Grand Canyon Near Sunset, Looking North

Grand Canyon National Park from the South Rim. The Permian Kaibab Limestone is the uppermost and youngest sedimentary unit in this location, extending horizontally across the skyline ~1000 feet higher than the same unit in the foreground where the photographer was standing. Resistant rocks (sandstone and limestone) form the steep cliffs and softer rocks (shale and mudstone) form the gradual slopes.