Interim Geologic Map of the Devils Slide Quadrangle, Morgan, and Summit Counties, Utah (OFR-691)

By: James C. CooganThe Devils Slide quadrangle is located northeast of Salt Lake City and southeast of Ogden, Utah along a national east-west transportation corridor (U.S. Interstate Highway 84 and the Union Pacific Railroad). The Weber River crosses the quadrangle, and cut Upper Weber Canyon between Henefer and Round Valleys. The valleys of Lost Creek and Main Canyon Creek (an extension of East Canyon) also enter the quadrangle. Pennsylvanian through Permian marine sedimentary strata and Mesozoic (Triassic and Jurassic) sedimentary rocks are exposed in an east-dipping homocline on both sides of Upper Weber Canyon. Conglomeratic rocks of the Cretaceous Weber Canyon and Evanston Formations are exposed on the east flank of the homocline, and unconformably overlie these older rocks. These synorogenic conglomeratic rocks and related thrust faults are unconformably overlain by the at least locally conglomeratic Tertiary Wasatch Formation. In addition to the conglomerates, the quadrangle is