Megalithic/ Iron Age in Tamilnadu
The burial system followed by the people of Neolithic period continued into the Megalithic period. A circular tomb using big stone slabs built upon the place of burial is known as a megalith. Such megaliths have been found in many parts of Tamilnadu . The urn burial system was another type of practice and is evidenced in Adichanallur (present Thoothukudi district). Black-ware is peculiar to burial sites in Tamilnadu. Interestingly, black-ware is found mostly in burial mounds and not in human habitations. In a majority of urn burials, the use of stone is almost non-existent. However, urn burials are grouped under megalithic because the materials - the pottery, iron objects, beads of semi-precious stones kept in them - are identical to those found in the stone burials.
The end of Megalithic burial practice is assigned to third-second centuries CE. During this period Brahmi writing akin to Ashokan Brahmi has been discovered in Kodumanal (Erode District). There is also evidence of the megalithic tradition continuing into later centuries. During the Sangam period people still remembered urn burials. The four primitive hero-stones with Tamil Brahmi inscriptions, datable to third to second centuries BCE found in the upper part of the Vaigai valley, support the authenticity of the hero stone tradition described in the Sangam Tamil literature in the context of cattle raids. Scholars infer, based on such evidence, that the some of the Sangam poems could be assigned to the early first century BCE or a little earlier. The tradition of erecting hero stones in memory of dead warrior-heroes is considered to be an extension of the menhir type of megalithic tradition. Menhirs, upright monumental stones, and dolmens made of big slabs or boulders are megalithic tombs found in Tamilnadu.