v] ANCIENT GEOGRAPHY 83 



only Australia, New Zealand and Madagascar are 

 isolated entities of importance. All the rest of the 

 world is at some time or other in roundabout, or 

 direct, continuity, chiefly owing to the juncture of 

 Africa by Arabia with India and the long-since con- 

 solidated Asia ; the two Americas are joined, for 

 a time also the Antilles. Since the Pliocene they 

 remained islands. North America finally separates by 

 the North Atlantic from Europe, but is variously 

 connected with Siberia across Behring's Straits. 



The most changeable of all regions was Europe, 

 not because it is geologically the best known, but it 

 is the newest continent. During Cretaceous and far 

 into Tertiary times Northern and Western Europe 

 formed an extension of the Canada-Greenland mass, 

 quite separate from Asia ; Central and South Europe 

 consisted mainly of a variable number of much- 



*/ 



changing island complexes. With the Miocene sepa- 

 ration from Greenland took place and joining of the 

 growing Europe to Siberia and South- West Asia, 

 and the central and southern islands became ab- 

 sorbed into the continent in the Pliocene. During 

 Pleistocene times Europe seems to have attained its 

 greatest dimensions, and with the receding ice the 

 Rhine and Elbe flowed across the present North Sea. 



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