Eighteen ancient 'panchaloha' idols of various deities were unearthed while a piece of land was being dug for construction of a school at Arundavampulam village near Porayar in Nagapattinam district.
Officials said the idols, unearthed on Friday, were taken by revenue officials, who later handed them over to the Government Museum here for safe custody.
Archaeologists opined that the idols might belong to the Chola period.
According to officials, this is the first time such large number of ancient panchaloha idols have been unearthed in the district from a single place.
Official sources estimated they might be worth several crores or rupees in the international market.