Stock photography, photos: Eroded Clay Formation Stock photos of Rain water erodes hard clay causing distinct formations. Theodore Roosevelt National Park, North Dakota. Photograph: © Matthew Thalman Click for a larger image and more information Keywords associated with this stock photo: abstract, rock, rocks, clay, erosion, soil erosion, water, formation, America, National Park, National Parks, North America, North Dakota, NP, Theodore Roosevelt National Park, Theodore Roosevelt NP, United States, United States of America, US, USA