Dirty Devil Canyons, Utah. A hiker pauses in a narrow water-sculpted canyon in the heart of the Colorado Plateau near the Dirty Devil River in south-central Utah. This canyon was carved through a layer of White Rim sandstone, the same layer which appears east of here in Canyonlands National Park. This sandstone achieves its maximum thickness of approximately 500 feet here along the Dirty Devil River and was deposited in the Permian Era about 250 million years ago. All of the erosion we see today on the Colorado Plateau, including the Grand Canyon, has occurred during the last 10 million years as this region was uplifted by colossal geologic forces.