To the east, beyond Caballo Reservoir, are rugged Caballo Mountains, uplifted about 3 miles above downdropped Rio Grande through, along fault scarp at edge of mountains.
Lowest slopes are ancient granites.
Black ironstone beds are at base of high cliffs which are formed by Paleozoic dolomites and limestones. Strategically located where the Santa Fe Trail emerges from Glorieta Pass, this is where Mexican Governor Manuel Armijo prepared to defend New Mexico against the American Army in 1846. Casa Colorada, a Spanish settlement with houses built of red adobe or earthen bricks, was established in this vicinity in the 1740's. This community was soon abandoned, probably as a result of Apache raids, but was reoccupied in 1823 and developed into a bustling trade center along the Camino Real. Return to New Mexico Photos home page or New Mexico page .