EXCURSIONS OF AN EVOLUTIONIST 



of the Black and Caspian seas ; and another 

 wide channel seems to have run west of the 

 Ural Mountains, connecting the Caspian area 

 with the Arctic Ocean, so that the warm waters 

 of the Indian Ocean found a free passage to the 

 very shores of Finland and Scandinavia. Ac- 

 cording to Professor Archibald Geikie, these 

 shallow seas disappeared early in Pliocene times, 

 leaving the Aral, Caspian, and Black seas in 

 something like their present isolation. While 

 eastern Europe thus began to acquire its present 

 contour, equally remarkable changes occurred 

 at the same time in the west;. The Atlantic 

 ridge between Britain and Greenland was sub- 

 merged, thus separating Europe from America, 

 and the connections of Norway with Spitzbergen 

 on the one hand and Scotland on the other were 

 also severed by the encroachments of the North 

 Sea. But the British Islands were still joined to 

 each other and to the Gaulish mainland ; the 

 whole of Britain jutting out from the continent 

 as a great triangular peninsula, with the Shet- 

 lands in the apex. The volcanoes of northwest 

 Britain gradually lost their fires during the 

 Pliocene age. Icebergs appeared in the North 

 Sea, and the general climate of Europe, though 

 still milder than to-day, was much colder than 

 it had been during the Eocene and Miocene 

 epochs. The vegetation began to lose its sub- 

 tropical aspect. Bamboos, evergreen oaks, and 

 26 



