Square Top South (Ordovician of the United States)

Where: Millard County, Utah (38.9° N, 113.3° W: paleocoordinates 7.5° S, 82.9° W)

• coordinate stated in text

• hand sample-level geographic resolution

When: Zone J trilobite zone, Lower Member (Wah Wah Formation), Blackhillsian (474.9 - 470.0 Ma)

• "(trilobite Zone J, uppermost Ibexian or middle Arenigian, uppermost Lower Ordovician)" Three collections 2, 18, and 20 meters above base of Wah Wah Formation.

• group of beds-level stratigraphic resolution

Environment/lithology: open shallow subtidal; lithified, intraclastic conglomerate and lithified, shelly/skeletal wackestone

• "shallow marine, storm-dominated depositional environment on a mixed carbonate and clastic passive shelf in a warm tropical climate."
• "Holotype 1810TX5 was collected ... on the upper surface of an echinoderm and trilobite skeletal grain-supported intraformational conglomerate about 10 cm thick with rounded, tabular, micritic pebbles. The specimen was buried by a rapid influx of terrigenous mud. Paratype 1810TX6 was ... preserved on an echinoderm and trilobite wackestone with small horizontal burrows." Paratypes 1964TX2-9, 11-14 (12 specimens) found in "a spiculitic micrite with a minor clay component and contains a few echinoderm fragments, trilobite skeletal grains, and one graptolite. Minor burrowing along and through the bed surface is also evident." "Paratype 1964TX10 found in "surface of a burrowed micrite with scattered echinoderm grain."

Size class: macrofossils

Collection methods: surface (float),

Primary reference: C. D. Sumrall, J. Sprinkle, and T. E. Guensberg. 2011. Comparison of flattened blastozoan echinoderms: Insights from the new Early Ordovician eocrinoid Haimacystis rozhnovi. Journal of Paleontology 75(5):985-992 [P. Novack-Gottshall/P. Novack-Gottshall]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 180739: authorized by Phil Novack-Gottshall, entered by Phil Novack-Gottshall on 30.07.2016

Creative Commons license: CC BY (attribution)

Taxonomic list

Show authors, comments, and common names
unclassified
  -
Trace fossil, Porifera indet.
Trace fossil
small horizontal burrows
Porifera indet. Grant 1836
rare
Radiocyatha
  - Soanitidae
Calathium sp.
Calathium sp. Billings 1865
rare
Edrioasteroidea
 Edrioasterida -
Edrioasterida indet.
Parablastoidea
 Parablastoidea -
Parablastoidea indet.
Eocrinoidea
  -
Eocrinoidea indet., Haimacystis rozhnovi
Eocrinoidea indet. Jaekel 1918
globular
Haimacystis rozhnovi Sumrall et al. 2011
 Rhombifera -
Glyptocystitida indet.
Glyptocystitida indet. Bather 1899
three genera
unclassified
  -
Asterozoa indet.
Graptolithina
  -
Graptolithina indet.
Graptolithina indet. graptolite
including large phyllograptid
Trilobita
  -
Trilobita indet.
Trilobita indet. Walch 1771 trilobite
pliomerids and others
Rhynchonellata
 Orthida -
Orthida indet.
Orthida indet. Schuchert and Cooper 1932
common
Cephalopoda
 Nautiloidea -
Nautiloidea indet.
Nautiloidea indet. Agassiz 1847 nautiloid
rare