The Caves

Over tens of thousands of years, crashing waves have gouged out the caves in a cliff of Jurassic sandstone about 160million years old. The two caves, which have separate entrances 40 metres apart, eventually became joined at the back during the long process of forming them. Because  the transport of beach sand is affected by storms and currents, cave entrances may have rocky pools or sandy floors, depending on the sea's actions.

In contrast to limestone caves, which are formed from chemical action as well as physical process of water pounding on rock, the Cathedral Caves were created by waves eroding the harder sandstone. Near-vertical fractures  in the sandstone provided weak points for the wave energy to slowly dismantle the sandstone faces. In time the overhanging rocks collapsed, creating caves with cathedral-like formations.

European naming
Known to Maori for centuries, Cathedral Caves received their name from a leading Dunedin physician, ethnologist and collector, Dr T.M. Hocken and his companions raised their voices and reported a 'reverberating' sound.