The exact same argument applied to things like pteropods, Atlanta, Spisula, Cooperella, Gari, eulimids, or practically any other mollusks that won’t only break if I step on them or throw them (I’ve tried with some already broken ones).
Shells like those are strong enough to survive significant pressure when they are filled with sediment, and/or because they are so small that the forces exerted on them are tiny. However, if the deposition was violent, how does a clam shell that is about as strong as an eggshell, but 170 mm x 100 mm, survive? Or something 1 mm across, that would shatter if I tried to pick it up with anything more forceful than surface tension from a wet paintbrush survive, and get deposited next to a 150 mm Mercenaria shell that weighs a few hundred grams?
There is one Yorktown Formation Deposit I know of that got smothered in mud by a storm. Most deposits do not look like that one.
Another problem: the standard layer sequence near the coast in the Carolinas is the following (generalized somewhat, and with a more complete section than most places have):
Topsoil
Coarse sand, some beach or river-deposited fossils, all recent species. (late Pleistocene)
Layer going from coarse sand to finer sand and shell hash back to coarse sand, mostly recent species. (mid-Pleistocene
Several more layers going from coarse sand to finer sand and shell hash back to coarse sand, with some patches of mud mixed in, decreasing proportions of recent species as you go down. (late Pliocene and early Pleistocene)
Sandy leached limestones, sandy unleached limestones, or more sandy shell layers, decreasing proportions of recent species as you go down, hitting zero by the mid-lower part of this. (early Miocene to mid-Pliocene)
Mostly biogenic leached limestones. (Paleocene to Oligocene)
Clay and clayy limestones. (Cretaceous)
Igneous and Metamorphic Bedrock. (Paleozoic or Precambrian)
How does that happen with rapid movement?