Down to Earth at Tuff Canyon by Daniel S. Barker. As soon as the volcanic ash stopped falling and settled into a white blanket over parts of what became Big Bend National Park, rainwater began to cut channels in it. At Tuff (another name for ash) Canyon near the Ross Maxwell Scenic Drive, water has carved a deep gouge through layers of ash, exposing lava beds beneath. This fascinating book tells about the geology, the plants, and the animals that inhabit this seemingly inhospitable area. 40 pages.