ammonites
USGS Mesozoic loc. 27037, Sun River area, Western Montana (Jurassic of the United States)

Where: Montana (47.6° N, 112.7° W: paleocoordinates 39.3° N, 51.0° W)

• coordinate stated in text

• small collection-level geographic resolution

When: Lower Sandstone Member (Sawtooth Formation), Bajocian (171.6 - 167.7 Ma)

• from lower sandstone member of Sawtooth formation; the Lower Sandstone member is probably of Bajocian age

• group of beds-level stratigraphic resolution

Environment/lithology: marine; lithified sandstone

• The lower member of the Sawtooth formation consists of siliceous sandstone and sandy limestone.

Size class: macrofossils

Reposited in the USGS

• collection was made by R. W. Imlay in 1958

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 68828: authorized by Martin Aberhan, entered by Sabine Nürnberg on 09.02.2007