1. Base of fresh ground water, approximately 3,000 Micromhos, in the Sacramento Valley and Sacramento-San Joaquin Delta, California Author/Creator: Geological Survey (U.S.), cartographer Publication/Creation: Menlo Park, California : Department of the Interior, United States Geological Survey, 1973 Format: Map Access & Availability: Loading
2. Bathymetric map : North Pacific Ocean Author/Creator: United States. National Oceanic and Atmospheric Administration Publication/Creation: Washington, D.C. : U.S. Dept. of Commerce, National Oceanic and Atmospheric Administration, National Ocean Survey, 1973 Format: Map Access & Availability: Loading