Why do they sort at all? Why aren't they all jumbled up? They appear in discrete layers. And while you're answering that, can you explain to me the layer of fern spores laid down just above the K/T boundary, which apparently was deposited and then covered by many layers of other strata during the Flood? Why would so many fern spores decide to layer just so?
Have you ever studied the effects of any recent local flood? It would either answer your questions or, more likely fill your trivia prone head with a thousand more.