HAYSTACK CANYON. Haystack Canyon, the bed of the intermittent Haystack Creek, begins north of Haystack Mountain in southwestern King County (at 33°27' N, 100°29' W) and runs south for seven miles to its mouth on the Salt Fork of the Brazos River, twenty miles northwest of Aspermont in northwestern Stonewall County (at 33°24' N, 100°25' W). With an elevation of 1,700 feet above sea level, the canyon bed is 319 feet below the peak of Haystack Mountain and 230 feet below the Bar S Ranch headquarters just to the north. The surrounding terrain features locally faulted rolling to steep slopes marked by gypsiferous red beds with dolomite. The land surface is composed of shallow clay and sandy loams that support juniper, cacti, and sparse grasses.