of water through the soluble limestone. The forest ensures that this process continues by supplying decaying vegetation to add to the acidity in the flowing water. The largest single feature in the karst region is the Barrytown syncline. Limestone is exposed on both flanks of the syncline with more recent gravels and mudstones occupying the low-lying area in between. These more easily erodible rocks overlie interstratal karst. The majority of known cave systems are in the western side of the limestone syncline where underground drainage patterns are concentrated mainly along horizontal lines of weakness in the bedding planes. Coastal region The Paparoa coastline is characterised by high cliffs cut away by waves from the Tasman Sea, with indented coves and sandy beaches. There are small islands offshore and rock pillars. These terraces were once islands, which became part of the mainland when New Zealand was uplifted quite recently in its geological history. The most well known feature of the coastal region is the Pancake Rocks and Blowholes at Dolomite Point, near Punakaiki, where evenly layered stacks of platey limestone have been eroded in places to form surge pools and blowholes. The Truman Track, located north of Punakaiki, provides access from to a headland via a short walk through coastal forest of ferns, nikau palms, podocarps and rātā, with flax nearer the coastline. Wildlife Bird habitats within the park range from on or near the coastline to the peak of the Paparoa Ranges. Several species such as tui, bellbird, kaka, New Zealand pigeon and parakeets migrate from winter habitat in the lower forests to summer habitat in the upland forests. A significant feature of the coast is the colony of the rare seabird, the Westland petrel or tāiko, that is located on densely forested terraces just south of Punakaiki river. The Westland petrel breeding site at Punakaiki has been identified as an Important Bird Area, by BirdLife International. Large colonies of New Zealand fur seals have been established adjacent areas around Westport such as at Cape Foulwind. Rare southern elephant seals and leopard seals also visit. Hector's dolphins (some of the highest population densities in the nation) and some other dolphins including killer whales can be observed close to shores as well. For whales, their number is still very small, but various species have been observed. Protection from mining Although Paparoa National Park is protected from mining by Schedule 4 of