IV TEMPERATE FOREST REGIONS 95 



later Tertiary deposits of Switzerland alone have yielded, 

 according to Professor Heer, 291 species of trees and 242 

 shrubs, or far more than the present rich flora of Eastern 

 Asia added to the poorer one of Europe. It is true that 

 this number includes the species of several distinct 

 deposits of somewhat different ages. But in the beds of 

 one single locality and period, at CEninghen, the remains 

 of nearly two hundred species of trees have been found ; 

 and it is in the highest degi^ee improbable that all which 

 lived there have been preserved, while it is certain that the 

 flora of (Eninghen was not so rich as that of Switzerland, 

 and was, a fortiori, very much poorer than that of Europe. 

 Making, therefore, all necessary deductions for imperfect 

 determinations of species, it is impossible to doubt that 

 the kinds of trees inhabiting Europe in late Tertiary times 

 were far more numerous and varied than they are now 

 even in Eastern Asia, which, as we have seen, is the richest 

 part of the north temperate zone. Since the period of 

 these deposits the climate of all these regions has greatly 

 deteriorated, culminating in a Glacial epoch which has 

 only recently passed away ; and to this is naturally 

 imputed the wonderful change from riches to poverty 

 which has come over the woody plants of Europe. But 

 we have still to ask, Why did not Eastern America and 

 Eastern Asia become equally poor ? And Professor Asa 

 Gray has now answered that question for us in a very 

 satisfactory manner. 



We must first call attention to the fact that when 

 Europe enjoyed a milder climate, with a rich and varied 

 flora, there was also an abundant vegetation, very similar 

 in character to that which now clothes our north 

 temperate latitudes, extending northward to the Arctic 

 circle and far beyond it. In Arctic America, in Green- 

 land, and even in Spitzbergen, there have been found 

 w^ell-preserved remains of maples, poplars, birches, and 

 limes, like those of Europe ; of magnolias, hickories, 

 sassafras, and Wellingtonias, like those of America; as 

 well as of gingko-trees and several other kinds now peculiar 

 to Japan. The period when these Arctic woods flourished 



