JR-201 (Cambrian of the United States)

Where: Mason County, Texas (30.6° N, 99.3° W: paleocoordinates 16.0° S, 98.1° W)

• coordinate estimated from map

• outcrop-level geographic resolution

When: Crepicephalus trilobite zone, Cap Mountain Member (Riley Formation), Guzhangian (500.5 - 497.0 Ma)

• local Maryvillia zone is within Crepicephalus Laurentian trilobite zone

• bed-level stratigraphic resolution

Environment/lithology: marine; lithified, glauconitic, brown, gray limestone

• ...brown to gray, fine to medium granular, glauconitic and occasionally oolitic sandy or silty limestone...it can be subdivided into a lower limestone unit [ending at 63 feet at James River], a middle siltstone and silty limestone unit [ending at 125 feet at James River], and an upper limestone unit.

Size class: macrofossils

Collected by A. R. Palmer in 1947-48; reposited in the USNM

Collection methods: mechanical,

Primary reference: A. R. Palmer. 1954. The Faunas of the Riley Formation in Central Texas. Journal of Paleontology 28(6):709-786 [P. Wagner/P. Wagner]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 208621: authorized by Melanie Hopkins, entered by Melanie Hopkins on 07.04.2020

Creative Commons license: CC BY (attribution)

Taxonomic list

Show authors, comments, and common names
Lingulata
 Acrotretida - Acrotretidae
Opisthotreta depressa
Trilobita
 Ptychopariida - Lonchocephalidae
? Lonchocephalus sp.
? Lonchocephalus sp. Owen 1852 trilobite
 Ptychopariida - Kingstoniidae
Kingstonia pontotocensis
 Ptychopariida - Catillicephalidae
Pemphigaspis inexpectans
 Ptychopariida - Crepicephalidae
Crepicephalus australis n. sp., "Maryvillia cf. ariston" = Coosina ariston, Coosia cf. albertensis
Crepicephalus australis n. sp. Palmer 1954 trilobite
"Maryvillia cf. ariston" = Coosina ariston Walcott 1916 trilobite
 Ptychopariida - Tricrepicephalidae
Tricrepicephalus coria