Phantom Ranch Tour - the Tonto Platform and the Inner Gorge

This view is looking west from the South Kaibab Trail toward the Tonto Platform and the Inner Gorge. A mule/hiking trail crosses the Tonto Platform to Platform Point (center right). The name Tonto Group is applied to the Cambrian-age sequence of formations in the Grand Canyon including the Tapeats Sandstone, Bright Angel Shale, and Muav Limestone, from bottom to top respectively. The Tonto Platform is an erosional landscape feature associated with the soft and and easily eroded Bright Angel Shale. In contrast, the underlying Tapeats Sandstone that caps the rim of the Inner Gorge is more resistant to erosion (Beus, 1987). The bush in the foreground is Mormon tea (Ephedra viridis) (USDA, [2010]).