This vector data set contains the rock unit polygons for the surficial geology in the Delaware Coastal Plain covered by DGS Geologic Map Series No. 19 (Frankford and Selbyville Quadrangles). The geological history of the surficial units of the Frankford and Delaware portion of the Selbyville Quadrangles is that 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. Mapping was conducted using field maps at a scale of 1:12,000 with 2 foot contours. Stratigraphic boundaries drawn at topographic breaks reflect detailed mapping related to contours not shown on this map. An additional dataset of datapoints used to generate rock unit polygons for the surficial geology in the Delaware Coastal Plain covered by DGS Geologic Map Series No. 19 (Frankford and Selbyville Quadrangles) exists for use in conjunction with this dataset.
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+/- 1 foot. Drill holes and hand auger holes have been averaged together to get this value.
+/- 20 feet. Boring sites are located on topographic base maps and aerial photography. Spot checking of these locations using GPS has verified this accuracy.
Please give proper credit to the Delaware Geological Survey.
Tomlinson, J.L., Ramsey, K.W., and Andres, A.S., 2013, Geologic map of the Frankford and Selbyville Quadrangles, Delaware: Delaware Geological Survey Geologic Map Series No. 19, scale 1:24,000.