Natural Bridges - overhanging cliffs of Cedar Mesa Sandstone

This view shows overhanging cliffs of Cedar Mesa Sandstone along the Sipapu Bridge Trail (a spur trail that leads to the over overlook area in the previous image). This view shows dark lines of desert varnish covering the pink sandstone of the upper Cedar Mesa Sandstone. The desert varnish is a thin crust of manganese and iron oxide that precipitated on the rock surface as episodic rains fell on the landscape above and dissolved the minerals as water flowed downhill. As the water seeped and trickled over the cliff faces and ledges, the water evaporated leaving behind traces of the minerals, salts, and organic residues responsible for the formation of the desert varnish (Dorn and Oberlander, 1982; Garvey and others, 2008).