Sidney Tobias, age 9, of Monroe, La., for his question:

WHEN WAS BIG BEND NATIONAL PARK ESTABLISHED?

Big Bend National Park is the last great wilderness area of Texas. It covers over 700,000 acres and is one of the few places in the world where geological processes are so clearly shown that an untrained person can understand them.

Texas gave the land for the park to the federal government in 1935. The park was opened in 1944.

The park was named for the Big Bend of the Rio Grande which runs along its southern boundary.

The Chisos Mountains in the park were created by volcanic eruptions in the Age of Dinosaurs and by the later action of erosion. Various canyons reveal geological history for the past 100 million years. or about one fifth of the Earth's known history.

Fossil trees millions of years old can also be found in the park.