ammonites
USGS "blue file" Loc. 13390 (Carboniferous of the United States)

Where: Fergus County, Montana (46.9° N, 109.1° W: paleocoordinates 5.4° N, 35.2° W)

• coordinate estimated from map

• small collection-level geographic resolution

When: Otter Formation, Serpukhovian (326.4 - 318.1 Ma)

• From the bottom 6 inches of this unit. JA: late Chesterian is Serpukhovian according to Mii et al. 1999 (GSA Bull 111:960-973)

• bed-level stratigraphic resolution

Environment/lithology: lagoonal; poorly lithified, black, brown, green, silty, calcareous shale

• Environment was often hypersaline. Numerous gypsiferous beds are common, as well as stromatolites ("calcareous algae").
• siltstone and shale, green, calcareous, platy weathering, slightly resistant, basal 6 inches is black but weathers rusty brown to orange.

Reposited in the USGS

Collection methods: surface (in situ),

Primary reference: W. H. Easton. 1962. Carboniferous formations and faunas of central Montana. United States Geological Survey Professional Paper 348:1-126 [J. Alroy/M. Sommers] more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 5653: authorized by John Alroy, entered by Mike Sommers on 09.11.1999

Creative Commons license: CC BY-NC-ND (attribution-noncommercial-no derivatives)