Story: Limestone country

Oligocene limestone beds (32–22 million years old) are visible as cliffs in a largely tree-covered hillside near Punakaiki on the West Coast. The Punakaiki blowholes are on the headland at lower right. Rivers that flow to the coast have cut deep gorges into this limestone layer. In heavy rainfall areas such as the West Coast, much of the karst landscape is hidden by the dense rainforest.