Gratton Limestone Formation, Maxwell (Ordovician of the United States)

Where: Tazewell County, Virginia (37.1° N, 81.6° W: paleocoordinates 29.6° S, 61.8° W)

• coordinate estimated from map

• outcrop-level geographic resolution

When: Gratton Limestone Formation, Caradocian (460.9 - 449.5 Ma)

• Ashbyan

• formation-level stratigraphic resolution

Environment/lithology: cherty/siliceous limestone

• Thick-bedded dove-gray calcilutytes; weathered surfaces of the third calcilutyte are light gray to creamy white. This zone locally contains intercalations of dark-gray cherty limestone.

Size classes: macrofossils, microfossils

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 34216: authorized by Steven Holland, entered by Tori Hanson on 21.08.2003

Creative Commons license: CC BY (attribution)

Taxonomic list

Ostracoda
 Beyrichiacea - Eurychilinidae
Primitiella constricta Ulrich 1894 ostracod
Ulrich
 Palaeocopida -
 Leperditicopida - Leperditiidae
"Isochilina sp." = Leperditia (Isochilina)
"Isochilina sp." = Leperditia (Isochilina) Jones 1858 ostracod
Gastropoda
 Murchisoniina - Eotomariidae
Eotomaria sp. Ulrich and Scofield 1897 snail
 Murchisoniina - Loxonematidae
Omospira cf. laticincta Ulrich and Scofield 1897 snail
Ulrich
 Murchisoniina - Subulitidae
Subulites sp. Emmons 1842 snail
Cephalopoda
 Orthocerida - Orthoceratidae
Orthoceras sp. Breynius 1832
(common)
Stromatoporoidea
 Labechiida - Aulaceratidae
Cryptophragmus antiquatus Raymond 1914
Raymond (very rare)
 Labechiida - Stromatoceriidae
Stromatocerium rugosum Hall 1847
Hall (rare)
Tetradium
  -