Coal the heat and pressure of deep burial causes the loss of water, methane and carbon dioxide and an increase in the proportion of carbon. Thus first lignite (also called "brown coal"), then sub-bituminous coal, bituminous coal, and lastly anthracite (also called "hard coal" or "black coal") may be formed. The wide, shallow seas of the Carboniferous Period provided ideal conditions for coal formation, although coal is known from most geological periods. The exception is the coal gap in the Permian–Triassic extinction event, where coal is rare. Coal is known from Precambrian strata, which predate land plants—this coal is presumed to
Coal Island, New Zealand is one of only nine islands in the area that is completely free of introduced mammalian pests. Since then, endangered endemic birds such as tokoeka (Haast brown kiwi) and mōhua (yellowhead) have been released on the island. Coal Island, New Zealand Coal Island is an island in Fiordland, in the southwest of New Zealand's South Island. Its Māori name is Te Puka-Hereka Island, which translated means The Tied Anchor, but the island is commonly known as Coal Island. Situated at the southern end of Fiordland's west coast, Coal Island lies in the entrance to Preservation Inlet, between Puysegur Point and