My research has focused on the rich mammalian fossil record preserved in Cenozoic nonmarine sediments of the central Great Plains and adjacent Rocky Mountain basins. I am especially interested in the relationship of vertebrate fossils to ancient depositional environments. This has led me to explore the widespread Upper Oligocene and Miocene sediments of western Nebraska and eastern Wyoming, particularly where fine-grained volcaniclastic rocks contribute to the preservation of fossil mammals. In these rocks, certain types of bone accumulations correspond to particular depositional settings, and this information can be used to predict the location of important fossil sites.

Lower Miocene sediments in western Nebraska are recognized as the source of a number of mammalian bonebeds within fine-grained volcaniclastic sequences. I am attempting to explain these rich fossil deposits and their historical development within a regional geological context. This context is the result of volcanic activity associated with plate movements. In the past few years, we have extended this work to the John Day Basin in central Oregon. The evolution of mammalian carnivores is another of my research interests. Mammalian carnivores from the Cenozoic provide useful biostratigraphic tools because of the rapid evolution and wide geographic dispersal of numerous lineages. My early work was dedicated to the development of anatomical markers that could be used to clearly differentiate lineages. At present, I am attempting to apply these results to clarify evolutionary patterns and processes within the Carnivora during the Cenozoic.

I currently teach courses in vertebrate paleontology, mammalian paleontology, site analysis, and human origins. I see particular promise in student research directed toward understanding the geological context of vertebrate fossil occurrences in Cenozoic rocks of the Great Plains, and in the application of this information to questions about climate, evolution, and regional geologic history.