(San Francisco) San Francisco, Cal., Apr 1, 80, red integral rate cds with san-serif letters (SAF-300, R6) on 1850 cover to Utica, N.Y., matching straight line "Paid" handstamp and manuscript "Per Steamer Tennessee" ship endorsement at bottom left; light wax seal stain at center and partial backflap, otherwise Very Fine, a rare integral rate postmark used between April and July of 1850, only a few examples known, accompanied by newspaper clipping regarding this sailing. Estimate  $300 - 400. $0 (Image)