Brockocystis nodosaria-Polytryphocycloides Assoc., Llandovery, Eastern Iowa (Silurian to of the United States)

Where: Iowa (42.4° N, 91.3° W: paleocoordinates 19.1° S, 57.6° W)

• coordinate based on political unit

• basin-level geographic resolution

When: Blanding Formation, Rhuddanian to Rhuddanian (443.4 - 438.5 Ma)

• "Early to Middle Llandovery (late A-C3?)...According to Witzke (1981b) and Bowman (1985) the Waucoma is likely equivalent to the Tete des Morts, Blanding, and lower Hopkinton Formations, which crop out farther east in Iowa."

Environment/lithology: open shallow subtidal; bioturbated, shelly/skeletal wackestone and bioturbated, shelly/skeletal grainstone

• Associated with corals and stromatoporoids, interpreted as BA 2.
• Blanding: "desne, fine-grained, very cherty dolomite with varying amounts of terrigenous clastics (generally mionor compared to the carbonate proportion) and carbonate mud...more argillaceous toward its base. The dominant lithology is horizontally bedded, crinoidal wackestone..."

•Waucoma and Brassfield: "undolomitized limestones with very low terrigenous clastic and chert content and echinoderm wackestone to grainstone (commonly packstone) fabrics"

•"Some degree of bioturbation in all three units...crossbedding and graded bedding..."

Primary reference: T. J. Frest, C. E. Brett, and B. J. Witzke. 1999. Caradocian-Gedinnian echinoderm associations of Central and Eastern North America. Paleocommunities--a case study from the Silurian and Lower Devonian 638-783 [M. Foote/K. Koverman/P. Wagner]more details

Purpose of describing collection: paleoecologic analysis

PaleoDB collection 26691: authorized by Michael Foote, entered by Michael Foote on 24.10.2002

Creative Commons license: CC BY (attribution)

Taxonomic list

unclassified
  -
Anthozoa
 Heliolitida - Halysitidae
Halysites sp. von Waldheim 1813 tabulate coral
 Heliolitida - Heliolitidae
Heliolites sp. Dana 1846 tabulate coral
 Auloporida - Syringoporidae
Syringopora sp. Goldfuss 1826 tabulate coral
 Favositida - Favositidae
Favosites sp. Lamarck 1816 tabulate coral
 Rugosa -
Rugosa indet. horn coral
 Stauriida - Arachnophyllidae
Arachnophyllum sp. Dana 1846 horn coral
Trilobita
 Phacopida - Encrinuridae
Encrinuridae indet. Angelin 1854 trilobite
 Phacopida - Calymenidae
Calymene sp. Brongniart 1822 trilobite
Strophomenata
 Strophomenida -
Strophomenida indet. Opik 1934
pholidostrophid
 Strophomenida - Leptellinidae
"Merciella sp." = Leptellina (Merciella)
"Merciella sp." = Leptellina (Merciella) Lamont and Gilbert 1945
 Strophomenida - Stropheodontidae
 Strophomenida - Rafinesquinidae
Leptaena sp. Dalman 1828
Rhynchonellata
 Rhynchonellida -
 Pentamerida - Stricklandiidae
Stricklandiidae indet. Schuchert and Cooper 1931
Microcardinalia sp. Boucot and Ehlers 1963
 Orthida -
Orthida indet. Schuchert and Cooper 1932
 Orthida - Dalmanellidae
Isorthis sp. Kozlowski 1929
 Orthida - Rhipidomellidae
? Dalejina sp. Havlicek 1953
 Orthida - Platystrophiidae
 Orthida - Hesperorthidae
Flabellitesia sp. Zhang 1989
 Atrypida - Atrypidae
Plectatrypa sp. Schuchert and Cooper 1930
Gastropoda
 Euomphalina - Platyceratidae
Platyceras sp. Conrad 1840 snail
 Euomphalina - Euomphalidae
Straparollus sp. de Montfort 1810 snail
Cephalopoda
 Nautiloidea -
Nautiloidea indet. Agassiz 1847 nautiloid
 Rhombifera - Callocystitidae
Crinoidea
 Inadunata -
 Calceocrinida - Calceocrinidae
Calceocrinidae indet. Meek and Worthen 1869 Sea lily
Edrioasteroidea
  - Pyrgocystidae
Pyrgocystis sp. Bather 1915
Cyclocystoidea
  - Cyclocystoididae
Polytryphocycloides sp. Smith and Paul 1982
Sievertsia sp. Smith and Paul 1982