Further south, tributaries of the Piako River drain the east side of the range and streams flow to the Waikato on the west.

Overlain with volcanic ash, they've mainly formed clay podzol soils, with poor drainage,[17] which are prone to sheet erosion, particularly on grazed, steep land.

Miranda Unit (Mkm), at the north end, is 13–10 Ma, also of basaltic and pyroxene andesite, but including dacite, tuff and hornblende.

[20] There is a 24.8 km (15.4 mi) Department of Conservation walkway[21] along the range, allowing excellent views of Mt Te Aroha, Firth of Thames, Huntly power station, hill country south of Auckland and the Waikato Plains.

All the large kauri trees have been logged, but now about 42% of the native vegetation is protected from clearance, some 58% of the rest being kanuka and manuka scrubland, mainly on the eastern foothills.