Magnetostratigraphic studies will be conducted on the middle and late Eocene Uinta Formation, Uinta Basin, northeastern Utah, which is the classic collecting area for later Eocene mammal faunas in North America. Three sections will be taken to tie in most of the fossil localities: Wagonhound Canyon-Kennedy's Basin; north of Ouray; and Indian Canyon, where there are several K/Ar dates. These magnetostratigraphic sections will be tied to the work of Flynn (1986) and Walton (1986) on similar-aged strata of Wyoming, California, and Texas, to refine the middle-late Eocene mammal biochronology of North America. This, in turn, will allow later Eocene mammalian faunal changes to be tied to the worldwide timescale and examine how mammal faunas responded to the most significant change of climate in the entire Tertiary.
