Lava and Ash Talus, Sullivan Bay, James Island, Galápagos Islands, March 10, 1966

Crabs and Sea Lions, Espinosa Point, Fernandina Island, Galápagos Islands, April 7, 1966

Turquoise Bay and Black Rocks, Hood Island, Galápagos Islands, May 25, 1966

Blue-footed Booby, Champion Island, Galápagos Islands, May 30, 1966

Wolf and Darwin Volcanoes, Alcedo Mountain, Isabela Island, Galápagos Islands, May 4, 1966

Scalesia Tree, Santa Cruz Island, Galápagos Islands, April 23, 1966

Moss on Lava Flow near Grindavik, Iceland, June 19, 1972

Moss on Lava Flow near Grindavik, Iceland, June 19, 1972

Travertine in Sun, Sitting Bull Falls, Guadalupe Mountains, New Mexico, May 11, 1977

Flaked Rock on Bentonite, Black Place, New Mexico, June 8, 1977

Pueblo Bonito, Chaco Canyon, New Mexico, June 9, 1977

Marsh, Bosque del Apache, New Mexico, October 30, 1980

Hudson River, Frozen, New York, February 1958

Second Pylon, Medinet Habu, West Thebes, Egypt, January 23, 1973

Grass, Braulio Carrillo Park, Costa Rica, March 16, 1984

Fallen Aspen Leaves, Platero Road, Colorado, September 28, 1978

Upper Rio Grande, Stony Pass Road, Colorado, September 29, 1978

Green Seaweed (West), Espinosa Point, Fernandina Island, Galápagos Islands, April 7, 1966

Wind Clouds Over Dunes, Indian Springs, Colorado, September 12, 1976

Foxtail Grass, Indian Spring, Great Sand Dunes National Monument, Colorado, September 11, 1976