Paleogene geology of Texas

The Solitario (El Solitario) is a large geologic formation in Big Bend Ranch State Park in West Texas. When viewed from above, it suggests an impact crater; though it is actually the eroded remains of a laccolith. The approximate center of the Solitario is located east southeast of Presidio, Texas, just west of the line dividing Brewster and Presidio Counties. The formation covers a circular area of approximately . The geology of the Solitario is complex. In 1988, the state of Texas purchased the property containing the Solitario and created Big Bend Ranch State Park.