USGS D1872 (Cretaceous of the United States)

Also known as Pierre Shale (USGS D1872)

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: Baculites perplexus ammonoid zone, Mitten Black Shale Member (Pierre Shale Formation), Campanian (83.6 - 72.1 Ma)

• Was bed 29.

• bed-level stratigraphic resolution

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

• "shale, dark gray, contains ls concretions that weather light brown, yellowish gray, moderate brown, yellowish brown and dark yellowish orange. Persistent beds of concretions are present at base and at top and at 19, 50, and 74 ft above base; concretions in upper 4 ft may be septarian with yellow calcite."
• "shale, dark gray, contains ls concretions that weather light brown, yellowish gray, moderate brown, yellowish brown and dark yellowish orange. Persistent beds of concretions are present at base and at top and at 19, 50, and 74 ft above base; concretions in upper 4 ft may be septarian with yellow calcite."

Size class: macrofossils

Reposited in the USGS

Collection methods: mechanical,

• "[collected] from concretions 75 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 1727: 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
Bryozoa
  -
Bryozoa indet.
Bryozoa indet. Ehrenberg 1831
pyriporoid bryozoan
Bivalvia
 Myalinida - Inoceramidae
"Inoceramus subcompressus" = Cataceramus subcompressus
"Inoceramus subcompressus" = Cataceramus subcompressus Meek and Hayden 1860 clam
Cephalopoda
 Ammonitida - Baculitidae
Baculites perplexus
Baculites perplexus Cobban 1962 ammonite
 Ammonitida - Scaphitidae
Hoploscaphites sp.
Hoploscaphites sp. Nowak 1911 ammonite
sp. nov.