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Organic-rich shales have become increasingly important to unconventional petroleum reservoirs, and tools such as the gamma-ray have been used to locate them due to the radioactivity of elements such as uranium, potassium, and thorium present within shales. Complex sedimentary processes of organic-rich black shales are responsible for highly variable geochemical signals. Generally, there is a strong correlation between gamma-ray signature, as a result of radioactive uranium (U), and total organic carbon (TOC) in many Devonian black shales due to similar depositional processes of U and TOC. However, this strong correlation between U and TOC does not seem to be present within the Cleveland Shale interval based on gamma-ray data.