Boulder Bank
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Through Rock (geology) and Harbor
Geology and geography
The Boulder Bank is composed of granodiorite. The source of this rock is Mackay Bluff. It is still debated what process or processes have resulted in this odd structure. Longshore drift, however, is the most accepted hypothesis for creation. The main objection for longshore drift as the explanation is that Tasman Bay does not receive enough wave action to move the large boulders in a south west direction. Studies have been conducted since 1892 to determine speed of boulder movement. Rates of the top course gravel movement have been estimated at 7.5 m (25 ft) a year.
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The Cut
The Cut was made to enable the Nelson port to allow the increasing demands of sea transport for the Tasman area. Construction started in 1903 and in 1905 a 61 m (200 ft) wide entrance was operational. Today the Cut is 150 m (490 ft) wide and dredged every six months to maintain a depth of 10 m (33 ft).
Lighthouse
The Boulder Bank Lighthouse was erected in 1862. It is located near the port end of the Boulder Bank and was New Zealand's second permanent lighthouse. It is registered with the Historic Places Trust as a category I structure with registration number 41.