USNM 31a, Log Cabin Mbr, Pioche Hills (Cambrian of the United States)

Also known as 31a

Where: Lincoln County, Nevada (37.9° N, 114.5° W: paleocoordinates 3.3° S, 93.0° W)

• coordinate based on nearby landmark

• outcrop-level geographic resolution

When: Log Cabin Member (Pioche Shale Formation), St Davids (513.0 - 501.0 Ma)

• "Lower Cambrian Limestone and interbedded siliceous shales of the Pioche Formation, just above quartzite" [Walcott, 1908a, p. 11; Walcott, 1912, p. 192]. Probably correlates to Delamaran stage. Early Middle Cambrian in age. The Log Cabin Member is approximately 50 m thick in the Pioche Hills.

• bed-level stratigraphic resolution

Environment/lithology: shelly/skeletal, calcareous limestone and silty mudstone

• The Log Cabin Member is part of a fourth or fifth order cycle bounded by erosional surfaces. The overall lithostratigraphic package shown by the Log Cabin Member is of a coarsening and shallowing upward succession, consistent with a highstand systems tract deposit.
• Bioclastic limestone within silty mudstone

Size class: macrofossils

Reposited in the USNM

• Described specimens are deposited in the US National Museum, Washington, D.C. No preparatory or collection methods described.

Primary reference: C. D. Walcott. 1908. Cambrian sections of the Cordilleran area. Smithsonian Miscellaneous Collections 53(5):167-230 [A. Miller/A. Hendy/A. Hendy]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 50115: authorized by Austin Hendy, entered by Austin Hendy on 08.05.2005, edited by Jonathan Marcot

Creative Commons license: CC BY (attribution)

Taxonomic list

• Exhaustive for trilobites.
 Ptychopariida - Ptychopariidae
Plagiura extensa2, Kochiella augusta2, "Kochaspis cf. eiffelensis" = Kochiella eiffelensis1
Plagiura extensa2 Palmer and Halley 1979 trilobite
Kochiella augusta2 Walcott 1886 trilobite
"Kochaspis cf. eiffelensis" = Kochiella eiffelensis1 Rasetti 1951 trilobite
 Ptychopariida -
Hadrocephalites sp.2 Sundberg and McCollum 2002 trilobite
Kochaspis liliana2 Walcott 1886 trilobite
 Corynexochida - Oryctocephalidae
Oryctocephalus primus2 Walcott 1886 trilobite
 Corynexochida - Zacanthoididae
Stephenaspis highlandensis2 Sundberg and McCollum 2003 trilobite
 Redlichiida - Olenellidae
Olenellus gilberti n. sp.3 White 1874 trilobite