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11 



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11 



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I I 



21P 



THE GEOLOGICAL HISTORY OF PLANTS. 



t^ tiary, as a whole, was of a generalised character ; 



i now confined to the southern and northern hemi- 



xcres respectively being then common to both. It 

 would thus seem that the present geographical diversities 

 must have largely arisen from the great changes in cli- 

 mate and distribution of land and water in the later 

 Tertiary. 



The length of our discussion of the early angiosperm- 

 ous flora does not permit us to trace it in detail through 

 the Miocene and Pliocene, but we may notice the con- 

 nection through these in the next chapter, and may refer 

 to the magnificent publications of Heer and Lesquereux 

 on the Tertiary floras of Europe and America respect- 

 ively. 



