Ammonoosuc Volcanics of Billings (1935) - metarhyolite tuff, lapilli tuff, and tuff breccia

Coarsely porphyritic, greenish-gray, light-bluish-gray, or medium-bluish-gray metarhyolite tuff, lapilli tuff, and tuff breccia. Quartz and plagioclase phenocrysts commonly as large as 5 mm. Stratified rocks of the Bronson Hill arch and Sawyer Mountain belt.
State Vermont
Name Ammonoosuc Volcanics of Billings (1935) - metarhyolite tuff, lapilli tuff, and tuff breccia
Geologic age Upper and Middle Ordovician
Lithologic constituents
Major
Metamorphic > Metaigneous > Metavolcanic > MetarhyoliteCoarsely porphyritic, greenish-gray, light-bluish-gray, or medium-bluish-gray metarhyolite tuff, lapilli tuff, and tuff breccia. Quartz and plagioclase phenocrysts commonly as large as 5 mm.
References
NGMDB product