Plate 57
The north face of Scott’s Bluff, Neb., showing sedimentary sandstones above and clays below. The type of erosion is characteristic of arid regions. Courtesy of the U. S. Geological Survey
The north face of Scott’s Bluff, Neb., showing sedimentary sandstones above and clays below. The type of erosion is characteristic of arid regions. Courtesy of the U. S. Geological Survey