About 1.2 million years ago, a volcano in the highlands above Tully Gorge (Windy Hill, near Ravenshoe) produced a lava flow that just reached the lowlands, filling an ancestral valley; it is now evident as basalt rocks and reddish soils.
Near the low end of the basalt, the Tully River now flows along one side of the basalt.
Here, the Tully River has cut into the side of the basalt, revealing the columns formed in the rock by fairly rapid cooling of the lava.