Bourkes Luck Potholes

To Nobbywebfoot - Thanks for the interesting information. The only thing I know about them is that they are formed by the natural swirling action of the water as it flows downstream, however, it may well be that some hard object at the bottom causes the action on a softer material. If you ever get the chance, it is well worth a visit to the area. It is full of Geological and historical interest.

I wonder if these are formed the same way as similar but smaller pot holes found on the coast. Here each one usually has a small but harder pebble in the bottom than the surrounding rock. Such as flint pebbles in chalk. Swirled around by the motion of waves it would carve out the pot hole being slowly ground and polished itself. As a child, once shown this phenomenon, I would inspect these pebbles looking for especially smooth, round or remarkably patterned ones. Ensuring that I replaced it with a new hard pebble which had promise. Can any one please tell me why there is only ever one such pebble, albeit sometimes with a few much smaller tiny pebbles. Many years later I was shown such a pot hole buried in the ground a long way from the sea with its pebble still in situ!

Nice shot,
thanks

spectacular sight