Ouachita Mountains collecting locality C (Cambrian of the United States)

Where: Arkansas (34.7° N, 93.0° W: paleocoordinates 22.3° S, 89.3° W)

• coordinate estimated from map

• outcrop-level geographic resolution

When: Elvinia trilobite zone, Collier Shale Formation, Furongian (497.0 - 485.4 Ma)

• bed-level stratigraphic resolution

Environment/lithology: deep subtidal shelf; lithified lime mudstone

• Channel-form debris flows. Clast deposits that occur in channel-form geometries are known from locality A and perhaps also at localities C and F. The best exposed channel (locality A) is approximately 20-25 m across and about 4 m thick. The clasts are lenticular with tapered margins, perhaps in part due to structural stretching, and range in size from less than 1 to about 5 cm thick and from 2 to 30 cm long. Graded bedding is not observed; however, the long axes of the clasts are usually subparallel to bedding...At locality A the upper contact of the debris flow is undulatory and is capped by a carbonate turbidity-flow deposit. The channel-form debris flow deposits at locality A (perhaps also C and F) may represent either proximal flow or flow retained in a channel system.
• The dark-gray to black limestone clasts [containing fossils] have micritic, microspar, and finely crystalline textures. They are abundant in the channel-form deposits and are supported by a calcareous, bluish-gray shale/slate matrix.

Size class: macrofossils

Primary reference: S. R. Hohensee and J. H. Stitt. 1989. Redeposited Elvinia Zone (Upper Cambrian) trilobites from the Collier Shale, Ouachita Mountains, west-central Arkansas. Journal of Paleontology 63(6):857-879 [M. Hopkins/M. Hopkins]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 229130: authorized by Melanie Hopkins, entered by Melanie Hopkins on 16.02.2023

Creative Commons license: CC BY (attribution)

Taxonomic list

Artiopoda
 Agnostida - Agnostidae
Kymagnostus harti Hohensee and Stitt 1989
Neoagnostus dilatus Hohensee and Stitt 1989
Trilobita
  - Nepeidae
Xenocheilos minutum Wilson 1949 trilobite
 Olenida - Dokimokephalidae
Kindbladia wichitaensis Resser 1942 trilobite
Dellea suada Walcott 1890 trilobite
 Olenida - Pterocephaliidae
Pulchricapitus fetosus Hohensee and Stitt 1989 trilobite
Pterocephalia sanctisabae Roemer 1849 trilobite