Bluets, Red River Gorge, Kentucky, April 17, 1968

Pine Cones and Lava, Craters of the Moon [National Monument], Idaho, July 2, 1975

Lupin and Grass, Craters of the Moon [National Monument], Idaho, July 3, 1975

Dwarf Eriogonum and Lava, Craters of the Moon [National Monument], Idaho, July 3, 1975

Waterfall, Lake Hagavatn, Iceland, August 11, 1972

Outflow from Hagavatn (Lake), Central Iceland, August 11, 1972

Outflow from Hagavatn (Lake), Central Iceland, August 11, 1972

Red and Black Lava with Lichen, Craters of the Moon [National Monument], Idaho, July 2, 1975

Yellow Flowers in Lava Field, Craters of the Moon [National Monument], Idaho, July 2, 1975

Dogwood in Oak Grove, Red River Gorge, Kentucky, April 17, 1968

Hard Inclusions in Sandstone, Gray's Arch Trail, Red River Gorge, Kentucky, April 18, 1968

Blue Vitrified Lava and Lichen, Craters of the Moon [National Monument], Idaho, July 2, 1975

Blue Penstemon, Craters of the Moon [National Monument], Idaho, July 2, 1975

Olive Orchard and Yellow Flowers, Segesta, Sicily, March 22, 1967

Redbud Tree in Bottom Land, Red River Gorge, Kentucky, April 17, 1968

Weathered Stump, Great Spruce Head Island, Maine, August 2, 1954

Dew on Spider Web, Great Spruce Head Island, Maine, July 31, 1954

Roots and Eroded Sandstone, Gray's Arch Trail, Red River Gorge, Kentucky, April 18, 1968

Sandstone Cliff, Detail, Double Arch Trail, Red River Gorge, Kentucky, April 18, 1968

Rock Bridge, Swift Camp Creek, Red River Gorge, Kentucky, April 19, 1968