USGS Loc. D4078 San Juan Basn [Lewis Shale] (Cretaceous of the United States)

Where: New Mexico (36.4° N, 106.8° W: paleocoordinates 43.4° N, 78.1° W)

• coordinate stated in text

• outcrop-level geographic resolution

When: Didymoceras nebrascense ammonoid zone, Lewis Shale Formation, Late/Upper Campanian (83.5 - 70.6 Ma)

• STRATIGRAPHIC RELATIONS: From the Lewis Shale, for which lithostratigraphic relations are not discussed. AGE: Late Campanian, on the ammonoid biostratigraphy; Didymoceras nebrascense zone. STRATIGRAPHIC POSITION: About unknown position within formation.

• bed-level stratigraphic resolution

Environment/lithology: marine; lithified, concretionary, gray, calcareous shale

• SPECIFIC LITHOLOGY: Gray weathering limestone concretions in shale. LITHIFICATION: Lithified, assumed on the neighboring collections.

Size class: macrofossils

Preservation: concretion

Reposited in the USNM

Collection methods: surface (in situ),

• COLLECTOR: Scott, 1963; Dane, Landis, Cobban, 1963. REPOSITORY: USNM.

Primary reference: W. A. Cobban, E. R. Landis, and C. H. Dane. 1974. Age relations of upper part of Lewis Shale on east side of San Juan Basin, New Mexico. New Mexico Geological Society Guidebook, 25th Field Conference, Ghost Ranch 279-282 [A. Hendy/A. Hendy/A. Hendy]more details

Purpose of describing collection: biostratigraphic analysis

PaleoDB collection 88556: authorized by Austin Hendy, entered by Austin Hendy on 14.04.2009

Creative Commons license: CC BY (attribution)

Taxonomic list

• COVERAGE: Exhaustive for ammonoids and bivalves. NOMENCLATURE: Authoritative publication, with modern nomenclature and species-resolution identifications.
 Myalinida - Inoceramidae
Inoceramus aff. turgidus Anderson 1958 clam
 Ammonitida - Baculitidae
Baculites pseudovatus Elias 1933 ammonite
 Ammonitida - Nostoceratidae
Didymoceras nebrascense Meek and Hayden 1856 ammonite