From introduction: The investigations on which the greater part of this report is based were carried on by E. T. Hancock, the senior author, during the summer of 1911. They were undertaken by the United States Geological Survey under a comprehensive plan for collecting information about the undeveloped fuel resources of the Western States, both as a step toward the conservation of the coal resources of the United States and as a means of supplying the demand for information concerning the many valuable coal fields of the Western States.

Abstract: The Willow Creek Wilderness Study Area (CO-010-002) and the Skull Creek Wilderness Study Area (C-010-003), which contain 13,368 acres and 13,739 acres, respectively, are in northwest Colorado near the Utah border. There are no identified resources in either of the study areas. The study areas have low resource potential for undiscovered uranium, vanadium, copper, and all other metals; oil and gas; and coal.

From abstract: Uranium deposits and radioactivity anomalies have been found in the eastern half of the area underlain by the Browns Park formation in northwestern Colorado, south-central Wyoming, and northeastern Utah. The deposits are in eolian, lacustrine, and fluvial sandstones, tuffaceous sandstones, and limestones all of which were deposited on two converging pediments during Miocene time. At least one eastern and one western facies of lacustrine and fluvial sedimentary rocks are separated by a belt of eolian sandstones. The faces may be distinguished in the field and by petrographic and heavy-mineral studies in the laboratory.

This report studies the geology of mineral deposits in Mount Harris, Pilot Knob, Elkhead Creek, and Daton Peek quadrangles in northwestern Colorado.

From abstract: Large increases in coal mining currently (1979) taking place in the Yampa River basin are expected to continue during the 1980's and may adversely impact both the ground-water and surface-water quality in the basin. One potential source of adverse impact is the dissolution of soluble minerals contained in the overburden material disturbed during the mining. This potential impact was investigated using digital ground-water transport-modeling techniques.