two small sediment aprons adjacent to Rehoboth Bay and Bethany Beach, 

 a shoreface shoal complex just north of the Del aware -Maryland State line, 

 and Fenwick shoal. Hen and Chicken is a large shoal extending southeast 

 from Cape Henlopen for approximately 19 kilometers (10 nautical miles) . 

 The shoal shows a maximum relief of nearly 6 meters over the surrounding 

 sea floor on the southwest side; on the northeast side the water depths 

 increase steadily into the thalweg of the estuary entrance (Fig. 8). 

 Minimum water depth over the crest is approximately 1.5 meters. Sheridan, 

 Dill, and Kraft (1974) found that this large sand body overlies a steeply 

 dipping (12.2 meters in 4 kilometers or 40 feet in 2.5 miles) surface of 

 estuarine--shallow marine silt and gravel. 



The two "aprons" or "lobes" of sediment north and south of Indian 

 River Inlet are contained within a general bulge in the shoreface, as 

 defined by the 12-meter contour, and comprise sets of small linear ridges 

 or mounds rising to depths of less than 6 meters below MLW. Surface sed- 

 iments and morphology of the southern lobe off Bethany Beach were studied 

 in detail by Moody (1964) , who made a prestorm and poststorm comparison 

 of changes in shoal morphology after the study area was devastated by the 

 storm of March 1962. During the survey period (1961-63), the ridges mi- 

 grated 76 meters (250 feet) to the southeast, compared to an average rate 

 of 3 meters per year over a 42-year average. 



South of Bethany Beach, the dominant ridge and swale topography of 

 the northern Delmarva shelf begins. The northernmost shoal lies between 

 Bethany Beach and the Maryland State line. As outlined by the 12-meter 

 contour, the ridge is broad with low relief, and has four low crests 

 which increase in relative relief in a seaward direction. Seaward of 

 the shoreface ridge system is a large isolated linear ridge (Fenwick 

 shoal) which is the northernmost feature of this type in the study area. 

 The shoal is 9.7 kilometers (6 miles) from shore, 6.4 kilometers (4 miles) 

 long and 2.4 kilometers (1.5 miles) wide, and rises from the intervening 

 swale area 15 to 18 meters (50 to 60 feet) below MLW up to within 7.6 

 meters of the water surface. 



4. Maryland Inner Shelf . 



The entire inner shelf area of Maryland (Fig. 9) is dominated by a 

 prevailing ridge and swale topography. Ridges exist as either isolated 

 shelf features or shoreface-connected features (Fig. 6, profile B-B'). 

 Some shoal crests are shallow enough to be classified as navigation 

 hazards. The length of many of the shoals exceeds 9 kilometers (5 nauti- 

 cal miles); widths are commonly on the order of 1.8 kilometers (1 nautical 

 mile). Relief varies from 3.1 meters (arbitrarily defined here as the 

 minimum relief for recognition of a shoal) up to 10 meters. Without 

 exception, the shoals are oriented northeast-southwest, creating a small 

 acute angle with the shoreline. 



Duane, et al . (1972) and Field and Duane (1976) noted that the distri- 

 bution of linear-shoal fields on the mid-Atlantic shelf is related to the 

 convex barrier spits of each coastal compartment. The entire Maryland 



