USGS Mesozoic loc. 27506, Sun River area, Western Montana (Jurassic of the United States)

Where: Montana (47.7° N, 112.7° W: paleocoordinates 40.4° N, 52.1° W)

• coordinate stated in text

• small collection-level geographic resolution

When: Upper Siltstone Member (Sawtooth Formation), Bathonian (168.3 - 166.1 Ma)

• upper siltstone member of Sawtooth formation; the Upper Siltstone member is probably of Bathonian age

• group of beds-level stratigraphic resolution

Environment/lithology: marine; lithified siltstone

• The upper siltstone member consists of yellow calcareous siltstone and fine-grained sandstone.

Size class: macrofossils

Reposited in the USGS

• collection was made by R. W. Imlay 1959

Primary reference: R. W. Imlay. 1962. Jurassic (Bathonian or Early Callovian) Ammonites from Alaska and Montana. Geological Survey Professional Paper 374-C:1-32 [M. Aberhan/S. Nurnberg]more details

Purpose of describing collection: biostratigraphic analysis

PaleoDB collection 68858: authorized by Martin Aberhan, entered by Sabine Nürnberg on 10.02.2007

Creative Commons license: CC BY (attribution)

Taxonomic list

Bivalvia
 Cardiida - Anthracosiidae
"Pleuromya subcompressa" = Myacites (Pleuromya) subcompressa
"Pleuromya subcompressa" = Myacites (Pleuromya) subcompressa Meek 1873 clam
 Mytilida - Mytilidae
 Ostreida - Pinnidae