USGS Visual Identifier

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GEOLEX database

Geologic Unit: Walloomsac

Publication:
Ratcliffe, N.M., 1974, Bedrock geologic map of the State Line 
   quadrangle, Columbia County, New York, and Berkshire County, 
   Massachusetts: U.S. Geological Survey Geologic Quadrangle 
   Map, GQ-1142, 1 sheet, scale 1:24,000 [http://ngmdb.usgs.gov/
   Prodesc/proddesc_10682.htm]
Usage in Publication:
Walloomsac Formation*

Modifications: Geologic Province: Dominant Lithology:
 Age modified
 Biostratigraphic dating
 New England province
 

Summary:
Basal limestone of Walloomsac contains pelmatozoans, bryozoans, algae remains, and conodonts. Conodonts exposed at No Bottom Pond indicate a Middle Ordovician or slightly younger age (according to J. Huddleston, USGS). Age of whole unit is Middle and Late(?) Ordovician.
Source: GNU records (USGS DDS-6; Reston GNULEX).


Publication:
Zen, E-an (editor), Goldsmith, Richard (compiler), Ratcliffe, 
   N.M. (compiler), Robinson, Peter (compiler), Stanley, R.S. 
   (compiler), Hatch, N.L., Jr., Shride, A.F., Weed, E.G.A., 
   and Wones, D.R., 1983, Bedrock geologic map of Massachusetts: 
   U.S. Geological Survey Special Map, 3 sheets, scale 
   1:125,000
Usage in Publication:
Walloomsac Formation*

Modifications: Geologic Province: Dominant Lithology:
 Overview
 New England province
 

Summary:
Used as Walloomsac Formation of Middle Ordovician age. Mapped as one main unit and three informal, unnamed subunits. Subunit consisting of tan to dark-blue laminated quartzite and calcareous quartzite was previously mapped by other workers as Bellowspipe Quartzite [name not used on this map].
Source: GNU records (USGS DDS-6; Reston GNULEX).


Publication:
Baskerville, C.A., 1992, Bedrock and engineering geologic maps 
   of Bronx County and parts of New York and Queens Counties, 
   New York: U.S. Geological Survey Miscellaneous Investigations 
   Series Map, I-2003, 2 sheets, scale 1:24,000
Usage in Publication:
Walloomsac Formation*

Modifications: Geologic Province: Dominant Lithology:
 Revised
 Areal limits
   

Summary:
In this map area, Manhattan Schist member A is replaced by Walloomsac Formation based on work by Jackson and Hall (1982), Hall (in press), and A.A. Drake (1990., pers. commun.).
Source: GNU records (USGS DDS-6; Reston GNULEX).


Publication:
Ratcliffe, N.M., Potter, D.B., and Stanley, R.S., 1993, Bedrock 
   geologic map of the Williamstown and North Adams quadrangles, 
   Massachusetts and Vermont, and part of the Cheshire quadrangle, 
   Massachusetts: U.S. Geological Survey Miscellaneous Investigations 
   Series Map, I-2369, 13 p., 2 sheets, scale 1:24,000
Usage in Publication:
Walloomsac Formation*

Modifications: Geologic Province: Dominant Lithology:
 Age modified
 Biostratigraphic dating
 New England province
 

Summary:
Thin limestone unit near base of Walloomsac locally contains abundant bryozoan fragments, cup corals, pelmatozoan hash, and conodonts that indicate that the base of the Walloomsac is Rocklandian (middle and late Caradocian) or younger. Age of unit is Middle Ordovician.
Source: GNU records (USGS DDS-6; Reston GNULEX).