From Caroline and Ron on their trip to Australia and New Zealand: (!!!)

The strangest thing this morning. I collected some shells and rocks at an NZ beach, the southern side of the northern-most tip, some rocks and shells and bits and pieces washed up on the sand right at the tide line, picked out of the foaming waves. Found them last night in their baggie, and opened it, expecting stink. No stink, which makes no sense as at least one of the shells had seaweed green edges. Perhaps they needed washing to release the stink? so set them to soak overnight. This morning still no stink but one of the rocks, a silver-gray with a gold stripe, had completely disintegrated. Fine silt and sand, silvery grey with a little gold beach sand. How in the world could this lump of mud feel like a rock in the high tide?

And:

DCD collected a large rock from the Anchorage beach with lots of imbedded seashells and worm holes, interesting bricabrac and contours. He set the rock on the front porch overnight. The next morning it had disintegrated into a small pile of shells and some dirty powdered clay and a little sand. So there you have it: mud can withstand wave action but not drying out. Also interesting is that these lumps of apparently useful clay were found on coastlines of aboriginal peoples that do not have a clay-using culture. My guess about that is neither culture has a food tradition requiring extended periods of low to moderate heat. Australian Aboriginals, the Maori, and the Alaskan folks eat raw seafood, fresh fruits and vegetables in season, raw or gently toasted meat. They neither one stew or boil or bake, all of which require the kinds of continuous heat from a fire that clay also requires to fire into a solid non-porous (not meltable) substance. If they have fires they are small, grass-fed, and short-lived comparatively.