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National Geologic Map Database

Geologic Unit: Ammonoosuc

Usage:

Ammonoosuc Volcanics (CT*,ME*,MA*,NH*,VT*)


Subunits:

(alphabetical) --all in NH: Lyman Member, Mullikin Brook Member, Smutty Hollow Member, West Bath Member.


Geologic age:

Ordovician*


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

Type locality: in district bounded on north by Slate Ledge School and Partridge Lake, and on south by Youngs Pond (Ogontz Lake) and Tinkerville, Grafton Co., northern NH. Named from old Ammonoosuc mining district of Hitchcock (1878) [a 100+ sq mi area situated northwest of Ammonoosuc River (btw. Woodsville and Littleton), south of Moore Reservoir, and east-southeast of Connecticut River, covering parts of Littleton, St. Johnsbury, Woodsville, and Moosilauke 15-min quadrangles, Grafton Co., northern NH] (Billings, 1934a,b, 1935, 1956).


AAPG geologic province:

New England province*


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

Asterisk (*) indicates published by U.S. Geological Survey authors.

"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 ([ ]).