Editing Okefenokee Swamp (section)

== Origin ==
The Okefenokee was formed over the past 6,500 years by the accumulation of peat in a shallow basin on the edge of an ancient Atlantic coastal terrace, the geological relic of a Pleistocene estuary. The swamp is bordered by Trail Ridge, a strip of elevated land believed to have formed as coastal dunes or an offshore barrier island. The [[St. Marys River (Florida–Georgia)|St. Marys River]] and the [[Suwannee River]] both originate in the swamp. The Suwannee River originates as stream channels in the heart of the Okefenokee Swamp and drains at least 90 percent of the swamp's watershed southwest toward the Gulf of Mexico. The [[St. Marys River (Florida–Georgia)|St. Marys River]], which drains only 5 to 10 percent of the swamp's southeastern corner, flows south along the western side of Trail Ridge, through the ridge at St. Marys River Shoals, and north again along the eastern side of Trail Ridge before turning east to the Atlantic.