"Mount Harris is of basaltic formation, but I could not observe any columnar regularity in it, although large blocks are exposed above the ground. The rock is extremely hard and sonorous"

Charles Sturt's quote is referring to Mount Harris, a basaltic formation situated in Australia. Basalt is a type of igneous rock that is formed when molten lava cools and solidifies. Sturt observed that the rock was exceptionally difficult and sonorous, indicating that it made a ringing sound when struck. He also kept in mind that big blocks of the rock were exposed above the ground, but he might not observe any columnar consistency in it. This implies that the rock did not have a routine pattern of columns or pillars, which is a common feature of basaltic developments. Sturt's observations recommend that Mount Harris is an unusual basaltic development, which it might have been formed in a distinct method.