Red Rock Canyon, NV

The great sandstone cliffs at Red Rock, thousands of feet high, are made up of the Aztec Sandstone.  This formation, about 180 - 190 million years old, is comprised of lithified sand dunes that formed in a vast desert that covered a large part of the southwestern United States during the Jurassic time.  Lithification is the process of changing unconsolidated sediment into sedimentary rock.  Massive cross-bedding, typical of aeolian (wind) deposits, is a result of the shifting wind direction across the Jurassic dune field and is seen in the Aztec Sandstone rock outcrops.