Black River Group - undivided

Thin-bedded to massive dolostone, sandy dolostone, and light-gray limestone; vertical burrows in basal beds; upper beds fossiliferous with black chert. Rocks of the Laurentian Margin. Part of the Adirondack lowlands and Lake Champlain lowlands (west of the Orwell and Champlain thrusts).
State Vermont
Name Black River Group - undivided
Geologic age Upper Ordovician
Lithologic constituents
Major
Sedimentary > Carbonate > Limestone (Bed)Light-gray limestone.
Sedimentary > Carbonate > Dolostone (Bed)Thin-bedded to massive dolostone, sandy dolostone.
Incidental
Sedimentary > Chemical > Chert (Bed)Upper beds fossiliferous with black chert.
References
NGMDB product
Counties Addison - Franklin - Grand Isle