The park road passes through this tunnel near the Rio Grande Overlook in eastern Big Bend National Park. The tunnel cuts through massive limestone beds of the Santa Elena Formation of Early Cretaceous age (Albian Age - deposited around 100 million years ago) (Scheubel and Mruk, 1994; Stamm and Soller, 2008).

The URL is: https://gotbooks.miracosta.edu/gonp/bibe/html2/bb203.htm Last modified: 8/8/2010