USGS Visual Identifier
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Geologic Unit: Clough

Clough Formation (MA*,NH*,VT*)
Clough Quartzite (MA*,NH*)
Clough Quartzite of Bolton Group (CT*)

Silurian, Early*
Llandoverian, late*

Geologic Province:
New England province*

Areal Extent:

Type Locality:
Clough Hill district, Moosilauke quadrangle, central NH (Billings, 1934).

Unit Name History:
Named Clough conglomerate in NH (Billings, 1934).
Revised to Clough Formation in MA (Hadley, 1946).
Redescribed as Clough Quartzite in NH (Billings, 1955).
Redescribed as Clough Quartzite in CT (Dixon and Lundgren, 1967).
Redescribed as Clough Formation / Quartzite of Bolton Group in CT (Goldsmith and Dixon, 1968).
MA State Geol. Map usage; Biostratigraphic dating (Zen and others, 1983).
Assigned to Bolton Group in CT (Rodgers, 1985).
Areal limits; Overview (Hatch and others, 1988).
Areal limits (Moench, 1990).
Revised; Areal limits; Age modified; Biostratigraphic dating (Moench and others, 1995).
NH State Geol. Map usage (Lyons and others, 1997).

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