Carolina bays are elliptical, shallow depressions found on unconsolidated sediments of the coastal plain region of eastern North America from Maryland to Florida. Most of these unique geomorphic features occur in North and South Carolina, with Horry and Dillon Counties having the most bays. Of the thousands of bays that once dotted the coastal plain, only about 219 have been preserved, and only 36 of these are in pristine condition. Carolina bays are found both singly and overlapping, but most have their long axes aligned generally in a northwest/southeast direction. They range in size from three acres to thousands of acres. Most of the bays in South Carolina are dry all year round; many fill with water during the rainy season; and some are wet all year round. Many bays contain cypress-tupelo communities, Virginia bays, red maples, sweet gums, and willows, among other tree species. The moss that grew in many of the bays over time created thick deposits of peat that in the past were harvested for garden use.
Carolina bays form unique habitats occupied by several endangered animal and plant species, including bobcat, osprey, bear, mock bishop’s weed, and rose coreopsis. In the past, rather than treasuring and seeking to preserve the bays, loggers cut their trees, drained them, and then used their rich, organic soils for farming. Many bays continue to be cultivated, but both private owners and government agencies are working to preserve as many as possible.
There are three major theories regarding the formation of Carolina bays, but the definitive explanation has yet to emerge. The most accepted theory proposes that during the Pleistocene epoch prevailing southwest winds blew across water-filled depressions near the coast and, in time, the wind and water sculpted the land into northwest-southeast trending bays. Less accepted is the theory that the bays were formed in inland estuaries or tidal flats sculpted by tidal eddy currents. Least plausible, but most dramatic and enticing, is the theory that meteorites hit the coastal sediments and formed the bays. This theory gained acceptance in the 1930s before earth science had the sophisticated technologies and data analyses that are used today. It is now clear that the meteorite theory is unsupported by any geologic evidence. There are no gravity or magnetic data to support meteorite impact, nor is there any shocked quartz in the sand around the bays. Meteorites generally create round craters, not ovals, and the shape of the Carolina bays is overwhelmingly elliptical. Also, there are no bays found in Piedmont rock, a necessity if a random meteor shower had occurred; they are found only on the coastal plain. Woods Bay State Park near Turbeville and Little Pee Dee State Park near Dillon have been established to preserve the bays and are available for the public to visit.
Kovacik, Charles F., and John J. Winberry. South Carolina: The Making of a Landscape. 1987. Reprint, Columbia: University of South Carolina Press, 1989.
Murphy, Carolyn H. Carolina Rocks! The Geology of South Carolina. Orangeburg, S.C.: Sandlapper, 1995.