Ferdinand Vandeveer Hayden Dr . Ferdinand Vandeveer Hayden ( September 7 , 1829 – December 22 , 1887 ) was an American geologist noted for his pioneering surveying expeditions of the Rocky Mountains in the late 19th century . He was also a physician who served with the Union Army during the Civil War . Early life . Ferdinand Hayden was born in Westfield , Massachusetts . As a young boy he was fascinated with all nature and wildlife , the likes of which led him into the field of medicine . He worked in Cleveland under J . P . Kirtland and thereafter in Albany , NY , where he worked under James Hall , of the " Geological Survey of New York " . He graduated from Oberlin College in 1850 and from the Albany Medical College in 1853 , where he attracted the notice of Professor James Hall , state geologist of New York , through whose influence he was induced to join in an exploration of Nebraska Territory , with Fielding B . Meek to study geology and collect fossils . Hall sent him on his first geological venture in the summer of 1853 . Being of independent mind Hayden ended his commission with Hall , and with the encouragement of S . F . Baird , and a partial sponsorship from the Smithsonian Institution , he spent the remainder of the 1850s on various exploring and collecting expeditions in the northern Missouri River areas . In 1856 and 1857 , Hayden accompanied exploration expeditions led by Lieutenant G . K . Warren and in 1859 , the Raynolds Expedition of 1860 led by Captain William F . Raynolds , both of the Topographical Engineers . One result of which was his " Geological Report of the Exploration of the Yellowstone and Missouri Rivers in 1859 – 1860 " ( 1869 ) . During the Civil War he was actively employed as an army surgeon . He rose to be chief medical officer of the Army of the Shenandoah . Geological surveys . After the American Civil War Hayden led geographic and geologic surveys of the Nebraska and Western Territories for the United States Government . 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 Sante Fe . In 1870 he received an $ 25 , 000 governmental grant to lead a 20 - man expedition to South Pass , Fort Bridger , Henry ' s Fork , and back to Cheyenne . About this time , he also became identified with the Megatherium Club at the Smithsonian Institution in Washington , D . C . To measure distances during their journeys into the western frontier Hayden employed the use of an odometer , a device used by mappers to estimate distances traveled . The device was mounted on a mule - drawn cart that measured distances as the cart wheels rolled along . Because of rough terrain the device was accurate to within about 3 % . Yellowstone . In 1871 , Hayden led a geological survey into the Yellowstone region of northwestern Wyoming . The survey consisted of some 50 men which included notables such as Thomas Moran , painter and famous frontier / Civil War photographer William Henry Jackson . 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 " was instrumental in convincing Congress to establish Yellowstone as the first U . S . National Park , aided by Jackson ' s stunning large - format photographs and Moran ' s dramatic paintings . These publications also encouraged the westward expansion of the United States . Legacy . From his twelve years of labour and annual survey journeys there resulted a most valuable series of volumes in all branches of natural history and economic science ; and he issued in 1877 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 with him for further scientific study . Much of what he brought back is still housed in the collection of the Smithsonian Institution . American paleontologist Joseph Leidy obtained most of his fossil specimens from Hayden . Later life . Hayden was made professor of geology at the University of Pennsylvania in 1865 with the help of Leidy . Upon the reorganization and establishment of the United States Geological Survey in 1879 he acted for seven years as one of the geologists . He died at Philadelphia on the 22nd of December 1887 . Honors . Hayden Valley in Yellowstone is named after him . The town of Hayden , Colorado , located in the Yampa River valley , is named for him . Many mountain peaks have been named after Hayden as well . The sedge " Carex haydeniana " was named for him by Stephen Thayer Olney , in 1871 . A garter snake , " Thamnophis radix haydenii " was named for him by Robert Kennicott in 1860 ; although it was in a different genus at the time . A land snail , " Oreohelix haydeni " was named for him by William Gabb in 1869 . Hayden Hall at the University of Pennsylvania which formerly housed the dental school now houses the bioengineering and earth sciences departments . Other publications . With FB Meek , he wrote ( " Smithsonian Institution Contributions " , v . 14 . Art . 4 ) " Palaeontology of the Upper Missouri , Pt . 1 , Invertebrate . " His valuable notes on Native American dialects are in " The Transactions of the American Philosophical Society " ( 1862 ) in " The American Journal of Science " ( 1862 ) and in The Proceedings of the American Philosophical Society ( 1869 ) . With ARC Selwyn he wrote North America ( 1883 ) for Stanford ' s " Compendium " .