Dowling Bay Limestone:
The stone is found at Dowling Bay between Port Chalmers and the Otago heads and also at Hooper’s Inlet and at Sandymount as well as about 32 kilometres (20miles) further out to sea. The limestone is greyish and impure and contains bands of sandy mudstone at both Dowling Bay and Waipuna Bay. The fossils it contains show it to be similar in age to Goodwood Limestone. This ends the Sedimentary rocks exposed along the Otago Coast in the Dunedin vicinity. It must be remembered that out at sea the process is still going on and the fossils being formed there are those of modern animals and plants.
Following the formation of the last of these sedimentary rocks a change in sea level took place as the land lifted, perhaps as a preliminary to the volcanic activity which soon followed.
Caversham sandstone:
The stone is moderately hard and has been used for building, although not really suitable. It is white or light grey when first broken but weathers to a cream or light yellow colour seen in the high sea-cliffs of Otago. The base is glauconitic or argillaceous and the dominant quartz sand content varies from about 40% to 70% throughout the total depth of up to 228 metres (750ft). Many fossils are present including scallops, oysters, echinoderms, ostracods, rare corals, bryozoa and whales. The age is lower Miocene or upper Oligocene about 30 million years ago.