A Magnetometer Survey of the Kings Bay, Georgia Entrance Channel

The St. Marys River forms the state boundary between extreme southeast Georgia and extreme northeast Florida. Located in the Atlantic Coastal Plain physiographic district, the river enters the Atlantic Ocean between Cumberland Island on the north and Amelia Island on the south. These are barrier islands representing relict marine terraces of the Silver Bluff formation, created by late Pleistocene sea level transgression. The islands are fronted on the west by a complex of stream channels and extensive salt marshes of the Cumberland Sound, which in turn border the moderate bluffs of the mainland. The Kings Bay Naval Support Base is located on such a bluff. Reactivation of the military installation at Kings Bay has created the need for an improved navigation channel into the Cumberland Sound along the course of the St. Marys River. The current channel is maintained by the U.S. Army Corps of Engineers at a width of 400 ft and a depth of 40 feet. Improvements in the channel will entail expansion to 500 ft in width and an overall depth of 51 ft at mean low water. The existing 6.5 mile channel would be extended an additional 7.5 miles eastward into the Atlantic, while a 6,000 ft long and 1,200 ft wide turning basin and two settling basins would be provided adjacent to the channel. Dredged material is slated to be dumped in both offshore disposal sites and near shore beach nourishment areas. Prior to these improvements, consideration of potential submerged cultural resources was required, resulting in a magnetometer survey of the proposed channel areas. The magnetometer survey was performed during the week of June 30 - July 3, 1986 by OSM Archaeological Consultants. Related archival work was performed in two phases: the records of the Georgia State Site Files located in Athens were reviewed on June 17, 1986, while the records located at the Florida Division of Archives, History, and Records Management in Tallahassee were inspected on July 14, 1986.