Twenty-nine samples of sedimentary rocks of Triassic age from the Sun Valley U mine in northern Arizona were analyzed spectrographically; 11 of these samples contained 0.005 to 0.1% of the rare metallic element, Re. The Re is associated with U and Mo (and probably with Pb and Zn). It is probably in the form of the water soluble oxide (Re 2 O 7 ) or perrhenic acid (HReO 4 ). The Re may have been contained originally in the mineral jordisite. This is indicated by the association of the rhenium oxide with the water-soluble Mo mineral, ilsemannite. The Sun Valley mine is the only U deposit on the Colorado Plateau known to contain any Re.