Large-scale cross stratification is common in the Navajo Sandstone. Cross stratification like this forms from migrating sand dunes where deposition outpaces erosion. The dipping layers form on the downwind side of a migrating sand dune, and the sand was migrating from right to left. The entire wall shown here represents a single bed within the Navajo Sandstone. For scale, the trees in the foreground are about 20 feet tall (about 7 meters). |