September 13, 2004
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows about two dozen circular depressions, each with a circular mesa on its floor. These were once meteor impact craters. The craters were filled with layered material, buried, and then exhumed and eroded. The dark, elliptical feature in the lower left (southwest) corner of the image is a butte composed of the layered rock that once completely covered the craters in this image. These landforms are located in a depression eroded into the floor of a much larger, partially-filled impact crater located near 35.1Â°S, 356.5Â°W. The image covers an area approximately 3 km (1.9 mi) across and is illuminated by sunlight from the upper left.