Bed 9g (Lancha Limestone) - Pacheta Mbr, Lowell Fm, Ninety One Hills (Cretaceous of the United States)

Where: Cochise County, Arizona (31.4° N, 109.9° W: paleocoordinates 32.0° N, 63.5° W)

• coordinate based on nearby landmark

• outcrop-level geographic resolution

When: Pacheta Member (Lowell Formation), Aptian (125.0 - 113.0 Ma)

• STRATIGRAPHIC RELATIONS: Immediately overlying the Morita Fm (Aptian) and underlying the Joserita Mbr (Aptian) of the Lowell Fm (Aptian-Albian). THICKNESS: 11 ft thick bed. AGE: Aptian, based on ammonite and trigoniid biostratigraphy. STRATIGRAPHIC POSITION: Immediately above contact with Morita Fm and below Bed 9f of the Pacheta Mbr.

• bed-level stratigraphic resolution

Environment/lithology: lithified, gray, red, blue, sandy, cherty/siliceous limestone

• ENVIRONMENT: Environmental data not reported, presumably shallow water carbonate. PROVINCE: Pedregosa basin
• SPECIFIC LITHOLOGY: Grayish. bluish-gray and pinkish limestone in places arenaceous or partly silicicified. LITHIFICATION: Lithified, based on facies description, figures and age.

Size class: macrofossils

Reposited in the USNM

• COLLECTOR: A. Stoyanow, assisted by G. Scott, J.B. Reeside, and R.W. Imlay. REPOSITORY: USNM, Washington and U. Texas and Bureau of Economic Geology, Texas.

Primary reference: A. Stoyanow. 1949. Lower Cretaceous stratigraphy in southeastern Arizona. Geological Society of America Memoir 38:1-156 [A. Hendy/A. Hendy]more details

Purpose of describing collection: biostratigraphic analysis

PaleoDB collection 65011: authorized by Austin Hendy, entered by Austin Hendy on 18.09.2006

Creative Commons license: CC BY (attribution)

Taxonomic list

• COMPLETENESS: Not exhaustive, but representative of common and biostratigraphically significant forms. NOMENCLATURE: Authoritative publication for ammonites and bivalvia, and hence these carry species-level names; other taxa often not designated with species-level names.
Show authors, comments, and common names
Bivalvia
 Nuculida - Nuculidae
Acila (Truncacila) schencki
Acila (Truncacila) schencki Stoyanow 1949 divaricate nutclam
 Ostreida - Gryphaeidae
Exogyra lancha
Exogyra lancha Stoyanow 1949 oyster
 Arcida - Cucullaeidae
Idonearca stephensoni
Idonearca stephensoni Stoyanow 1949 clam
 Trigoniida - Trigoniidae
Trigonia reesidei
Trigonia reesidei Stoyanow 1949 clam