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moeraki
 A little fishing
village on the coast south of Oamaru has become famous for a
geological wonder on its windswept sands.
The Moeraki Boulders are huge spherical stones that are scattered
over the sandy beaches, but they are not like ordinary round
boulders that have been shaped by rivers and pounding seas. These
boulders are classed as septarian concretions, and were formed in
ancient sea floor sediments. They were created by a process
similar to the formation of oyster pearls, where layers of
material cover a central nucleus or core. For the oyster, this
core is an irritating grain of sand. For the boulders, it was a
fossil shell, bone fragment, or piece of wood. Lime minerals in
the sea accumulated on the core over time, and the concretion
grew into perfectly spherical shapes up to three metres in
diameter.
 The original mudstone seabed has since been
uplifted to form coastal cliffs. Erosion of the cliffs has
released the three tonne captive boulders, which now lie in a
haphazard jumble across the beach. Further erosion in the
atmosphere has exposed a network of veins, which gives the
boulders the appearance of turtle shells. Similar boulders occur
at Shag Point, and the nearby swimming beach of Katiki. In
Hawke’s Bay in the North Island, scientists have found that
the central core of similar boulders contained perfectly
preserved skeletons of turtles, sea snails and extinct reptiles,
such as plesiosaurs.
 Moeraki has a long history of Maori
occupation, which is represented in the town today by the
Kotahitanga Maori Church and a pa site nearby. This small seaport
town was the first European settlement in North Otago. Behind the
town a road leads to the lighthouse where you can find a
yellow-eyed penguin sanctuary and a seal colony. There are other
walks of ecological interest around the coast, and through the
Trotter’s Gorge native forest. South of Moeraki is the town
of Palmerston, where you can follow an historical scenic route to
Central Otago.
Moeraki makes a fascinating stopover point, both for the dramatic
coastal scenery and the curious geological phenomenon on the
beaches.
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