MILITARY GEOLOGY AND THE APACHE WARS, SOUTH WEST UNITED STATES

The Apache Wars fought in the South West United States for much of the nineteenth century had a consistent theme of the testing of Apache homelands that created a cycle of violence. Recent studies of the archaeology of these battlefields have identified a pattern of Apache warfare that demonstrates a strong engagement with terrain. The high desert terrain of the South West provided a means of constructing a fortified battlefield in which the effect of terrain multiplication magnified the effort of the few Apache warriors. Ambush was a favoured tactic. Military theorists consider the use of terrain from the perspective of at least four basic issues: 1, vantage – observing and being observed by your enemy; 2, going – the nature of the ground traversed; 3, fortification – the means of creating field fortifications; 4, supply – the possibility of supplying the needs of the army from the ground. The battles of the Apache Wars show elegantly how these principles work. The Battle of Hembrillo Canyon, 6-7 April 1880, is a good example, fought in the Hembrillo Basin in southern New Mexico. The Basin is developed in the north-south trending San Andres mountains, and comprises north-south striking Late Paleozoic sedimentary rocks of Permian and Carboniferous age, with a regional dip of around 10°W. The Permian rocks comprise mudrocks and sandstones which are freely weathering to create a series of steps. These slopes and cap rocks were to be used to advantage by the Apaches in 1880. The Battle of Hembrillo Canyon is a battle in which two units of the US Cavalry (6th and 9th) were deployed against a numerically inferior force. The Apaches used the advantages of terrain to greatest effect. From a vantage perspective, the Apaches were well sited; they had prepared fortifications, and were always able to occupy the eastwards facing sandstone scarp edges, which were denied the US soldiers of the 6th Cavalry, who were pinned down on exposed dip slopes to the east. Breastwork fortifications were used widely, built along the scarps, denying access to the more open dip slopes, and creating a strong, integrated system of natural fortifications. Ultimately, this battle was inconclusive. But as Hembrillo and other battles and skirmishes of the long running Apache Wars shows, the Apaches were masters of their battlefields, using geology to the greatest effect in multiplying the firepower of a numerically inferior force.