Geologic units in Clarendon county, South Carolina

Bear Bluff Formation (Pliocene) at surface, covers 63 % of this area

One of the older coastal terrace sequences in the Carolinas. Equivalent to Windsor Fm.

Waccamaw Formation (Pleistocene) at surface, covers 20 % of this area

Another Carolina costalized terrace of early-middle Pleistocene age. Deeply weathered.

Duplin Formation (Pliocene) at surface, covers 8 % of this area

Coastal terrace of Carolinas. Pliocene equivalent to Yorktown. Deeply weathered.

Alluvial Valley Swamp (Quaternary) at surface, covers 6 % of this area

Unconformable on all underlying units, fluvial sand and gravel at base, grading upwards into fine sands and silts, local peat. May be overrun with recent sediments from forest cutting and agriculture.

Tidal Marsh (Quaternary) at surface, covers 3 % of this area

Peat and muck deposits along tidal margins of esturaries and back bays. Deposits range from a few feet to 60+ feet deep. Locally include silt and fine sand and clay as levees on tidal channels. At depth peaty material may be accumulated from fresh water plants. Peat at the surface dominated by spartina and other salt tolerant species.

Socastee Formation (Pleistocene) at surface, covers < 0.1 % of this area

Low coastal formation in Carolinas like Penholoway but younger and lower in altitude.