[X] My Assistant

[SigurRosFan]

http://photojournal.jpl.nasa.gov/catalog/PIA07732

Informatively image release.

[dvandorn]

You will also note, very much evident in your enhancement and, I believe, a real feature -- a large circular feature that the last small bright circle you mention lies within. The boundary between the light and dark terrain directly to the north, and to the northwest especially, of that bright crater-like circle describes the upper third of a larger circular feature. That feature continues into the dark terrain as a series of darker arcs that are near-continuous with the arc above, forming the largest circular feature in the entire image.

Basin? Huge caldera? Volcanic collapse feature?

-the other Doug