 A series of sandstone rockshelves and rock pools fringe the entire coastline and Port Hacking Estuary Line of the National Park broken on by small sandy beaches and gentle freshwater inlets.Some of the most commonly encountered molluscs in this habitat include black nerites ("Nerita atramentosa"), turbin snails ("Turbo undulata"), zebra snails ("Austrocochlea porcata") as well as the commercially farmed Sydney rock oyster ("Saccostrea glomerata").One of the most common and distinctive seaweed species that grow among the rock pools and the nearshore rockshelves is Neptunes necklace ("Hormosira banksii") a seaweed made of small buoyant fleshy bead-like structures which resemble strongly that of a necklace.