Late Cretaceous (Maastrichtian)

Hell Creek Formation

McCone County, Montana, USA

Fine 0.4 inch jaw section with one molar

Mammal, Marsupial.

In the Late Cretaceous marsupials were common in North America but most, including Pediomys, died out during the K/T extinction.  Marsupials survived but were rare until becoming extinct on that continent by the Late Miocene.