1850 (May 8) Panama to San Francisco, Cal., sent by Charles Loring (Chile forwarding agent) enroute from Valparaiso to New York City and Boston, carried on Law's Columbus from Panama May 16th to San Francisco, red "San Francisco Cal. 6 Jun" cds with matching "Ship 6" clamshell rating handstamp, Very Fine, A rare strike of the San Francisco fancy clamshell ship rating handstamp in red. Estimate  $300 - 400. $0 (Image)