Pierre Shale (USGS D1942, D1943) (Cretaceous of the United States)

Where: Niobrara County, Wyoming (43.3° N, 104.3° W: paleocoordinates 49.2° N, 71.6° W)

• coordinate estimated from map

• small collection-level geographic resolution

When: lower unnamed shale Member (Pierre Shale Formation), Campanian (83.6 - 72.1 Ma)

• bed-level stratigraphic resolution

Environment/lithology: offshore; lithified, concretionary, ferruginous, gray, red, calcareous shale

• "shale, dark gray, contains contains small reddish brown weathering ironstone concretions and larger tan weathering ls concretions that have cone-in-cone structure."
• "shale, dark gray, contains contains small reddish brown weathering ironstone concretions and larger tan weathering ls concretions that have cone-in-cone structure."

Reposited in the USGS

Collection methods: mechanical,

• "[collected] from lower half"

Primary reference: 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]more details

Purpose of describing collection: biostratigraphic analysis

PaleoDB collection 1643: authorized by John Alroy, entered by Mike Sommers on 19.05.1999

Creative Commons license: CC BY (attribution)

Taxonomic list

• "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."
Cephalopoda
 Ammonitida - Nostoceratidae
Exiteloceras sp. Hyatt 1894 ammonite
 Ammonitida - Baculitidae
Baculites rugosus Cobban 1962 ammonite
 Ammonitida - Scaphitidae
Hoploscaphites sp. Nowak 1911 ammonite
sp. nov.
 Ammonitida - Placenticeratidae
Placenticeras sp. Meek 1876 ammonite
 Nautilida - Nautilidae
Eutrephoceras sp. Hyatt 1894
Bivalvia
 Nuculanida - Nuculanidae
Nuculana sp. Link 1807 pointed nut clam
 Pectinida - Pectinoidae
Pecten nebrascensis scallop
(Chlamys)
 Ostreida - Ostreidae
Ostrea sp. Linnaeus 1758 oyster
 Myalinida - Inoceramidae
Inoceramus sp. Sowerby 1814 clam
sp. nov.
 Lucinida - Lucinidae
Lucina sp. Bruguière 1797 clam
Gastropoda
 Trochoidea - Turbinidae
? Atira nebrascensis snail
originally entered as "? Atira nebrascensis"
 Sorbeoconcha - Aporrhaidae
Drepanocheilus nebrascensis snail
originally entered as "Drepanochilus nebrascensis"
 Sorbeoconcha - Naticidae
Scaphopoda
 Dentaliida - Dentaliidae
Bryozoa
  -
Bryozoa indet. Ehrenberg 1831
membraniporoid bryozoan
Bryozoa indet. Ehrenberg 1831
pyriporoid bryozoan