Terra Cimmeria (edm - Natural Colors; credits: Lunar Explorer Italia)

On the right side of this edm, is a valley filled with dark material and a central, bright ridge. If the valley was carved by liquid water, then this ridge may mark a former stream channel where coarse-grained sediment was deposited, which has survived erosion more effectively than the finer-grained sediment in the valley outside the channel.
Similar "Inverted Channel Deposits" are visible elsewhere on Mars, and some examples in the Southern Highlands have been inferred to contain chloride salts (similar to table salt).
The color and texture of the possible Inverted Channels in this image are similar to those inferred to contain chlorides, which may have been deposited when salty water evaporated.
Considered together, the features in this image attest to a history of water-related activity at this location on Mars.