Late Cretaceous marine deposits of the U.S. Western interior afford unparalleled opportunity for study of thoracican cirripeds, which are far better represented than suggested by the published record. Remains of these organisms have received scant attention, partly because of minute specimen size and partly because disarticulated skeletal elements bear close resemblance to fragments of associated ostreid bivalves. In the study area cirriped remains occur in rocks of wide lithologic variety from many stratigraphic horizons, and are preserved abundantly in the articulated state. At key localities well.studied stratigraphic sections will be searched systematically for cirriped specimens, which will be the basis for taxonomic, biostratigraphic, and paleoecologic analysis. Common occurrence and local great abundance of fully articulated thoracican cirripeds in targeted formations is unique among Upper Cretaceous stratigraphic sections of the world. Taxonomic and biostratigraphic evaluation of such materials will aid immensely in expanding scientific knowledge of Late Cretaceous cirriped evolution, which is at present very poorly understood. Analysis of preservation, abundance, orientation, substrates, associated fossils, and accompanying sedimentary structures will enable us to evaluate the role of thoracican cirripeds in marine communities of the Western Interior Sea.
