Geology

The geology of Big Bend Ranch State Park reflects profound changes over the past 600 million years of Earth’s history.

A deep ocean, the Ouachita Basin, covered the Big Bend and much of the southeastern United States some 570 million years ago, long before the age of dinosaurs. Erosion and uplift worked together to expose the limestone rock of this ancient sea floor in the Contrabando lowlands and the upended “flatirons” that form the rim of the Solitario.

The Solitario is a feature born of fire. Magma from deep within the Earth pushed upward to create a 10-mile in diameter blister-like bulge, or a volcanic laccolith.  Erosion and a complex series of eruptions have shaped the basin-like feature known today as the Solitario.

As you pass the dark peaks and mesas between Redford and Lajitas or along the main park road, imagine glowing cone-like vents and gaping fissures spewing red-hot ash and molten rock. Lava from these eruptions eventually hardened into the rhyolite and basalt rock that form the Bofecillos Mountains.

The range’s many cracks and fissures trap groundwater to create the region’s numerous springs—life-giving oases in the desert.

Flora

Plants throughout the park exist in a moisture-dependent mosaic, sometimes lush but more often sparse. Big Bend Ranch State Park has no designated forests; reliable shade does not exist.

Native plants range from arid-adapted cacti to water-loving cottonwoods. Common species of succulent include varieties of prickly pear and cholla. Ocotillo is a common desert shrub in the region.

Learn about Dr. Warnock's Herbarium.

Fauna

Big Bend Ranch State Park’s animal life varies, depending on the habitat.

Water-dependent beavers are common along the Rio Grande, while desert specialists like the black-throated sparrow are found in our desert shrublands.

The park has a healthy black bear population and hosts another of the region’s predators, the mountain lion. Mule deer and non-native aoudad are important to mountain lions’ diets.

The park is also the eastern-most range boundary for the Mojave rattlesnake, which occur here along with black-tail, mottled rock and western diamondback rattlesnakes.