laminated silt and clay with partings of fine sand. Their appearance closely 

 resembles varve sequences related to seasonal sedimentation under quiet, low- 

 energy conditions (Fig. 7). The surface elevation of this unit, termed the 

 Flushing Formation by Newman (1977), varies considerably from near sea level 

 to about -40 meters; its thickness has been documented by Williams (1976) to 

 be 137 meters in the Orient Point buried channel and could be as much as 240 

 meters in a deep valley that runs southwest into the Sound at New Haven 

 Harbor. The origin of the deposits is long-term lacustrine deposition related 

 to glacial Lake Flushing that occupied deeper parts of the Sound from 15,000 

 to about 13,500 years ago (Newman, 1977). This lake was created immediately 

 after retreat of the Harbor Hill glacier from Long Island and probably was 

 formed by damming of channels in the Block Island Sound region by glacial 

 fill. The exact lateral extent of these lake deposits is difficult to deter- 

 mine but similar, and probably related deposits, are present in deep valleys 

 on the western end of Long Island and in the valley just south of New Haven; 

 similar strata have been reported in eastern Long Island Sound and even parts 

 of Block Island Sound (Bertoni, Dowling, and Frankel, 1977). The acoustic 

 profiles from this survey also show that most of the central parts of the 

 Sound contain stratified sediments overlying bedrock. 



The remainder of the Pleistocene sediments directly overlie either the 

 lacustrine beds or bedrock and consist of glacial till and stratified deltas 

 and outwash fans (mostly composed of sand and gravel) that originated adjacent 

 to the moraines or as deposits from the melt-water streams that drained from 

 the glaciers. As an economic resource these deposits are by far the most 

 important, and their extent and character are covered in detail in the next 

 section. 



The late Wisconsin-age Harbor Hill Moraine is nearly continuous across the 

 entire north shore of Long Island and has been studied by many researchers 

 interested in Pleistocene glacial events. It apparently resulted from a gla- 

 cier that covered the Sound and parts of New England to the north, but much of 

 the moraine actually consists of kame and kettle deposits marked by a high 

 degree of stratification. The seismic profiles off the north shore of Long 

 Island show no evidence of actual till deposits present. The shoreface region 

 to depths of -18 meters consists of lobate and coalescing fans and deltas made 

 up of medium- and coarse-grained sands that are outwash from the Harbor Hill 

 Moraine. 



A number of researchers have recognized evidence, in the form of short, 

 discontinuous, low-relief moraines, that glaciers younger than the Harbor Hill 

 advance have occupied the Connecticut mainland. Goldsmith (1960) identified 

 the Ledyard Moraine about 13 kilometers north of the Sound near New London, 

 and also showed the position of the Middletown Moraine about 32 kilometers 

 north of the Sound in central Connecticut. He attributes these moraines to 

 temporary halts in the retreat of the glacier that formed the Harbor Hill 

 Moraine. More recently, Flint (1968) and Flint and Gebert (1976) described 

 the form and composition of the Madison and Old Saybrook Moraines on the coast 

 east of New Haven (and their seaward extensions) and the Lordship outwash head 

 southeast of Bridgeport. 



Flint (1968) was never able to locate or identify the moraine that had 

 formed the Lordship outwash head but he speculated that it was possibly a 

 western extension of the Madison or Branford Moraines, and that the outwash 



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