"...You're talking barrier islands/strips? Backfilled by wave action? Hurricanes? Tusnamis? Rising oceans? ..."
Yes, yes, yes, yes, and more. Once sea level becomes relatively stable for a while, barrier islands form along continental edges of low gradient (such as along our eastern and southeastern coasts). Backbarrier areas accrete soil and soil-forming material rapidly; this includes wind-and wave-deposited mineral material, as well as organic detritus from saltmarsh vegetation (and the saltmarsh vegetation itself acts as a filter to trap suspended sands, silts and clays). One of my colleagues at the Smithsonian Environmental Research Center, in neighboring Anne Arundel County, has measured >14 feet of Holocene deposition (mostly organic) in a saltmarsh along the Chesapeake Bay. This rate of deposition is by no means unusual.
By the way, I'm convinced that earth is frequently (on a geologic time scale) bombarded by various metorites and cometary fragments. I just don't think such bombardment is responsible for Carolina Bays.
"I'm convinced that the earth is frequently...bombarded by...metorites."
The book "Comet" by Carl Sagan and Ann Druyan, 1997 has a lot of interesting information on the causes of boloid movement through the inner solar system, especially from the Oort Cloud.