Photograph of a map of California from the geological survey of 1853 conducted by Lieutenant R. W. Williamson, United States Topographical Engineer. Transcription reads: "exploration and surveys for a R.R. Route from the Mississippi River to the Pacific Ocean. War Department. Geological map of a part of the state of California, explored in 1853 by Lieut. R.S. Williamson, U.S. topological engineer. Prepared to accompany the report of William P. Blake, geologists of the expedition", " Lith of survey Mayer & Knapp, NY".