Mill City, Colorado, Sept 29/66, manuscript territorial postmark on cover to Philadelphia, Pa., franked with manuscript canceled 1861, 3¢ rose, with original enclosure describing miner's trek over Argentine Pass; light file fold affecting stamp, otherwise Very Fine. Estimate  $200 - 300. Mill City was an important smelter town and stagecoach stop. The post office became Dumont in 1879, after the territorial period. $0 (Image)