was necessarily from northern latitudes to southern, and from higher altitudes to lower, 

 we see that the distribution of these plants points to two directions of migration. The 

 one migration is from the north southward, a continuation of the great southward 

 movement, of which the Reuverian formed a part; but not like that characterized by 

 the presentsday isolation of its several branches. In this later movement, the flora, being 

 of a more cooktemperate type, was able in a much greater degree to survive throughout 

 the temperate regions of Europe and Asia. The second stream of migration appears 

 almost certainly to have originated in the mountainous parts of Europe and Asia, and 

 to have radiated outwards. It is noticeable that this second line of migration is much 

 more pronounced in the Cromerian than in the Teglian. 



In conclusion, we would add one note of caution. It must not be assumed that 

 because in Pliocene times — and for that matter even at the present day — we see clear 

 evidence of a connexion between the floras of Western Europe, China, and North 

 America, that therefore there was necessarily land connexion between these countries 

 in comparatively recent times. Far from itl The time needed for a large flora, such as the 

 temperate Chinese and North American, and probably also the Reuverian, to spread 

 from its original home in the remote North to the southern latitudes where it lives now, 

 or did live in the past, must have been great. And it is probable, that long before the 

 last stream of migrants had reached our latitudes, the connexion had been broken 

 behind, by cold, desert, or by sea. The date when the Reuverian flora flourished as a 

 polar flora, or one inhabiting the high plateau, the "roof of the world", of Tibet, may 

 well have been far back in Tertiary times. 



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