Mars Index - Top Ten MER Images - Top Raw Images
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Horizontal layers of light-colored rocks, crossed here and there by vertical cracks, run from the lower left corner to the top right corner of this image. Scattered on top of the rocks are small, round concretions. Between the rock layers are layers of dark sediment. In three of the layers, small rings surrounded by dust mark the places where the rover's rock abrasion tool ground holes in the rock.
Grounds for Grinding
With balls of water-indicating minerals, scattered like marbles on rock laid down through history, scientists gave this site the go-ahead for some discovery-driven drilling.

Image Credit: NASA/JPL/Cornell