Plettenberg Bay

Region: Caves West of the Tsitsikama National Park

Oumatijie Arch

At first glance, access to the eastern edge of the bay appears
impossible at sea level, as the sloping quartzite beds dip directly into
the sea. Closer inspection reveals that the bedding plane directly
behind the cliff has been removed, leaving a 60m long archway as passage
to the other side of the bay. A second, much shorter arch allows further
progress along the coast.

The cave was formed when the sea was at least about 20m higher than it
is today. A soft layer of shale was removed by wave action, leaving the
current tunnel slot. The roof of both entrances of the cave could not
support itself, and collapsed, leaving a tunnel under one of the bedding
planes, with an unstable rubble cone at each end.