The Bright Angel Trail, which we will ascend 1340 m (4380 ft) from the Colorado River, follows a fault trace, giving a natural line into the canyon. From the Colorado River the trail cuts steeply up through Precambrian rocks in the Devil's Corkscrew, until reaching the Great Unconformity and the overlying Cambrian Tapeats sandstone (525 Ma). It then follows a broad ledge formed in the Bright Angel shale, before climbing to Indian Gardens (out of view at lower left).
All images copyright © 2016 F.W. Vollmer and may not be used without permission.