1. Maps of elevation of top of Pierre Shale and surficial deposit thickness with hydraulic properties from borehole geophysics and aquifers tests within and near Ellsworth Air Force Base, South Dakota, 2020-21 Author/Creator: Geological Survey (U.S.), cartographer Publication/Creation: [Reston, Va.] : U.S. Department of the Interior, U.S. Geological Survey, 2023 Resource Type: Map Access & Availability: Loading