D. A. Ponce R.J. Blakely 2001 A depth to basement map of the Death Valley groundwater model area was prepared using over 40,0000 gravity stations as part of an interagency effort by the U.S. Geological Survey and the U.S. Department of Energy to help characterize the geology and hydrology of southwest Nevada and parts of California. application/pdf 10.3133/mf2381E en Map showing depth to pre-Cenozoic basement in the Death Valley ground-water model area, Nevada and California reports