- Usage in publication:
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- Elma Submember
- Modifications:
-
- Named
- Dominant lithology:
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- Shale
- AAPG geologic province:
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- Appalachian basin
Summary:
Ledyard Member of Ludlowville Formation of the Hamilton Group is subdivided into newly named Winspear and overlying Elma submembers. The Elma includes 10 to 12 m of dark gray shale with prominent limy concretions in the upper half of the Ledyard. Contains the Bullis trilobite beds and the Pond Brook interval, which includes the Mt. Vernon limestone bed at its top. The base of the Elma is the top of the Athol Springs bed, a prominent limestone bed, here included in the Winspear. Unit underlies the Spring Brook Submember of the Wanakah Member of the Ludlowville. Age is Middle Devonian.
["Submember" not recognized as a formal stratigraphic rank term (CSN, 1933; ACSN, 1961, 1970; NACSN, 1983, 2005). Considered informal until formally published. The rank or lithologic term should not be capitalized.]
Source: GNU records (USGS DDS-6; Reston GNULEX).
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 conflicts with nomenclatural guidelines (CSN, 1933; ACSN, 1961, 1970; NACSN, 1983, 2005, 2021). May be explained within brackets ([ ]).