Feldhausen and Ali (1975) performed multivariate analysis on grain-size 

 data from 57 sample sites in the central and western basins of the Sound and 

 identified 5 distinguishable sedimentary facies. They then related the facies 

 to environments of deposition and subsequent modification by wind- and tide- 

 generated currents. A major conclusion was that the rivers entering the Sound 

 at present contribute minor volumes of sediment. 



Bohlen (1975) reported results of a 2-year study to measure the suspended- 

 sediment budget at 11 sites in eastern Long Island Sound. In contrast to 

 other studies which show the central and western basins to behave like an 

 estuary, Bohlen found that the eastern basin is well mixed and dominated by 

 wind stress, tidal currents, and river discharge. 



For about the past 5 years, a group of researchers at Yale University has 

 been reporting on studies done primarily in the central and eastern basins. 

 Gordon (1974) examined by quantitative means the settling processes and 

 dispersion of dredge material dumped at the authorized dump ground off New 

 Haven. Gordon and Pilbeam (1975) established bottom current meters at 28 

 stations to measure current velocities and the relationship to transport of 

 bottom sediment. Bokuniewicz, Gebert, and Gordon (1976) used high-resolution 

 acoustic profiles and short cores to estimate the areas and volumes of the 

 unconsolidated sediments in the entire Sound in an attempt to produce a total 

 sediment budget. One conclusion was that the volume of estuarine muds in 

 place greatly exceed volumes that could have been supplied by rivers over the 

 past 8,000 years and they propose that the open shelf is a primary source. 

 Bokuniewicz, Gordon, and Kastens (1977) presented results of a study on the 

 morphology and migration of a field of large sand waves (up to 4 meters high) 

 in eastern Long Island Sound. They reported that sand waves will not form 

 if more than 10 percent mud or 12 percent coarse sand (or larger) is present, 

 and that most waves were asymmetric to suggest transport into the Sound 

 predominates. 



Recent studies by Sirkin (1976), Flint and Gebert (1976), and Newman 

 (1977) have shown that late Wisconsin Glaciation in the Long Island region 

 has been very complex and that the moraines and outwash deposits are often 

 superimposed. Also, there is clear evidence that glacial advances younger 

 than the one that left the Harbor Hill Moraine on the north of Long Island 

 have occurred, and their discontinuous moraines are still present. 



II. GEOMORPHOLOGY AND SHALLOW SUBB0TT0M CHARACTER 



1. Shallow Subbottom Structure and Stratigraphy. 



Examination of the 700 kilometers of acoustic profiles collected shows 

 that four major horizons or reflection units are present in Long Island Sound 

 within the depth and resolution range of the equipment, usually about 91 and 

 0.5 meter, respectively. These are: (a) the floor of the Sound or sediment- 

 water interface; (b) the top of Pleistocene sediments which include subre- 

 flectors from glacial till, sand and gravel outwash, and lacustrine fine- 

 grained strata; (c) the glaciated surface of Cretaceous-age semiconsolidated 

 sedimentary rocks; and (d) the deeply dissected and smoothed surface of pre- 

 Cretaceous consolidated rocks consisting of Precambrian and Paleozic bedrock 

 and possibly Triassic strata in the region between New Haven and Northport, 

 Long Island. The findings in this report agree with much of the basic 



21 



