GSWW Section 8 – Pattersons Camp to Simsons Camp

The magnificent limestone cliffs of the Glenelg River (Bocara) were once a seabed!

Watch carefully near water areas and you may be fortunate to see the brilliant red and blue colours of the stunning Azure Kingfisher, often first seen as a small bird darting quickly along the edge of the river in the shadows.

Here in its lower reaches, the Glenelg River has carved its way through a limestone plateau and formed a limestone gorge. This Oligocene/Miocene era limestone consists mainly of calcium-carbonate CaCO3, (the same as the Mount Gambier building limestone) is sedimentary and was once part of the sea floor of the ancient Southern Ocean.

This limestone is an accumulation of marine fossils, which often can be seen with the naked eye. The limestone plateau is full of horizontal (forming bedding planes) and vertical joints. Caves were formed along these joints as the limestone is dissolved by rain and river water.

The Princess Margaret Rose Cave was formed along a vertical joint widened by this solution process. It was later filled with speleothems, formed by rain water percolating through from the surface, absorbing dissolved calcium-carbonate CaCO3 and depositing it in crystallised form inside the almost closed atmosphere of the cave.

In quiet bush places there are rare animals such as Heath Rats, Southern Brown Bandicoot, Swamp Antechinus and potoroos. Some other animals found here, although not always easily seen, include platypus, possums, koalas, echidnas. Kangaroos and wallabies are often seen and the last of the wombat colonies is now only found on the north side of the river.

Today ancient caves provide shelter and act as nurseries to small bats. However thousands of years ago they were deadly pit traps to Giant Kangaroo and Marsupial Lions roaming the area. Ancient bones testify to their passing too close to caves verticle entrance.

Some smaller birds found here include colourful and busy honeyeaters, kingfishers and ground dwelling birds such as the large emu. Watch carefully for the rare but locally common Rufous Bristlebird as it dashes about the undergrowth and pathways of the heathlands.