USGS Visual Identifier
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Geologic Unit: Tyrone

Tyrone Limestone of High Bridge Group (KY*)
Tyrone Member of High Bridge Limestone (VA)

Ordovician, Middle*
Geologic Province:
Cincinnati arch*

Areal Extent:

Type Locality:
Type area: vicinity of Tyrone, Anderson Co., KY (Miller, 1905).

Unit Name History:
Named Tyrone beds (Miller, 1905).
Revised to Tyrone Limestone of Highbridge Group (Hamilton, 1948).
Extended into VA (Ross and Moore, 1953) [From GNC index card files; not synopsized].
Designated Tyrone Limestone of High Bridge Group (Cressman, 1964).
Overview (Wahlman, 1992).
Overview; Age modified (Frey, 1995).

Note: If you need more information, please contact Nancy Stamm (
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
Database project personnel
Last modified: 15-Jan-2013