Clyde Roettger, age 9, of Richmond, Va., for his question:

How did coal get into the earth?

A coal fire burns to ashes in a few hours. Yet it took the earth many millions of years to make that black shiny coal. The recipe was started perhaps 250 million years ago. If we could go back to those faraway days we would hardly recognize our beautiful world.

There wore no birds soaring in the sky and only a few four footed animals crawling on the ground, There were no flowers and no trees we could recognize except a few giant ferns. The Great Smokeys had not yet poked up their hazy heads, the proud Rockies and the Sierra N6vada mountains did not exist.

The ancient seas washed over great areas of our country several times and retreated.  The center of the continent and much of the west was swamp land, though the sea water which flooded it was net so salty as it is today. The oceans and the swampy marshes teemed with fish and other sea dwellers all living in fear of hordes of hugs hungrv sharks.

The weather was warm and wet and all sorts of strange plants thrived in the swampy sea marshes. There were giant horse tails as tall as our birch trees. There were huge fern trees with giant fronus there were plenty of insects. Giant dragonflies with wings four feet wide zoomed through the scrawny branches of the forests. A few sluggish salamanders wallowed in the muddy swamps.

The strange trees lived and died, falling into the muddy marshes. There they could not decay because the water was still and stagnant. Stagnant water contains no oxygen and the bacteria which cause plants to decay cannot live without oxygen. Masses of old trees and leaves piled up in the shallow seas.

As time went on the face of the earth changed. Mountains grew up from the hollows.   The swamps dried out and the waters washed back to the oceans. After millions of years, the weather wore down the new mountain tops and piled up new layers of dirt and soil., The old forest became buried under layers of rock. The heat and weight of these upper layers caused the buried forest to turn into coal.

The process was very slow. The moisture and many of the gases were squeezed out. Only the carbon was saved, and it is carbon which makes coal burn as a good fuel. After countless ages, the old forest became a bed of rather soft brown lignite. Lignite is a coal, out not too good as a fuel. This is because it is only about 67 percent carbon. If lignite is left for more millions of years it becomes black bituminous coal, This makes a much better fuel because it is 88 percent carbon. After more millions of years, the buri