Diamphidiocystis drepanon-Savagella Comm., Orchard Creek Shale, Scales Fm.: Richmondian, Illinois

List of taxa
Where & when
Geology
Taphonomy & methods
Metadata & references
Taxonomic list
Edrioasteroidea - Isorophida - Agelacrinitidae
Hystrichopsydrax sp. Guensburg 1988
Savagella sp.
Edrioasteroidea - Isorophida - Lebetodiscidae
Euhydrodiskos sp. Guensburg 1988
Edrioasteroidea - Isorophidae
? Isorophus sp. Foerste 1916
Edrioasteroidea - Pyrgocystidae
? Pyrgocystis sp. Bather 1915
Stylophora - Mitrata - Anomalocystitidae
Enoploura sp. Wetherby 1879
Stylophora - Mitrata
Diamphidiocystis drepanon
Crinoidea
Crinoidea indet. Miller 1821
Rhombifera - Callocystitidae
Lepadocystis sp. Carpenter 1891
Strophomenata - Strophomenida - Rafinesquinidae
Rafinesquina sp. Hall and Clarke 1892
Rhynchonellata - Orthida - Dalmanellidae
Paucicrura sp. Cooper 1956
Tentaculitida
Tentaculitida indet. Ljaschenko 1955
unclassified
Bryozoa indet. Ehrenberg 1831
Gastropoda - Bellerophontida - Bucaniidae
Phragmolites sp. Conrad 1838
Bivalvia
Pelecypoda indet. Goldfuss 1820
synonym of Bivalvia
Trilobita - Corynexochida - Illaenidae
Bumastus sp. Murchison 1839
Trilobita - Asaphida - Asaphidae
Isotelus sp. Dekay 1824
Anthozoa - Stauriida - Streptelasmatidae
Salvadorea randi
see common names

Geography
Country:United States State/province:Illinois
Coordinates: 37.2° North, 89.5° West (view map)
Paleocoordinates:24.7° South, 62.9° West
Basis of coordinate:based on political unit
Geographic resolution:local area
Time
Period:Ordovician Epoch:Late/Upper Ordovician
Stage:Katian 10 m.y. bin:Ordovician 5
*Epoch:Ashgill
*Local age/stage:Richmondian
Key time interval:Richmondian
Age range of interval:449.80000 - 446.00000 m.y. ago
* legacy (obsolete) database fields
Stratigraphy
Geological group:Maquoketa Formation:Scales Member:Orchard Creek Shale
Stratigraphic resolution:member
Stratigraphy comments: "Richmondian of current Illinois usage" 1-3 m above contact with Thebes Sst.
Lithology and environment
Primary lithology:burrows,bioturbation silty,calcareous "shale"
Secondary lithology:burrows,bioturbation argillaceous "limestone"
Includes fossils?Y
Includes fossils?Y
Lithology description: "At te single known locality scattered shelly fossils are sparsely distributed in calcareous silty shales and hard argillaceous limestones...grazing trails, burrows, and burrow mottling...most fossils except trilobites are whole..."
Environment:deep subtidal indet. Tectonic setting:cratonic basin
Geology comments: "Guesburg (1988) interprets theunit as a low-energy environment with a rapid rate of depostion and occasional moderate wave or current activity. He facored a shallow subtidal position, but the rate of depostion and comparison with better known communities from rocks of similar age and environment (e.g. other Maquoketa Group communities) suggest a more offshore position, perhaps corresponding with an outer BA 3 to well into 4, somewhat restricted Silurian assemblage." This community is grouped by authors with others having a deeper shelf environment relative to the shoal margin communities.
SEP environmental call based on given information and regional context
Taphonomy
Collection methods and comments
Reason for describing collection:paleoecologic analysis
Collection method comments: Some overlap with PBDB collections 23235-6, 23521-2, 23682, 23684, 23783-4, and 23810-11, but not a duplicate entry.
Metadata
Database number:26684
Authorizer:M. Foote Enterer:M. Foote
Modifier:S. Peters Research group:marine invertebrate
Created:2002-10-24 05:01:48 Last modified:2003-05-04 12:41:01
Access level:the public Released:2002-10-24 05:01:48
Creative Commons license:CC BY
Reference information

Primary reference:
4379. 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]