GEOLEX database Geologic Unit: Keyser Usage: Keyser Formation (PA*,VA,WV) Keyser Limestone (WV*,MD*,VA*,PA*) Keyser Limestone of Helderberg Group (PA,VA*,WV*,MD*) /Keyser Formation of [†]Cayuga Group (VA) [†Cayuga, at its type locality has been abandoned as a lithostratigraphic term, and has been used as a chronostratigraphic term (Cayugan Stage) for some time. To prevent confusion, the use of Cayuga as a lithostratigraphic term should be avoided.] Age: Silurian, Late* Pridolian* Devonian, Early* Lochkovian* Geologic Province: Appalachian basin* Areal Extent: MD* PA* VA* WV* Type Locality: Keyser, Mineral Co., WV. (Ulrich, 1911) Subunits: Byers Island Member (PA*,VA*,WV*), Jersey Shore Member (PA*,VA*,WV*), La Vale Member (MD*,PA*,VA*,WV*), Clifton Forge Sandstone Member (WV*,VA*), Big Mountain Shale Member (VA*,WV*) Unit Name History: Named (Ulrich, 1911). Described (Swartz and others, 1913). Subdivided (Swartz, 1929). Revised; Biostratigraphic dating (Denkler and Harris, 1988). Overview (Faill and others, 1989). Biostratigraphic dating (Harris and others, 1994). Note: If you need more information, please contact Nancy Stamm (nstamm@usgs.gov). Asterisks (*) indicate usage by the U.S. Geological Survey. Other usages by state geological surveys. "No current usage" implies that a name has been abandoned or that it has fallen into disuse. Former usage and, if known, replacement name given in parentheses (). Slashes (/) indicate unit name usage violates the 1983 North American Stratigraphic Code. This violation may be explained within brackets ([ ]). U.S. Department of the Interior, U.S. Geological Survey, Reston, VA, USA URL http://ngmdb.usgs.gov/ngmdb/ngm_catalog.ora.html Database project personnel Last modified: 7-Jan-2007