DEPARTMENT OF THE INTERIOR 



UNITED STATES GEOLOGICAL SURVEY 



GEOKGE OTIS SMITH, Director 



Bulletin 361 



CENOZOIC MAMMAL HORIZONS OF 

 WESTERN NORTH AMERICA 



BY 



HENRY FAIRFIELD OSBORN 



WITH 



FAUNAL LISTS OF THE TERTIARY MAMMALIA 

 OF THE WEST 



BY 



WILLIAM DILLER MATTHEW 



WASHINGTON 



GOVERNMENT PRINTING OFFICE 



1909 



