Ouachita Mountains collecting locality D (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

• Sheet-form debris flows. -These deposits have a very high ratio of shale matrix to limestone clasts. Actual geometries of the deposits are difficult to assess because the allochthonous mud matrix is very similar to the surrounding autochthonous hemipelagic mud. Although the clasts are randomly distributed, their long axes are crudely parallel to the apparent bedding in discrete layers that are tens of centimeters thick, suggesting a sheet-form geometry. Deposits of this type are found at localities B, D, and E and possibly at localities F, K, L, N, and P (see Figure 1). Distribution of clasts at locality J suggests a multiple sheet-form flow or thicker debris-flow deposit. Competence of the mud matrix presumably was high enough to completely support clasts as large as the scarce small boulders observed at localities L and J. Common clast textures include micritic, microspar, and finely crystalline limestones and some shales. Clastsize is variable from pebbles to small boulders. Evidence of lithification prior to erosion and redeposition as clasts is indicated by angular fracturing and truncation across internal laminations. Deposits of this type probably represent either unconsolidated debris over-flow or a more distal facies.
• dark-gray to black limestone clasts [containing fossils] have micritic, microspar, and finely crystalline textures.

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 229131: authorized by Melanie Hopkins, entered by Melanie Hopkins on 16.02.2023

Creative Commons license: CC BY (attribution)

Taxonomic list

Trilobita
 Corynexochida - Cheilocephalidae
Cheilocephalus brachyops Palmer 1965 trilobite
Pseudokingstonia exotica Palmer 1965 trilobite
 Ptychopariida - Catillicephalidae
 Ptychopariida - Phylacteridae
Aphelotoxon lumaleasa Hohensee and Stitt 1989 trilobite
Drabia typica Hu 1979 trilobite
Cliffia lataegenae Wilson 1949 trilobite
Cliffia magnacilis Hohensee and Stitt 1989 trilobite
 Ptychopariida - Kingstoniidae
 Ptychopariida - Elviniidae
Irvingella major Ulrich and Resser 1924 trilobite
Jessievillia radiatus n. sp. Hohensee and Stitt 1989 trilobite
Elvinia roemeri trilobite
  - Nepeidae
Xenocheilos minutum Wilson 1949 trilobite
 Olenida - Dokimokephalidae
Pseudosaratogia lata Wilson 1951 trilobite
Kindbladia wichitaensis Resser 1942 trilobite
Apachia genaitholix Hohensee and Stitt 1989 trilobite
Dellea sp. Wilson 1949 trilobite
Dellea planafrons n. sp. Hohensee and Stitt 1989 trilobite
Dellea suada Walcott 1890 trilobite
 Olenida - Pterocephaliidae
Pterocephalia sanctisabae Roemer 1849 trilobite
Pulchricapitus fetosus n. sp. Hohensee and Stitt 1989 trilobite
Housia vacuna Walcott 1890 trilobite
Morosa bothra Stitt 1971 trilobite
 Olenida - Olenidae
"Simulolenus sp." = Olenus
"Simulolenus sp." = Olenus Dalman 1827 trilobite
Artiopoda
 Agnostida - Agnostidae
Neoagnostus dilatus Hohensee and Stitt 1989
Kymagnostus harti n. sp. Hohensee and Stitt 1989