The Writing is on the Wall
These U-shaped ridges along this crater's interior wall provide clues to an ice-rich past. The curved, scalloped ridges, called moraines, are made up of rocks that the glacier collected as it moved downslope.
Even after the ice disappears, the glacial moraines remain, marking the furthest extent (or end) of the glacier. The parallel linear ridges on the wall may mark past levels of the glacier. Although glaciers move slowly, ice is a very powerful way to modify the surface of a planet.
The map is projected here at a scale of 50 centimeters (19.7 inches) per pixel. (The original image scale is 60.9 centimeters [24.0 inches] per pixel [with 2 x 2 binning]; objects on the order of 183 centimeters [72.0 inches] across are resolved.) North is up.
The University of Arizona, in Tucson, operates HiRISE, which was built by Ball Aerospace & Technologies Corp., in Boulder, Colorado. NASA's Jet Propulsion Laboratory, a division of Caltech in Pasadena, California, manages the Mars Reconnaissance Orbiter Project for NASA's Science Mission Directorate, Washington.