Otuataua Stonefields Reserve

The Historic Reserve contains Pukeiti and Otuataua volcanoes. Pukeiti is one of the smallest scoria cones in the Auckland Volcanic Field with an extensive lava flow field spread out mainly to its north. The small cone is capped with a small crater that is sacred to the local iwi, please keep out of it. Over the stone wall to the northwest of the cone is a long trench with levees on either side - the route of one of the youngest lava flows - the molten lava flowed along up to the top of the levees and when the supply stopped it drained away leaving the trench.
Otuataua was a much larger scoria cone but all that is left today is its quarried out stump. The huge grassed hollow is NOT the crater but the remediated quarry. The cone used to rise up another 30 m above the present level of the stump remnants. Its natural crater was breached to the north and an extensive lava flow field stretches out to the north from the cone. Upper parts of the lava flows have been quarried away leaving some cuttings through the lower flanks of the scoria cone that are intruded by a basalt dike and has thin rootless lava flows within the scoria pile.
The naturally rocky lava flow field of Otuataua was used extensively for gardening by pre-European Maori and archaeological remains of whare sites, gardening stone heaps, rows and walls are everywhere. Many of the modern stone walls between paddocks were built by European farmers.

Why do you think the lava flows from Pukeiti have a smooth surface whereas the lava flows from Otuataua are extremely rocky?
Climb to the highest point on the stump of Otuataua scoria cone for panoramic views of the Manukau Harbour and the stonefields.
Explore the lava flow fields of both volcanoes - they are full many interesting features and landforms.
How can you tell what is an intrusive dike and what is a rootless lava flow in the quarry face of Otuataua?