Harwoods Hole is a huge hole, 357 metres deep (connected to Starlight Cave), with its entrance on top of Tākaka Hill. A long time ago a stream flowed into the chasm and from there through a cave into The Gorge Creek. After some time the stream formed another underground entrance closer to its headwaters. The valley it had flowed through became a dry valley, and Harwoods Hole became a dry cave. This process is common in karst landscapes. It is called headwater retreat, as the place where the stream goes underground retreats closer and closer to its headwaters over time.
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Photograph by Lloyd Homer
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