overlying and mixed with medium sand and pea gravel. These fine materials 

 may be older Holocene back-barrier sediments which are being reexposed as 

 barrier migration progresses landward, or they may result from contemporary 

 fine detritus being flushed out of Moriches Inlet during intense storms or 

 strong ebbtides. In either case, this area should be avoided as a borrow 

 site until more detailed data are available. 



j. Area J . Area J occupies the shelf region between Moriches Inlet 

 and Shinnecock Inlet and extends seaward about 4 miles (6.4 kilometers) 

 to the 90-foot (27.4 meters) depth contour, which expresses several 

 northwest-trending shoals (Fig. 28) . This area contains seven cores 

 (37, 38, and 74 through 78) which are evenly distributed, and exhibit 

 sand for their entire lengths; the minimum length is 3.5 feet (1.1 meters) 

 at core 76, and the maximum length is 18 feet (5.5 meters) at core 77. 

 Based on these core data and on the seismic records the minimum thickness 

 is 3 yards (2.7 meters) and the potential thickness is 6 yards (5.5 meters) 

 of sand blanketing the area. Thus, this area contains the largest volume 

 of potential sand (Table 5), all within the 90-foot depth contour. The 

 western boundary marks the transition from clean sand to the gray silt 

 and clay (core 73) which overlies older peat materials derived from a 

 lagoon which occupied this region about 7,500 years B.P. (Table 5). These 

 lagoonal sediments are too fine and organically rich to be suited for 

 beach fill; their presence should be anticipated beneath the modern shelf 

 sand cover in other areas. 



k. Area K . Area K covers the largest shelf area and extends offshore 

 a maximum of 8 miles (12.9 kilometers) (Fig. 28). The tentative seaward 

 limit parallels the 90-foot depth contour and includes the areas where 

 seismic lines U and V are located (Fig. 2). Twelve cores are positioned 

 within this area, nine cores within 3 miles (4.8 kilometers) of the coast 

 and the other three closely spaced along seismic line V (Figs. 2 and 16) 

 normal to a linear shoal. While the core coverage is not ideally distri- 

 buted, the seismic records show the stratigraphy in the cores probably 

 extends throughout the area. Based on sand recovered in the cores and by 

 extrapolation on seismic records the minimum sand thickness is judged to 

 be 2 yards (1.8 meters) while the potential is 3 yards. 



1. Area L . This area is a rectangular region extending more than 7 

 miles (11.3 kilometers) off Fire Island (Fig. 29). It is covered by a 

 1-mile-grid (1.6 kilometers) spacing of seismic records and contains cores 

 8, 9, 20, 61, and 114. The sea floor has a gentle seaward slope with a 

 pronounced northwest ridge and swale surface fabric. Presence of shoal 

 topography seaward of area L may warrant extending the southern boundary; 

 however, data are only available for the western section, and use of an 

 area with greater than 10-raile (16.1 kilometers) distance from shore would 

 probably be economically prohibitive because proven sand resources from 

 adjacent area M are closer to project beaches. Of the five cores in area 

 L, four contain suitable sand for their entire lengths; the exception, 

 core 114 (Fig. 2), contains 8 feet (2.5 meters) of suitable sand under- 

 lain by 3 feet (0.9 meter) of clean but very fine sand. Based on this 

 core information, the minimum sand thickness is 3 yards and because 



74 



