Loc. 8. M-18. Road cut on Arkansas Hwy 27, ~16.1 km sw of Marshall (Carboniferous of the United States)

Where: Searcy County, Arkansas (35.8° N, 92.8° W)

• Paleocoordinates: 21.5° S, 43.7° W (Wright 2013)

• coordinate estimated from map

• outcrop-level geographic resolution

When: Imo Formation, Serpukhovian (330.9 - 323.2 Ma)

• Elvirian (E2b-c). late Chesterian is Serpukhovian according to Mii et al. 1999 (GSA Bull 111:960-973)

• bed-level stratigraphic resolution

Environment/lithology: offshore; lithified, concretionary, black, gray, sandy grainstone and shale

• "The environment of deposition...relatively shallow water, low energy offshore area undergoing slow continuous deposition of terrigenous clay with periodic higher-energy incursions of carbonate sediments."
• ...as much as 104 m of dark-gray to black, fissile, clay shale w/ numerous, large, bright-red, orange, or brown concretions. ...the lower 36 m...contains thin limestones, sandstones, and conglomerates.

Reposited in the OSU, USNM

Primary reference: R. D. Hoare, M. J., I.I.I. Heaney, and R. H. Mapes. 1989. Bivalves (Mollusca) from the Imo Formation (Mississippian, Chesterian) of North-Central Arkansas. Journal of Paleontology 63(5):582-603 [P. Wagner/P. Wagner]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 69305: authorized by Pete Wagner, entered by Pete Wagner on 24.02.2007

Creative Commons license: CC0 (CC0)

Taxonomic list

Show authors, comments, and common names
Bivalvia
 Nuculida - Nuculidae
"Nuculopsis okawensis" = Nuculavus okawensis, Economolopsis gordoni
"Nuculopsis okawensis" = Nuculavus okawensis Schenck 1939 nut clam
Economolopsis gordoni Hoare et al. 1989 nut clam
 Nuculanida - Sareptidae
Paleyoldia angustia, Paleyoldia bruta
Paleyoldia angustia Hoare et al. 1989 clam
Paleyoldia bruta Hoare et al. 1989 clam
 Nuculanida - Polidevciidae
Phestia wortheni, Phestia obtusa
Phestia wortheni Hoare et al. 1989 clam
Phestia obtusa Hoare et al. 1989 clam