This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows the odd patterns of erosion on the floor of Reull Vallis, a major valley system east of the Hellas Basin in the martian southern hemisphere. Somewhat circular features in this image may have once been meteor craters that were eroded and deformed by erosive processes. This image is located near 42.1°S, 254.5°W. The picture covers an area about 3 km (1.9 mi) wide. Sunlight illuminates the scene from the upper left.