The Maria Fold and Thrust Belt underwent generally thick-skinned (involving basement rocks) North-South trending crustal shortening in the Cretaceous.

The structures of the MFTB are exposed by later generally East-West trending large-scale crustal extension in the Miocene, through what is known to geologists as the Colorado River Extensional Corridor.

This North-South shortening is anomalous, as crustal shortening in the rest of the North American Cordillera is oriented generally East-West because of the generally East-West compression that was due to the subduction of the Farallon plate under western North America.

Because this large area incorporates so many major geological features, the diversity of vegetation and landforms is exceptional.

The desert wash woodland found here provides food and cover for burro deer, coyote, bobcat, gray fox, and mountain lion.