The Moeraki Boulders are a group of large spherical “stones” on Koekohe Beach near Moeraki on New Zealand’s Otago coast. These boulders are actually concretions that have been exposed through shoreline erosion from coastal cliffs. Even today, there are still boulders remaining in the mudstone that will, eventually, fall on to the beach as they come lose due to erosion!
The boulders are one of the most fascinating and popular attractions on the South Island.
They originally started forming in ancient sea floor sediments around 60 million years ago, and the largest boulders are estimated to have taken about 4 million years1 to get to their current size.