WHAT IS COAL AND HOW IS IT FORMED?
Coal is a combustible rock that was formed by the accumulation and partial decay of vegetation. When coal was forming millions of years ago, most of the state was a low coastal plain bordered on the west and southwest by a shallow sea. A large variety of plants grew in great swamps which covered this coastal plain ([fig. 9]). When the plants died, they accumulated in the swamps to form thick masses of peat that were eventually covered by shallow seas and buried beneath mud and sand. Periodically, the region was above sea level, new swamps developed, new peat deposits accumulated, and more sediments were laid down. This process occurred repeatedly until over 3,000 feet of sediments had been deposited. Then the sediments were slowly compacted and hardened so that sandstones, shales, limestones, and coals were formed.
Figure 8—Estimated total oil production by counties from 1888 through 1963.
Counties producing oil in January 1965 Total Production 2,464,758,000 barrels 46 counties producing
Figure 9—Reconstruction of coal-forming swamp.