Early geological studies in southwestern and south-central New Mexico
— Barry S. Kues

Geologic studies in New Mexico commenced with the beginning of American administration of the territory in the late 1840s. In southern New Mexico, moderately accurate geographical information was largely limited to the areas along the Rio Grande, as indicated by the Parke-Kern map of 1851. The earliest geological observations were published by Topographical Engineer Lt. W. H. Emory, attached to Kearny’s invading army in 1846; by Adolph Wislizenus, an independent naturalist, in 1846; and by Boundary Commissioner John R. Bartlett in 1851-52. Emory’s observations mainly concerned rock types, rudimentary stratigraphy, and aspects of the Rio Grande and its valley. Wislizenus was the first to observe early Paleozoic strata in the El Paso area. Bartlett, in his “personal narrative”, observed and published illustrations of several geological features, including the “Giant of the Mimbres”, the Santa Rita copper mines, and Cookes Peak. More substantive geologic studies of southern New Mexico were conducted during the Pacific Railroad 32nd parallel survey (1854-1855); Pope’s artesian well expedition (1855-1856); and the post-Gadsden Purchase conclusion of the Boundary Survey (1854-1856) supervised by W. H. Emory. The western branch of the 32nd parallel survey, led by Lt. John Parke, included the geologist Thomas Antisell, who described and interpreted the geology of southwestern New Mexico from the Arizona border to the Rio Grande and Organ Mountains, including geologic cross sections and a geologic map of the region he traversed. Many of his observations are detailed and accurate, and he was the first to suggest that faulting along the Rio Grande might be responsible for uplifting regions to the west. However, he erred in identifying large areas between the igneous mountain ranges of southwestern New Mexico as Permian, and in mapping Cretaceous strata in the Mesilla Valley. George Shumard, attached to Pope’s artesian well expedition, made reconnaissance studies of the area between El Paso and Las Cruces; the region west of the Rio Grande (including the Goodsight-Sierra de las Uvas uplift, Cookes Range, Florida Mountains, and Santo Tomas-Black Mountain volcanic fields); the Jornada del Muerto and San Andres and Organ Mountains; and the geology along the western margin of the Jornada (Fra Cristobal, Caballo, Dona Ana, San Diego, and Robledo Mountains, and Cutter sag volcanic field). Shumard’s studies are perceptive and accurate in many respects, but he missed observing the thick early Paleozoic sections in the San Andres and Caballo Mountains, and erred in interpreting the Precambrian cores of these ranges as Cenozoic intrusions responsible for their uplift. The final Boundary Survey report had little geologic information on southern New Mexico, but Emory contributed some observations of the El Paso area, and James Hall wrote an important paper, with a geologic map of New Mexico, synthesizing observations of Carboniferous and Cretaceous strata in the territory and correlating them with equivalent strata throughout the United States.