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National Geologic Map Database
Geologic Unit: Bullis
Map showing publication footprint
  • Usage in publication:
    • Bullis trilobite beds
  • Modifications:
    • Named
  • Dominant lithology:
    • Shale
  • AAPG geologic province:
    • Appalachian basin
Publication:

McCollum, L.B., 1991, Revised stratigraphy, sedimentology, and paleoecology of the Ledyard Member, Ludlowville Formation, New York, IN Landing, Ed, and Brett, C.E., eds., Dynamic stratigraphy and depositional environments of the Hamilton Group (Middle Devonian) in New York State, Part II: New York State Museum Bulletin, no. 469, p. 107-128.


Summary:

Ledyard Member of Ludlowville Formation subdivided into newly named Winspear and Elma submembers [informal]. Bullis trilobite beds are 25 to 50 cm thick and occur within the Elma, between 19.5 and 21 m above the base of the Ledyard in every locality studied by author. The Bullis is described as a faunal interval of densely crowded trilobite carapaces and small pectinid bivalves within an otherwise uniform shale sequence. Underlies Pond Brook interval (new). 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 ([ ]).

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