[MAP] United States Geological Survey / VANDEVEER HAYDEN, Ferdinand. Preliminary Map of Central Colorado Showing the Region Surveyed in 1873 and 1874. Washington, D.C., 1875. 580 x 635 mm. Black and white. Map on thin paper folded through the middle. Traces of folds, small cracks in margins, paper slightly creased, minimal foxing. Detailed map of the western half of Colorado published by the United States Geological Survey. To the west, the map extends to the Grand Junction area, and south to Silverton and the San Miguel and Mount Wilson areas. Ferdinand Vandeveer Hayden, nicknamed by the Sioux "the man who picks the stones out of the stream", was one of the great geologists of the 19th century. In the 1860s, Hayden gained great renown as a geologist, and was appointed official U.S. geologist for the Geological Survey of the Territories. This position marked a milestone in his career, as he led numerous expeditions to the American West. Notably, between 1871 and 1872, he led an exploration of the region that was to become Yellowstone National Park; his reports played a major role in the creation of this first national park in 1872. Hayden's greatest contribution to geological literature was the Geological Atlas of Colorado, published in 1877. This work was the result of extensive expeditions throughout Colorado, meticulously documenting the state's geography and geology. The atlas featured maps of unprecedented accuracy, covering not only Colorado, but also adjacent areas of Utah, Arizona and New Mexico. Hayden also exerted an academic influence, having been affiliated with the University of Pennsylvania, where he held a professorship in geology. His fieldwork and academic contributions built up a vast body of knowledge that served future generations of researchers and explorers. Ferdinand V. Hayden died on December 22, 1887 in Philadelphia, Pennsylvania. His memory lives on in the many natural sites that bear his name, such as Hayden Valley in Yellowstone and Mount Hayden in Colorado. His contributions to 19th-century geology remain a cornerstone of the American geological and geographical sciences. Provenance: Geological Society of France.