P-618 (Cambrian of the United States)

Where: Mason County, Texas (30.9° N, 99.0° W: paleocoordinates 16.2° 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)

• local Maryvillia zone is within 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 in Pontotoc section], a middle siltstone and silty limestone unit [ending at 570 feet in Pontotoc section], and an upper limestone unit [ending at 640 feet in Pontotoc section]

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: biostratigraphic analysis

PaleoDB collection 208705: authorized by Melanie Hopkins, entered by Melanie Hopkins on 09.04.2020

Creative Commons license: CC BY (attribution)

Taxonomic list

Show authors, comments, and common names
Trilobita
 Ptychopariida - Tricrepicephalidae
Meteoraspis cf. loisi
 Ptychopariida - Crepicephalidae
"Maryvillia cf. ariston" = Coosina ariston, Coosia cf. albertensis
"Maryvillia cf. ariston" = Coosina ariston Walcott 1916 trilobite