1 map: col.; Relief shown by contours and spot height. Depths shown by contours and soundings; Shows Crater Lake and the Mount Mazama region; Base map: U.S. Geological Survey 1:62,500 special series Crater Lake National Park and vicinity, Oregon, 1956. Base map title located lower left of map; "Geology after Williams, 1942. GPO 996-245."; In upper right corner: "Prepared in cooperation with the National Park Service."; Explanation: airborne and flow pumice, lavas, pyroclastic rocks, and cinder cones, pre-Mazama lavas, location of the test well and areas discussed in text are clearly marked by F.J. Frank and A.B. Harris; Map accompanies open-file report: Water-resources appraisal of Crater Lake National Park, Oregon and Geological Survey water-supply paper: Hydrology of Crater, East and Davis Lakes, Oregon; Hydrology of Crater, East and Davis Lakes, Oregon, an Oregon Geological Survey water-supply paper accompanies: Water-resources appraisal of Crater Lake National Park, Oregon