Rock formation near Lees Ferry, Arizona.

Glacial action on rock in Marquette, Michigan.

Black and white photograph of Hanging Rock at the Pikes Peak Cog Railway.

Black and white photograph of Lena Billington Merrill standing below Point Lookout, Yellowstone National Park.

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 a horse-drawn coach in the Hoodoos, Yellowstone National Park. Five people are visible sitting on the coach.

Black and white photograph of Jupiter Terrace, Yellowstone National Park. Taken by Robert Merrill from above. Water damage is visible on the image, which was scanned from the negative.

Black and white photograph of Hymen Terrace, Yellowstone National Park. Two women can be seen standing in the foreground of the image.

Black and white photograph of anticline rocks near Ontario, Canada. Taken by Robert Merrill, looking north across water. Water damage is visible on the image, which was scanned from the negative.

Black and white lantern slide of glacial grooves and a measuring stick on Kelleys Island, Ohio.

Black and white lantern slide top-down view of glacial grooves on Kelleys Island, Ohio.

Black and white lantern slide of Robert Merrill standing in a 6-foot deep glacial groove with a measuring stick on Kelleys Island, Ohio.