Crater

Crater, from the Greek krater, a bowl, the hollow formed by the explosive action, in the summit of a volcanic cone. Volcanic craters vary in size from the tiny orifices of small parasitic cones to huge circular chasms. That of Kilauea in the Sandwich Isles, the largest on the earth in an active state, is seven miles in circuit; but it is exceeded by others now extinct. These again are far exceeded by those on the surface of the moon, the action of its internal heat upon its surface having been far more violent in our comparatively small satellite than on our earth. The lunar crater Tycho is fifty miles in diameter and that of Copernicus not much smaller; whilst, if the "walled plains," such as Schickard and Clavius, are volcanoes, we must admit craters 133, and even 142 miles in diameter.