I know for a fact that New England was an impact site but there is some sort of strange connection to the Carolina Bays as well. Perhaps the wave of debris that caused the comet swept many different substances with it. Still, Carolina Bays were not under an ice sheet. The ice sheet did not extend that far south 12,900 years ago.
My theory is that the Carolina Bays were formed when gigantic chunks of ice were thrown out of the ice sheet by impact, and then melted. If I remember correctly, the book SC posted said something about CB type shapes found elsewhere, and that lines along the long axis of the oval mostly pointed toward Lake Michigan. Since there may have been more than one boloid strike, other bays could also have been produced with a different axis orientation.