Pierre Shale (USGS D1958) (Cretaceous of the United States)

Where: Niobrara County, Wyoming (43.3° N, 104.3° W: paleocoordinates 49.8° N, 78.5° W)

• coordinate estimated from map

• small collection-level geographic resolution

When: upper unnamed shale Member (Pierre Shale Formation), Maastrichtian (72.1 - 66.0 Ma)

• bed-level stratigraphic resolution

Environment/lithology: offshore; lithified, gray shale and limestone

• "Shale. dark gray; weathers light medium gray; contains some brown weathering ls concretions 6 in thick and 9 in diam, which in upper few ft and at base are very fossiliferous."

Reposited in the USGS

Collection methods: mechanical,

• "[collected] from upper few feet"

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 1583: authorized by John Alroy, entered by Mike Sommers on 17.05.1999

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."
 Serpulimorpha -
? Diploconcha sp.
originally entered as "? Diploconcha sp."
 Arcida - Cucullaeidae
"Idonearca shumardi" = Cucullaea (Idonearca)
"Idonearca shumardi" = Cucullaea (Idonearca) clam
 Myalinida - Inoceramidae
? Inoceramus cf. fibrosus Meek and Hayden 1857 clam
originally entered as "? Inoceramus cf. fibrosus"
 Pectinida - Anomiidae
Anomia sp. Linnaeus 1758 jingle
 Pectinida - Oxytomidae
Oxytoma nebrascana Evans and Shumard 1857 scallop
 Nuculida - Nuculidae
Nucula planimarginata Meek and Hayden 1857 nut clam
 Protobranchia - Nuculanidae
Nuculana evansi pointed nut clam
 Opisthobranchia - Bullidae
Bullopsis aff. cretacea Conrad 1858 snail
originally entered as "Bullopsis aff. cretacea"
 Neogastropoda - Melongenidae
 Neogastropoda - Fasciolariidae
 Stromboidea - Aporrhaidae
Drepanocheilus evansi snail
originally entered as "Drepanochilus evansi"
 Naticoidea - Naticidae
 Pyramidelloidea - Scaphandridae
 Ammonitida - Scaphitidae
Discoscaphites sp. Meek 1870 ammonite
sp. nov.
 Ammonitida - Baculitidae