MI-63 Geologic Sections Across Colorado (Tweto) Download Publication Details Five geologic sections that supplement Tweto’s 1979 MI-16 Geologic Map of Colorado. Includes brief text on Late Paleozoic, Early Mesozoic, Laramide, and Post-Laramide uplifts and basins, and index map of section lines with tectonic features. 1 plate. Digital PDF download. MI-63D Citations Tweto, Ogden. “MI-63 Geologic Sections Across Colorado.” Geologic map. Miscellaneous. Washington, D.C.: U.S. Geological Survey and the Colorado Geological Survey, 1983. https://coloradogeologicalsurvey.org/publications/tweto-geologic-sections-colorado.