Ogden Tweto 1956 <p>The triangular area bounded by the most productive mining districts of central Colorado- Leadville, Climax-Kokomo, and Gilman-Red Cliff- is of economic interest not only because of its close spatial relation to these districts but because it is closely related geologically. &nbsp;It contains the same rocks as the adjoining mining districts and is closely related to them structurally. &nbsp;It shows widespread evidence of weak mineralization at the surface and may contain ore deposits at depth, as the zones that have been productive in the adjoining mining districts lie beneath a cover of younger rocks in much of the area.</p> application/pdf 10.3133/mf34 en U.S. Geological Survey Geologic map of the Tennessee Pass area, Eagle and Lake counties, Colorado reports