Moeraki Boulders, Koekohe Beach, Otago Coast, New Zealand

The Moeraki Boulders are unusually large and spherical boulders lying along a stretch Koekohe Beach on the wave cut Otago coast New Zealand between Moeraki and Hampden, and are located at 45°20′42.99″S 170°49′33.82″E. They occur scattered either as isolated or clusters boulders within a stretch beach where they have been protected in a scientific reserve. The erosion by wave action mudstone, comprising local bedrock and landslides, frequently exposes embedded isolated boulders. These boulders are grey-colored septarian concretions, which have been exhumed from the mudstone enclosing them and concentrated on the beach by coastal erosion.
Local Māori legends explained the boulders as the remains eel baskets, calabashes, and kumara washed ashore from the wreck an Arai-te-uru, a large sailing canoe. This legend tells the rocky shoals that extend seaward from Shag Point as being the petrified hull this wreck and a nearby rocky promontory as being the body the canoe's captain. In 1848 W.B.D. Mantell sketched the beach and its boulders, more numerous than now. The picture is now in the Alexander Turnbull Library in Wellington. The boulders were described in 1850 colonial reports and numerous popular articles since that time. In more recent times they have become a popular tourist attraction, ten described and pictured in numerous web pages and tourist guides.
The most striking aspect the boulders is their unusually large size and highly spherical shape, with a distinct bimodal size distribution. About one-third the boulders range in size from about 0.5 to 1.0 metres (1.5 to 3 ft) in diameter, the other two-thirds from 1.5 to 2.2 metres (4.6 to 6.7 ft), the majority being nearly to almost perfectly spherical. A minority them are not spherical, being slightly elongated parallel to the bedding the mudstone that once enclosed them.