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

Chadwick, G.H., 1933, Great Catskill delta, and revision of late Devonic succession: Pan-American Geologist, v. 60, nos. 2-5., (No. 2, p. 91-107, Sept. 1933; No. 3, areal refinements, p. 189-204, Oct. 1933; No. 4, revised correlations, p. 275-286, Nov. 1933; and No. 5, p. 348-360, Dec. 1933)


Summary:

The name Sonyea is applied to the combined Middlesex and Cashaqua, which are a natural unit, exposed on Cashaqua Creek, near Portage, NY. Unit is overlain by Attica (combined Rhinestreet and Hatch), and included in Nunda group.

Source: GNU records (USGS DDS-6; Reston GNULEX).


Map showing publication footprint
  • Usage in publication:
    • Sonyea Formation*
  • Modifications:
    • Areal extent
  • AAPG geologic province:
    • Appalachian basin
Publication:

de Witt, Wallace, Jr., and Roen, J.B., 1985, Correlation and geographic extent of some Middle and Upper Devonian and Lower Mississippian black shales in the Appalachian basin, IN Stratigraphic notes, 1984: U.S. Geological Survey Bulletin, 1605-A, p. A45-A57.


Summary:

Sonyea Formation (as its Middlesex Shale Member) extended from southwestern NY and western PA into eastern OH, western MD, and WV.

Source: GNU records (USGS DDS-6; Reston GNULEX).


Map showing publication footprint
  • Usage in publication:
    • Sonyea Formation*
  • Modifications:
    • Overview
  • AAPG geologic province:
    • Appalachian basin
Publication:

de Witt, Wallace, Jr., Roen, J.B., and Wallace, L.G., 1993, Stratigraphy of Devonian black shales and associated rocks in the Appalachian basin, IN Roen, J.B., and Kepferle, R.C., eds., Petroleum geology of the Devonian and Mississippian black shale of eastern North America: U.S. Geological Survey Bulletin, 1909-B, p. B1-B57.


Summary:

In outcrop in western NY, the Sonyea consists of a basal black shale, the Middlesex Shale Member, and an upper gray shale with limestone nodules, the Cashaqua Shale Member. Members grade eastward into sequence of siltstone and silty shale, which is part of the general turbidite facies of the Catskill delta. The Middlesex is about 65 ft thick in the reference section 0.8 mi south of the village of Middlesex, Yates Co., NY. Thickens eastward to 75 ft at Chidsey Point Gully. Thins westward to 6 ft in Erie Co. Occurs in subsurface of PA, OH, WV, and MD, but is apparently is not present in VA. Makes up most of the Sonyea in the subsurface. The Cashaqua is thin, but recognizable from western NY, through PA and Garret Co., MD, to southwestern WV and has also been identified in southeastern OH. Age is Late Devonian.

Source: GNU records (USGS DDS-6; Reston GNULEX).


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

Asterisk (*) indicates usage by the U.S. Geological Survey. Other usages by state geological surveys.

"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 ([ ]).