GEOLOGICAL SURVEY OF ILLINOIS, 



A. H. WORTHEN, DIRECTOR. 



VOLUME VII. 



GEOLOGY i PALEONTOLOGY 



GEOLOGY, 



By A. H. WORTHEN. 



PALEONTOLOGY, 



I!v A. H. WORTHEN, ORESTES St. JOHN and S. A. MILLER, 



\VITH AN ADDENDA 



BY CHARLES WACSU.ID W, H, BARKIS, 



BY JULIUS MAYEK & CO., BOSTON, MASS. 



PUBLISHED 



BY AUTHORITY OF THE LEGISLATURE OF ILLINOIS. 



MAY, 1883. 



