Title
Correlation chart of Pennsylvanian rocks in Alabama, Tennessee, Kentucky, Virginia, West Virginia, Ohio, Maryland, and Pennsylvania showing approximate postion of coal beds, coal zones, and key stratigraphic units [electronic resource] / by Leslie F. Ruppert, Michael H. Trippi, and Ernie R. Slucher.
Published
Reston, Va. : U.S. Dept. of the Interior, U.S. Geologic Survey, 2010.