detritus or to Holocene fine-grained organic-rich muds (core 39), In 

 either case, type III sands appear to be relict or palimpsest sediments 

 being winnowed and acted upon by modem marine processes. Core 1, direc- 

 tly south of Plum Island (Fig. 2) is 13.5 feet (4.2 meters) long and shows 

 11 feet (3.4 meters) of pebbly, fine to coarse sand overlying 1 foot (0.3 

 meter) of peat. The peat is underlain by gray compact clay extending to 

 the bottom of the core. The 11 feet of sand probably originated from ero- 

 sion of the Harbor Hill Moraine corssing Orient Point and Plum Island, 

 and was deposited on the type V sediment surface which underlies much of 

 the shelf of eastern Long Island. The other six cores in the Gardiners 

 Island region which contain type III sediments (cores 3, 6, 7, 9, 11, and 

 12) at the surface range in length from 4.7 feet (1.4 meters) (core 12) 

 to 14 feet (4.2 meters) (core 9) and contain typical reworked outwash 

 detritus (fine to coarse sand with rounded pebbles of varying composition) 

 for their tal lengths. 



d. Type IV Sediment . The granular material in this sediment is in 

 the very fine sand to silt-size range (0.0625 to 0.125 millimeter; 4 to 3 

 phi) (Fig. 22). Cores indicate this sediment is restricted to four areas 

 on the south shore, two on the shoreface off Fire Island, one directly 

 seaward of Moriches Inlet, and one seaward of Shinnecock Inlet. Other 

 areas of type IV sediment probably exist but present core coverage pre- 

 cludes more precise definition of their location and extent. The most 

 westerly exposure of type IV sediment is defined by cores 65 and 67 

 (Fig. 2). Core 65 contains nearly 6 feet (1.8 meters) of clean, well- 

 sorted, very fine sand for its total length; core 67, only about 1 mile 

 (1.6 kilometers) south, exhibits more variable stratigraphy for its length 

 of 17.2 feet (5.3 meters). Core 67 contains a top one-half foot (15.2 

 centimeters) of dark silt-clay overlying 8.5 feet (2.6 meters) of clean 

 types II and III sediment (medium to coarse sand with rounded pebbles); 

 it then grades into compact clay with a peat stratum 13 feet (4 meters) 

 down the core. Below the peat, sediment texture becomes increasingly 

 coarser to where the bottom 0.3 foot (10.2 centimeters) is medium sand. 

 Core 72, located about 6 miles (9.7 kilometers) east of the type IV sedi- 

 ment locality, is in 30 feet (9.2 meters) of water on the shoreface and 

 exhibits 4 feet (1.2 meters) of type IV material overlying 1 foot (0.3 

 meter) to the core bottom) of clean type III sediments. The next easterly 

 occurrence of type IV sediment is in core 73, 1.5 miles (2.4 kilometers) 

 offshore from Moriches Inlet. This core is 15 feet (4.6 meters) long and 

 contains 5 feet (1.5 meters) of type IV sediment overlying 1 foot of peat. 

 Below the peat, type IV sediment continues for another 6.5 feet (2 meters) 

 and grades into silty fine sand with wood fragments for the bottom 2.5 

 feet (0.8 meter). The shoreface region off the western spit adjacent to 

 Shinnecock Inlet contains marginal quantities of type IV sediment as 

 defined by core 37. This core is 5.3 feet (1.6 meters) long, in 32 feet 

 (9.8 meters) of water, and contains 2.5 feet of very fine to fine quart- 

 zose sand overlying 1.5 feet (0.5 meter) of poorly sorted, very fine to 

 coarse sand with rounded pebbles and large shell valves. The bottom 1.3 

 feet (0.4 meter) of sediment grades finer again into very fine to fine 

 sand. Occurrence of type IV sediment in the study area appears to be 

 restricted to the south shore of Long Island, specifically the shoreface 



58 



