Newton Crater is a large basin formed by an asteroid impact that occurred more than 3 billion years ago. It is approximately 178 miles across. The picture shown here (top) highlights the north wall of a specific, smaller crater located in the southwestern quarter of Newton Crater (above). The crater of interest was also formed by an impact; it is about 4.4 miles across and has many narrow gullies eroded into it. These are hypothesized to have been formed by flowing water and debris flows. Hundreds of individual water and debris flow events might have occurred to create the scene shown here. The individual deposits at the ends of channels in this Mars Orbiter Camera (MOC) image mosaic were used to get a rough estimate of the minimum amount of water that might be involved in each flow event. For a flow containing only 10% water, these estimates conservatively suggest that about 660,000 gallons of water are involved in each event.