|The Grand Canyon of the Yellowstone,|
1872, Thomas Moran
Eventually, he accompanied Ferdinand V. Hayden's U.S.Geological Expedition throughout the West where he gathered material for some of his most important works. In 1872 he painted the Grand Canyon of the Yellowstone. His work was undoubtedly a strong influence upon Congress in that during the same year, it established Yellowstone as America's first national park.