154 DISCUSSIONS IN CLIMATOLOGY. 



supposition that at that time there were probably 

 several channels extending from equatorial to Arctic 

 regions through the eastern and western continents, 

 allowing of a continuous flow of intertropical water 

 into the Arctic Ocean. Mr. Wallace expresses his 

 views on the point thus: — 



" The distribution of the Eocene and Miocene forma- 

 tions shows that during a considerable portion of the 

 Tertiary period an inland sea, more or less occupied 

 by an archipelago of islands, extended across Central 

 Europe, between the Baltic and the Black and Caspian 

 Seas, and thence by narrower channels south-eastward 

 to the valley of the Euphrates and the Persian Gulf, 

 thus opening a communication between the North 

 Atlantic and the Indian Ocean. From the Caspian, 

 also, a wide arm of the sea extended during some part 

 of the Tertiary epoch northwards to the Arctic Ocean; 

 and there is nothing to show that this sea may not 

 have been in existence during the whole Tertiary 

 period. Another channel probably existed over Egypt 

 into the eastern basin of the Mediterranean and the 

 Black Sea; while it is probable that there was a 

 communication between the Baltic and the White Sea, 

 leaving Scandinavia as an extensive island. Turning 

 to India, we find that an arm of the sea of great width 

 and depth extended from the Bay of Bengal to the 

 mouths of the Indus ; while the enormous depression 

 indicated by the presence of marine fossils of Eocene 

 age, at a height of 16,500 feet in Western Thibet, 

 renders it not improbable that a more direct channel 

 across Afghanistan may have opened a communication 

 between the West-Asiatic and Polar seas." * 



My acquaintance with the Tertiary formations of 

 the globe, and with the distribution of land and water 



* "Island Life," p. 184. 



