1 



THE EOCENE PERIOD 783 



the fact that the nummulitic limestone occurs at elevations of more 

 than 10,000 feet in the Alps, up to 16,000 feet in the Himalayas, 

 and 20,000 feet in Tibet. The principal elevation of the Pyrenees, 

 Carpathian, Caucasus, Thian Shan, and other high mountains of 

 Eurasia, is post-Eocene. In the Old World, therefore, as well as 

 in the New, the greater relief features of the present were unde- 

 veloped in the Eocene period. 



Other continents. In Africa, marine Eocene is known along the 

 northern and western coasts, and in the Soudan. It is known also 

 in South Australia, New Zealand, and Tasmania, though not gen- 

 erally sharply differentiated from the later Tertiary. At the head 

 of the great Australian Bight, there is a thick bed of Eocene chalk. 

 Eocene beds are also known in various islands of the Pacific. 



The Tertiary formations of South America have not been closely 

 correlated with those of other regions. There is marine Eocene 

 along some parts of the western coast, in Patagonia * (Magellanian 

 series) , where the beds are usually unconf ormable on the Cretaceous, 

 probably in Argentina, and along at least a part of the coast of 

 Brazil. 2 Eocene beds of non-marine origin also occur in Patagonia. 3 



Eocene beds, not always distinctly separable from the Oligo- 

 cene, are extensively developed in the West Indies, where limestone 

 is the dominant type of rock. In the Caribbean region they occur 

 up to elevations of 5,000 feet on the mainland, and 10,500 feet in 

 Hayti. 4 It was formerly thought that the Atlantic and Pacific 

 oceans connected freely across Panama during the early Tertiary, 

 but the work of Hill renders it doubtful whether there were more 

 than shallow and restricted connections in the Eocene, and whether 

 there was connection of any sort later. 



General geography of the Eocene. Eocene geography was very 

 different from that of the present time, and the differences were 



1 Hatcher, Am. Jour. Sci., Vol. IX, 1900, pp. 97-99; also Vol. IV, 1897, 

 pp. 334-337. 



2 Branner, Bull. Geol. Soc. Am., Vol. XIII, Stone Reefs of Brazil. Mus. 

 of Comp. Zool., Bull. 44, pp. 27-53. 



3 Ameghino, L'age des Formations Sedimentaries de Patagonia, Anales 

 de la Sociedad Crentipica Argentina, 1903. 



4 Hill, Geological History of the Isthmus of Panama and Portions of 

 Costa Rica. Bull. Mus. of Comp. Zool., Cambridge, 1898. 



