Strata embraced by Chazyan and Black River groups of Butts (1940) are subdivided into 29 zones. The name Cliffield is proposed for zones 1 through 9, including succession from base of basal clastics to top of second zone of calcilutite. Facies variations whereby lithologically distinctive zones grade locally into a thickness of indistinguishable calcilutites prevent succession herein assigned to Cliffield from being subdivided into mappable formations. Where various zones are distinct, as in most parts of Tazewell Co., five members are recognized (ascending): Blackford, Five Oaks limestone, Lincolnshire limestone, Ward Cove limestone, and Peery formation (all new). Maximum thickness is 1142 ft south of St. Clair Station; minimum thickness is 345 ft on northwest side of Thompson Valley. Underlies Benbolt limestone (new); contact a disconformity; disconformable over Beekmantown dolomite; top of Beekmantown is an erosional surface with maximum relief of about 200 ft. As here defined, includes beds which Butts has called Murfreesboro, Mosheim, Lenoir, Holston, and Ottosee.

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

Pg. 1145-1160. Cliffield group in southeastern Virginia and northeastern Tennessee includes (ascending) Blackford, Five Oaks, Lincolnshire, Thompson Valley (new), Ward Cove (restricted), and Peery formations. Age is Middle Ordovician.

Source: US geologic names lexicon (USGS Bull. 1200, p. 837-838).