A photo of Sierra De San Vicente.

This view is looking south toward the Sierra De San Vicente in northern Mexico from the unpaved River Road in southern Big Bend National Park. The mountain range is a large fold (a plunging anticline) in Cretaceous limestone that is being exhumed by the gradual regional erosion in the Big Bend/Rio Grande region. The river flows through a canyon on the north side of this great fold (hidden in the low gray hills around the fold). Creosote bush (Larrea tridentata) and a few scattered spring wildflowers are all that grow amongst the rocky desert pavement (USDA, [2010]). A section of the River Road is to the left.