Juniata Formation

Red to greenish-gray, thin- to thick-bedded siltstone, shale, subgraywacke, and protoquartzite; interbedded conglomerate; thickness 180 feet in east, increases to 500 feet in west.
State Maryland
Name Juniata Formation
Geologic age Ordovician
Lithologic constituents
Sedimentary > Clastic > Sandstone
Sedimentary > Clastic > Sandstone > Graywacke
Sedimentary > Clastic > Mudstone > Shale
Sedimentary > Clastic > Siltstone
Sedimentary > Clastic > Conglomerate
Comments secondary lithologic description from USGS Geologic Names lexicon (ref. MD004): Juniata can be divided into three informal units: a lower red sandstone, a middle red siltstone and shale, and an upper quartzitic sandstone. [Members of Swartz, 1957, not used.] Lower sandstone is a fine-grained graywacke, slightly argillaceous in places. Middle sequence is grayish-red shale and silty shale with some interbeds of thick-bedded, very fine grained sandstone. Upper sandstone is generally upward-coarsening red shale, silty shale, siltstone, and sandstone.

Cleaves, E.T., Edwards, J., Jr., and Glaser, J.D., 1968, Geologic Map of Maryland: Maryland Geological Survey, Baltimore, Maryland, scale 1:250,000.

In 1995 the Water Resources Division of the U.S. Geological Survey digitized the geologic map of Maryland from the 1968 paper map (Reference MD001). Information about products from the Maryland Geological Survey can be found at http://www.mgs.md.gov/.

NGMDB product
Counties Allegany - Washington