Theresa Peek, age 10, of Shreveport, Ta., for her question:

What made the Grand Canyon?

Andy has just returned from a visit to Grand Canyon and someday you also must visit this stupendous natural wonder. For no description, not even a three dimensional movie, can do justice to its magnificent size shapes and colors. The colors of the rocky terraces challenge the rainbow and they are changing every moment with shifting sunlight and clouds.

You stand on the rim of the canyon and look across to the opposite rim, maybe eight miles away. Each rim spills down in a series of sculptured terraces to the gorge a mile below. Down there is the Colorado Rivers the busy engineer that cut and carved the canyon. It is a swift, rapids filled river and naturally it could not do all that work without getting somewhat dirty.

The busy river began its great work about 50 million years ago. At that time it was a fast flowing surface river, rushing down the slopes of the western mountains. For countless ages this had been a rotation of ups and downs. Sometimes the land sank and filled with a shallow sea. Then the trough. heaved up to form a range of mountains. Some 50 million years ago old Mother Earth decided to hump her back once again. Slowly, slowly the surface of this western region began to rise. And in spite of the rising ground, the busy Colorado decided to keep to its old path.

It was always a swift, strong river, able to sweep away the stones in its path. As the ground rose, it was able to dig a channel. As the earth heaved upward, this channel became deeper. The channel became a gorge. In about 50 million years the great canyon was a mile deep. The busy Colorado had cut through layers and layers of the earth's crust.

The layers are the colored bands which now form the walls and terraces of Grand Canyon. The oldest layers, at the bottom of the gorge, were formed some 500 million years ago. Their rocks have been squeezed under great pressure, and some are so hard and dense that you cannot nick them with a with a steal hammer. There is one such rock, with a steel hammer for you to try, in the Grand Canyon Museum.

The youngest rocks are at the rim of the canyon. In geological tune they were formed oily yesterday. Near the top, we find a layer of pink cliffs. They bear the imprints of the first flowering plants: As the river dug, a little lower down the rocks bear records of the giant dinosaurs who lived maybe 100 million years ago,

Far down the canyon is a chocolate colored layer bearing fossil records of the first small reptiles. Still farther down are records of the first amphibians and of ancient plants. Just above the steep plunge to the river the ancient rocks bear fossils of the trilobites. Some 400 million years ago, these small crawlers were the most advanced creatures on earth. In carving its paths the busy river has laid bare for us the pages of the earth’s diary of life on earth.