one inch sedimentary rock 75 million years 75 million years sedimentary rock 75 million years one inch it’ll be gone one inch sedimentary rock sedimentary rock sedimentary rock 75 million years 75 million years 75 million years Badlands formations Says the National Park Service sedimentary rock sedimentary rock 75 million years it’ll be gone one inch Says the National Park Service Badlands geological formations NPS web site sedimentary rock one inch sedimentary rock 75 million years Badlands geological formations rock formations one inch 75 million years sedimentary rock sedimentary rock it’ll be gone 75 million years one inch one inch one inch 75 million years one inch one inch one inch Badlands geological formations sedimentary rock Says the National Park Service geologic formation it’ll be gone 75 million years it’ll be gone geologic formation https://www.nps.gov/badl/learn/nature/geologicformations.htm geologic formation National Parks website 75 million years 75 million years sedimentary rock one inch sedimentary rock one inch it’ll be gone