Kevin Schafer / Eroded rock formations of bentonite clay in the high desert, Cathedral Gorge State Park, Nevada

Kevin Schafer / Bentonite clay deposits, Painted Hills, John Day National Monument, Oregon

Yva Momatiuk & John Eastcott / Layers of soft stone of various colors with color-banded clay surface, Bentonite Hills, Capitol Reef National Park, Utah

Yva Momatiuk & John Eastcott / Layers of soft stone of various colors with a color-banded clay surface, Bentonite Hills, Capitol Reef National Park, Utah

Jeff Foott / Pinon Pine (Pinus edulis) and Bentonite Hills, Metate Arch, Devil's Garden, Grand Staircase-Escalante National Monument, Utah

Kevin Schafer / Bentonite clay deposits, Painted Hills, John Day National Monument, Oregon

Kevin Schafer / Bentonite clay deposits, Painted Hills, John Day National Monument, Oregon