Lake Mead - "Rocks of the Grand Wash Trough"

This view is looking northeast from a low hilltop next to Pierce Ferry (high and dry because of low reservoir levels in Lake Mead when this photo was taken in 2005 or 2006). The white layer on the left side of the image is an ancient volcanic ash deposit overlying older stream gravel deposits. These rocks are a part of the "Rocks of the Grand Wash Trough" of Late Miocene to Pliocene age (Bohannan, 1984; Faulds and others, 2008).