SOLITARIO. The Solitario, a circular domal uplift with a nine-mile diameter, stands on the Presidio-Brewster county line between Fresno Creek on the west and Saltgrass Draw on the east (at 29°27' N, 103°49' W). It was formed when an igneous intrusion uplifted the dome several thousand feet, vented lava, collapsed the roof, and left a prominent rim of Cretaceous limestone. The collapsed dome is now a topographic depression drained by intermittent streams through three canyons in the rim called Lefthand Shutup, Lower Shutup, and Righthand Shutup. Four summits rise above the depression. Needle Peak (4,608 feet), Solitario Peak (4,786 feet), and Fresno Peak (5,131 feet) are located in Presidio County. Eagle Mountain (4,819 feet) is in Brewster County. The light reddish-brown to brown sand and rough pebbled ground support sparse grasses, cacti, and scrub brush. The Solitario stands on an isolated site and was named for the Spanish word meaning "lonely." In 1909 W. A. Robbins and S. H. Eaton found a lime rock in the Solitario which could be used in lithography. Although fine lithographic stones were available only by importation at the time, little use was made of the discovery.
Geology of the Big Bend Area and Solitario Dome, Texas (Midland: West Texas Geological Society, 1986). Geology of the Big Bend Area, Texas (Midland: West Texas Geological Society, 1965).