A huge limestone mass on southern coast is?

The Great Australian Bight is a large open bay in the southern coast of Australia. It is located between the Eyre Peninsula in South Australia and Cape Pasley in Western Australia. The Great Australian Bight is known for its rugged coastline, which is characterised by high cliffs, headlands and long sandy beaches. The bay is also home to a diverse range of marine life, including whales, dolphins, sea lions and fish.