Geology
Sandstone
33 destinations along 28 roads
The red rock is older than it looks like it should be — most of it is petrified desert, dunes from a Sahara-scale sand sea that blew across the Colorado Plateau some 190 million years ago, then buried, cemented, and lifted back into the light. Look for the long diagonal sweep of cross-bedding in a Navajo Sandstone cliff and you're reading the face of a Jurassic dune. The red is iron, rusting in place. Slickrock, cliff, and arch all begin here.