Original sentence: The Mescalero Escarpment forms the western edge of the great Llano Estacado, a vast plateau or tableland in the south-western United States
Edited sentence: Extending north south along the western edge of the Mescalero Escarpment lies a vast sand sheet called the Mescalero Sands, named for the Mescalero Apaches who once hunted in these sandhills.In 1928, Nelson Horatio Darton of the United States Geological Survey observed: “On the east side of the Pecos Valley in southern New Mexico there are very extensive sand hills formed of deposits known as the ‘Mescalero Sands,’ which are doubtless of Quaternary age ...”   In places, these sands climb up and over the Mescalero Escarpment and spread out over portions of the Llano Estacado.The Mescalero Escarpment, also known as the Mescalero Ridge, forms the western edge of the great Llano Estacado, a vast plateau or tableland in the southwestern United States