Panama, 1885, "U.S. Postal Agency. Panama", purple duplex with circular cork grid cancel on immaculate envelope, fresh and Extremely Fine. Estimate  $600 - 800. ONE OF ONLY THREE RECORDED SAMPLE USAGES OF THIS U.S. POSTAL AGENCY PANAMA MARKING. This was a sample of the U.S. Postal Agency Panama datestamp sent from the Panama Consulate to the U.S. Department of State in August 1885. Three samples are known and only one on a commercially used cover. $0 (Image)