BULLETIN 



OF THE 



UNITED STATES GEOLOGICAL AND GEOGRAPHICAL SURVEY 

 OF THE TERRITORIES. 



VoLUiiE VI. 1880. Number 1. 



Art. I.— The Vegetation ol* the Roeky JHoimtaiii Re- 

 gion and a Comparison ivith that oi* other Parts 

 of the World. 



By Asa Oray and Josepli D. Hooker. 



THE VEGETATION OP THE ROCKY MOUNTAIN REGION. 



The vegetation of the wide central tract which lies between the At- 

 lantic United States and those which border on the Pacific is replete 

 with interest and imj)ortancej both scientific and economical. We are 

 to sketch its general features, as made known to us by personal obser- 

 vation, by the published observations of others, and by the botanical 

 studies to which we have been devoted. For doing this to much i)ur- 

 X)ose, it is necessary to compare or to contrast the vegetation of the dis- 

 trict in question with that of the more fertile regions on both sides, and 

 with a somewhat similar wide interior district in another part of the 

 northern temperate zone. 



By "the Atlantic States," as contradistinguished from those of the 

 Pacific, we here mean not only those which touch upon the Atlantic 

 Ocean, but also those which border the Mississippi Elver, on its western 

 as well as its eastern side ; the great woodless plains being taken as 

 their western limit. The term "Eocky Mountain Eegion," here used in 

 its widest sense, and in the lack of a better appellation, we propose to 

 apply in general in such wise as to include the gradually elevated pla- 

 teau which flanks the eastern base of the Eocky Mountains on the one 

 hand, and the equally elevated district or plateau, thickly traversed by 

 mountain ranges, which extends westward to the eastern base of the 

 Sierra ISTevada of California, and the Cascade Mountains further north. 

 As to the Eocky Mountains themselves, it is most convenient and nat- 

 ural, from our i)oint of view, to comxDrise under this general designation 

 all the ranges as far west as the Wahsatch inclusive. 



We understand the term Cor diU eras, brought into use by Professor 



1 GB 



