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
What Cheer, Iowa What Cheer, Iowa What Cheer (pronounced 'WOT-cheer') is a city in Keokuk County, Iowa, United States. It is a former coal town, and from the 1870s to the early 1900s was one of the major coal-producing centers of Iowa. Its greatest recorded population was 3,246, in the 1890 census. Since the 1910s, the population has fallen to 646 in the 2010 census. What Cheer was founded in 1865 as Petersburg, named after Peter Britton, its founder. This name was rejected by the Post Office, forcing a change of name. Joseph Andrews, a major and veteran of the American Civil War,