MS-39 Geologic Map of the Basalt Quadrangle, Eagle, Garfield, and Pitkin Counties, Colorado Download Publication Details The Basalt quadrangle covers about 58 square miles in Eagle, Garfield, and Pitkin Counties, which is located in the Roaring Fork River Valley and includes the town of Basalt. Includes cross section; map unit correlation; shaded-relief map with geology overlay; and booklet of extended descriptions of map units, geologic setting, structural geology, economic geology, and references. Note that MS-39 is the digitally produced, full color version of the original black-and-white open-file report OF-98-01. However, this digital map and accompanying booklet were slightly modified from the original OF-98-01, incorporating (1) edge matching the geology shown on the Basalt quadrangle with adjacent quadrangles and (2) interpretation of the geology of the mapped area with respect to the regional knowledge acquired by mapping contiguous quadrangles. 22 pages. 1 color plate (1:24,000). Digital PDF download. MS-39D Citations Streufert, Randall K., Beth L. Widmann, and Robert M. Kirkham. “MS-39 Geologic Map of the Basalt Quadrangle, Eagle, Garfield, and Pitkin Counties, Colorado.” Geologic. Map Series. Denver, CO: Colorado Geological Survey, Department of Natural Resources, 2008. https://coloradogeologicalsurvey.org/publications/geologic-map-basalt-quadrangle-eagle-garfield-pitkin-colorado-2.