It was probably the most complex volcano in the Auckland volcanic field, consisting of five significant scoria cones and about a dozen smaller scoria mounds, sitting inside a large explosion crater.
The dating of the eruption to 28,500 years ago is one of the three most reliable eruption datings (as of 2011) for the more than 50 volcanoes in the Auckland volcanic field, the other two being Maungarei at 10,000 years ago, and Rangitoto Island, 500-1500 years ago.