USGS Visual Identifier
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Geologic Unit: Potsdam

Potsdam Sandstone (NY*,VT)
Potsdam Sandstone of Beekmantown Group (NY)
Potsdam Sandstone of Saratoga Springs Group (NY)
Potsdam Formation (PA)
Potsdam Supergroup (IN-subsurface)

Cambrian, Late*
Ordovician, Early

Geologic Province:
Adirondack uplift*
New England province
Appalachian basin
Cincinnati arch
Areal Extent:
IN (subsurface)

Type Locality:
Potsdam, St. Lawrence Co., NY (Emmons, 1838).

Ausable (NY), Keeseville (NY), and Nicholville (NY*) Members in Potsdam Sandstone; Mount Simon Sandstone (IN) and Munising Group (IN) in Potsdam Supergroup.

Unit Name History:
Named (Emmons, 1838).
Revised (Cushing, 1901).
Extended into VT (Rogers, 1937).
Revised (Postel and others, 1959).
Revised to formation, incl. in Beekmantown Group and Saratoga Springs Group; Age modified (Fisher and others, 1961).
Revised (Fisher, 1968).
Extended into PA (Craft, 1979).
Overview (Fisher, 1984).
Extended into IN; Revised to Potsdam Supergroup (Droste and Patton, 1985).
Correlation and stratigraphy overview; Areal limits (Thompson, 1990).
Overview (Reed, 1993).

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