Forget Atlantis. Scientists have uncovered evidence of an ancient “lost continent” under the Indian Ocean island nation of Mauritius, according to a new study.

The continent, which geologists call “Mauritia,” formed part of present-day Madagascar and India. The rest of the continent probably sank beneath the sea 84 million years ago.

“We are studying the break-up process of the continents, in order to understand the geological history of the planet,” said study lead author Lewis Ashwal of the University of the Witwatersrand in South Africa.

The continent was likely part of the gigantic supercontinent Gondwana, which broke up to become Antarctica, Africa, Australia and South America.

The clue to the discovery was finding an ancient mineral on Mauritius that shouldn’t have been there.

By studying the mineral zircon, which is found in rocks spewed up by lava during volcanic eruptions, Ashwal and his colleagues discovered remnants of this mineral that were much too old to belong on the island of Mauritius.

“Earth is made up of two parts — continents, which are old, and oceans, which are ‘young,'” he said. On continents, rocks can be billions of years old, but nothing that old exists in the oceans, explained Ashwal.

Mauritius is only a few million years old, while some recently discovered zircon crystals on the island were estimated at 3 billion years old. “The fact that we have found zircons of this age proves that there are much older crustal materials under Mauritius that could only have originated from a continent,” says Ashwal.

The study said there are likely many pieces of various sizes of “undiscovered continent, collectively called Mauritia,” spread over the Indian Ocean.

The study appeared in the peer-reviewed British journal Nature Communications.