Grand Canyon National Park | Arizona.
Types of cross-strata in the Lower Permian Esplanade Sandstone of the Supai Formation: trough cross-strata above basal conglomerate on Topocoba Trail. Figure L5-E, U.S. Geological Survey Professional paper 1173. Photo by Ed McKee, courtesy of the US Geological Survey Photographic Library.
Online Resource: McKee, E., 1983, The Supai Group of Grand Canyon. https://pubs.usgs.gov/pp/1173/report.pdf
