Understood, hence my caveat. BTW, could you help any with the Wando formation? Does it generally follow the present coastline? How far inland, etc? And, so I don't have to spend hours looking, again, how does it fit in with the age of the bays, etc?
Here's a zoomed-out graphic of a geology map of the carolinas.
http://www.uwsp.edu/geo/projects/geoweb/participants/dutch/GRAPHIC0/StateGeolMaps/NC-SC1kp.gif
Notice the formation in pale yellow, notated as Qp. "Qp" stands for "Quaternary--Pleistocene". The Wando is a smaller subset of what is shown as Qp. (Older members of the Qp, not separated out on this map, exhibit Carolina Bays.) If you were to view a more detailed map, you would see fingers of it (the Wando) extending well inland along rivers that drain from the Piedmont, in areas that are now low fluviomarine terraces, but which were estuaries when the sediments of that formation were being laid down.
Go to this map:
http://pubs.usgs.gov/of/2004/1013/figures/fig4.html
and look in the upper left for the town of Cheraw. The Wando extends as a low terrace along the Great Pee Dee River almost up to Cheraw...it stops about 5 or 6 air-miles downriver of the town. Also notice the Orangeburg, Mechanicsville, and Surry scarps, which are shown as (broken) line symbols on this map. Look east, to the area between the Cape Fear and South Rivers in North Carolina, and down toward the Waccamaw River in South Carolina. Notice the location of largest bays (Lake Waccamaw, White Lake, Black Lake, Little Singletary Lake)in relation to the geologic formations shown on James P. Owen's 1989 geologic map of the area. Those huge bays are on an area that was a major estuary early in the Pleistocene, which was subsequently infilled during succeeding marine transgressions. This isn't coincidental...it's more evidence that Carolina bays are hydrologic, and not celestial, in nature.
The Sediments of the Wando were laid down approximately 70,000 years ago, according to Owens, and would have been exposed by marine regression some time after that (~60 ka?) That suggests that bays are older than the age of the Wando's exposure, i.e., older than 60,000 years...which is what Markewich and Stoller also propose.
Also: here's a geology map of Georgia...
http://home.att.net/~cochrans/geomap01.htm
The thing to notice is the "Fall Line", i.e., where the piedmont ends and the coastal plain begins. The bays in Georgia point directly away from it.