DELAWARE MOUNTAINS. The Delaware Mountains begin just south of Guadalupe Pass in northwestern Culberson County and stretch thirty-eight miles southeast (their center point is at 31°47' N, 104°47' W). The highest elevation in the Delawares is 5,632 feet above sea level. The mountains are characterized by long horizontal layers of sandstone, limestone, and shale, which were deposited in the sea at the edge of the Delaware Basin in Permian times, 250 million years ago. They and the Apache Mountains, to the south, are the uplifted eastern border of the salt flats in western Culberson County. The area's steep and rocky terrain is surfaced by shallow, stony soils that support live oak, piñon, juniper, and grasses. The mountains are named for the Delaware Indians.