492 



S 



14.GS: 

 CIR492 

 c. 1 



ILLINOIS GEOLOGICAL 

 SURVEY LIBRARY 



STATE OF ILLINOIS 



DEPARTMENT OF REGISTRATION AND EDUCATION 



Pennsylvanian Tree Fern Compressions 

 Caulopteris, Megaphyton, and 

 Artisophyton gen. nov. in Illinois 



Hermann W. Pfefferkorn 



ILLINOIS STATE GEOLOGICAL SURVEY 



Jack A. Simon, Chief Urbana, IL 61801 



CIRCULAR 492 1976 



