WALLACE CANYON. Wallace Canyon, a valley with an intermittent stream, begins a mile east of Farm Road 1024 in central Val Verde County (at 30°05' N, 101°18' W) and runs southeast ten miles to the Devils River one mile northwest of Sycamore Canyon (at 30°02' N, 101°11' W). Its path sharply dissects massive limestone that underlies flat terrain, forming a rugged and winding canyon. Wash deposits of sand, gravel, and mud cover the canyon floor. Generally dark, calcareous stony clays and clay loams support oaks, junipers, grasses, and mesquites.