4 mile SW Marathon section, collection 1 ( of the United States)

Where: Brewster County, Texas (30.2° N, 103.3° W: paleocoordinates 16.4° S, 92.2° W)

• coordinate estimated from map

• outcrop-level geographic resolution

When: Roberts Ranch Member (Dagger Flat Formation), Tremadoc (486.5 - 477.7 Ma)

Environment/lithology: basinal (); fine-grained, gray, sandy limestone and gray, green shale

• "dark gray ls and green to dark sh. deep water? (basinal) BA6."
• Limestone, sandy, fine-grained, finely cross-bedded, flaggy, dark gray; weathers moderate yellowish brown and interbedded with much greenish gray shale. Lower 10 feet forms ridge traceable for several hundred yards. Collection in base of these beds.

Size class: macrofossils

Collected by Wilson in 1951-52

Primary reference: J.L. Wilson. 1954. Late Cambrian and Early Ordovician Trilobites from the Marathon Uplift, Texas. Journal of Paleontology 28(3):249-285 [P. Wagner/P. Wagner]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 279: authorized by Jack Sepkoski, entered by Mike Sommers on 20.11.1998

Creative Commons license: CC BY (attribution)

Taxonomic list

• This collection record was created to encompass all of the collections made from Dagger Flat and described in Wilson 1954; this record now represents the first collection made from this section and new records have been created for the other collections from the section.
Show authors, comments, and common names
Artiopoda
 Agnostida - Diplagnostidae
"Litagnostus sp." = Pseudagnostus
"Litagnostus sp." = Pseudagnostus Jaekel 1909
 Agnostida - Agnostidae
"Geragnostus rudis" = Trilobagnostus rudis
"Geragnostus rudis" = Trilobagnostus rudis Salter 1864
Trilobita
 Olenida - Olenidae
Leptoplastus sp.
Leptoplastus sp. Angelin 1854 trilobite