This was a fantastic talk by Vic Semeniuk covering the old beach and dune surfaces visible at Cottesloe. I had not heard of the importance of freshwater seepage in the formation of what I have always assumed were purely wave cut platforms.
Pictured below is a trowel with bubbles formed at the upper end of the swash zone(?). In the pinkish cream areas below the same bubble structures can be seen preserved in limestone. I wish I had been to the talk the night before.