USGS D13294, Judith River [Kevin Mbr, Marias River Shale] (Cretaceous of the United States)

Also known as USGS D13208, Deerfield Colony Road

Where: Fergus County, Montana (47.3° N, 109.7° W: paleocoordinates 51.0° N, 71.9° W)

• coordinate stated in text

• local area-level geographic resolution

When: Scaphites depressus ammonoid zone, Kevin Member (Marias River Shale Formation), Late/Upper Coniacian (89.3 - 85.8 Ma)

• STRATIGRAPHIC RELATIONS: From the Kevin Mbr of the Marias River Shale, for which lithostratigraphic relationships are not described. AGE: Late Coniacian; on the basis of ammonite biostratigraphy; Scaphites depressus zone. STRATIGRAPHIC POSITION: From the MacGowan concretionary bed.

• bed-level stratigraphic resolution

Environment/lithology: marine; lithified, concretionary, ferruginous shale

• SPECIFIC LITHOLOGY: Prominent rusty interval within the overall dark shale of the slope. It is a concretionary, conglomeratic, glauconitic, fine-grained sandy limestone and limy sandstone containing coarse sand grains, granules, and small to large pebbles of chert as well as shell fragments. LITHIFICATION: Lithified, on the basis of facies description.

Size class: macrofossils

Preservation: mold/impression, replaced with phosphate

Reposited in the USNM

• COLLECTOR: Not stated, but presumably Cobban, c. 1970's. REPOSITORY: USNM or USGS.

Primary reference: W. A. Cobban, T. S. Dyman, and K. W. Porter. 2005. Paleontology and stratigraphy of upper Coniacian–middle Santonian ammonite zones and application to erosion surfaces and marine transgressive strata in Montana and Alberta. Cretaceous Research 26(3):429-449 [A. Hendy/A. Hendy]more details

Purpose of describing collection: biostratigraphic analysis

PaleoDB collection 89500: authorized by Austin Hendy, entered by Austin Hendy on 26.05.2009

Creative Commons license: CC BY (attribution)

Taxonomic list

• COVERAGE: Includes characteristic fossils from many invertebrate groups. NOMENCLATURE: Not an authoritative publication, but with modern nomenclature and species-resolution identification.
 Decapoda - Necrocarcinidae
Necrocarcinus sp. Bell 1863 crab
 Myalinida - Inoceramidae
Inoceramus sp. Sowerby 1814 clam
 Ostreida - Gryphaeidae
Pycnodonte sp. Fischer von Waldheim 1835 oyster
 Ostreida - Pteriidae
Phelopteria sp. Stephenson 1953 pearl oyster
 Cardiida - Arcticidae
Veniella sp. Stoliczka 1870 clam
 Pholadomyida - Pholadomyidae
Pholadomya sp. Sowerby 1823 clam
 Xenophoroidea - Xenophoridae
Xenophora sp. Fischer von Waldheim 1807 carrier shell
 Sorbeoconcha - Turritellidae
Turritella sp. Lamarck 1799 turret shell
 Ammonitida - Collignoniceratidae
Protexanites sp. Matsumoto 1955 ammonite
 Ammonitida - Scaphitidae
Scaphites sp. Parkinson 1811 ammonite
 Ammonitida - Baculitidae
Baculites asper Morton 1830 ammonite
Baculites codyensis Reeside 1927 ammonite
? Rostellites sp. Conrad 1854