Terry Niver, age 7, of Omaha , Nebraska

How is chalk made?

The stalk of blackboard chalk was made by countless little sea creatures, Their family name is Fornaminifera which means the window‑makers, It's a good name for them because they were experts at building tiny houses with windows. The houses were made of limey shell. The window was a tiny lookout through which the small creatures could see what was going on in the world, He also used it to take in food and water.

The little chalk makers were very plentiful towards the end of the Age of Reptiles when the great dinosaurs roamed the earth. They lived in the shallow waters of the warm seas. Countless trillions of them built their little lime houses and died. The chalky shells fell to the floors of the ancient seas. There were so many of them that they gathered there in immense piles. The sea floor was covered in deep layers of them.

As time went on, the seas changed and shrank. New dry land poked up along the beaches. Some of this new land was covered with piles of tiny shells from the lit,raa window builders, This material dried out and became covered with blown' dust and dirt, In time it became sandwiched between other rocky layers,  The little shells were packed and pressed together to form layers of chalk.