[Illustration: Distinctive pads of pricklypear cactus make this most ubiquitous of cactuses readily recognizable across its extensive range, which encompasses Southwest deserts and the Potomac River banks near Washington, D.C.] Anglo-Americans took no interest in Big Bend until the Mexican War of 1848 fixed the border along the Rio Grande. In the 1850s, two U.S. Boundary Survey teams traveled downriver by boat and mule train, and their published reports give the first scientific look at Big Bend country and its plants and wildlife. But for the next quarter-century Big Bend belonged to the Indians, and to the U.S. troopers who pushed endless patrols across its everlasting wilderness, facing sun, thirst, alkali dust, danger, and sometimes death, for $13 a month. The Mescaleros knew the country. They knew how to use its mountains, caves, canyons, and arroyos, and where to find water, wood, grass, and game. But tracked at last into their most secret and remote retreats, nothing remained for them but the reservation. As for the Chisos Apaches, they were tricked into Mexico by a promise of asylum, only to be captured and killed or dispersed across Mexico. Although Big Bend Indians had long used cinnabar red in their war paint and rock paintings, not until the end of the last century did commercial mining of cinnabar ore begin. To look at the ruins of Terlingua and Study Butte today, it is hard to imagine that 2,000 souls lived and worked just west of the park. Yet the Chisos Mining Company was once the world’s second largest quicksilver mine, producing 100,000 flasks of mercury between 1900 and 1941. The park’s own Mariscal Mine had a relatively short life and never really made money. All of the mines finally succumbed when the rich ore veins played out and the price of quicksilver fell. Similar fates overtook the copper, zinc, and lead mines that drew a couple thousand people to both sides of the river near present-day Boquillas. These mines were located in Mexico’s Sierra del Carmen and the ore crossed the river to the U.S. side via a steam-driven aerial tramway. Mule-drawn wagons and trucks then hauled it over the Old Ore Road to railhead at Marathon 160 kilometers (100 miles) away. [Illustration: The Chisos Mountains loom as an island rising above an arid Chihuahuan Desert.] To feed the miners, Anglos and Mexicans set up irrigated farms near Boquillas, along Castolon valley, and at Terlingua Abaja. These activities took an enormous toll on Big Bend’s natural resources. Woodsmen scoured the country far and wide for timber for buildings and for firing mine furnaces. Ore train mules fed heavily on the chino grama grass. And when the mines failed and the farmers abandoned their fields, they left the land so bare that much time went by before the desert shrubs began taking over.