Okay Quarry [Ozan Fm] (Cretaceous of the United States)

Where: Howard County, Arkansas (33.8° N, 93.9° W: paleocoordinates 37.9° N, 65.7° W)

• coordinate based on nearby landmark

• outcrop-level geographic resolution

When: Bostrchoceras polyplocum ammonoid zone, Ozan Formation (Taylor Group), Late/Upper Campanian (83.5 - 70.6 Ma)

• STRATIGRAPHIC RELATIONS: From the Ozan Fm, which is regionally overlain by the Annona Fm, both of the Taylor Gp. AGE: Late Campanian on the basis of ammonite biostratigraphy; Bostrchoceras polyplocum zone. STRATIGRAPHIC POSITION: From very top of Ozan Fm.

• bed-level stratigraphic resolution

Environment/lithology: lithified lime mudstone

• ENVIRONMENT: Shallow marine cabonate setting.
• SPECIFIC LITHOLOGY: Grey weathering chalky marl. LITHIFICATION: Lithified, on the basis of figured specimens.

Size class: macrofossils

Preservation: cast, mold/impression

Collected by Kennedy et al. in 1973-1974; reposited in the USNM

Collection methods: surface (in situ),

• COLLECTOR: W.J. Kennedy, W.A. Cobban, R.E. Burkholder, and B.F. Clardy, 1974-1974. REPOSITORY: USNM, Washington DC.

Primary reference: W. J. Kennedy and W. A. Cobban. 1993. Upper Campanian ammonites from the Ozan-Annona Formation boundary in Southwestern Arkansas. Bulletin of the Geological Society of Denmark 40:115-148 [A. Hendy/A. Hendy/A. Hendy]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 83055: authorized by Austin Hendy, entered by Austin Hendy on 06.08.2008

Creative Commons license: CC BY (attribution)

Taxonomic list

• COVERAGE: Exhaustive for ammonoids, and including informally listed bivalves and gastropods. NOMENCLATURE: An authoritative publication, with modern nomenclature and species-resolution identifications.
Cephalopoda
 Ammonitida - Nostoceratidae
Didymoceras sp. Hyatt 1900 ammonite
Didymoceras donezianum Michailov 1951 ammonite
Nostoceras (Nostoceras) archiacianum d'Orbigny 1842 ammonite
 Ammonitida - Diplomoceratidae
Neancyloceras cf. bipunctatum Schl├╝ter 1872 ammonite