Loretta Tucker., age U., of Winston Salem,, N.C., for her question:

How is limestone formed?

Fossils, of course., are the remains of living things. And living things, past or present., seem far removed from the lifeless rocks. But, of all. Things, some rocks are formed from fossils, and limestone may be rated as one of these. The ancient seas teemed with tiny shellfish, and through the ages countless hosts of them lived and died.

Their crusty shells sifted dawn through the water. The floor of the Sea became Piled with layers of limy shells mixed with silty ooze. As the face of the earth changed., some Of these layers were lifted high and dry. After patient ages, these layers became hard, dry layers of lumpy limestone.