FEB., 1912. MAMMALS OF ILLINOIS AND WISCONSIN CORY. 



39 



Transition Zone This zone is characterized by comparatively few 

 distinctive animals and plants, but covers a territory which repre- 

 sents the southern limit of many northern species and the northern 

 limit of many more southern species. 



Upper Austral, Lower Austral and Tropical Zones In the Upper 

 Austral Zone we find trees such as oaks, hickories, chestnuts, etc., 

 in abundance, which are gradually succeeded by persimmons, mag- 

 nolias, cyprus, etc., in the Lower Austral Zone; and again by palms, 

 bananas, etc., in the Tropical Zone, which in eastern United States 

 is represented only in southern Florida. As with the plant life, 

 there is a corresponding change in the fauna of these different zones, 



Map showing Life Zones in eastern North America, from Hudson Bay to the Gulf of Mexico. 

 Copied from the U. S. Biological Survey's Fourth Provisional Zone Map of North America prepared 

 by C. Hart Merriam, Vernon Bailey, E. W. Nelson, and E. A. Preble, 1910. 



