Map PDF PDF of Drift Thickness of the Middle Illinois River Valley General Information: Description One 37" x 44" map sheet; includes map, legends, and descriptive text with 3 figures. Publication Details: Publication Date 2014 Authors Richard C. Berg E. Donald McKay III Barbara J. Stiff Map Details: Series ID IMAP 18 Theme Drift Thickness Scale Category Regional Scale 1:62,500 Ordering Information https://shop.inrs.illinois.edu/map-series.html#3624
