Cliffield Formation, Blackford Member, Pounding Mill Branch (Ordovician of the United States)

Where: Tazewell County, Virginia (37.1° N, 81.7° W: paleocoordinates 30.4° S, 67.6° W)

• coordinate estimated from map

• outcrop-level geographic resolution

When: Blackford Member (Cliffield Formation), Llanvirn (468.0 - 458.4 Ma)

• Whiterockian

• member-level stratigraphic resolution

Environment/lithology: black, gray chert and gray limestone

• dark-gray to black chert interbedded with subordinate light-gray fine-grained limestone; in weathered expoosures, limestones have been dissolved; chert weathers white and breaks into rectangular blocks; average thickness is 30 feet.

Size class: macrofossils

Primary reference: B. N. Cooper and C. E. Prouty. 1943. Stratigraphy of the Lower Middle Ordovician of Tazewell County, Virginia. Bulletin of the Geological Society of America 54:819-886 [S. Holland/T. Hanson/T. Hanson]more details

Purpose of describing collection: biostratigraphic analysis

PaleoDB collection 33446: authorized by Steven Holland, entered by Tori Hanson on 30.07.2003

Creative Commons license: CC BY (attribution)

Taxonomic list

Show authors, comments, and common names
Rhynchonellata
 Orthida - Plectorthidae
Plectorthis sp.
Plectorthis sp. Hall and Clarke 1892
 Orthida - Plaesiomyidae
Dinorthis sp., Dinorthis cf. atavoides
Dinorthis sp. Hall and Clarke 1892
Dinorthis cf. atavoides Willard 1928
Willard
Gastropoda
 Euomphalina - Helicotomidae
Ophiletina sp., Helicotoma sp.
Ophiletina sp. Ulrich and Scofield 1897 snail
Helicotoma sp. Salter 1859 snail
Trilobita
 Phacopida - Pterygometopidae
Calliops sp.
Calliops sp. Delo 1935 trilobite
Ostracoda
 Palaeocopida - Leperditellidae
Leperditella sp.
 Leperditicopida - Leperditiidae
Leperditia fabulites
Leperditia fabulites ostracod
(Conrad)