The rocks are about the size and shape of my Dad’s big Masonic Bible. So they are not “small rocks”. At least if you were tossing them...
And the theory has always been that they slid along the mud when it rained. Like anywhere else out there, the mud would be very fine and slippery. This is the first time I’ve heard the ice sheet theory.
Well I mean Bible sized or smaller as opposed to boulders. I could easily imagine flat pieces of ice subject to strong or even moderate winds being able to generate the kinds of forces that could move smallish rocks across a slippery mud surface.