This feature is found on the Forestier Peninsula and is an inter-tidal rock platform, a common enough coastal landform. But an unusual set of geological circumstances has given rise to this very rare structure. The flat-lying siltstone was cracked by stresses in the earth’s crust sometime between 60m and 160m years ago – in three directions. One set of cracks, seen below as joints, lies NE, another E and the third, NW. The result, exacerbated by marine erosion, has created a tiled appearance:

 

At sea level (see photographer’s shadow for scale) ‘pans’ and ‘loafs’ can be distinguished. Further away from the sea the pavement dries out for longer allowing greater development of salt crystals. The salt forms on the surface and erodes the face more quickly than the joints. The surface of the pavement is lowered while the joints which erode more slowly form rims.

These pans contrast with the loaves nearer the sea where joints are eroded by sand and water action more quickly than the surface making Hovis-like shapes. Eventually the loaves are dislodged by wave action and the process repeats.

 

As you can see above, however, the whole thing is so astonishingly regular that you’d swear it was a mason’s quarry. An amazing sight.