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
John A. Burns what he described as an entrenched, corrupt political machine. He narrowly lost, even though Burns significantly outspent him in a savvy campaign that included sophisticated use of expensive image-building television spots. Most in the state's large Japanese population remained loyal to Burns, who had spearheaded their rise to political power during the 1950s. Before Neil Abercrombie lost in 2014 this race stood as the closest anyone came to a primary defeat of an incumbent governor of Hawaii. Burns' running-mate in 1970, George Ariyoshi, ran to succeed Burns as governor in 1974, defeating Gill in the Democratic primary. Burns became ill