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Four Corners and Southwestern Colorado

Spectacular geological map of the region, colored based upon the mineralogical content.

The map covers southwestern Colorado, the San Juans, and contiguous parts of Utah, Arizona, and New Mexico, as surveyed in 1874 and 1875 by the Hayden Survey. The map extends from Fort Lewis (Durango) in the east to Mt. Sneffels, San Miguel (Telluride), and the Mesa Verde (Colorado) and Navajo lands in northeastern Arizona. The topographical details in the Mesa Verde area are exceptional. Many early mining towns are shown in the San Juan region, reflecting the locations of the earliest mining boom towns in the region.

The map shows Cenozoic, Mesozoic, Palaeozoic, and Archaean formations, as well as Placer Bars and Silver and Gold Bearing formations. Thermal springs are noted with red circles.

Ferdinand Vandeveer Hayden led geographic and geologic surveys of the Nebraska and Western Territories for the United States Government after the Civil War. In 1867, he was appointed geologist-in-charge of the United States Geological and Geographical Survey of the Territories. Hayden organized and led previous expeditions into the Rocky Mountains, both before and after the Civil War. In 1869, he led an expedition along the Front Range to Denver and Santa Fe. In 1870, he received a $25,000 governmental grant to lead a 20-man expedition to South Pass, Fort Bridger, Henry's Fork, and back to Cheyenne.

In 1871, Hayden led a geological survey into the Yellowstone region of northwestern Wyoming. The survey consisted of about 50 men, including Thomas Moran, painter, and William Henry Jackson, a famous frontier photographer. The following year, Hayden and his work, Preliminary Report of the United States Geological Survey of Montana and Portions of Adjacent Territories; Being a Fifth Annual Report of Progress, were instrumental in convincing Congress to establish Yellowstone as the first U.S. National Park, aided by Jackson's photographs and Moran's paintings. These publications also encouraged the westward expansion of the United States.

From Hayden's twelve years of labor and annual survey journeys, there resulted a valuable series of volumes in all branches of natural history and economic science. In 1877, he issued his Geological and Geographical Atlas of Colorado. The last of the annual survey journeys was in 1878. As a result of Hayden's extensive geological work, he uncovered numerous dinosaur fossils, which he brought back east for further scientific study. Much of what he brought back is still housed in the collection of the Smithsonian Institution.