USGS Earth Science Photographic Archive digital file: hjk00774
Within 15 miles of the Confluence, cliffs along the Green River contain thin lenticular beds of limey mudrock bearing crinoids, brachiopods and other marine fossils. These beds are within the Rico Formation of Pennsylvanian age. The Rico Formation overlies the Paradox Formation that is only partially exposed downstream in parts of Cataract Canyon. These rocks represent the oldest formation exposed in the canyon system between Dinosaur National Park and Marble Canyon.
