1896 USGS Mount Diablo Quad 15 Minute 1st edition in Copper Engraving

16.5 x 20" folio 15 minute sheet in Blue and Tan issued

as a 1st edition of this series. clean and important.

It is the sheet covering the towns of Dublin , San Ramone and Claytn , all within a few miles of Mt Diablo, center starting point for all western US surveys. Starting in 1843 with the Wilkes Ex.Ex and John Fremont, as part of the initial triangulation for accessing the Bay and California by the Americans and Used from then on as one of three high points : Table Mt. (Mount Tamalpias), Blue Mt. (Twin Peaks) and Devil's Mt. (Mount Diablo) . Includes newly assigned icons for advising content through legend along both side margins. rare and fun. still highly important and functional.