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. Written for adults but clear enough for older kids, this fascinating book tells the story of how volcanic eruptions and erosion combined to form one of the most interesting landscapes in a park that's all about interesting landscapes. Organized by major vantage points of the overlook and trail, it uses labeled photos to help the reader spot pyroclastic flows, ballistic blocks, gas escape pipes, lava pillows, and more! 40 pages.