Isorthis Comm., Much Wenlock Lst. (Silurian of the United Kingdom)

Where: England, United Kingdom (52.0° N, 2.0° W: paleocoordinates 28.9° S, 12.7° W)

• coordinate based on political unit

• local area-level geographic resolution

When: Much Wenlock Formation, Homerian (430.5 - 427.4 Ma)

• lundgreni, ludensis and nassa zones

• formation-level stratigraphic resolution

Environment/lithology: marine; ferruginous, intraclastic, shelly/skeletal grainstone and green, silty mudstone

• "..occurs in isolated bioherms, composed entirely of closely packed brachiopods. Lithofacies deposited close to wave base, in a generally high energy environment. Common rip up clasts of green silty mudstone suggest finer, argillaceous debris periodically settled from suspension. Sedimentology indicates close to normal wave base with occasional quiescent conditions. Specimens in small clusters or bioherms, showing growth defects related to packing of shells."
• "ferruginous crinoidal grainstone lithofaces" From Ratcliffe (1991) (ref. 6688): a poorly bedded crinoidal grainstone unit [with] rip-up clasts [see geology below].

Size class: macrofossils

Primary reference: K. T. Ratcliffe. 1999. Brachiopod assemblages from the Much Wenlock Limestone Formation of England and Wales. In A. J. Boucot and J. D. Lawson (eds.), Paleocommunities--a case study from the Silurian and Lower Devonian 399-407 [M. Foote/M. Foote/M. Foote]more details

Purpose of describing collection: paleoecologic analysis

PaleoDB collection 23291: authorized by Michael Foote, entered by Michael Foote on 11.07.2002

Creative Commons license: CC BY (attribution)

Taxonomic list

• Only brachiopods are studied thoroughly.
Show authors, comments, and common names
Rhynchonellata
 Spiriferida - Cyrtiidae
Eospirifer sp., Cyrtia sp.
Eospirifer sp. Schuchert 1913
Cyrtia sp. Dalman 1828
 Atrypida - Atrypidae
Atrypidae indet., Atrypa reticularis
Atrypidae indet. Gill 1871
ribbed atrypid
Atrypa reticularis Linnaeus 1758
 Orthida - Dalmanellidae
Isorthis spp., Resserella sp.
Isorthis spp. Kozlowski 1929
Resserella sp. Bancroft 1928
 Orthida - Rhipidomellidae
Dalejina sp.
Dalejina sp. Havlicek 1953
 Rhynchonellida - Trigonirhynchiidae
Microsphaeridiorhynchus sp.
 Rhynchonellida - Hebetoechiidae
Sphaerirhynchia wilsoni
Sphaerirhynchia wilsoni de Sowerby 1816
Strophomenata
 Strophomenida - Strophochonetidae
Protochonetes minimus
Protochonetes minimus Sowerby 1839
 Strophomenida - Strophodontidae
Pholidostrophia sp.
Pholidostrophia sp. Hall and Clarke 1892
 Strophomenida - Amphistrophiidae
Amphistrophia (Amphistrophiella) filosa
 Strophomenida - Leptostrophiidae
Leptostrophia sp.
Leptostrophia sp. Hall and Clarke 1892
 Strophomenida - Rafinesquinidae
Leptaena sp.
Leptaena sp. Dalman 1828