Janet Zukowski, age 10, of Philadelphia, Pennsylvania, for her question:

How were sea mounts formed?

We are used to the ups and downs on the bumpy land. A few years ago, ocean¬ographers began mapping the floor of the ocean. This is not easy because the solid bottom of the sea is hidden under two or three miles of deep, dark water. Special ships and instruments were needed. Small sections are being explored, one by one. And they have given us a lot of surprises. The sea bed turns out to be just as bumpy as the land, if not bumpier.

The ups and downs were formed by the restless earth's crust, which also forms hills and mountains on the land. Many undersea mountains were formed by undersea volcanoes. Others are strange, steep sided humps with flat table tops. They are

shaped somewhat like the mesas of our Western deserts. These desert mesas were left standing when water and blowing sands wore down the softer layers of rock around them. But no one is sure how the mesa shaped sea mounts were formed. However, we do have a special name for them. They are called "guyots."