This tinted lithograph of “Colorado Desert and Signal Mountain" was produced after an original sketch by expedition artist Charles Koppel (fl. 1853-1865). It was printed as Plate XI in Volume V, Part I, following page 40, in the "General Report," part of the “Routes in California, to Connect with the Routes near the Thirty–Fifth and Thirty–Second Parallels, Explored by Lieutenant R. S. Williamson, Corps of Topographical Engineers, in 1853."
The volume was printed as part of the "Reports of Explorations and Surveys, to ascertain the most practicable and economical route for a railroad from the Mississippi River to the Pacific Ocean" in 1856 by A. P. O. Nicholson (1808-1876) of Washington, D.C.
