Pierre Shale (USGS D1891) (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: Red Bird Silty Member (Pierre Shale Formation), Campanian (83.6 - 72.1 Ma)

• bed-level stratigraphic resolution

Environment/lithology: offshore; concretionary, brown, gray, silty, calcareous shale and limestone

• "shale, silty, weathers light gray, contains a few small light-brown weathering ls concretions in lower 15 ft. Locally a mass of tepee butte ls is present 32 ft above base."
• "shale, silty, weathers light gray, contains a few small light-brown weathering ls concretions in lower 15 ft. Locally a mass of tepee butte ls is present 32 ft above base."

Reposited in the USGS

Collection methods: mechanical,

• "[collected] from 32 ft above base"

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 1712: authorized by John Alroy, entered by Mike Sommers on 03.06.1999

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."
Show authors, comments, and common names
Bivalvia
 Lucinida - Lucinidae
Lucina sp.
Lucina sp. Bruguière 1797 clam
 Myalinida - Inoceramidae
"Inoceramus subcompressus" = Cataceramus subcompressus
"Inoceramus subcompressus" = Cataceramus subcompressus Meek and Hayden 1860 clam
Cephalopoda
 Ammonitida - Baculitidae
Baculites gilberti
Baculites gilberti Cobban 1962 ammonite