PRAIRIE CANYON. Prairie Canyon, a valley with an intermittent stream, begins in south central Terrell County (at 29°57' N, 102°02' W) 1½ miles southwest of U.S. Highway 90 and runs four miles northeast to a point (at 30°00' N, 101°59' W) on Thurston Canyon, a half mile south of the Southern Pacific tracks. Its course dissects massive limestone on flat terraces and hard limestone and mud on rolling terrain. Generally dark, calcareous, stony clays and clay loams support oaks, junipers, grasses, and mesquites. The canyon was named for the rolling prairies found in the area.