North of Shrewsbury Rocks Coastal Plain strata are buried by up to 100 feet of 

 Pleistocene sediments. (See Table 2.) Considerable relief occurs on the upper surface of the 

 Coastal Plain strata as a result of deep subaerial erosion during Pleistocene lower sea levels. 

 This pervasive downcutting is mostly attributable to the erosive effects of the ancestral 

 Raritan, Hudson, Shrewsbury, and Navesink Rivers and possibly to a southern advance by 

 an outlier of the main glacial ice sheet. An ice prong may have funneled through The 

 Narrows, exceeding the terminal moraine limits crossing Long Island and Staten Island, to 

 transgress several miles south onto the shelf. Further discussion of this idea and evidence for 

 its plausibility will be presented later. The Pleistocine erosion surface on top of the Coastal 

 Plain strata becomes deeper in places northward from Shrewsbury Rock toward Long 

 Island. Seismic profile records immediately south of Rockaway Beach have limited 

 penetration and show a hint of possible Coastal Plain reflections 150 to 180 feet below 

 present sea level. In places east of the head of the Hudson Channel erosional remnants of 

 apparent Coastal Plain rock project within about 50 feet of the sea floor but none of the 

 records in the immediate inner bight exhibit evidence of actual sea floor outcrops of Coastal 

 Plain strata north of the Shrewsbury cuesta. 



A second type of sedimentary bedding exhibited on the seismic records are large scale 

 and very complex crossbed features which are restricted to an elongate buried basin, 6 miles 

 long and 2.5 miles wide, parallel to and 1 mile east of Sandy Hook, included in Williams and 

 Field, 1971. (See Figure 6.) Boundaries of the area of cross stratification are identifiable on 

 the seismic records and seemingly grade into flat -lying sediments around the periphery. The 

 boundaries to the north appear to narrow and apparently the crossbed sediment is truncated 

 by the buried shelf extension of the Hudson Channel which has been artifically deepened in 

 the construction of the Ambrose Navigation Channel. Attempts at following the crossbed 

 strata on geophysical records north of the channel to the shelf south of Rockaway Beach 

 have been unsuccessful. 



The records indicate that the material underlying the crossbeds dips slightly to the 

 southeast and appears to be more massive and continuous than the overlying sediment. 

 Descriptions of material from Coast Guard bore hole No. 2 (Fig. 6, and Table 3), taken to 

 evaluate foundation conditions for the Scotland Light Navigation Tower, support our 

 conclusions that strata below 100 feet (MLW) are Cretaceous age Coastal Plain sediments 

 which were eroded and subsequently covered by deposition of overlying crossbed sand and 

 gravel. Figures 7 and 8 show five reduced seismic profiles for the trackline locations shown 

 in Figure 6. These profiles are typical of the actual seismic profiles within the crossbed 

 boundaries and show the complexity, size, and structural framework of the sedimentary 

 features. 



At the northern limit of the crossbed area, Line A (Fig. 7) shows the topmost 10 to 15 

 feet of sediment to be flat -lying stratified material of probable Holocene age resting on the 

 truncated tops of planar, massive, crossbed structures. Thickness of the crossbed unit 



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