Adams & Co's Express/Humboldt Bay. Bold double-lined blue oval handstamp with matching boxed "Paid" at left on cover to Moquelumne Hill, franked with precancelled 1851 3¢ dull red with blue double circle Adam's & Co/San Francisco transit datestamp; portion of cover cut out and repaired with stamp placed over (which may not originate), Very Fine appearance, still a rare usage. Estimate  $150 - 200. $0 (Image)