The range stands about 700 or 800 feet above the plains, and is composed of great masses of black basalt.

It is probably part of the latest series of volcanic rocks in South Africa.

At the eastern end these hills have curious fungoid or cup-shaped hollows, of a size which suggests the idea of craters.

Within these are masses of the rock crystallized in the columnar form of this formation.

The tops of the columns are quite distinct, of the hexagonal form, like the bottom of the cells of a honeycomb, but they are not parted from each other as in the Cave of Fingal.