Saucelito, Novr 8th / (18)51 (Marin), stampless folded letter to Sonora Tuolumne County with dateline "U.S. Steamer Massachusetts Saucelito Novr 8th / 51", which received postmark at San Francisco 12 Nov and handstamp "5" (unpaid rate), Very Fine, quite possible the earliest usage, the Saucelito post office was not established until 1870. Estimate  $100 - 150. $0 (Image)