uns BOTANICAL GAZETTE [OCTOBER 
the transformation that has been made from the monotonous 
plateau of early Cretaceous times, covered with a rather tame 
flora, to the richly diversified configuration of the mountains 
and plains of today, clothed with the most magnificent forests 
(excepting those of the Pacific slope) to be found anywhere in 
the western hemisphere. The ecologic disposition of the vege- 
tation with reference to the topography next concerns us. 
[ Zo be concluded.| 
