Sediments were deposited from the Devonian, Mississippian, and Pennsylvanian periods. The division between Pennsylvanian and Mississippian comes from North American stratigraphy. Canadian scholars were divided between dating it to the Devonian period or to the Pennsylvanian. The Silesian is roughly contemporaneous with the late Mississippian Serpukhovian plus the Pennsylvanian. The first amniotes apparently arose in the Pennsylvanian subperiod of the Carboniferous. All modern classes of fungi were present in the Late Carboniferous (Pennsylvanian Epoch). Pennsylvanian and Permian formations can be seen in Cataract Canyon and San Juan Canyon. Seawater trapped in the subsiding basin created thick evaporite deposits by Mid Pennsylvanian. Foothills of the Smoky Mountains are from the Pennsylvanian and Permian Dollarhide formations. These were exposed and rounded by weathering during the Pennsylvanian & Permian Periods. The Ouachitas are composed of Cambrian through Pennsylvanian sedimentary rocks. DeVille was fired and replaced by Pennsylvanian guitarist Richie Kotzen. The ecoregion is mountainous, forested, and underlain by Pennsylvanian sandstone, shale, and siltstone. This margin existed until Laurasia and Gondwana collided in the Pennsylvanian subperiod to form Pangea. About 68% of Illinois has coal-bearing strata of the Pennsylvanian geologic period.