Trace fossils in fluvial deposits of the Duchesne River Formation (Eocene), Uinta Basin, Utah

A diverse suite of nonmarine trace fossils is present in a late Eocene sandstone siltstone mudstone sequence in the Duchesne River Formation of northeastern Utah. On the basis of primary sedimentary structures and stratification sequences, the beds are interpreted as deposits in meandering and braided stream environments. The trace fossils include Ancorichnus, "Muensteria", ?Palaeophycus, Scoyenia, Skolithos, two unidentified ichnotaxa, and rhizoliths. Insects and oligochaetes apparently made most of the animal traces in moist or wet, cohesive stream sediment during subaerial exposure or under thin water cover.