Through the End of the Cretaceous in the Type Locality of the Hell Creek Formation in Montana and Adjacent Areas

Gregory P. Wilson, Department of Biology, Burke Museum of Natural History, Culture, University of Washington, Seattle, Washington, 98195-1800, USA, William A. Clemens, Museum of Palentology, University of California, Berkeley, California, 94720-4780, John R. Horner, Museum of the Rockies, Montana State University, Bozeman, Montana, 59717-0400, Joseph H. Hartman, Harold Hamm School of Geology, Geological Engineering, University of North Dakota, Grand Forks, North Dakota, 58202-8358