Erie Colorado, Mar 15, 1873, manuscript postmark canceling on 1870, 3Ā¢ green entire to Newark Valley, N.Y., Very Fine and choice, the only recorded territorial postmark from this post office, illustrated in Jarrett's Colorado book. EstimateĀ $300 - 400. In addition to agriculture, Erie was a center for coal mining, one of several such towns. $0 (Image)