Theodore Athanas  age 11 of Ephrata –Penn.

What causes limestone deposits?

Some of the earth's limestone rock was made hundreds of millions of years ago. It‑was made by little creatures that lived in the ancient seat They were tiny shell fish that took limey chemicals from the water to make their homes. They‑lived and died in countless: numbers through countless ages. Through the years: piles of their shells settled and collected on the sea beds.

Sometimes the sea retreated and deserted them. The damp sea beds became dry land. The shells were pressed and hardened into solid rock. This rook is limestone  made mostly of the chemical calcium carbonate.

Millions of years later came men who learned to use this shell made rock as building material. It is easy to cut limestone into slabs and it wears well. For some 5 000 years the pyramids have stood the test of time  and weather. They are made of slabs of limestone cut axed hauled by the ancient Egyptians.

Some of the rock used to build the pyramids is called nummulitic limestone. It was formed from the dried and cemented shalls of a little creature called foraminifera of the same family that built a great deal of the worlds chalk. Many of the shells are from a foraminifera called nummulite. Generally you need a magnifying glass to see the ancient shells in limestone. But same of them are as large as twenty‑five cent pieces. They are round in shape and grooved like pinwheels. This numtulitic limestone was made some 50 million years ago.

There is limestone  plenty of it„ in North America. It rests in places once flooded by ancient seas. There is limestone in the Valley of the Mississippi. Over this land in ancient days the Arctic Ocean once reached down to join hands with the Gulf of Mexico. There is limestone along the St. Lawrence River and around the Great Lakes. Some of this stone has gone through a further har4ening process and become dolomite. There is still more limestone in Texan and the Rocky Mountain region.

All this limestone was made by little creatures living millions of years ago  but sometimes Nature makes limestone from soil and running hater. Limes. calcium cai4bonat e j dissolves in water when there is carbon dioxide in the air. Caves are usually chiseled through limey soil. Water dripping down the roofs of these castes carries a heavy load of lime and such other chemicals; It drips,  evaporates and leaves its chemicals behind. They form the beautiful stalagmites and stalactites on the floors and roofs of caves.

Nowadays limestone is used for more than buildings. It is shoveled into the furnaces that smelt iron from its ores. It is used in the making of portland cement and hence concrete. Some is even used as fertilizer  which is fair enough for the lime used by the little shell makers once belonged to the land. It was stolen by busy streams and dumped into the seal Now it returns to neutralize unhealthy acids in the soil.