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National Geologic Map Database

Geologic Unit: Keyser

Usage:

Keyser Formation (PA*,VA,WV)
Keyser Limestone (MD*,PA*,VA*,WV*)
Keyser Limestone of Helderberg Group (MD*,PA,VA*,WV*)
/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.]


Subunits:

Big Mountain Shale Member (VA*,WV*), Byers Island Member (PA*,VA*,WV*), Clifton Forge Sandstone Member (VA*,WV*), Jersey Shore Member (PA*,VA*,WV*), LaVale Member (MD*,PA*,VA*,WV*).


Geologic age:

Late Silurian to Early Devonian (Pridoli to Lochkovian)*


Type section, locality, area and/or origin of name:

Named from exposures at Keyser, [Keyser 7.5-min quadrangle], Mineral Co., northern WV (Ulrich, 1911).


AAPG geologic province:

Appalachian basin*


For more information, please contact Nancy Stamm, Geologic Names Committee Secretary.

Asterisk (*) indicates usage by the U.S. Geological Survey. Other usages by state geological surveys.

"No current usage" (†) implies that a name has been abandoned or has fallen into disuse. Former usage and, if known, replacement name given in parentheses ( ).

Slash (/) indicates name does not conform with nomenclatural guidelines (CSN, 1933; ACSN, 1961, 1970; NACSN, 1983, 2005). This may be explained within brackets ([ ]).