- Usage in publication:
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- Bird Mountain grit and conglomerate
- Modifications:
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- Areal extent
- AAPG geologic province:
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- New England province
Summary:
Pg. 337-340. There is little doubt that Bird Mountain grit and conglomerate occupies same stratigraphic relations to schists of Taconic Range east of it as the upper Silurian. Rensselaer grit [Lower Cambrian(?) now] does to those of same range in Massachusetts and New York. [Bird Mountain is in Castleton quadrangle, west of West Rutland, Rutland Co., west-central VT.]
Source: US geologic names lexicon (USGS Bull. 896, p. 191).
- Usage in publication:
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- Bird Mountain grit*
- Modifications:
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- Principal reference
- AAPG geologic province:
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- New England province
Dale, T.N., 1900, A study of Bird Mountain, Vermont: U.S. Geological Survey Annual Report, 20, pt. 2, p. 15-23.
Summary:
Pg. 15-23. Bird Mountain grit. Grit and conglomerate interbedded with muscovite (sericite) schist; pebble of pre-Cambrian granite and gneiss and either Cambrian or Ordovician crystalline limestone, and calcareous and micaceous quartzite. Is petrographically different from Resselaer grit. Probably belongs in upper part of Ordovician and later than Calciferous. Overlies Berkshire schist [which is now classified as Upper and Middle (Trenton) Ordovician.]
[Bird Mountain is in Castleton quadrangle, west of West Rutland, Rutland Co., west-central VT.]
Source: US geologic names lexicon (USGS Bull. 896, p. 191).
- Usage in publication:
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- Bird Mountain grit
- Modifications:
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- Age modified
- AAPG geologic province:
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- New England province
Summary:
Pg. 1084, 1090. Bird Mountain grit. Considered a thick facies of Zion Hill formation of [Early] Cambrian age.
Source: US geologic names lexicon (USGS Bull. 1200, p. 347).
- Usage in publication:
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- Bird Mountain grit
- Modifications:
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- Age modified
- AAPG geologic province:
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- New England province
Summary:
Pg. 40, 41-42, pl. 2 (geol. map). Bird Mountain grit. Several lenses of coarse clastics interbedded with rocks of Nassau formation. Although some parts of the rock may be called more accurately conglomerate, arkose, graywacke, and quartzite, on the whole the common angularity of fragments and dominant proportion of quartz grains justify term grit. Name used here only in a lithologic sense to designate facies of Nassau formation. Mapped as pre-Cambrian or Lower Cambrian (?).
Notable exposures on top of Bird Mountain and on large hill 2 mi southwest.
Source: Publication; US geologic names lexicon (USGS Bull. 1200, p. 1812).
- Usage in publication:
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- Bird Mountain Grit of Dale (1900)*
- Modifications:
-
- Mapped
- AAPG geologic province:
-
- New England province
Summary:
Bird Mountain Grit of Dale (1900). Dark-gray to greenish gray and whitish gray, massive, chlorite-quartz wacke, pebble conglomerate and purple-gray hematitic lithic wacke rich in fragmental plagioclase, phosphatic nodules and fragments of gray quartzite, purple and green slate chips. Interpreted as a coarse-grained variant of some of the Zion Hill Quartzite, well exposed in and around Bird Mountain. Unit resembles in stratigraphic position and lithology the Rensselaer Graywacke Member of the Nassau Formation (of Potter, 1972) in the Bennington area. Age is Neoproterozoic and Early Cambrian.
Source: Publication.
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 ([ ]).