Where: Montana (48.6° N, 112.4° W: paleocoordinates 56.3° N, 78.3° W)

• coordinate based on nearby landmark

• small collection-level geographic resolution

When: Upper Member (Two Medicine Formation), Late/Upper Campanian (83.5 - 70.6 Ma)

• Upper Two Medicine Formation (upper Campanian) of northwestern Montana, about 55

•m below the contact with the Bearpaw Shale. The Two Medicine Formation is about 650 m thick and consists primarily of mudstones, siltstones, and fine-grained lenticular sandstones, interbedded with bentonites of varying thickness (Dawson 1885; Stebinger 1914; Rogers et al. 1993). The Upper Two Medicine has been dated by Rogers et al. (1993) using radioisotopes at 74 Ma (10 m below top of formation), an age accepted by Eberth (1997) and Trexler (2001). The top of the Dinosaur Park Formation was given an age of 74-74.5 Ma by Eberth (1997), but of 75 Ma or older by Hamblin (1994). Eberth (2005) refined this to around 74.9 Ma. Thus, the uppermost Two Medicine sediments are slightly younger than the latest Dinosaur Park beds.

• bed-level stratigraphic resolution

Environment/lithology: terrestrial; gray siltstone

Size class: macrofossils

Collected by J. Horner & MOR field crews in 1986-1987

Collection methods: quarrying, surface (in situ), mechanical,

• MOR, Museum of the Rockies, Boseman, Montana, USA

Primary reference: K. Carpenter. 1990. Ankylosaur systematics: example using Panoplosaurus and Edmontonia (Ankylosauria: Nodosauridae). In K. Carpenter & P. J. Currie (ed.), Dinosaur Systematics: Approaches and Perspectives 281-298 [M. Carrano/M. Carrano/M. Carrano]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 138980: authorized by Roger Benson, entered by Roger Benson on 05.02.2013, edited by Matthew Carrano

Creative Commons license: CC BY (attribution)