Black and white lantern slide of petroglyphs found in Parral, Mexico.

Black and white lantern slide of petroglyphs found in Parral, Mexico.

Black and white lantern slide of a rock formation with petroglyphs in Parral, Mexico.

Black and white lantern slide of petroglyphs found in Parral, Mexico.

Black and white lantern slide of a switchback mountain road near Jacala, Mexico.

Colored lantern slide of the Norton Mounds site in Wyoming, Michigan.

Black and white lantern slide of soil layers with measuring device.

Black and white lantern slide of an excavated burial site. The lantern is labeled "Deep skeleton, uppermost section."

Black and white lantern slide close-up view of a human skeleton excavated from a burial site.

Black and white lantern slide of an excavated burial site with two human skeletons. A man can be seen sitting on the edge of the pit.

Black and white lantern slide of an excavated burial site with exposed human skeleton under an elderberry tree.

Black and white lantern slide of an excavated burial site with a human skeleton.

Black and white lantern slide of an excavated burial site with a human skeleton. Three archaeologists stand at the edge of the pit, looking down at the remains.

Black and white lantern slide of an excavated burial site with a human skeleton.

Black and white lantern slide of an excavated burial site with a human skeleton.

Black and white lantern slide of an excavation cut with two partially excavated clay lamps.

Black and white lantern slide of a "deep fireplace" at the Uyak Bay site.

Black and white lantern slide of an excavated gravesite. The label on the slide reads, "Interm. Skeleton under slabs."

Black and white lantern slide of a slab of rocks near a beach. The label on the slide reads "The 'slab walk,' lower section."

Black and white lantern slide of an excavation cut at the Uyak Bay site.

Black and white lantern slide of six men standing around an excavated human skeleton. One man leans on a shovel, another leans on a pickaxe.

Black and white lantern slide of an excavation site at Uyak Bay, Alaska. A sign at the site reads "Government Excavations U.S. National Museum, Visitors Welcome, Admission 20 Shovelfulls."

Black and white lantern slide (dark) of an aerial view of Juneau, Alaska.

Black and white lantern slide of Robert H. Merrill standing on a runway in front of an airplane.