The two fragments, called microcontinents, are possibly leftovers from when India, Antarctica, and Australia were part of a supercontinent known as Gondwana (see a map of Earth during this time.)

The plateaus, the combined size of West Virginia, have long been known to cartographers as the Batavia Seamount and the Gulden Draak—or Golden Dragon.

But not much else was known about the features, other than their location, about 1,000 miles (1,600 kilometers) west of Perth, Australia (map).

To fill in the gaps, an international team of scientists recently mapped the seabed and dredged samples from as deep as 8,200 feet (2,500 meters). (Read more about