Geological map of Yellowstone National Park based on work by William Henry Holmes in 1878

Geological map of Yellowstone National Park based on work by William Henry Holmes in 1878 as part of Ferdinand Vandeveer Hayden’s United States Geological and Geographical Survey of the Territories, with topography mapped by Henry Gannett and triangulation by Allen David Wilson.  From the Twelfth Annual Report of the United States Geological and Geographical Survey of the Territories: Maps and panoramas, plate 6.