This is a handsome map of Central America, including an essential Panama geological survey.
It illustrates the various proposed routes for a land transit that would cut weeks off a journey from the Atlantic to the Pacific. The map shows four possible routes: “Across the Isthmus of Tehuantepec;” “From Port Sn. Juan del Norte to Port Realejo;” “From the Lake Nicaragua to Port San Juna del Sur;” and “Between Charges (Atlantic) and Vaca de Monte (Pacific).”
A large and colorful inset shows the geological formations on the Isthmus of Panama and the planned route in great detail. With the discovery of gold in California, this chart gained particular prominence and was copied in a U.S. government report (Ex. Doc. No. 75 1st Sess. 31st Cong.). This example comes from that report, published in 1852.