Black and white photograph of Mud Volcano, Yellowstone National Park.

Black and white photograph of a group of people standing next to the Mud Volcano at Yellowstone National Park (mile 17450).

Black and white photograph of the Norris Geyser Basin, Yellowstone National Park. Taken by Robert Merrill, looking north. Several figures can be seen at a long distance. Water damage is visible on the image, which was scanned from the negative.

Black and white photograph of the Norris Geyser Basin, Yellowstone National Park. Taken by Robert Merrill, looking northeast. A man can be seen standing at the left of the image, and a horse-drawn carriage appears to be driving up the road from the…

Black and white photograph of Obsidian Cliff, Yellowstone National Park. Water damage is visible on the image, which was scanned from the negative.

Black and white photograph of the Old Faithful geyser in eruption, Yellowstone National Park.

Black and white photograph of a crowd of people watching Old Faithful erupt in Yellowstone National Park (mile 17649.)

Black and white photograph of a woman and a boy in front of the Petrified Tree at Yellowstone National Park (mile 17527).

Black and white photograph of a stone pillar. The image is somewhat blurry.

Black and white photograph of Punch Bowl Spring, Yellowstone National Park.

Black and white close-up photograph of Punch Bowl Spring in Yellowstone National Park.

Black and white photograph of a woman named Rebecca looking at a chipmunk, Yellowstone National Park. Water damage is visible on the image, which was scanned from the negative.