Where: Montana (48.2° N, 112.9° W: paleocoordinates 40.6° N, 51.8° W)

• coordinate estimated from map

• small collection-level geographic resolution

When: Middle Shale Member (Sawtooth Formation), Bajocian to Bajocian (170.3 - 166.1 Ma)

• near base of middle member of Sawtooth formation and 20 ft above base of formation; the Middle Shale member is probably of Bajocian to Bathonian age

• bed-level stratigraphic resolution

Environment/lithology: marine; lithified shale

Size class: macrofossils

Reposited in the USGS

• collection was made by R. W. Imlay in 1944

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 68829: authorized by Martin Aberhan, entered by Sabine Nürnberg on 09.02.2007, edited by Pedro Monarrez

Creative Commons license: CC BY (attribution)