564 EOCENE AND OLIGOCENE PERIODS 



series) and probably elsewhere in Argentina, and along at least a 

 part of the coast of Brazil. 1 Non-marine beds occur in Patagonia. 

 Eocene beds are extensive in the West Indies where limestone 

 is the dominant rock. Formations of this age are said to occur up 

 to elevations of 10,500 feet in Hayti. 2 It was formerly thought 

 that the Atlantic and Pacific oceans connected freely somewhere 

 south of the United States 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 con- 

 nection of any sort later. 



General Geography of the Eocene 



The geography of the Eocene was very different from that of the 

 present time, and the differences were perhaps even greater than has 

 been indicated. It has been conjectured that North America was 

 connected with Asia on the west, by way of Alaska, and with Europe 

 on the east, by way of Greenland and Iceland. Land seems to have 

 failed of making a circuit in the high latitudes of the north only by 

 the strait or sound east of the Urals. In the southern hemisphere, 

 it has been surmised that Antarctica was greatly extended, con- 

 necting with South America, Australia, and possibly with Africa, 

 and that Africa and South America were connected across the 

 Pacific from some earlier time until after the beginning of the 

 Eocene. The basis for these conjectures is found in the distribution 

 of life at that time, as shown by fossils. 



If these conjectured extensions of land were real, it will be seen 

 that the division of land and water in the northern and southern 

 hemispheres was far less unequal than now, that the land was massed 

 in high latitudes to a great extent, and that tropical seas were more 

 extensive. If extensive polar lands were the cause of glacial periods, 

 as some have thought, the geographic conditions of the Eocene were 

 favorable in the extreme for glaciation, if the relations sketched 

 above were the real ones. In spite of this, the climate of the period 

 seems to have been genial, and less markedly zonal than now. 



Close of the Eocene. During the later part of this period, and 



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

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



2 Hill, Geological History of the Isthmus of Panama and Portions of Costa 

 Rica. Bull. Mus. of Comp. Zool., Cambridge, 1898. Also J. P. Smith, Science, 

 Vol. 30, 1909, p. 348. 



