Hamilton's Gap at low tide.

Apart from coastal sandstone, which is compacted sand and easily breaks down, the only true rock on the Peninsula is its base below sea level. The distinctive hills are wind-sculpted dunes, up to 300m high. On the west coast, at Karioitahi, Cochrane's Gap: Te Ara o Te Po or Hamilton's Gap: Waimatuku, you can see the high sand cliffs being molded and carved by wind and water each day to new spectacular forms.