August 1955 
Urbana, Illinois 
Y¥Oltume 20, Afrficle Ss 
BULLETIN 
of the 
ILLINOIS NATURAL HISTORY SURVEY 
HARLOW B. MILLS, Chief 
Hill Prairies 
of Illinois 
ROBERT A. EVERS 
Printed by Authority of the 
STATE OF ILLINOIS 
WILLIAM G. STRATTON, Governor 
DEPARTMENT OF REGISTRATION AND EDUCATION 
VERA M. BINKS, Director 
ge NATURAL 
HISTORY SURVEY 
LIBRARY 
