Fully covered impact craters, whose outlines are still visible, are also known as ghost craters
. One such ghost crater
is located in the immediate vicinity of the second largest impact crater.
Other such ghost craters
occur in southern Oceanus Procellarum and elsewhere, and one just south of Plato has its own informal name: Ancient Newton.
The images also show a number of 'ghost craters
', which were once fully formed craters, but water or wind eroded their rims and filled them by depositing sediments.
The gentle grade means that you'll see this dome only when the Sun's rays graze the surface--exactly the conditions necessary to glimpse the ghost craters
. Opportune low Sun angles occur at waxing gibbous (between 9 and 10 days old) and waning crescent (between 24 and 25 days old).
The remnants of such ghost craters
are difficult to observe and are best seen when the terminator is near.