osborn contended that against the prevalent theory of Asiatic origin of 

 these mammals were two important facts: first, that the known Oligocene 

 and Lower Miocene mammals of the Bugti beds of Sind are markedly Euro- 

 pean in type, and contain no African elements; second, that if these animals 

 had originated in Asia some of them would have found their way into North 

 America as early as or earlier than into Europe ; third, there is the important 

 fact that all these animals appear suddenly in Europe without any known 

 ancestors in the older geologic formations. 



This hypothesis of Osborn up to the present time, however, appears to 

 be confirmed only so far as the Proboscidea and Hyracoidea are concerned. 



Autochthonous orders of Africa. — ■ These hypotheses of Tullberg, Stehlin, 

 and Osborn, that Africa has been an important center of adaptive radiation, 

 enjoyed a partial but most welcome verification in 1901 when Mr. Hugh J. L. 

 Beadnell of the Geological Survey of Egypt and Dr. C. W. Andrews of the 

 British Museum of London announced the discovery of numerous fossil land 

 mammals in Upper Eocene and Lower Oligocene strata exposed in the Fayum 

 about eighty miles southwest of Cairo. Between 1901 and 1905 the explora- 

 tion and collection of these beds were actively continued.' One unexpected dis- 

 covery succeeded another: Africa, far from being a continent parasitic upon 

 Europe and Asia, was proved through these discoveries to be a partly depend- 

 ent but chiefly independent center of a highly varied life, a great breeding 

 place not only of animals which subsequently wandered into Europe, but of 



' Andrews, A Descriptive Catalogue of the Tertiary Vertebrata of the Fajalm, Egj^pt. 



London, 1900. 

 Osborn, H. F., Milk Dentition of the Hyracoid Snghntherium from the Upper Eocene of 



Egypt. Bull. Amer. Mus. Nat. Hist., Vol. XXIL Art. xiii, July 25, 1906, pp. 263-266. 

 Osborn, H. F., The American Museum Expedition to the Fayum Desert. The Nation, Vol. 84, 



no. 2177, Mar. 21, 1907, pp. 271-272. 

 Osborn, H. F., The Fayiim Expedition of the American Museum. Science, n.s. Vol. XXV, 



no. 639, Mar. 29, 1907, pp. 513-516. 

 Osborn, H. F., Hunting the Ancestral Elephant in the FayClm Desert. Discoveries of the Re- 

 cent African Expedition of the American Museum of Natural History. The Century 



Magazine, Vol. LXXIV, Oct., 1907, no. 6, pp. 815-835. 

 Osborn, H. F., New Fossil Mammals from the Fayiim Oligocene, Egj'pt. Bull. Amer. Mus. 



Nat. Hist., Vol. XXIV, Art. xvi. Mar. 25, 1908, pp. 265-272. 

 Osborn, H. F., New Carnivorous Mammals from the Fayum Oligocene, Egypt. Bull. Amer. 



Mus. Nat. Hist., Vol. XXVI, Art. xxviii, Sept., 1909, pp. 415-424. 



