I am a sedimentary geologist with a wide array of research interests. My work has largely centered on the interpretation of sedimentary rocks and structures. I do process-oriented studies of a variety of primary sedimentary structures, bedforms, and stratification, as well as paleoenvironmental analyses of lithofacies in rocks of various ages. I also study aspects of Earth history, primarily late Precambrian and Paleozoic strata. My early work was centered on the Precambrian–Cambrian boundary interval and in later years I focused on middle/late Cambrian and earliest Ordovician history on nearly every continent. This work was extended to include detrital zircon geochronology, carbon isotope stratigraphy, and aspects of tectonic reconstructions. I have worked in the Himalaya and Southeast Asian region for the last 12 years, and have done three seasons in Antarctica, specifically the Transantarctic Mountains. I am presently involved in studies of Devonian strata of the southwest U.S.; Cambrian strata in the Rocky Mountains, Antarctica, Himalaya, and Inner Mongolia; analysis of wave ripple dynamics using a flume at MIT; and a number of other projects.