Highland o«r 1.000 Feet. 

 Upland un(Jerl,000 Feet. 

 Lowland under GDO Feet. 



Fig. 1. — Map of North America. (Keprodnced from Meiklejohn's Oroscopic 

 Map, by permission of Messrs. Meiklejohn & Son.) 



[Til face J}. 1. 



