Y'r 





AUTIIOK'S KDITIOX. 



DEPARTMENT OF THE [NTERIOR. 

 TOOTED 8TATES GEOLOGICAL AND GEOGRAPHICAL BUBVEY. 



F. V. HAYDEN, U. S. Geologist-in-Charge. 



tin: vkcktation 



OP mi: 



ROCKY MOUNTAIN REGION, 



A N I > 



A COMPARISON WITH THAT OF OTHER PARTS 

 OF THE WOULD. 



]5Y 



ASA GRAY and SIR J. D. HOOKER, F, R. S. 



THE BULLETIN OF THE BUJtVJCY, VOL VI. No. I. 



Washington, February 11, 1881. 



