Robuta

https://www.usgs.gov/publications/early-pennsylvanian-currents-southern-appalachian-mountains Early pennsylvanian currents in the southern Appalachian Mountains | U.S. Geological Survey Measurement of more than 1200 cross-beds in lower Pennsylvanian sandstones of the southern Appalachian Mountains reveals a broad pattern of sediment transport... early pennsylvanianin the