Bed 7, Shenandoah Valley (Ordovician of the United States)

Also known as Edinburgh Formation, Liberty Hall Facies; Bed 7

Where: Virginia (38.0° N, 79.0° W: paleocoordinates 30.2° S, 59.3° W)

• coordinate estimated from map

• small collection-level geographic resolution

When: Liberty Hall Member (Edinburg Formation), Caradoc (458.4 - 449.5 Ma)

• Listed as Middle Caradoc. Local series age stated as M1-3

• formation-level stratigraphic resolution

Environment/lithology: offshore shelf; lithified, black limestone and poorly lithified, black shale

• Age is M1-3 (=upper two-thirds of Black Riveran) according to Holland Cincinnatian stratigraphy website. Shaw and Fortey designate this facies as lower slope
• Dense, black, medium to thick-bedded limestone intercalated with black graptolitic shale

Size classes: macrofossils, mesofossils

Primary reference: B. N. Cooper and G. A. Cooper. 1946. Lower Middle Ordovician stratigraphy of the Shenandoah Valley, Virginia. Geological Society America Bulletin 57:35-113 [P. Novack-Gottshall/P. Hearn/J. Ju]more details

Purpose of describing collection: biostratigraphic analysis

PaleoDB collection 76337: authorized by Phil Novack-Gottshall, entered by Paul Hearn on 19.11.2007

Creative Commons license: CC BY (attribution)

Taxonomic list

• Unit 7 is 285 feet thick, but listed as faunally homogeneous throughout; lists common species
Show authors, comments, and common names
Pterobranchia
 Graptoloidea - Climacograptidae
Climacograptus sp.
Climacograptus sp. Hall 1865 climacograptid
 Graptoloidea - Diplograptidae
Diplograptus sp.
Diplograptus sp. graptolite
 Graptoloidea - Dicranograptidae
Nemagraptus gracilis, Dicellograptus sp.
Nemagraptus gracilis Hall 1847 graptolite
Dicellograptus sp. Hopkinson 1871 graptolite
 Rhombifera - Echinosphaeritidae
Echinosphaerites sp.
Echinosphaerites sp. Wahlenberg 1818
Artiopoda
 Agnostida - Metagnostidae
"Arthrorhachis elspethi" = Trinodus elspethi
"Arthrorhachis elspethi" = Trinodus elspethi Raymond 1925
Trilobita
 Corynexochida - Styginidae
"Bronteopsis gregaria" = Raymondaspis gregarius
"Bronteopsis gregaria" = Raymondaspis gregarius Raymond 1920 trilobite
 Trinucleida - Raphiophoridae
Ampyx sp., Ampyxina sp.
Ampyx sp. Dalman 1827 trilobite
Ampyxina sp. Ullrich 1922 trilobite
 Asaphida - Remopleurididae
Robergia sp.
Robergia sp. Wiman 1905 trilobite
Rhynchonellata
 Orthida - Plaesiomyidae
Multicostella bursa
 Orthida - Dalmanellidae
"Resserella cf. rogata" = Paucicrura rogata
"Resserella cf. rogata" = Paucicrura rogata Sardeson 1892
Strophomenata
 Strophomenida - Sowerbyellidae
Ptychoglyptus sp.
Ptychoglyptus sp. Willard 1928