The New Albany Shale is an organic-rich Devonian and Mississippian geologic formation in the Illinois Basin, named for exposures near New Albany, Indiana. Composed mainly of brown, black, and green shale with lesser dolomite and sandstone, it formed in an anoxic marine environment that preserved abundant organic matter. Its black shales commonly contain pyrite, elevated uranium-related radioactivity, phosphorus, and heavy metals. Divided into six members, it correlates with similar formations across surrounding basins. The unit is economically important as a major source of natural gas and oil shale and as a likely source rock for petroleum in older formations around the basin.