The leader was Leonie Smith.
After leaving a car at Gibson Steps to ferry the drivers back, our group of seven met ranger Dennis Currell at the top of the track down to Clifton Beach. He told us how he was monitoring a pair of Hooded Plovers that had been nesting on the beach since 1998. Their nest sites in bits of stranded seaweed above high water level are prone to several hazards: being trodden on, extra high tides and foxes. We were pleased to see the pair and two grown young at the place Dennis expected them to be.
The spectacular cliffs reveal a geological section from the Lower Pliocene Gellibrand marl at the base, up to the familiar buff-coloured Middle Miocene limestones higher up, representing an age range from roughly 20 to 15 million years ago. At the top of the cliff are more recent dune limestones or calcarenites dating from the Pleistocene, that are about 1 million years or less.
The Gellibrand marl is a grey clay with fossils such as gastropods, bivalves, scaphopods, and bryzoa. Also present are the darker grey burrows that feeding creatures made when the sediment was still mud. These are known as trace fossils.
Fallen blocks of calcarenite reveal near-surface features such as soil pipes, and rhizoconcretions where calcium carbonate mimics plant roots.
Near Gibson Steps, a small cave, perhaps 50 cm in diameter, has been exposed in the cliffs. The fresh water flowing from it has formed a protuberant mass of stalactites. Similar “sand stalactites” line the cliff nearby where run-off flows over the cliff edge.
A non-geological find was a 30 cm fish with a prominent spine on its back. Sadly we also counted six dead Little Penguins.
Our thanks to Leonie and Dennis for a very interesting walk.