The Katiki Formation was defined by McKay in 1887 and comprises about 100 metres (330ft) of gently north to northeast dipping and generally massive, dark grey, indurated, sandy siltstones. The Katiki Formation overlies more proximal marine sandstones of the Herbert Formation and, below that, non-marine quartzose sandy to pebbly coal measures of the Shag Point Group.[2]
Cruickshank, A.R.I.; Fordyce, R.E. (2002), "A new marine reptile (Sauropterygia) from New Zealand: further evidence for a Late Cretaceous Austral radiation of cryptoclidid plesiosaurs", Palaeontology, 45 (3): 557–575, Bibcode:2002Palgy..45..557C, doi:10.1111/1475-4983.00249