View of East Basin from Haskin Ridge (huge)
The dark areas here are probably analagous to the dark "cave" area in Ultreya. They look similar in
orbital photos. What I see here is dark sand dunes that look similar to the white sand dunes seen
at the bottom of craters in Meridiani. What is making them dark is not clear.
Courtesy of a visitor to unmannedspaceflight.com named James Calvin.