1 map : color; 45 x 33 cm, folded to 14 x 22 cm
Scale 1:62,500 (W 89°15ʹ--W 89°00ʹ/N 42°15ʹ--N 42°00ʹ). ; Detached from: Economic and geologic papers / Illinois State Geological Survey. Urbana, Ill. : State of Illinois, Department of Registration and Education, Division of the State Geological Survey, 1923. (Bulletin No. 43).; Relief shown by contours and spot heights.; 'Geology by J. Harlen Bretz ; surveyed in 1918.'; 'A. Hoen & Co. Baltimore, Md.'; 'Bull. No. 43, Plate IV.'