EXPLORING WITH HAYDEN: Hayden and his men -- Yellowstone and the Tetons -- Colorado -- The Mount of the Holy Cross and the cliff dwellings -- CLARENCE KINGS'S FORTIETH PARALLEL SURVEY: King's formative years -- The birth of the Survey -- The Great Basin -- The Great Salt Lake and the Rockies -- The diamond hoax -- Scientific publications -- POWELL'S SURVEY OF THE PLATEAUS AND CANYONS: Powell as schoolteacher and soldier -- Preliminary explorations in Colorado -- The men and the river -- Preparation for another trip -- The second trip -- The great plateau -- THE WHEELER SURVEY: SCIENCE THE ARMY WAY: Soldiers and surveyors -- Mapping the West -- 1879: The end of the great surveys.