The ?Berriasian-Cenomanian Cedar Mountain Formation (CMF) in Utah is a significant unit as it preserves the transition from Jurassic to Cretaceous ecosystems. It preserves distinctive faunal, especially dinosaur, assemblages, and encompasses an interval of fluctuating climate and dramatic biotic changes (in the terrestrial realm, origin and spread of angiosperms). Recent stable C isotope and zircon analyses have revealed that the basal Yellow Cat Member of the CMF may at some localities be as old as Berriasian, with zircons from two localities providing well-constrained maximal depositional ages of approximately 135 mya (early Valanginian). The Yellow Cat Member is a laterally constrained unit deposited by a northward-trending, low sinuosity river system, and comprises fluvial, lacustrine and paleosol sediments. We present here palynological data from two measured sections of the Yellow Cat Member that are approximately 11 km apart, Jim’s Pond and Lake Madsen. Samples from the lower Yellow Cat, represented by seven samples at Jim’s Pond, are overwhelmingly dominated by the xerophytic conifer Classopollis (Cheirolepidiaceae) and its frequent co-dominant, Exesipollenites, an unknown seed plant likely representing a wind-pollinated canopy tree (?Cupressaceae). Other conifers (Pinaceae, Araucariaceae, unquestioned Cupressaceae, ?Podocarpaceae, ?Voltziales) are distinctly subordinate. Other seed plants are rare and include Caytoniaceae, Gnetales and Ginkgoales or Bennettitales. Spores are rare, and include bryophytes, smooth triletes of uncertain affinity and members of the Osmundaceae, Lycopodiales, and Schizaeales. Species of Schizaeales are particularly important for palynostratigraphy, and support correlation of the lower Yellow Cat Member with basal Cretaceous assemblages from England, Germany, France and the Netherlands. The upper Yellow Cat, represented by only one sample, shows a drop in the xerophyte Classopollis and concomitant increase in other conifers and Exesipollenites. Spores remain low in overall abundance, but display a distinct increase in diversity. Both observations may suggest cooling and/or increased precipitation in the upper Yellow Cat, although local facies effects may have greater impact on floral composition. Yellow Cat palynofloral assemblages resemble underlying Jurassic Morrison Formation assemblages in that many of the same morphotaxa are recognized in both formations, but relative abundance of certain taxa shifts. Notably, Classopollis is present but quite rare in the upper Morrison Formation but becomes much more abundant in the Yellow Cat Member, and many of the same conifer morphospecies extend through both formations. However, the Yellow Cat Member is marked by first appearance of numerous taxa, including species of the Schizaeales, as well as Foraminsporis, Densoisporites, Couperisporites, Interulobites and others, rather than by extinctions. It is not until the spread of angiosperms in the Albian-Cenomanian that terrestrial macrofloras undergo dramatic biotic turnover.