Born-Digital or AnalogAnalogTranscriptColorado tunnel. Idaho Springs district Colo. Mentioned. R. M. News. Dec. 7, 1879. p.10 c.3 Development. R. M. News. Sept. 22, 1880.p.7 c.2 R.M. News. July 20, 1881. p.6 c.l Description. R. M. Hews. May 20, 1880. p.6 c.2 0CollectionWestern History Subject IndexRelated MaterialWestern History Subject Index AbbreviationsType of MaterialIndex CardLanguageeng
Colorado tunnel. Idaho Springs district Colo, [34338]. Denver Public Library Digital Collections, accessed 10/02/2026, https://digital.denverlibrary.org/nodes/view/1193963
