c. Shoal-Retreat Massif , The term, shoal-retreat massif (Swift, 

 et al . , 1972) refers to the clusters or fields of relict shoals that 

 extend seaward from old depositional centers. Such centers of sediment 

 accumulation may be adjacent to sites of previous (or existing) inlets 

 or they may be adjacent to cape features or cuspate forelands. Shoal - 

 retreat massifs are large arcuate submarine sand bodies with linear and 

 curvilinear shoals or ridges superimposed on the surface (Fig. 5,C). 

 Individual ridges are seldom parallel to each other or to the general 

 trend of the entire massif. Their orientation with respect to each other 

 is not constant, and although they are generally subparallel, they often 

 change in orientation with distance offshore. Shoal-retreat massifs are 

 commonly associated with the large capes-cuspate forelands of the Atlantic 

 southeast (Capes Canaveral, Romain, Fear, Lookout, and Hatteras) . Along 

 the mid-Atlantic Bight shoreline, shoal -retreat massifs occur adjacent to 

 estuarine openings and adjacent to discontinuities in each of the barrier 

 island compartments. Along the Delmarva coastline, this discontinuity 

 occurs at the southern end of Assateague Island. 



d. Shelf-Transverse Valleys . The most apparent erosional features 

 on the Atlantic Continental Shelf are the shelf transverse valleys which 

 extend from the coastline out across the shelf (Fig. 5,D). The major 

 valleys in the mid-Atlantic region have been identified by Swift, et al . 

 (1972) as the Block, Long Island, Hudson, Great Egg, Delaware, Susquehanna. 

 Virginia Beach, and Albermarle Valleys. These valleys, originally cut 

 during periods of lower sea level, have been modified and topographically 

 subdued by the deposition of coastal sands into the retreating river- 

 estuary mouths. The Delaware shelf valley at the northern limit of the 

 study area is one of the more prominent shelf valleys of the Atlantic 

 coast. 



2 . Survey of Delaware Bay to Chesapeake Bay . 



As pointed out by Fisher (1968), Duane, et al . (1972), Kraft, Biggs, 

 and Halsey (1973), and Field and Duane (1976), the coastline of the mid- 

 Atlantic Bight is comprised of a series of separate coastal compartments, 

 each containing a headland. area, a small northward-growing spit, and a 

 long convex barrier spit followed by a chain of small barrier islands 

 extending south of the headland. The morphology of the adjacent shelf 

 varies as much in detail along each of the coastal compartments as does 

 the shoreline. 



Cross-shelf profiles plotted from map data (Fig. 6) clearly show 

 regional changes both in slope and width of the shoreface and also the 

 presence and relative relief of shoals (Fig. 7). Profile A-A' crosses 

 a large ebb shoal (Hen and Chicken) , a channel of the ancestral Delaware 

 River, and part of the main shelf valley. The large, broad positive- 

 relief features along the profile are depositional features associated 

 with the estuary shoal complex at the mouth of the retreating Delaware 

 Bay. The shoreface is relatively steep and smooth in this area and has 

 no perturbations. 



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