USGS D2118: Early/Lower Maastrichtian, Wyoming

List of taxa
Where & when
Geology
Taphonomy & methods
Metadata & references
Taxonomic list
Anthozoa - Scleractinia - Caryophylliidae
? Trochocyathus sp. Milne-Edwards and Haime 1848
originally entered as "? Trochocyathus sp."
Cephalopoda - Nautilida - Nautilidae
Eutrephoceras montanaense (Meek 1876)
Cephalopoda - Ammonitida - Scaphitidae
Discoscaphites sp. Meek 1870
sp. nov.
Cephalopoda - Ammonitida - Baculitidae
Baculites grandis Hall and Meek 1854
Bivalvia - Arcida - Cucullaeidae
Idonearca shumardi
spelled with current rank as Cucullaea (Idonearca)
Bivalvia - Myalinida - Inoceramidae
Inoceramus sp. Sowerby 1814
? Inoceramus fibrosus (Meek and Hayden 1857)
originally entered as "? Inoceramus fibrosus"
Bivalvia - Pectinida - Anomiidae
Anomia sp. Linnaeus 1758
Bivalvia - Pectinida - Pectinidae
Pecten nebrascensis
(Chlamys)
Bivalvia - Ostreida - Bakevelliidae
Gervillia sp. Defrance 1820
Bivalvia - Ostreida - Pteriidae
Pteria sp. Scopoli 1777
Bivalvia - Poromyida - Cuspidariidae
Cuspidaria sp. Dall 1886
Bivalvia - Nuculida - Nuculidae
Nucula cancellata Meek and Hayden 1857
(Pectinucula)
Bivalvia - Nuculanida - Nuculanidae
Nuculana evansi
Polychaeta - Serpulimorpha
? Diploconcha sp.
originally entered as "? Diploconcha sp."
see common names

Geography
Country:United States State/province:Wyoming County:Niobrara
Coordinates: 43.3° North, 104.3° West (view map)
Paleocoordinates:49.7° North, 79.1° West
Basis of coordinate:estimated from map
Geographic resolution:small collection
Time
Period:Cretaceous Epoch:Late/Upper Cretaceous
Stage:Maastrichtian 10 m.y. bin:Cretaceous 8
*Epoch:Senonian
Key time interval:Early/Lower Maastrichtian Ammonoid zone: Baculites grandis
Age range of interval:70.60000 - 66.00000 m.y. ago
* legacy (obsolete) database fields
Stratigraphy
Formation:Pierre Shale Member:upper unnamed shale
Regional section:formation Regional bed:427 - 451 ft
Regional order:top to bottom
Stratigraphic resolution:bed
Stratigraphy comments: Pierre shale, from grown limestone concretions 427 - 451' below top; was bed 96
Lithology and environment
Primary lithology:gray lithified silty "shale"
Secondary lithology: "limestone"
Environment:offshore Tectonic setting:cratonic basin
Geology comments: "Shale. dark gray; basal 2-3 ft. very bentonitic, forming a gray bare gumbo surface; rest of unit silty, containing a few small very fossiliferous brown weathering limestone concretions."
Taphonomy
Modes of preservation:body
Size of fossils:macrofossils
Collection methods and comments
Collection methods:mechanical,field collection
Reason for describing collection:biostratigraphic analysis
Museum repositories:USGS
Taxonomic list comments:"The fossils are ordinarily well-preserved. Most of the cephalopod shells and the inner nacreous layer of Inoceramus are aragonitic, especially specimens from above the Red Bird Silty Member. Shell material and specimens from the Red Bird member and the upper 50' of the underlying Mitten Member is partially transformed to calcite...Ammonites...of the [mid-upper third] of the Mitten Member are...entirely aragonite whereas shell material [of underlying material] is completely transformed to calcite."
Metadata
Also known as:Pierre Shale (USGS D2118)
Database number:1582
Authorizer:J. Alroy Enterer:M. Sommers
Modifier:P. Wagner Research group:marine invertebrate
Created:1999-05-17 16:26:58 Last modified:2024-03-17 14:38:16
Access level:the public Released:1999-05-17 16:26:58
Creative Commons license:CC BY
Reference information

Primary reference:

45. J. R. Gill, W. A. Cobban, and P. M. Kier. 1966. The Red Bird Section of the Upper Cretaceous Pierre Shale in Wyoming. United States Geological Survey Professional Paper 393-A:1-73 [J. Alroy/M. Sommers/A. Clement]