USGS Earth Science Photographic Archive digital file: hjk00723
Massive beds of Navajo Sandstone display vertical dark streaks called "desert varnish." Desert varnish consists of a surface coating of manganese and iron hydroxide mineral precipitates, probably derived from leaching of soils on the tops of the cliffs. Desert shrub oaks and occasional cottonwoods grow along the shady side canyons of the Green River.
