The Hurricane Ridge syncline is in the most westerly portion of the folded and thrust-faulted Appalachians in Tazewell County, Virginia, and Mercer County, West Virginia. Late Mississippian rocks are exposed in the trough of the syncline. The Hurricane Ridge syncline was being actively downwarped during deposition of the Upper Mississippian sequence. A greater thickness of sediment accumulated in the trough than in adjacent areas. During deposition of the prominent sandstones, finer and lighter grains were washed into the trough, and coarser quartz sands free of mica and clay were left on the structural flanks. A source area near the southeast flank of the syncline supplied pebbles and finer clastic particles to the depositional area. Continuing downwarp induced the partly lithified sediments to slump and flow toward the structural trough. Turbidity currents were generated on the southeast flank and were blocked by structural reversal on the northwest flank. Partial reduction of maroon sediments occurred periodically in the deeper water along the trough. Locally on the southeast flank of the Hurricane Ridge syncline, the Upper Mississippian beds were upturned and subjected to erosion prior to deposition of the overlying Pennsylvanian.