Abstract Results of a study of the micropaleontology of three outcrop sections of late Cretaceous and Paleocene formations in the Sand Wash and Piceance Basins demonstrate the value of palynology in the solution of correlation problems. Useful data consist of restricted ranges of sixteen palynomorph species and genera, and relative frequencies of five palynomorph species, genera, and groups. Occurrences of arenaceous Foraminifera in two sections support the palynomorph data. Correlation by micro fossils of formations from Hayden, Colorado, to Meeker confirms the equivalence of the Iles, Williams Fork, “Lewis,” Lance, and Fort Union Formations of the Sand Wash Basin to the Iles, Williams Fork, and lower Wasatch Formations of the Piceance Basin. Approximate time lines drawn from Hayden to Meeker divide the Williams Fork Formation at Meeker into equivalents of the Williams Fork, “Lewis,” and Lance Formations of the Hayden section. Pollen species reported from the Paleocene of Montana and New Mexico are found in the Fort Union Formation at Hayden and in the unnamed lower member of the Wasatch Formation at Meeker. Comparison of microfossil s from the Meeker and Wolf Creek sections in the Piceance Basin shows that a lithogenetic and approximate time equivalent of the Trout Creek Sandstone at Meeker can be found 1500 feet above the Rimrock Sandstone at Wolf Creek. The Cretaceous-Tertiary boundary is misplaced at Wolf Creek. Approximately 1000 feet of beds mapped as Tertiary lower Wasatch Formation contain late Cretaceous palynomorphs and are equivalent to lower Williams Fork, pre-“Lewis” beds of the Meeker section.