[crater] The outer rim of Röntgen has been heavily eroded by subsequent impacts, and it now forms an uneven, jumbled ring of ridges in the surface. There is a relatively fresh, cup-shaped crater along the common rim between Röntgen and Nernst. The interior floor of Röntgen is nearly level, with only a few patches of uneven terrain near t... Found on http://en.wikipedia.org/wiki/Röntgen_(crater)