Rock art engravings found in Goa are the earliest known traces of human life in India.[16] Goa, situated within the Shimoga-Goa Greenstone Belt in the Western Ghats (an area composed of metavolcanics, iron formations and ferruginous quartzite), yields evidence for Acheulean occupation.[17] Rock art engravings (petroglyphs) are present on laterite platforms and granite boulders in Usgalimal near the west flowing Kushavati river and in Kajur.[18] In Kajur, the rock engravings of animals, tectiforms and other designs in granite have been associated with what is considered to be a megalithic stone circle with a round granite stone in the centre.[19] Petroglyphs, cones, stone-axe, and choppers dating to 10,000 years ago have been found in various locations in Goa, including Kazur, Mauxim, and the Mandovi-Zuari basin.[20] Evidence of Palaeolithic life is visible at Dabolim, Adkon, Shigao, Fatorpa, Arli, Maulinguinim, Diwar, Sanguem, Pilerne, and Aquem-Margaon.