White Rim Sandstone layer is more resistant to erosion. It's visible as large chunks and caprocks sitting atop the more easily eroded Organ Rock Shale.
NPS/Chris Wonderly
Deposited:
Permian Period (245 to 286 million years ago)
Depositional Environment:
Wind-blown beach sands
Appearance:
White, cross-bedded sandstones forming cliffs and caprocks
Examples:
White canyon rim marking the inner gorge of the Colorado and Green rivers at the Island in the Sky district of Canyonlands
