Where: Weld County, Colorado (40.8° N, 104.2° W: paleocoordinates 41.4° N, 101.0° W)

• coordinate based on political unit

• small collection-level geographic resolution

When: Pawnee Creek Formation, Barstovian (16.3 - 12.5 Ma)

• upper part of formation sensu stricto, and there is a "radioisotopic" (Ar-Ar?) date of 14.4 Ma for an ash in the middle level of the formation: Woodburne 1996a

•this date apparently is an average of the dates of 14.5 +/- 0.09 and 14.3 +/- 0.02 Ma (Ar/Ar) given by Dold and Prothero 2003 for the "middle part of the section"

Environment/lithology: terrestrial

Primary reference: R. H. Tedford, T. Galusha, M. F. Skinner, B. E. Taylor, R. W. Fields, J. R. Macdonald, J. M. Rensberger, S. D. Webb, and D. P. Whistler. 1987. Faunal succession and biochronology of the Arikareean through Hemphillian interval (late Oligocene through earliest Pliocene epochs) in North America. In M. O. Woodburne (ed.), Cenozoic Mammals of North America: Geochronology and Biostratigraphy 153-210 [J. Alroy/J. Alroy/P. Wagner]more details

Purpose of describing collection: biostratigraphic analysis

PaleoDB collection 18203: authorized by John Alroy, entered by John Alroy on 05.08.1992, edited by Jonathan Marcot

Creative Commons license: CC BY (attribution)