FOREST GEOGRAPHY AND ARCHAEOLOGY. 233 



the period of refrigeration, deeply covered a very large part 

 of the forest-area ; much to the narrowness of the forest-belt, 

 to the want of summer rain, and to the most unequal and 

 precarious distribution of that of winter. 



Upon all these topics questions present themselves which 

 we are not prepai-ed to discuss. I have done all that I could 

 hope to do in one lecture if I have distinctly shown that the 

 races of trees, like the races of men, have come down to us 

 through a prehistoric (or pre-natural historic) period ; and 

 that the explanation of the present condition is to be sought 

 in the past, and traced in vestiges and remains and survi- 

 vals ; that for the vegetable kingdom also there is a veritable 

 Archaeology. 



