Larry Evers, age 9, of Denton, Tex., for his question:

HOW OLD ARE THE CARLSBAD CAVERNS?

Carlsbad Caverns is a chain of huge underground caves in southeastern New Mexico. The caverns became a national park in 1930. Scientists tell us that the limestone in the caverns probably formed in a shallow inland extension of the ocean about 200 million years ago.    Then when the Rocky Mountains were formed about 60 million years    ago, the cavern area rose above sea level and water began hollowing out the limestone to form the caves.

Stalactites and stalagmites, in white and pastel shades, form beautiful shapes that look like Chinese temples, heavy pillars and lacy icicles.

One chamber is called the Big Room. It is 4,000 feet long and 625 feet wide. At one point, the ceiling is 285 feet high.

One part of the caverns contains millions of bats that fly out at dusk in warm weather in search of insects.

Paintings on the entrance wall of the cave show that Indians at one time used the cave for living quarters.