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 Punch Bowl Spring, Yellowstone National Park.

Black and white photograph of the Riverside Geyser in eruption, Yellowstone National Park. Taken by Robert Merrill looking southeast.

Black and white photograph of the Riverside Geyser in eruption, Yellowstone National Park. A group of people are standing and watching the geyser erupt. Taken by Robert Merrill looking east.

Black and white photograph of the Grotto Geyser at rest, Yellowstone National Park.

Black and white photograph of the Beehive Geyser, Yellowstone National Park, with Lena Billington Merrill facing the camera.

Black and white photograph of the Beehive Geyser in eruption, Yellowstone National Park. Lena Billington Merrill can be seen at a short distance from the geyser.

Black and white photograph of the Beehive Geyser before eruption, Yellowstone National Park. A man and a woman are standing near the geyser.

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

Black and white photograph of two bears by the Fountain Hotel, Yellowstone National Park.

Black and white photograph of a bear by the Fountain Hotel, Yellowstone National Park.The ground around the bear appears to be scattered with discarded metal cans.

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

Black and white photograph of the Minute Man Geyser in eruption at Yellowstone National Park.

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 Golden Gate Canyon at Yellowstone National Park. Taken by Robert Merrill, looking south.

Black and white photograph of Jupiter Terrace at Yellowstone National Park. Taken by Robert Merrill from below.

Black and white photograph of terraces at Yellowstone National Park. Taken by Robert Merrill, looking south from hill.

Black and white photograph of terraces at Yellowstone National Park. Taken by Robert Merrill, looking southeast from hill.

Black and white photograph of terraces from Point Lookout, Yellowstone National Park. A large group of people can be seen standing along one area.

Black and white photograph of a group of seventeen people at Angel's Rest, Yellowstone National Park.

Black and white photograph of several people at the top of Jupiter Terrace at Yellowstone National Park.

Black and white photograph showing view of Pikes Peak, Colorado below timber line.

Black and white photograph, taken by Robert Merrill, looking southeast toward lakes. Likely taken near Pikes Peak, Colorado.

Black and white photograph, taken by Robert Merrill, looking southwest toward Cripple Creek, Colorado.