Upper Weeks Formation at North Canyon, House Range, UT (Cambrian of the United States)

Where: Millard County, Utah (39.2° N, 113.3° W: paleocoordinates 5.2° S, 88.2° W)

• coordinate stated in text

• outcrop-level geographic resolution

When: Weeks Formation, Dresbachian (501.0 - 485.4 Ma)

• group of beds-level stratigraphic resolution

Environment/lithology: deep subtidal shelf; lithified, peloidal, gray lime mudstone and lithified, yellow siltstone

• The unit consists of approximately 300 m of shallowing-upward, mostly thin-bedded lime mudstones with variable but limited amounts of sand-sized and finer siliciclastic sediments. upper Weeks Formation, which consists primarily of thinly bedded (0.5-4.0 cm) silty lime-mudstone. The silt to fine quartz sand portion of this facies typically forms thin, reddish-orange, irregular laminae and parting surfaces between grey lime-mudstone with common peloids

Size class: macrofossils

Preservation: soft parts, replaced with silica

Collection methods: quarrying, mechanical,

• Quantitative paleoecologic sample from approximately 20cm interval

Primary reference: S. E. Peters. 2003. Evenness, richness and the Cambrian-Paleozoic faunal transition in North America: an assemblage-level perspective. The University of Chicago 1-279 [S. Peters/S. Peters/P. Wagner]more details

Purpose of describing collection: paleoecologic analysis

PaleoDB collection 50592: authorized by Shanan Peters, entered by Shanan Peters on 18.05.2005

Creative Commons license: CC BY (attribution)

Taxonomic list

Trilobita
 Agnostida - Agnostidae
 Agnostida - Marjumiidae
Modocia weeksensis n. sp. trilobite
 Ptychopariida - Llanoaspididae
 Ptychopariida - Cedariidae
Cedaria minor trilobite
 Ptychopariida - Menomoniidae
Menomonia semele trilobite
Nephalicephalus beebei n. gen. n. sp. trilobite
 Ptychopariida - Norwoodiidae
 Ptychopariida - Tricrepicephalidae
 Ptychopariida - Lonchocephalidae
  -
Selenocoryphe platyura n. gen. n. sp.
Selenocoryphe platyura n. gen. n. sp. trilobite
Xiphosura
 Aglaspida - Beckwithiidae
Lingulata
 Lingulida - Obolidae
Lingulella sp. Salter 1866