Vertebrate Paleontology and Paleoecology of Paleocene Black Peaks Formation, Big Bend National Park, Texas

The fauna of the Black Peaks Formation is the southernmost large Paleocene fauna of North America. It contains 29 species of mammals belonging to 28 genera and includes three new species, a barylambdid pantodont, a multituberculate, and an insectivore. The 170-meter (560-foot) thick formation has three principal faunal levels. The lowest level is latest Torrejonian or earliest Tiffanian in age, the second is early Tiffanian, and the third is Clarkforkian. The formation was deposited by meandering rivers; the climate in the region was semitropical to tropical with alternating wet and dry periods of greater than seasonal duration.