Carolina bay
Carolina bays are oval-shaped depressions found in coastal Delaware, Maryland, North Carolina, South Carolina, and northeastern Georgia. Their size varies from one to several thousand acres. About ten to twenty thousand of them are present, often in groups which vary in alignment a few degrees off a northeast-southeast trend. The bays have many different vegetative structures, based on the depression depth, size, hydrology, and subsurface. Many are marshy; a few of the larger ones are (or were before drainage) lakes. Some bays are predominately open water with large scattered pond cypress, while others are composed of thick, shrubby areas (pocosins), with vegetation growing on floating peat mats. Generally the southeastern end has a higher rim composed of white sand. They are named for the Bay trees that are frequently found in them, not because of the frequent ponding of water.
USGS aerial photo of Carolina bays; north is at top. The bays are especially rich in biodiversity, including some rare and/or endangered species. Species that thrive in the bays' habitat include birds, such as wood storks, herons, egrets, and other migratory waterfowl, mammals such as deer, black bears, raccoons, skunks, and opossums. Other residents include dragonflies, green anoles and green tree frogs. The bays contain trees such as black gum, sweet gum, magnolia, bald cypress, maple, and shrubs such as sumac, button bush, gallberry and red bay. Plants common in Carolina bays are water lilies, sedges and various grasses. Some of the rare plants are found include bladderwort, butterwort, fetterbush, loblolly bay, pitcher plant, pond cypress, pond pine, red bay, sundew and sweet bay.
Some of the bays have been greatly modified within human history, under pressure from farming, highway building, housing developments and golf courses. Carvers Bay, a large one in Georgetown County was used as a bombing practice range during World War II. It has been drained and is mostly used for tree farming today. Others are used for vegetable or field crops with drainage.
In South Carolina, Woods Bay, on the Sumter-Clarendon County line near Turbeville has been designated a state park to preserve as much as possible in its natural state. Also in Clarenden County (near Manning) another bay, Bennett's Bay is a Heritage Preserve.
Various theories have been proposed to account for them, including action of sea currents when the area was under the ocean or the upwelling of ground water at a later time. The most accepted theory today is that a combination of processes including climate change, wind erosion, and changes in the water table are responsible for the shapes and orientations of these ancient landforms. An older theory that they are impact craters created by a meteor shower has frequently been discarded because of the lack of extraterrestrial material, their oblong shape, and the various ages and orientations. The bays are believed to have been formed through several climate cycles and have a broad age range in different regions. Many have relatively distinct geomorphologies, whereas a large number a clearly dissected with a more clearly developed soil horizon indicating a much older bay. However, at least one very large crater that is much older has been identified at Snows Island, at the junction of Lynches River and the Pee Dee River.
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