Originally posted by WPRESTO The outliers, sea stacks, sea arches, are easy to understand. They are remnants of where the land used to be. Large blocks of rock mixed into sand of a shoreline that is being eroded are also easy to understand. To get the Australian beach, the sand must be derived from the local shoreline, and the sedimentary rock of the shoreline would be composed of the same mix as the beach = sand with scattered fist-size well-rounded cobbles. That pushes back the problem to how was that bedrock rock formed with such an odd, heterogeneous mix of particle sizes. Also, I think the beach pictured is an depositional structure = the sand is being transported in from elsewhere rather than being autochthonous.
Thank you very much for a very comprehensive and interesting analysis. Geology is certainly one of the most fascinating studies I know of. It reminds me of a quote my
close, personal friend Albert Einstein once uttered, "The more you know, the less you know." In other words, once you come to an answer to a question or a solution to a problem,
it opens doors to more questions. Again, many thanks.
TT