A large number of prehistoric posthole sites of pillared halls have been found in the valley of the Gayathripuzha, a left-bank tributary of the Bharathapuzha, suggesting that they are sites of Neolithic settlements.
The socket remains (cupules/postholes) have been found on several rock outcrops at the foothills of Thenmala of the Western Ghats in the Palakkad Gap zone.
These findings were part of research in the region by V. Sanal Kumar, Director of the Geo-Heritage Archaeology Research Centre. He, with the help of some historians and archaeological researchers, had unearthed some such sites recently. But most of these sites are getting vandalised or being used by quarry operators illegally in the absence of any steps to protect them by the Archaeological Department or the State government.