USGS Visual Identifier
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Geologic Unit: Milroy

Milroy Member of Loysburg Formation (PA*)
Milroy Limestone (PA)
Milroy Limestone of Loysburg Group (PA)

Ordovician, Middle*
Geologic Province:
Appalachian basin*
Areal Extent:

Type Locality:
Type area: Bellefonte to Pleasant Gap, Nittany Valley, Centre Co., PA (Swartz and others, 1955).

Unit Name History:
First used (Swartz and others, 1955).
Revised (Rones, 1969; Chafetz, 1969).
Overview (Berg and others, 1980).

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