The large, grey spherical Moeraki Boulders (some almost 2m in diameter) lie partially submerged in the sandy beach at the tide line, about 2km before you hit Moeraki village. Their smooth skins hide honeycomb centres, which are revealed in some of the broken specimens. The boulders once lay deep in the mudstone cliffs behind the beach and, as these were eroded, out fell the smooth boulders, with further erosion exposing a network of surface veins. The boulders were originally formed around a central core of carbonate of lime crystals that attracted minerals from their surroundings – a process that started sixty million years ago, when muddy sediment containing shell and plant fragments accumulated on the sea floor. They range in size from small pellets to large round rocks, though the smaller ones have all been taken over the years, leaving only those too heavy to shift.
Maori named the boulders Te Kaihinaki (food baskets), believing them to have been washed ashore from the wreck of a canoe whose occupants were seeking pounamu. The seaward reef near Shag Point was the hull of the canoe, and just beyond it stands a prominent rock, the vessel’s petrified navigator. Some of the Moeraki Boulders were hinaki (baskets), the more spherical were water-carrying gourds and the irregular-shaped rocks farther down the beach were kumara from the canoe’s food store. The survivors among the crew were transformed at daybreak into hills overlooking the beach.