Big Bend National Park
The vertical joints highlight a wall-like serrated ridge of a volcanic dike along the River Road. The dark intrusion stands out in contrast to the surrounding white outcrops of tuffaceous sandstone and volcanic ash. The rocks are part of the Chisos Formation of Eocene and Oligocene age (Bohannon, 2004).
Next Image Return to Main Page
The URL is:
Last modified: 8/8/2010