From abstract: Siliciclastic and minor carbonate rocks of the lower part of the Middle Pennsylvanian Minturn Formation of north-central Colorado were deposited in alluvial-fan, braidplain, Gilbert-delta, shoreline, and paralic, and offshore-marine environments. These strata can be divided into twelve genetic sequences that are generally bounded by transgressive surfaces of erosion or paralic flooding surfaces, and are characterized by thin and thick transgressive units. This report examines the paleogeography of this area.
From summary: The USGS (U.S. Geological Survey) and the USBM (U.S. Bureau of Mines) studied 10,414 acres of the Bull Gulch (CO-070-430) Wilderness Study Area in Eagle County, Colorado. The area has identified, minable sand and gravel deposits; there are no other identified resources. It has moderate mineral resource potential for gypsum and anhydrite, and low potential for all metals, including uranium, coal, oil and gas, and geothermal resources.