Maps showing formation temperatures and configurations of the tops of the Minnelusa Formation and the Madison Limestone, Powder River basin, Wyoming, Montana, and adjacent areas

This report is part of a study to describe the hydrologic framework needed to evaluate the water resources of the Paleozoic age aquifers in the Northern Great Plains coal region (fig 1). Preliminary studies by the U.S. Geological Survey and State agencies in Wyoming, Montana, and South Dakota have indicated that these aquifers might provide significant percentage of the water requirements for coal development. Data in this report are needed to help evaluate the potential of the Paleozoic age aquifers as a source for water supplies. The results will also be used to provide information for the orderly development of the aquifers.