RS-25 Coal Resources of the Castle Rock (1/2° x 1°) Quadrangle, Colorado Download Publication Details Laramie Formation and Denver Formation coal zone coal resources calculated from pre-existing data and core drilling program. Includes overburden isopach, isopach, structure contour, drill hole and mine data points on maps; cross sections. 136 pages. 5 figures. 3 tables. 17 plates (1:100,000). Digital PDF download. RS-25D This quadrangle covers 1900 square miles and is located predominately in Elbert County. It also extends into Douglas and El Paso Counties. Within the quadrangle the major structural feature is the Denver Basin. The coal beds occur in the Laramie Formation and Denver Formation of the Denver Basin. Much of the information obtained during this investigation is presented in map and table format. Citations Eakins, Wynn, and Margaret S. Ellis. “RS-25 Coal Resources of the Castle Rock (1/2° x 1°) Quadrangle and Adjacent Area, Colorado.” Coal. Resource Series. Denver, CO: Colorado Geological Survey, Department of Natural Resources, 1987. https://doi.org/10.58783/cgs.rs25.vhxa1823. CGS Publications. https://coloradogeologicalsurvey.org/publications/coal-resources-castle-rock-quadrangle-colorado/.