The glacial, lower Tertiary, and Upper Cretaceous aquifer systems in the Williston and Powder River structural basins within the United States and Canada are the uppermost principal aquifer systems and most accessible sources of groundwater for these e
Thamke, Joanna N. jothamke@usgs.gov,LeCain, Gary D.,Ryter, Derek W. dryter@usgs.gov,et al. Hydrogeologic framework of the uppermost principal aquifer systems in the Williston and Powder River structural basins, United States and Canada. 2014-01-01.