UM Collections 2 (unlisted numbers - Univ. MO, Columbia) (Carboniferous to of the United States)

Also known as Sando et al. Amsden Hill Loc.25

Where: Fremont County, Wyoming (42.6° N, 108.7° W: paleocoordinates 0.8° N, 39.5° W)

• coordinate estimated from map

• small collection-level geographic resolution

When: Anthracospirifer welleri-shawi zone, Horseshoe Member (Amsden Formation), Chesterian to Chesterian (339.4 - 314.6 Ma)

• Float from middle red shale unit in lower part of Amsden Fm. "Late Mississippian (Chesterian)."

• bed-level stratigraphic resolution

Environment/lithology: offshore; lithified, red, silty, sandy, calcareous shale and gypsiferous, shelly/skeletal shale

• horseshoe: predominantly fissile, platy or blocky siltstone, shale, and mudstone. weathers bright red to grayish red or purple. thin beds and lenses of platy, white to red, fine grained, commonly calcareous quartz sandstone occur sporadically throughout member. thin beds of silty, sandy, or argillaceous limestone are rare in central wy, significant proportion in western wy. dolomite is a rare constituent. limestone beds are either fine grained and unfossiliferous or fine to medium grained and contain a shelly fauna. anhydrite and gypsum present at several localities. represents offshore marine facies of the transgressing amsden sea.

Collection methods: "Fossils listed by Morey, 1935, p474-482."

Primary reference: W. J. Sando, M. Gordon, Jr., and J. T. Dutro. 1975. Stratigraphy and geologic history of the Amsden Formation (Mississippian and Pennsylvanian) of Wyoming. United States Geological Survey Professional Paper 848A:1-83 [J. Alroy/M. Sommers/M. Uhen]more details

Purpose of describing collection: biostratigraphic analysis

PaleoDB collection 5690: authorized by John Alroy, entered by Mike Sommers on 15.11.1999

Creative Commons license: CC BY (attribution)

Taxonomic list

 Palaeocopida - Amphissitidae
 Platycopida - Hollinellidae
 Platycopida - Cavellinidae