Shells found in rocky area of Rethimno commercial port

An unspecified number of shells were found Friday by an underwater fisherman in a rocky area of the commercial port of Rethimno on the northern side of the Fortetza fort, on the island of Crete.
They are very old shells and are located at a depth of about 10 metres and according to a port official they are in a state of rust, while their size is about 40 centimetres.

The wider region was being patrolled and the port authorities did not allow fishermen or swimmers to approach since the shells are scattered over a large area (about 100 metres).