1. Thermal maturity map of Devonian shale in the Illinois, Michigan, and Appalachian Basins of North America Author/Creator: East, Joseph A. Publication/Creation: [Reston, Va.] : U.S. Dept. of the Interior, U.S. Geological Survey ; Denver, Colo. : For sale by U.S. Geological Survey, 2012 Resource Type: Map Access & Availability: Loading