Zion National Park

Large-scale cross-bedding is common throughout Zion National Park. The cross-bedding is typical of ancient sand-dune deposits of the Navajo Sandstone. During Early Jurassic time (about 202 to 176 million years ago), the region was part of a great sandy desert, probably similar in size and scale to the ergs (dune fields) of the modern Sahara Desert or Arabian Peninsula (Blakey, 1994).