This episode of Bonanza tells the story of Philip Deidesheimer, inventor of square-set timbering, one of the greatest advances in mining technology of the Old West.
The year is 1860, the setting is the Ophir Mine on the north end of Virginia City. Originally aired 1959.
The map that appears in the opening credits has been turned ‘sideways,’ north is on the left. The Ponderosa Ranch was situated between Lake Tahoe and the Virginia Range.