Cerro Castellan and Tuff, Big Bend NP (M)
This peak is the major landmark of the Santa Elena Canyon area of Big Bend National Park. It is especially prominent from the store and ranger station at Castolon. From that point, it forms a major portion of the skyline.
This formation is one of many surprises that are found in Big Bend. There is a layer of sedimentary limestone, covered with a lava flow. The hard cap of lava has resisted erosion, while the surrounding softer rock eroded away. The white tuff (volcanic ash) was deposited long after most of the erosion had taken place. The volcanic activity in this area was violent and long lasting.