A strip of land, now buried beneath the Indian Ocean floor, was believed to have existed between 85 million and two billion years ago. (FOTOLIA)

Scientists have discovered evidence of a lost continent, but it's not Atlantis.

Researchers believe a strip of land — now buried beneath the floor of the Indian Ocean — was once a sub-continent between India and Madagascar, way back when the two were close together.

The sub-continent, which the scientists have named Mauritia, would have existed between 85 million and two billion years ago.

The researchers from London, Germany and Norway, studied grains of sand from the beaches of Mauritius, an island nation in the Indian Ocean. Some grains dated back to a volcanic eruption nine million years ago, but others were older.

"We found zircons that we extracted from the beach sands, and these are something you typically find in a continental crust. They are very old in age," the University of Oslo's Trond Torsvik told the BBC.

Mauritia would have disappeared 85 million years ago, the scientists speculate, when India drifted away from Madagascar.