1 . Sangamon Origin : Dunes along shoreline of the Pasquotank 

 basin. 



Perhaps the most plausible explanation might be that they 

 formed as a series of dunes along the south shore of a lagoonal 

 area during recession of the Sangamon sea. As discussed in the 

 formation of the marsh at 'Washington's Rice Farm', creation of 

 the Pasquotank drainage may have begun with the cutting of 

 Corapeake and Moss Swamps through the Suffolk Scarp during the 

 Illinoian glacial period. As these flowed together across the 

 flat plain of the Dismal, they would have formed a shallow stream 

 valley which may have been the precursor for the present sub-peat 

 drainage pattern partially mapped by Oaks and Whitehead (1979). 



With the rise of sea levels during the Sangamon, this area 

 was flooded as far west as the Suffolk Scarp, and some filling of 

 the shallow valley occurred. Deposition of the Norfolk and Sand 

 Bridge Formations would have softened the contours of the previous 

 drainage, leaving only a shallow estuarine basin. The mesic islands 

 could have formed in a lagoonal situation, along the southern rim 

 of this Pasquotank basin, as the Sangamon shoreline receded to the 

 east. 



Details of these sandy ridges are readily distinguishable on 

 color infrared aerial photography. Eolian origin is suggested by 

 their lenticular shapes and the repetitive pattern observable in 

 some groups. The islands are elongated from west to east, but 

 show a stacking pattern from north to south. In one remarkable 

 group, just east of the Gates/Pasquotank County line, a series of 

 five parallel ridges can be discerned. Similarly, a 



repeating pattern of ridges within an island group can be found 

 along the Pasquotank River farther east, and, less distinctly, 

 within the clusters in Gates County. 



If this hypothesis is correct, these ridges were probably 

 formed at the close of the last high stand of the Sangamon sea 

 and have been covered with vegetation since that time. 

 Unfortunately, since sea levels are presently rising (Bellis 

 et al. 1975), contemporary examples of coastal morphology 

 resulting from receding seas are not available for comparison in 

 this part of the Atlantic Coastal Plain. 



2. Wisconsin Origin : Fluvial sand deposits and associated dunes. 



The distribution of these ridges along the apparent former 

 course of the Pasquotank River suggests the possibility of 

 fluvial origin. Whether or not the Pasquotank drainage, with its 

 headwaters in Corapeake and Moss swamps, began to form in the 

 Illinoian, it is certain that it operated during the Wisconsin 

 since it can be seen directly beneath the post-Wisconsin peat. 



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