Thin to massive, intercalated beds of Pennslyvanian-age siltstone and sandstone of the Naco Formation exposed in a road cut on US 60, west of the intersection of US 60 with AZ 73. These silty, sandy calcareous red beds were deposited in a coastal-plain to shallow-marine settings during time of variable and changing sea level.
Photographer: Mike Conway
Photo Date: May 2017