Tiruvannamalai: Based on information from two persons in Padipallam village near Gingee in Villupuram taluk abutting Tiruvannamalai’s Vettavalam, the researchers visited the nearby Panchamada hillock where they discovered numerous pits with foot print like protrusions. Investigation revealed that the pits – said to be about 5,000 years told - were actually sites used by stone age man to sharpen his weapons and implements to make them more effective. As water was needed for the sharpening process such pits would usually be found near water sources. Similarly, many sharpening sites were located around a tarn atop the hillock.