Various geochemical parameters including type and abundance of organic matter (TOC), sulfide-sulfur quantities, fluctuations in bottom-water anoxicity (DOP), metal content differences, and sulfur isotope variations have been assessed in order to characterize Midcontinent Pennsylvanian black shales. Based on these geochemical parameters, the deposits can be grouped into three types: Mecca-type, Heebner-type, and Shanghai-type.