EXCURSIONS OF AN EVOLUTIONIST 



of Chalk." l The greater part of Europe might 

 then have been called a " Mediterranean Sea," 

 extending from England far into central Asia. 



The western highlands of Scotland remained 

 above water, but Bohemia, Switzerland, Spain, 

 and the Caucasus seem to have been submerged, 

 or reduced to islands. Still further submer- 

 gence occurred during the Eocene period, and 

 this in turn was followed by a long series of 

 elevations, resulting in something like the con- 

 figuration of Europe as we know it. Late in 

 the Eocene period the Pyrenees, Apennines, 

 Alps, Carpathians, and Caucasus had risen to 

 their present or even to higher altitudes. While 

 an inland sea flowed over the Netherlands and 

 Normandy, the rest of Gaul was dry land, and 

 at its northwestern extremity was joined to 

 Britain. The British Islands, in turn, were 

 joined to each other and to Scandinavia and 

 Spitzbergen, as also to Iceland and Greenland. 

 If Columbus had lived in those days, he could 

 thus have walked on solid land all the way 

 from Spain to the New World. 



Two immediate consequences of this great 

 upraising of land made the Eocene period an 

 era of singular interest in the history of the 

 European continent. The first was the inva- 

 sion of Europe by placental mammals, which 

 speedily supplanted the lower forms that had 



1 Huxley, Lay Sermons, pp. 192-222. 



16 



