Within it, the travellers could easily discover by their glasses an immense number of terraced ridges, probably landslips, alternating with stratifications resulting from successive eruptions.

Here and there, but particularly in the southern side, they caught glimpses of shadows of such intense blackness, projected across the plateau and lying there like pitch spots, that they could not tell them from yawning chasms of incalculable depth.

Outside the crater the shadows were almost as deep, whilst on the plains all around, particularly in the west, so many small craters could be detected that the eye in vain attempted to count them.
"Many circular mountains of this kind," observed Barbican, "can be seen on the lunar surface, but _Copernicus_, though not one of the greatest, is one of the most remarkable on account of those diverging streaks of bright light that you see radiating from its summit.

By looking steadily into its crater, you can see more cones than mortal eye ever lit on before.

They are so numerous as to render the interior plateau quite rugged, and were formerly so many openings giving vent to fire and volcanic matter.