Relief shown by contours and spot heights"Geology based on field work by E.D. McKay, R.C. Berg, A.J. Stumpf, and C.P. Weibel, 2001-2005.""This mapping was funded in part by the Illinois Dept. of Transportation to support planning for upgrade of Illinois Route 29.""Digital cartography by J. Carrell, J. Domier, and Z. Golshani, Illinois State Geological Survey. GIS support by P. Johnstone, L. Smith, and B. Stiff, Illinois State Geological Survey.