It is a circular crater with a rim that has not been significantly eroded.

There is a small circular crater along the western rim.

This is a circular crater with a somewhat worn rim.

This is a circular crater with an interior floor about half the total diameter.

This is a roughly circular crater that has not suffered significant impact.

This is a circular crater with a slightly eroded outer rim.

There was a circular crater in the center of the thirty-hectare sprawl.

Nevertheless a pair of small, circular craters lie across the western rim.

This circular crater is slightly unusual for its lack of interesting features.

The furnace itself, he now saw, was a circular crater, fifteen feet across, in the black stone.