Mapped as Hall Stream member of Gile Mountain formation. Highly feldspathic grit, probably of volcanic origin and feldspathic chlorite-ankerite schist and amphibolite. Unit is uppermost member of Gile Mountain. Age is Early Devonian.
Occurs northeast of Nulhegan River, [Averill 15-min quadrangle, Essex Co., northeasternmost VT].
[Typographical error on map: the name should be Halls Stream.]
Source: Publication; US geologic names lexicon (USGS Bull. 1200, p. 1650-1651); GNU records (USGS DDS-6; Reston GNULEX).
Pg. 24, 25, 27, pl. 1 (geol. map). Halls Stream Grits [unranked] in Giles Mountain Formation. Name Halls Stream applied to grits that occur in lenses in Gile Mountain Formation in Averill area, Vermont and New Hampshire [not mapped in New Hampshire]. Do not appear to be related to Sherbrooke grits, hence name Sherbrooke not applicable in area. Halls Stream volcanics also used in report. Age is Early Devonian.
[Type area]: excellent outcrops along eastern slopes of Halls Stream valley about 3.5 mi north of Beecher Falls (Essex Co., northeastern VT), north of VT-NH State line and along the International border, [in area around Lat. 45 deg. 03 min. N., Long. 71 deg. 30 min., western edge Pittsburg 7.5-min quadrangle, Coos Co., northern NH]. Name credited to Prof. James B. Thompson, Jr., Harvard Univ.
Source: Publication; US geologic names lexicon (USGS Bull. 1350, p. 316).
grits at Halls Stream (informal) in Ironbound Mountain Formation. Thick-bedded feldspathic volcaniclastic grit and interbedded gray slate. Exposed in northern New Hampshire. Equivalent to Grenier Ponds Member of Ironbound Mountain Formation in western Maine. Age is Early Devonian.
Source: Publication.
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