1877 Geological and Geographical Atlas of Colorado
DESCRIPTION
This monumental atlas was issued in 1877 by the United States Geological and Geographical Surveys of the Territories under the direction of Ferdinand. V. Hayden, one of the most influential figures in the development of American geological science. Produced as part of the federal government’s systematic exploration of the American West, the atlas presents the first comprehensive scientific mapping of the State of Colorado and adjoining portions of Utah, Arizona, and New Mexico.
The atlas is composed of two coordinated series of maps, as outlined in the list of sheets. The first series consists of four statewide maps at a scale of twelve miles to one inch, including a triangulation map, drainage map, economic map, and a general geological map. The maps in this atlas established the foundational framework of Colorado’s geography, illustrating river systems, mountain ranges, transportation routes, land use, and the broad distribution of geological formations across the state.
Topographical and Geological Mapping
The second and more detailed series comprises many large-format sheets, divided evenly between topographical and geological mapping, each covering identical areas at a scale of four miles to one inch. These sheets depict northwestern, northern central, central, western, southwestern, and southern central Colorado in remarkable detail. Finely engraved contour lines, representing approximately two hundred feet of vertical interval, convey the dramatic relief of the Rocky Mountains, plateaus, and river valleys, while roads, settlements, and survey points document human presence within the landscape.
The geological sheets overlay this topography with carefully applied color, distinguishing stratigraphic units ranging from recent deposits through sedimentary formations to metamorphic and eruptive rocks. Faults, folds, and lithological boundaries are clearly delineated, offering an unprecedented visual synthesis of Colorado’s complex geology. These maps reflect the results of extensive fieldwork conducted between 1873 and 1876 and represent a major step forward in correlating surface geology with underlying structure across a vast and rugged region.
Geological Sections and Panoramic Views
Among the most striking components of the atlas are the geological sections, which present long horizontal cross-sections through the terrain, illustrating the subsurface relationships of rock layers beneath mountain ranges, plains, and valleys. These diagrams translate three-dimensional geological complexity into readable form and demonstrate the scientific rigor with which Hayden’s survey approached questions of stratigraphy and structure.
The atlas also includes a series of finely engraved panoramic views, depicting major mountain groups such as the Pikes Peak region, the Sawatch Range, and the Elk Mountains. These sweeping landscapes serve both scientific and aesthetic purposes, helping readers visualize the form and scale of Colorado’s mountain systems while reinforcing the connection between observed surface features and the geological interpretations presented elsewhere in the volume.
Historical Significance
The Geological and Geographical Atlas of Colorado stands as one of the most important products of the Hayden Survey and a cornerstone in the history of American cartography and geology. Created only one year after Colorado achieved statehood in 1876, it provided policymakers, scientists, and settlers with authoritative information about the state’s natural resources, terrain, and economic potential.
More broadly, the atlas exemplifies the transition from exploratory mapping to systematic scientific survey in the United States. Its integration of triangulation, topography, geology, and visual representation helped establish standards that would later be adopted by the United States Geological Survey.
CONDITION
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