Remember how we were all taught that there are seven continents in kindergarten? You know the ones I’m talking about: North and South America, Europe, Asia, Africa, Australia, and Antarctica. Yeah? Well, that’s actually an “alternative fact.” It turns out that there is at least one more. Scientists have recently found evidence that there is a “lost continent” under present-day Mauritius in the Indian Ocean.

How do they know? It all comes down to rocks. Geologist Lewis Ashwal explains, “Earth is made up of two parts – continents, which are old, and oceans, which are ‘young.’ On the continents, you find rocks that are over four billion years old, but you find nothing like that in the oceans, as this is where new rocks are formed.” Since Mauritius is a volcanic island, none of the rocks on it are over nine million years old. However, while analyzing samples of the gemstone zircon on the island, Ashwal and his colleagues found some pieces that were roughly three billion years old.

What does this mean? Around 200 million years ago, the supercontinent Gondwanaland broke up (yes, there were other supercontinents besides Pangaea). It included present-day Africa, South America, Australia, India, and Antarctica. Once all those pieces were divided up, there were little bits left over, and these little bits were all eventually covered up by the lava from newly-forming islands. The Earth’s crust is actually thicker in these areas as a result.

But what does this mean? There are many fragments of the former Gondwanaland scattered all over the Indian Ocean. Lewis Ashwal and his team collectively call all these fragments “Mauritia” and hope to discover more remnants of the continent lost beneath the waves.