Geology of a part of Northwestern Uinta County, Wyoming

The part of northwest Uinta County, Wyoming, covered by this investigation, contains both igneous and sedimentary rocks. The igneous rocks are tuffs of late Eocene age. These tuffs comprise the Fowkes and Bridger (?) formations (Veatch, 1907), and are the youngest formations exposed in the area. Particular attention is paid to the Fowkes formation in an attempt to correlate it with the Norwood tuff of northeastern Utah. Mapped strata range in age from Lower Cretaceous to late Eocene. A major unconformity in the section spans most of Upper Cretaceous time. A second unconformity represents the Paleocene-Eocene transition time. Structural features include a major zone of normal faults, part of a broad syncline, a minor anticlinal fold, and landslide features. Most faults trend northerly, forming a parallel pattern. Economic interests in the area center around oil, coal, clay, and high­ way construction materials. No economic production of oil is noted at the time of this writing (1961).