Yellowstone National Park
Yellowstone National Park has one of the world's largest petrified forests, trees which were long ago buried by ash and soil and transformed from wood to mineral materials. This ash and other volcanic debris are believed to have come from the park area itself as the central part of Yellowstone is the massive caldera of a supervolcano. The park contains 290 waterfalls of at least , the highest being the Lower Falls of the Yellowstone River at .
Warren Angus Ferris
He kept a journal of his travels which were later published as the book "Life in the Rocky Mountains" (1940). On one trip in 1834, Ferris acted as a clerk for the American Fur Company in a trapping party to the mountains of western Wyoming. Out of curiosity, Ferris found Native American guides and made a side journey into what is today Yellowstone National Park. In his journal Ferris gave one of the first descriptions of the geysers of the Yellowstone region. 
From the surface of a rocky plain or table, burst forth columns of water of various dimensions, projected high in the air, accompanied by loud explosions, and sulphurous vapors, which were highly disagreeable to the smell. ...The largest of these wonderful fountains, projects a column of boiling water several feet in diameter, to the height of more than one hundred and fifty feet. ...These explosions and discharges occur at intervals of about two hours...