Slippery Creek, 20 (Belle Plains Formation) (Permian of the United States)

Also known as Locality 20 (Romer 1928), Locality Vc (Romer & Price 1940), Lyle locality, Pearce locality, Young locality, faunal Zone 2, Middle Wichita Group, Texas red-beds, redbeds

Where: Archer County, Texas (33.7° N, 98.9° W: paleocoordinates 0.1° N, 29.5° W)

• coordinate based on nearby landmark

• local area-level geographic resolution

When: Belle Plains Formation (Wichita Group), Artinskian (290.1 - 279.3 Ma)

• "about 450-500 feet above the Coleman Junction Limestone, and not far below the Beaverburk." Details for Faunal Zone 2 of Romer 1928: "Beyond the horizon of Godwin Creek is found a series of beds about 200 feet in thickness, of a transitional character, in which thin and impure limestones are occasionally present."

•the base of the Artinskian is just above Coleman Junction Formation (Wardlaw 2005, Permophiles), and the "Belle Plains" = Petrolia Formation is below the Waggoner Ranch Formation, whose base equals the base of the Bead Mountain Formation (Tabor et al. 2002), which is in the middle of the Artinskian (Wardlaw 2005)

• group of beds-level stratigraphic resolution

Environment/lithology: terrestrial; red claystone and limestone

• red-beds and "6-inch limestone"

Size class: macrofossils

Collection methods: Romer (1928) paper is a review of vertebrates from the Texas red-beds with previously unreported (or undetailed) localities.

Primary reference: A. S. Romer. 1928. Vertebrate faunal horizons in the Texas Permo-Carboniferous red beds. University of Texas Bulletin 2801:67-108 [J. Alroy/R. Whatley/W. Clyde]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 28146: authorized by John Alroy, entered by Robin Whatley on 25.01.2003, edited by Torsten Liebrecht and Emma Dunne

Creative Commons license: CC BY (attribution)

Taxonomic list

 Cotylosauria -
Archeria sp.3 Case 1918 tetrapod
MCZ 2075 and 2079
 Synapsida - Sphenacodontidae
Ctenospondylus casei n. gen. n. sp.1 Romer 1936 synapsid
AMNH 4047 (type)
Dimetrodon sp. Cope 1878 synapsid
 Synapsida - Ophiacodontidae
Varanosaurus wichitaensis n. sp.2 Romer 1937 ophiacodont
MCZ 1353 (type); UM 11665, 15438
Ophiacodon retroversus4 Cope 1878 ophiacodont
FMNH (WM) 458; MCZ 1470
Ophiacodon uniformis4 Cope 1878 ophiacodont
MCZ 1295
 Cotylosauria - Diadectidae
Diadectes sp. Cope 1878 tetrapod
 Temnospondyli - Zatracheidae
Zatrachys sp. Cope 1878 tetrapod
 Temnospondyli - Trimerorhachidae
Trimerorhachis sp. Cope 1878 tetrapod
entered as "Trimerorachis"
 Temnospondyli - Eryopidae
Eryops sp. Cope 1877 tetrapod