Riverdale (Paleocene of the United States)

Also known as L1, L5507, L6200

Where: McLean County, North Dakota (47.5° N, 101.2° W: paleocoordinates 52.1° N, 79.1° W)

• coordinate based on political unit

When: Sentinel Butte Formation, Tiffanian (61.7 - 56.8 Ma)

Environment/lithology: terrestrial

Primary reference: R. C. Holtzman. 1978. Late Paleocene Mammals of the Tongue River Formation, Western North Dakota. North Dakota Geological Survey Report of Investigations 65:1-88 [J. Alroy/J. Alroy/M. Uhen]more details

PaleoDB collection 14977: authorized by John Alroy, entered by John Alroy on 18.02.1993

Creative Commons license: CC BY (attribution)

Taxonomic list

• original locality is L1, others are newly discovered: Hartman et al. 1993
either Tongue River Fm. or Sentinel Butte Fm. according to Holtzman, but 23.2 m above base of Sentinel Butte Fm. according to Hartman and Kihm 1991
diverse molluscs listed by Hartman et al. 1993
Mammalia
 Cimolesta - Pantolestidae
Propalaeosinopa sp.2 Simpson 1927 eutherian
 Cimolesta - Titanoideidae
Titanoides primaevus Gidley 1917 pantodont
 Theriamorpha - Phenacodontidae
Phenacodus magnus3 Thewissen 1990 condylarth
Ectocion collinus1 Russell 1929 condylarth
 Procreodi - Arctocyonidae
Arctocyonidae indet. Murray 1866 condylarth
 Primates - Plesiadapidae
Plesiadapis sp. Gervais 1877 primate
not mentioned by Hartman et al. 1993
 Multituberculata - Ptilodontidae
Ptilodus kummae Krause 1977 multituberculate