⅛ mile north of the Gallatin River along the Pilgrim cliff, Logan (Cambrian of the United States)

Where: Logan County, Montana (45.9° N, 111.5° W: paleocoordinates 6.2° S, 81.3° W)

• small collection-level geographic resolution

When: Aphelaspis trilobite zone, Pilgrim Formation, Steptoean (497.0 - 493.5 Ma)

• The fossils are from a one foot square and 2 inch thick patch at the highest Pilgrim bed. Interpretted as the molts from a single population accumulation into a debris pile on the sea floor at a depth of 75-100 feet.

•Was Maentwrogian, but Alphelaspis is Steptoan (PJW).

• bed-level stratigraphic resolution

Environment/lithology: offshore; lithified, gray limestone

• very fine grained gray limestone

Size classes: macrofossils, mesofossils

Collection methods: bulk,

• The trilobites are regarded as being inhabitants of the paleolocality while the Labiostria fragments and gastropods represent transported material.

Primary reference: C. Lochman and C. Hu. 1962. An Aphelaspis Zone faunule from Logan, Montana. Journal of Paleontology 36(3):431-441 [M. Patzkowsky/P. Borkow/J. Ju]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 8662: authorized by Mark Patzkowsky, entered by Phil Borkow on 17.08.2000

Creative Commons license: CC BY (attribution)

Taxonomic list

 Tryblidiida - Tryblidiidae
Proplina loganensis n. sp. Lochman and Hu 1962
 Kiringellida -
Hypseloconus simplex Lochman and Duncan 1944
Hypseloconus simplex simplex
 Corynexochida - Cheilocephalidae
Cheilocephalus brevilobus Walcott 1916 trilobite
 Olenida - Aphelaspidae
"Labiostria sp." = Aphelaspis
"Labiostria sp." = Aphelaspis Resser 1935 trilobite
 Asaphida - Asaphidae
Maryvillia omega n. sp. Lochman and Hu 1962 trilobite
misspelled "Maryville" in abstract.
 Ptychopariida - Lonchocephalidae
Glaphyraspis parva Walcott 1899 trilobite