The Guadalupe Mountains, spanning West Texas and southeastern New Mexico, rise as a rugged limestone range containing Texas's highest summit, Guadalupe Peak, and the sheer face of El Capitan within Guadalupe Mountains National Park; bordered by the Pecos River valley and Llano Estacado to the east and north, the Delaware Mountains to the south, and the Sacramento Mountains to the west, the range exposes one of the world's clearest Permian-age fossil reefs, long studied by stratigraphers, paleontologists, and paleoecologists, while its springs, wildlife, and sheltered alcoves also drew the Mescalero Apaches, who harvested agave and left behind agave-roasting features — some surface scatters of fire-broken rock and, farther north, true mescal pits dug roughly seven feet across and three to four feet deep — alongside earlier midden circles attributed to the Carlsbad Basketmakers. - AsNotedIn