Pg. D2 (geol. map), D5; 1962, New York State Mus. Sci. Service Geol. Survey Map and Chart Ser., no. 2. Austerlitz Phyllite of Cossayuna Group. Name proposed for unfossiliferous purple and green phyllite that is widespread in eastern Rensselaer and eastern Columbia Counties. In type area unit is in fault contact on Middle Ordovician Balmville Limestone and Lower Ordovician Stockbridge Dolomite. Previously the Austerlitz has been lumped with "Berkshire" schist but it is certain that at least the black portion of the "Berkshire" is Middle Ordovician, hence it is unwise to continue to call the purple and green portion, whose age is in dispute, by same name. The Austerlitz may be eastern metamorphic equivalent of Mettawee and Nassau lithologies. In Cossayuna Group (new).
Type area: Austerlitz Township, east-central NY. Typical exposures along road to microwave tower atop hill, 1 mi west of Austerlitz, at falls on Punsit Creek, 0.8 mi south of Spencertown, and in Canaan Township along Boston and Albany RR, 0.25 mi southwest of main road intersection in Canaan, and extending for 0.7 mi along road to Rattlesnake Den from Queechy Lake.

Source: US geologic names lexicon (USGS Bull. 1350, p. 36).