AUTHOR'S EDITION. 



DEPARTMENT OF THE INTERIOR. 



UNITED STATES GEOLOGICAL AND GEOGRAPHICAL SURVEY. 



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



THE GEOGKAPHICAL DISTRIBUTION 



OF THE 



MAMMALIA, 



CONSIDERED IN RELATION TO THE PRINCIPAL 



ONTOLOGICAL REGIONS OF THE EARTH, 



AND THE LAWS THAT GOVERN THE 



DISTRIBUTION OF ANIMAL LIFE. 



BY 



JOEL ASAPH ALLEN. 



EXTRACTED FROM THE BULLETIN OF THE SURVEY, VOL. IV, No. 2. 



WASHINGTON, May 3, 1878. 



