Degraded Craters in Phlegra Montes

The larger craters in this image from NASA Mars Odyssey spacecraft showing a region north of Elysium Mons are buried and distorted almost beyond recognition.

The larger craters in this image from NASA Mars Odyssey spacecraft showing a region north of Elysium Mons are buried and distorted almost beyond recognition. http://photojournal.jpl.nasa.gov/catalog/PIA04007