1915 Panama California Exposition, San Diego, label affixed to Christmas post card to Wooster, O., franked with 1¢ green tied by "San Diego, Dec 19, 1909" flag machine postmark, with message regarding the exposition and perforated label "1915 San Diego Exposition, Planned in 1909" which may be contemporary, Very Fine, one, if not the earliest usage of the official San Diego Exposition seal design on cover. Estimate  $200 - 300. $0 (Image)