"Double Track, Eagle River Canon, Colo." A passenger train in the Eagle River Canyon. Verso of the postcard reads: "Eagle River Canon is between Leadville and Glenwood Springs, and is the center of considerable mining activity. One of the striking features of this Canon is in the fact that its walls are pierced near the summit with the shafts and tunnels of mines, and looking up the rugged heights, one catches glimpses of the shaft houses and...