The Waitakere Volcano was active for six to seven million years and built a volcano, 50km in diameter and 3000–4000m high on the floor of the sea. Fortunately for those of us Glen Edenites who live nestled in the lower reaches of the now-named Waitakere Ranges, the volcano gave up its activity 15 million years ago.

My cycle ride from Glen Eden, Auckland, takes me on a small detour besides Konini School Reserve, then a modest climb to Scenic Drive, the lip of the remnants of the volcano. Via the Watercare maintenance track I reach the Arataki Visitor Centre, gateway to the ranges' subtropical forest.
The next big climb takes me to the Television Transmission Tower on Waiatarua, 400 meters above sea level.
With my iPhone battery almost discharged, I cut short my usual trip to Swanson, descending Mountain Round to Kiwi Valley for an Eggs Benedict lunch. With two last shots left in my iPhone, I snapped the vineyards of Oratia that have recently harvested their grapes.

Reference: Bruce W Hayward, 'The Structure of the Land' Waitakere Ranges

http://www.waitakereranges.org.nz/geology.html