Plettenberg Bay Oumatjie Arch Cave
Peter Swart August 1998
Oumatjie Arch Cave
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.
Oumatjie smaller arch
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.
The next two caves to the east are 7m and 25m deep respectively. [Reece Swart, June 2019]