The Supai Sandstone formed between 280 and 300 million years ago (Arizona Ruins). A little history of the area is needed to fully understand the deposition process. During the Permian time period, Sedona was in fact a city on the coast of Pangea. Because of this positioning, Sedona was in the perfect place to receive millions of years’ worth of sand and sediment deposition which eventually lithified into the majority of the rock layers that we see above the Redwall Limestone’s conception. The constant receding and increasing of the ocean line resulted in some layers further on in Sedona’s history to be deposited by wind or river flow, as opposed to ocean deposition allowing for rocks that were formed under water to rest upon rocked formed by wind erosion and deposition in a unique and overall stunning way (Abbott and Cook pg. 175-180). The Supai sandstone was formed along the Pangean coastline and was deposited on top of the Redwall Limestone. It is mostly composed of shale and sandstone deposited by ancient sea waves. In comparison to other rock layers the Supai sandstone group is relatively thin.
The Supai Sandstone
(Left) Trees growing on the edge of the Supai Sandstone.