Origin and distribution of rocks of Ludlow age (Late Silurian) in the northern Appalachians

Strata of Ludlow (Late Silurian) age exposed in the northern Appalachians form five belts characterized by particular rock facies and parallel to the regional tectonic grain. Material balance calculations using fragmental quartz as an index suggest that source areas within the region were insufficient to supply all of the sediment. An upland area to the southeast on the present continental shelf is considered the most likely external source of sediments.