On the northeastern side of Kithnos island, near the village of Loutra was excvated the mesolithic settlement of Maroulas (9,000 - 8,000 BC). Maroulas site is the only open air settlement of this period that has been found in Greece. It consists of circular residences and graves. Among the findings there are tools made of flint, obsidian and quartz, as well as human skeletons one of which was found intact. During the excavation, about 30 paved floors were found which belonged to lodgings. Moreover there were found two semi subterranean circular construction in rock cavities. The burials (about 15 in number) were found beneath the paved floors. The skeletons were placed in a cross legged position. The fact that there are burials and lodgings in the same area shows that the people living there were hunters - gatherers probably living from shellfish collection and fishing.
The total area has an estimated surface of 2 acres but unfortunately part of the site has been destroyed by the sea erosion. The study of the findings from Maroulas site is very important since there are only a few mesolithic archaeological sites in Greece. The sites that come from this period on other Cycladic islands, such as Alonnisos, provide evidence of the population's migration in the Aegean sea and the habitation of the islands. The use of the obsidian from the neighboring Milos island shows an active participation of the cycladic islands in the evolution of the prehistoric man.