the 40m high cliff face is the sheared off remains of a basalt lava flow from the Nandewar Volcano which dominated the area 21 mya. The columnar fractures are a result of the cooling process. The basalt cools from the outside toward the centre, causing shrinkage cracks to form, commonly in a hexagonal pattern. The shape of the columns is attributed to the tensional stress. When the molten rock within the basalt lava flow cooled slowly and, importantly, evenly, this enabled the individual crystals within the molten rock to align perfectly with each other. It is exceptionally rare to find columns so perfectly formed and preserved and Sawn Rocks near Narrabri is recognised as one of the best examples of columnar jointing in Australia.