HiRISE image shows gullies and arcuate ridges in a crater in the southern hemisphere of Mars. The bright regions in this image are frost, probably water frost, that is deposited and removed seasonally. The arcuate ridges are the wavy features on the crater floor. Arcuate ridges resemble protalus ramparts that are found on Earth. Protalus ramparts form at the bottom of snow-covered slopes when rock debris becomes separated from the slope face and accumulates downslope. There is a mantled unit that covers the majority of the mid-latitudes of Mars that is thought to be ice-rich. It is unknown how arcuate ridges form on Mars, but they are thought to be a result of mass wasting of ice-rich materials, possibly sections of the mantled unit. The gullies seen in this image exhibit a range of morphologies. The large gully in the center of the image is deeply incised with a wide alcove. The gullies on the west (left) rim of the crater have small alcoves and tiny channels. A gully on the far left of the image extends all the way to the top of the slope. The alternating stripes on the left side of the image are camera artifacts, not Martian features.