Clarence Member of Onondaga Formation of Ozol (1964, unpub. Ph.D thesis) is revised as member of Onondaga Limestone. Replaces term "western (black chert) facies of Nedrow Member" of Oliver (1954). Type section is at village of Clarence, Erie Co., western NY. Consists of sparsely fossiliferous fine-grained limestone and dark-gray chert. Dunn and Ozol (1962) report chert content of 45 to 75 percent, compared to 5 to 20 percent for underlying members. Occupies same stratigraphic position as Nedrow Member in central and eastern NY. Both Clarence and Nedrow are underlain by Edgecliff Member and overlain by Moorehouse Member. Nedrow consists of argillaceous limestone with abundant brachiopods and platyceratid gastropods.

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

Authors informally propose two dominant, widespread facies of the Edgecliff Member of the Onondaga Limestone: the cherty, micritic Clarence facies, formerly known as the Clarence Member of western NY, and a coarse crinoidal, non- to sparsely cherty Jamesville Quarry facies. Clarence facies is present and relatively thick from Oaks Corners westward to Buffalo. It is a very minor component of the Edgecliff interval from Seneca Falls eastward to Albany, but south of Albany, along the Hudson Valley, a thick micritic, light-weathering, cherty facies reappears with the Edgecliff and into the Buttermilk Falls Formation in northeastern PA.

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