Where: Montana (44.0° N, 112.0° W: paleocoordinates 13.4° N, 34.9° W)

• coordinate based on nearby landmark

• small collection-level geographic resolution

When: Thaynes Formation, Spathian (251.3 - 247.2 Ma)

• Most recently, the Thaynes formation has been separated into four facies belts, which include a basinal facies, an outer shelf facies, an inner shelf facies, and a red bed facies. the basinal facies consists of dark grey to black very siltly lime mudstones and gray to loive drab siltstones and shales. The outer shelf facies belt is characterized by dark grayish brown whole fossil wackestone, ranging to light gray bioclastic grainstone, with minor interbedded sanstone, siltstone, and mudstone. The inner shelf facies includes a variety of lithologies, mainly fine-grained mudstone and silty limestone, along with less common dolomite, siltstone, and bioturbated mudstone.

• group of beds-level stratigraphic resolution

Environment/lithology: marine; limestone

Size class: macrofossils

Primary reference: J. K. Schubert and D. J. Bottjer. 1995. Aftermath of the Permian-Triassic mass extinction event: Paleoecology of Lower Triassic carbonates in the western USA. Palaeogeography, Palaeoclimatology, Palaeoecology 116:1-39 [D. Bottjer/N. Bonuso/N. Bonuso] more details

Purpose of describing collection: paleoecologic analysis

PaleoDB collection 32974: authorized by David Bottjer, entered by Nicole Bonuso on 21.07.2003