1. Reconnaissance geologic map of the Dubakella Mountain 15' quadrangle, Trinity, Shasta, and Tehama Counties, California Author/Creator: Irwin, W. P. 1919-2012. (William Porter) Publication/Creation: Reston, Va. : U.S. Dept. of the Interior, U.S. Geological Survey, 2011 Resource Type: Map Access & Availability: Loading
2. Reconnaissance geologic map of the Hayfork 15ʹ quadrangle, Trinity County, California Author/Creator: Irwin, W. P. 1919-2012. (William Porter) Publication/Creation: [Reston, Va.] : U.S. Dept. of the Interior, U.S. Geological Survey, 2010 Resource Type: Map Access & Availability: Loading
3. Reconnaissance geologic map of the Hyampom quadrangle, Trinity County, California Author/Creator: Irwin, W. P. 1919-2012. (William Porter) Publication/Creation: Reston, Va. : U.S. Dept. of the Interior, U.S. Geological Survey, 2010 Resource Type: Map Access & Availability: Loading