Denver City, Col., Mar 24, blue double circle date stamp on 1864 commission merchant corner card cover to New York City, franked with 1861, 3¢ rose tied by matching target handstamp, with original enclosure regarding mining in the area…From what I have seen and heard I am satisfied that in Colorado are the richest mines in the world, not gulch mines but quartz lead which is much better; cover with hint of toning at bottom, Very Fine. Estimate  $50 - 75. $0 (Image)