Pierre Shale (USGS D1937) (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, gray, yellow shale and limestone

• "shale, weathers med. gray; contains a few scattered yellowish gray weathering ls concretions, with more persistent beds of concretions at base and 56 ft and 76 ft above base; basal concretions have cone-in-cone structure."

Preservation: original aragonite

Reposited in the USGS

Collection methods: mechanical,

• "[collected] from concretions 76 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 1647: authorized by John Alroy, entered by Mike Sommers on 25.05.1999

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."
Show authors, comments, and common names
Bivalvia
 Carditida - Crassatellidae
Crassatella evansi
 Myalinida - Inoceramidae
Inoceramus aff. turgidus
Inoceramus aff. turgidus Anderson 1958 clam
originally entered as "Inoceramus aff. turgidus"
Scaphopoda
 Dentaliida - Dentaliidae
Dentalium sp.
Dentalium sp. Linnaeus 1758 tusk shell
Cephalopoda
 Ammonitida - Scaphitidae
Hoploscaphites sp.
Hoploscaphites sp. Nowak 1911 ammonite
 Ammonitida - Baculitidae
Baculites crickmayi
Baculites crickmayi Williams 1930 ammonite