CH. V] FOSSIL FLORA OF GREENLAND. 231 



likeness, though there are also differences. Moving 

 further south the differences increase until the resem- 

 blances almost entirely vanish. 



It is unnecessary to recapitulate the characters of 

 the faunas of the several regions here, as the matter has 

 been already treated of. Broadly speaking it is unques- 

 tionably the fact that the differentiation of the different 

 regions gradually increases as we pass southwards from 

 the north pole. We cannot of course hope to reduce to 

 an exact table the progressive differentiation of the fauna 

 along the lines of migration; some have moved more 

 rapidly, others have lagged behind ; while structural 

 changes have proceeded more rapidly in some groups 

 of animals than in others. But a survey of the facts 

 tends to prove the general accuracy of the conclusion that 

 the differentiation of faunas proceeds more rapidly the 

 further we get from the pole. 



It is obvious that if life originated at the north pole 

 the conditions of climate must have been more favourable 

 than at present. That this was so there is abundant 

 evidence to prove. The existence of a luxurious and at 

 least subtropical fauna in the arctic regions during the 

 Miocene period is justly termed by Mr Wallace "one of 

 the most startling and important of the scientific discoveries 

 of the last 20 years." In remote Greenland we find 

 abundant and well preserved remains of chestnut, walnut, 

 plum, vines and even magnolias. Further north still in 

 lat. 78° and 79° there was in Spitzbergen an almost equally 

 rich fauna, of which one member the swamp cypress 

 (Taxodium distichvm) is now a dweller in the southern 



