US. GEOLOGICAL SURVFY 



MONOGRAPH XXXVIII PL. XXI 



Counties 

 UX1NOIS 



GEOLOGIC FORMATIONS OF ILLINOIS AND WESTERN INDIANA 

 Compiled ftonvWorthen's map of Illinois 1875 and Phinneys map ol feidiana,US.G.S 1890 



11Y FRANK LEVERETT 



I89f 



