Bird Mountain Grit of Dale (1900)

Dark-gray to greenish-gray and whitish-gray, massive chlorite-quartz wacke, pebble conglomerate, and purplish-gray hematitic lithic wacke. Unit is rich in fragmental plagioclase, phosphatic nodules, fragments of gray quartzite, and purple and green slate chips. Interpreted as a coarse-grained variant of part of the Zion Hill Quartzite Member, 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 (CZnr). Rocks of the Giddings Brook, Sunset Lake, and Bird Mountain slices. Part of the Taconic Allochthon.
State Vermont
Name Bird Mountain Grit of Dale (1900)
Geologic age Lower Cambrian and Neoproterozoic
Lithologic constituents
Major
Sedimentary > Clastic > Sandstone > GraywackeDark-gray to greenish-gray and whitish-gray, massive chlorite-quartz wacke and purplish-gray hematitic lithic wacke.
Sedimentary > Clastic > ConglomeratePebble conglomerate.
Minor
Metamorphic > Metasedimentary > Metaclastic > SlatePurple and green slate chips.
Metamorphic > Metasedimentary > Metaclastic > QuartziteUnit is rich in fragmental plagioclase, phosphatic nodules, fragments of gray quartzite.
References
NGMDB product
Counties Rutland