transgression, and is only approximately superimposed on the ancestral fluvial 

 channel of the Delaware River. Modern shoals in the Delaware Bay entrance 

 have been derived from littoral drift moving along the New Jersey shore and 

 distributed by tidal currents in the estuary mouth. These shoals can be 

 traced seaward along the north flank of the Delaware Shelf Valley where they 

 presumably formed as estuary shoals during the Holocene transgression, and 

 thus can be considered an estuary-associated shoal retreat massif. These 

 shoals are oriented in a shore-parallel direction while the modern estuary 

 mouth shoals are oriented in a shore -normal direction. This can be attributed 

 to the effects of southwest trending, storm- generated currents that have dras- 

 tically modified the shoals after their formation. The large midshelf shoal 

 is interpreted as a delta that formed during a stillstand of sea level at 

 about -40 m below present level. On this delta are superimposed shoals that 

 are believed to be a cape retreat shoal massif that was created by littoral 

 drift convergence at a cuspate foreland that was developed on the delta. 



48. Although Swift (1973) did not have data on sediments, core data 

 from the modern shoals south of Cape May are contained in CERC MR 80-4 (Meis- 

 burger and Williams 1980) . These data indicated that modern shoals contain 

 large amounts of medium to coarse sand which is considered potentially usable 

 as beach fill material. Little data is available on the composition of the 

 off-lying shoal retreat massif; however, it seems likely that these shoals 

 were also created from littoral drift material and would be similar to the 

 modern shoals in the Delaware Bay entrance area. 



Fluvial Channels 



49. During the low sea level stand that accompanied the Wisconsin gla- 

 ciation, streams extended their channels across the present continental shelf 

 areas leaving behind fluvial deposits that in many cases have survived the 

 Holocene transgression. This is particularly true of the channel deposits 

 that are incised in the shelf surface with only the upper part exposed to ero- 

 sion. Floodplain and alluvial terrace deposits probably occur but seem to be 

 rare. Many of the larger streams have cut valleys that are not completely 

 filled, resulting in linear depressions on the shelf called shelf valleys 

 (Figure 6). Since the valleys must have been embayed for long periods of time 



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