Randy Katz, age 10, of Philadelphia, PA

How old is Grand Canyon?

This mighty ditch in the earths crust is a mile deep and in some places eight miles wide. It was cut into the solid rocks by the busy Colorado River and, after all this dirty digging, it is no surprise to discover that the swift waters are rather muddy. The job was started as the Rockies began to lift their pround heads above the ground. The stubborn river refused to be turned from its course by the rising slopes. The higher they grew, the deeper it dug down to keep its channel.

The tremendous job was started about 50 million years ago., It was slow work and from time to time there were long pauses and the growing mountains rested for a million years or so. During some of these pauses were created the splendid terraces that step down the walls of the stupendous canyon.