JR-120 (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: Cedaria - Crepicephalus trilobite zone, Cap Mountain Member (Riley Formation), Guzhangian (500.5 - 497.0 Ma)

• local Coosella zone spans Cedaria and Crepicephalus Laurentian trilobite zones

• bed-level stratigraphic resolution

Environment/lithology: marine; lithified, fine-grained, medium, glauconitic, brown, gray, silty limestone and lithified, ooidal, brown, gray siltstone

• ...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 the 1940s; 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 208648: authorized by Melanie Hopkins, entered by Melanie Hopkins on 08.04.2020

Creative Commons license: CC BY (attribution)

Taxonomic list

Show authors, comments, and common names
Kinsabia
  -
Kinsabia variagata
Lingulata
 Acrotretida - Acrotretidae
Opisthotreta depressa
Artiopoda
 Agnostida - Agnostidae
"Kormagnostus simplex" = Kormagnostus seclusus
"Kormagnostus simplex" = Kormagnostus seclusus Walcott 1884
Trilobita
  - Llanoaspididae
Arcuolimbus convexus
Arcuolimbus convexus Palmer 1954 trilobite
 Ptychopariida - Tricrepicephalidae
Tricrepicephalus coria, Tricrepicephalus texanus
 Ptychopariida - Marjumiidae
Coosella beltensis, Coosella granulosa