The rocks that make up Antelope Canyon are the petrified remains of prehistoric sand dunes formed by erosion of the sandstone by flash flooding. Rainwater, especially heavy during the monsoon season, runs into the extensive basin above the slot canyon, picking up speed and sand as it rushes into the narrow passageways.
Over time the passageways erode, making the corridors deeper and smoothing hard edges that form the characteristic "flowing"shapes in the rocks. At times the water cut its way into this sandstone with such tremendous force that it created eddies and whirlpools, which formed spiraling walls referred to as the Corkscrew formation. Looming overhead at almost every turn are many large overhangs with spiraling grooves carved into the sandstone creating breathtaking sites and images.
Around 10 AM we got back to the base and then left for Monument valley (see below).