In southern Colorado, southwest of Walsenburg, two prominent cone-shaped peaks rise east of the Sangre de Cristo Range. In light of other volcanic features throughout southern Colorado and northern New Mexico, one might think that these large mountains are extinct volcanoes.
In fact, the West and East Spanish Peaks were intruded as magma beneath the surface during the late Oligocene Period, some 25 million years ago. Encased within Cretaceous and early Tertiary sediments, the massive plutons and their lateral dikes of cooled magma rose during the Miocene-Pliocene Uplift and have since been uncovered by the forces of erosion. Similar Tertiary laccolithic mountains include the La Sal, Abajo and Henry Mountains of southeastern Utah.
The higher elevations of both mountains are now protected within the Spanish Peaks Wilderness Area; East Spanish Peak rises to almost 12,700 feet while the summit of West Spanish Peak is just over 13,600 feet. Visible from great distances throughout southeastern Colorado, these majestic peaks guard the eastern entrance to La Veta Pass, traversed by U.S. 160. West of the pass, the highway drops into the high desert terrain of the San Luis Valley, drained, in part, by the Rio Grande River.
