Clark Fork [Snowy Range Fm] (Cambrian of the United States)

Also known as HG#94.2

Where: Park County, Wyoming (44.8° N, 109.3° W: paleocoordinates 7.8° S, 82.3° W)

• outcrop-level geographic resolution

When: Illaenurus zone, Sage Member (Snowy Range Formation), Trempealeauan (492.5 - 485.4 Ma)

• Represent storm deposits. The formation as a whole represents a transitional facies, intermediate between nearshore clastics and outer-shel carbonates. The Sage Member (occurence of hardgrounds) is 36-67m thick with the hardgrounds forming on upper surfaces of carbonate, flat pebble conglomerates.

• member-level stratigraphic resolution

Environment/lithology: shallow subtidal; lithified, burrowed, hardground, flat-pebble, carbonaceous conglomerate

• General lithology of member: Greenish-gray, soft shale with abundant interbedded greenish carbonate, flat pebble conglomerates (intrasparrudites), calcarenites (biosparite), calcisilites (biopelmicrites and biopelsparites) and columnar to tabular algal limestones. Specimens associated with the hardgrounds. Lithology/placement of hardgrounds: upper surfaces of carbonate, flat pebble conglomerates.

Primary reference: C. E. Brett, W. D. Liddell, and K. L. Derstler. 1983. Late Cambrian hard substrate communities from Montana/Wyoming: the oldest known hardground encrusters. Lethaia 16(4):281-289 [M. Patzkowsky/P. Borkow]more details

Purpose of describing collection: paleoecologic analysis

PaleoDB collection 9921: authorized by Mark Patzkowsky, entered by Phil Borkow on 31.01.2001

Creative Commons license: CC BY (attribution)

Taxonomic list

unclassified
  -
Cyanobacteria indet. Stanier 1973
Renalcis
  - Chabakoviacea
Renalcis sp. Vologdin 1932
tentative identification
unclassified
  -
Echinodermata indet. Klein 1754
Represents at least 2 other echinoderms of unknown affinity and the unknown pelmatozoan holdfast.
Edrioasteroidea
  -
Edrioasteroidea indet. Billings 1858
Stylophora
  -
Stylophora indet. Gill and Caster 1960
Trilobita
  -
Trilobita indet. Walch 1771 trilobite