A Mountain of 'Petrified Water'- Pulpit Terrace and Mammoth Spring Hotel, Yellowstone Park, U.S.A.

Fort Yellowstone, among the mountains, headquarters of U.S. Troops guarding Yellowstone Park, U.S.A.

Fort Yellowstone, among the mountains, headquarters of U.S. Troops guarding Yellowstone Park, U.S.A.

Fort Yellowstone, among the mountains, headquarters of U.S. Troops guarding Yellowstone Park, U.S.A.

Fort Yellowstone, among the mountains, headquarters of U.S. Troops guarding Yellowstone Park, U.S.A.

From Yellowstone Park N. through its gateway over Gardiner to Gallatin Range (left) and Buffalo Plateau.

From Yellowstone Park N. through its gateway over Gardiner to Gallatin Range (left) and Buffalo Plateau.

From Yellowstone Park N. through its gateway over Gardiner to Gallatin Range (left) and Buffalo Plateau.

Six-horse tally-ho leaving mountain walled Gardiner for trip through Yellowstone Park, U.S.A.

Six-horse tally-ho leaving mountain walled Gardiner for trip through Yellowstone Park, U.S.A.

Six-horse tally-ho leaving mountain walled Gardiner for trip through Yellowstone Park, U.S.A.

Six-horse tally-ho leaving mountain walled Gardiner for trip through Yellowstone Park, U.S.A.

Six-horse tally-ho leaving mountain walled Gardiner for trip through Yellowstone Park, U.S.A.