Black and white photograph of the Constant Geyser at Yellowstone National Park. Several people can be seen on the left side of the image observing the geyser erupt.

Black and white photograph of the Daisy Geyser in eruption, Yellowstone National Park. A man is seen walking next to the geyser.

Black and white photograph of Lower Falls, Yellowstone National Park. Taken by Robert Merrill, looking down from brink.

Black and white photograph of a group of people standing next to the Dragon's Mouth at Yellowstone National Park (mile 17450).

Black and white photograph of the Roosevelt Arch entrance to Yellowstone National Park in Gardiner, Montana. The top of the arch reads for the benefit and enjoyment of the people. Water damage is visible on the image, which was scanned from the…

Black and white lantern slide copy of a geological map of Yellowstone National Park and Yellowstone Forest Reserve from an unknow source.

Black and white photograph of Gibbon Falls in Yellowstone National Park.

Black and white photograph of Gibbon Falls in Yellowstone National Park. Gibbon Falls is surrounded by mountains and forest.

Black and white photograph of Golden Gate Canyon at Yellowstone National Park. Taken by Robert Merrill, looking south.

Black and white photograph of the gorge below the lower falls at Yellowstone National Park.

Black and white photograph in portrait orientation of the Grand Canyon of the Yellowstone River, Yellowstone National Park. Taken by Robert Merrill, looking east below Grand View.

Black and white photograph in portrait orientation of the Grand Canyon of the Yellowstone River, Yellowstone National Park. Taken by Robert Merrill, looking south from Inspiration Point.