Where: Montana (46.7° N, 113.3° W: paleocoordinates 39.2° N, 52.5° W)

• coordinate estimated from map

• small collection-level geographic resolution

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

• from 44 ft of gray calcareous shale and shaly limestone whose base is about 73 ft above base of Sawtooth formation and whose top is about 113 ft below top of formation; the Middle Shale member is probably of Bajocian to Bathonian age

• group of beds-level stratigraphic resolution

Environment/lithology: marine; lithified, gray, calcareous shale

Size class: macrofossils

Reposited in the USGS

• collection was made by R. W. Imlay in 1945

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 68839: authorized by Martin Aberhan, entered by Sabine Nürnberg on 10.02.2007

Creative Commons license: CC BY (attribution)