LL-548 (Cambrian of the United States)

Where: Llano County, Texas (30.9° N, 98.6° W: paleocoordinates 16.5° S, 97.8° W)

• coordinate estimated from map

• outcrop-level geographic resolution

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

• The local Maryvillia trilobite zone is within the Crepicephalus Laurentian trilobite zone

• bed-level stratigraphic resolution

Environment/lithology: marine; lithified, fine-grained, medium, 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 [not present at Little Llano], a middle siltstone and silty limestone unit [ending at 465 feet at Little Llano], and an upper limestone unit [ending at 560 feet at Little Llano].

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 208658: 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
Lingulata
 Acrotretida - Acrotretidae
Opisthotreta depressa
Trilobita
 Ptychopariida - Crepicephalidae
"Maryvillia cf. ariston" = Coosina ariston
"Maryvillia cf. ariston" = Coosina ariston Walcott 1916 trilobite