A chain of mountains or hills that form a continuous line.

A shallow opening at the base of a cliff.

A dry area of ground covered with salt and other minerals.

A point higher than all other points in an area.

A volcano that ejects 240 cubic miles of debris.

Bowl-shaped land formed by glaciers.

Area of land where rain collects and drains into a waterway.

A bowl - shaped area of land.

Volcanic crater formed by the collapse of a magma chamber.

An outside river bank continually eroding.

A slight dip in the land formed by two parallel ridges.

Significant collision of two outer space objects.

A ridge cut short.

A small opening which lava erupts.

Exposed land within a river.