Wooden Shoe Arch, visible on the horizon, has been here for thousands of years. But the rock it's made of is much older.
During the Pennsylvanian age (300 million years ago) this area was inundated by an inland sea. As the water evaporated, it left behind a great salt basin into which many layers of sediments were deposited. Here red sediments from the mountains to the east interfingered with white coastal deposits. These sediments were later transformed into the red and white sandstone of the Cedar Mesa formation upon which you are now standing.
The buried salt, which flows under pressure and is dissolved by ground water, shifted under the sandstone, causing it to fracture. Weathering along the fractures carved Wooden Shoe Arch, and the other arches, spires, knobs, and fins visible today.
(Upper Graphic Caption)
Water, wind, and gravity slowly carved a hole in a weak spot in the sandstone to create Wooden Shoe Arch. The arch will continue to change as erosive forces enlarge the opening. Given time, it will wear away completely.
(Lower Graphic Caption)
Block diagram of the central area of Canyonlands National Park, showing the unstable salt bed that underlies the Cedar Mesa Sandstone and other layers. Wooden Shoe Arch is one of many remarkable features fashioned by erosion of the fractured sandstone.