Named the Grazier member of the Hatter formation for Grazier Mills, Huntingdon Co., central and south-central PA. Unit is middle member of Hatter. Consists of dark, dense, heavy-ledged, stylolitic limestone with wavy argillaceous partings. Unit weathers with rows of holes. Thickness is 33 feet at type locality. Overlies Eyer member and underlies Hostler member, both of the Hatter formation. The Grazier is of Middle Ordovician age.

Source: GNU records (USGS DDS-6; Reston GNULEX).

Raised the Grazier to the Grazier formation of the Hatter group in PA.

Source: GNU records (USGS DDS-6; Reston GNULEX).

The Hatter Formation has been recognized throughout the Valley and Ridge province in central PA, but changes character in the extreme northeast. According to Wagner (1966), it extends in the subsurface to WV. Unit consists of a basal fossiliferous limestone, overlain by fine-grained limestone containing shaly partings, which in turn is overlain by fucoidal, fossiliferous magnesian limestone. The basal Eyer Member is composed of fossiliferous, medium- to thick-bedded calcarenites interbedded with medium-bedded calcilutites and thin, irregular shaly partings. The middle Grazier Member consists of medium-dark-gray, medium- to thick-bedded calcisiltite and calcilutite. Upper Hostler Member is coarser grained than the Grazier, consisting mostly of calcisiltite and thin interbeds of calcarenite. Thickness measured along PA Rte 453 west of Pemberton. The Eyer Member is 3.4+/-0.4 m, the Grazier Member is 14.6+/-2 m, and the Hostler Member is 12+/-2 m thick. Best exposure of the unit is along the east side of PA Rte 453, approximately 10 m north of the first culvert drain from the north end of the roadcut, west of Pemberton, 7 km east of the northeast corner of the Bellwood quad. No basis given for Late Ordovician age assignment. [No mention of Black River Group.]

Source: GNU records (USGS DDS-6; Reston GNULEX).