Plettenberg Bay Gilead Cave
Length: 96m | Grade: 5D | Surveyed: 1998-07-13
Region: Caves West of the Tsitsikama National Park
Gilead Cave and Oumatjie Cave, Plettenberg Bay
Introduction
During the 1998 winter holidays, the Hitchcock Family, Stephan Moser,
Joan Vlok and I spent a few days exploring the coastline around
Plettenberg Bay and Nature's Valley.
Our highly scientific exploration technique involved choosing cave-like
place names on a 1:50000 map, then picnicking in the area, in the hopes
that cave entrances would present themselves for exploration. While we
were attempting to get to a place called Neusgate (Nostrils), we came
upon a house on a cliff, and met the owner, Mrs Dawn Leggat. She
informed us that although there was no known cave in the vicinity of
Neusgate, there was a cave that her son had discovered on her property.
A photograph of Neusgate revealed that it is a prominent outcrop of
rock, which bears an uncanny resemblance to the nose of at least one of
the members of our survey party! Mrs Leggat kindly gave us permission
to visit her cave, and sent us off in the right direction. After we had
surveyed the cave, we popped in to thank Mrs Leggat, and were invited in
to see the chocolate factory on her dining room table!
The next day, we made our way across to the Kranshoek Griekwa
Nedersetting, where we were directed to a bay marked on the map as
Ghanopad. The locals know the bay as Oumatjie, as an old lady used to
live on the cliff above the bay. Here we were rewarded with a splendid
cave, and two large arches.
While we were preparing to survey the cave, a number of the local
children came clambering up to the entrance, each carrying a dismembered
tentacle of a large octopus that they had caught. While we dined on
peanut butter sandwiches, the boys plunged their catch into the flames
of a roaring fire that they had built, and within minutes, their lunch
was well charred, and consumed with much relish.
Gilead Cave
Geology
A few kilometres to the west of Robberg, the coast is characterized by a
narrow, rocky strip at sea level, backed by 80m to 100m high quartzite
cliffs. The quartzite beds dip steeply towards the sea in the south,
with the strike running approximately parallel to the coast. The beds
have been differentially lifted along joints that run parallel to the
dip, and give the impression of large, steeply sloping steps.
Gilead Cave was formed when a light gray shale band was eroded from
between two quartzite beds. The remains of the shale band can be seen on
the northern ceiling of the cave (see cross section bb'). The north
wall/floor of the cave is a series of quartzite slabs, covered in a
light grey powdery dust, and littered with rubble that has fallen from
the ceiling.
Minerals
Most of the visibly interesting minerals occur towards the back of the
cave. White crystals and short silica stalagmites have formed along
joints in the ceiling, while a bank of dark red clay has formed in an
alcove in the northern wall. A 1m high column of red clay, which reaches
to the ceiling, tops a bank of the same red clay. The clay is possibly
allophane (Durrheim et al, 1994).
Biota
Although we did not search the cave for small animals, we noted signs of
porcupines and bats in the cave. The floor of the cave was littered with
quills and we found a small pile of bat droppings on the ledge that runs
along the northern wall. A number of 3cm long, white hairy moth
caterpillars were feeding on the bat droppings. These caterpillars
appear similar to the ones that occur in Woolly Worm Cave at De Hoop.
Archaeology
There are two large shell middens at the entrance to the cave, and
judging by the size of the shells in the middens, they don't make
limpets the way they used to. Mrs Leggat showed us a small digging
weight, and parts of a stone tool that they had found in the cave.
Apparently (Leggat pers comm) the slanting floor of the cave made it
unsuitable for habitation, so the cave was just used as a stop over, or
shelter. There were also a number of fossilized bones on the floor of
the cave, all baring fairly new teeth marks on them.