lagoon deposits

GM20 Geologic Map of the Millsboro and Whaleysville Quadrangles, Delaware

The geological history of the surficial units of the Millsboro Quadrangle and
Delaware portion of the Whaleysville Quadrangle was the result of deposition of the
Beaverdam Formation during the late Pliocene and its subsequent modification by
erosion and deposition related to sea-level fluctuations during the Pleistocene and late
Pleistocene upland swamp and bog deposition. The geology at the land surface was then
further modified by periglacial activity that produced dune deposits and Carolina Bays in

GM19 Geologic Map of the Frankford and Selbyville Quadrangles, Delaware

The geological history of the surficial units of the Frankford and Delaware
portion of the Selbyville Quadrangles was the result of deposition of the Beaverdam
Formation during the late Pliocene and its subsequent modification by erosion and
deposition related to sea-level fluctuations during the Pleistocene. The geology at the
land surface was then further modified by periglacial activity that produced dune deposits
in the map area. Surficial geologic mapping was conducted using field maps at a scale of

GM18 Geologic Map of the Bethany Beach and Assawoman Bay Quadrangles, Delaware

The geologic history of the surficial units of the Bethany Beach and Assawoman Bay Quadrangles is that of deposition of the Beaverdam Formation and its subsequent modification by erosion and deposition related to sea-level fluctuations during the Pleistocene. The geology reflects this complex history onshore, in Indian River Bay and Assawoman Bay, and offshore in the Atlantic Ocean.