Noted: It’s also unclear how much of the lost continent actually lies beneath the island of Mauritius. “They’ve found ancient crystals surrounded by younger rocks,” explains John Valley, who studies geoscience at the University of Wisconsin-Madison but didn’t participate in the recent study. “But they haven’t yet found any of the older rocks.” Although the crystals provide valuable evidence for the existence of this submerged land, how much of it lies down there remains a mystery. “It could be a massive buried continent, or just trace amounts of zircon crystals,” says Valley.