WEVERTON FORMATION

Site Locations: 

Weverton, mileage 57.50

         Nearest Access: Lock 31, mileage 58.10

 Harpers Ferry, mileage 60.55

         Nearest Access: Harpers Ferry Potomac bridge, mileage 60.67

  Rocks of the Weverton Formation create a mechanically strong, ridge forming, and erosion resistant assemblage of water worn and water deposited quartz sediments ranging in grain size from pebbles to silt.  The quartzite beds exhibit good sorting of the sand grains and cross bedding that demonstrate highly developed water action.  Conversely, the graywacke and conglomerate layers are not well sorted at all.  All of these are interbedded with layers of siltstone.  Paleocurrent studies suggest that the source of the sediments was to the west with a shoreline to the east.

    In general the minerals that comprise the various Weverton layers are such as to impart an overall dark coloration to it with the exception of the light colored sandy metasiltstones.  A variety of compositions are exhibited in the conglomerate pebbles: blue and red quartz, magnetite, dark opaque minerals, and blue-green phyllite.  The Weverton has undergone moderate metamorphism since its original deposition.  It is highly folded, as exposed on two structural ridge lines, the Blue Ridge and South Mountain.  The latter is a duplication of the Blue Ridge having been displaced some three miles to the east by the tectonic activity that caused the Short Hill Fault.  Prior to the faulting, the Blue Ridge must have been much higher in elevation by a factor of two or three with the Weverton standing nearly vertically on its west flank, a most imposing sight. 

Top of Page