The Sillakkudi Formation is a Late Cretaceous (Campanian) geological formation located in Tamil Nadu, India it forms part of the Ariyalur Group. It dates to the Campanian of the Late Cretaceous.
Description.
The formation was deposited in a Shallow Marine setting as it shows signs of a mobile deposition of substrate. The diversity of the Mollusc fauna of the formation also indicates a shallow marine deposition.
Fossil content.
Lamellibranchs and echinoid fragments have been reported from the Sillakkudi formation.