UNITED STATES. Panama-Pacific International Exposition, 1915. Official Medal. San Francisco. Silver "So Called Dollar" 30.12 gm. 38 mm. Winged Mercury opening the Panama Canal locks; the Argo (from Jason and the Argonaughts, a symbol of navigation) sailing through; "ON! SAIL ON! in small letters below right; TO COMMEMORATE THE OPENING OF THE PANAMA CANAL MCMXV around / Two female figures representing the hemispheres reaching across a globe holding cornucopias, a seagull below; PANAMA PACIFIC INTERNATIONAL EXPOSITION SAN FRANCISCO CALIFORNIA MCMXV around. HK 399. PCGS MS65; choice; an exceptional example.