Devonian Reef Conservation Park - WA

A 'Great Barrier Reef' fringed an ancient Kimberley land mass during the Devonian period, between 375 and 350 million years ago, when a tropical sea filled the Canning and Bonaparte Basins. Remnants of the reef are preserved in the West Kimberley as ranges of low, rugged hills extending for 300 kilometres. The reef probably extended for more than 1000 kilometres around the seaward margin of the Kimberley and is also seen north of Kununurra, where it forms the Ningbing Range.

The structure was built by lime-secreting organisms, mainly calcareous algae and extinct coral-like organisms called stromatoporoids. Though corals were present, they were much less important in reef-building than the corals of modern times. Gastropods, brachiopods, bivalves and stromatolites were also present in and around the reef.

The ancient reef now forms a chain of often steep-sided, low limestone ranges, up to 300 metres above sea level, which rise from 40 to 150 metres above the surrounding Fitzroy River floodplain. Boab trees often grow on the rocky hillsides.