A 2500 year old glass bead making unit and an iron age graveyard was unearthed as a part of the ongoing excavation in and around Porunthal, 12 kilometre from Chennai. Professor K Rajan of the archeology department of university of pondicherry said that the excavation of the 5.5 hectare spread Paasi Medu (bead mound) on the ancient East-West Trade route linking Tamil Nadu and Kerala, revealed the presence of a glass bead manufacturing unit.They also recovered thousands of beads in various colours including red, white, black, yellow, maroon and green from the site along with 30 identical redware bowls, triangular terracotta pieces and two furnaces.