The Kallamedu Formation is a Late Cretaceous (Maastrichtian) geologic formation located in the Ariyalur district of Tamil Nadu, India that forms part of the Ariyalur Group.

[1] It dates to the Maastrichtian of the Late Cretaceous.

Dinosaur remains and petrified wood samples are among the known fossils recovered from this formation.

[2] The Kallamedu Formation likely represented a fluvial environment.

The high organic carbon content of some of the rocks are consistent with a swamp.