shelves (both buried and not buried) were shown to be identical in relief, 

 profile, and cross section to channel features on land. These observa- 

 tions proved that the channels were formed by fluvial processes. Results 

 of these studies using seismic equipment are covered by Ewing, Pichon, and 

 Ewing (1963), Knott and Hoskins (1968), Garrison (1970), and Uchupi (1970). 

 Use of sophisticated high-resolution seismic reflection equipment enabled 

 Grim, Drake, and Heirtzler (1970) to accurately map and delineate the 

 intricate drainage channel network in Long Island Sound; McMaster and 

 Ashraf (19 73) provided valuable information on the paleodrainage con- 

 figuration on the southern New England inner shelf; and Williams and 

 Duane (1974) showed that a buried channel 300 feet (91.4 meters) in 

 depth underlies the geomorphic sea floor expression of the Hudson Channel 

 seaward of New York Lower Bay. Williams (1975) showed that ocean dimiping 

 of assorted wastes has filled and significantly modified the Hudson Channel 

 since about 1890. 



The seismic records from the south shore and eastern shelf of Long 

 Island show that a more intricate system of major ancestral drainage 

 channels is present than is suggested by the sea floor morphology. 

 Figure 13 shows the channels generally trend northwest-southeast and 

 on the records they exhibit considerable differences in width, depth, 

 and profile form. In the figure, each channel is designated a letter 

 for easy reference in this discussion. In several instances, channels 

 identified on the Atlantic shelf were traced by projection, similarity 

 of profile, and thalweg depth to buried channels reported on the Long 

 Island mainland in various professional papers. 



The most westerly buried channel A (Fig. 13) is the ancestral Raritan 

 Channel first reported by MacClintock and Richards (1936) from examination 

 of test borings taken along a north-south proposed bridge line connecting 

 northern New Jersey to Staten Island. Raritan Channel is about 1 mile 

 (1.6 kilometers) wide, cut 170 feet (52 meters) into the Upper Cretaceous- 

 age Raritan Formation, and filled almost level to the present bay floor 

 by fine-grained estuarine sediments. The channel was probably primarily 

 excavated by Pleistocene melt-water runoff from upland glaciers and pos- 

 sibly secondarily eroded by isolated glacial ice lobes which reached south 

 of the main ice front. Subsequently, the channel was filled by lacustrine 

 deposits from Lakes Passaic or Hackensack which occupied the area west of 

 present-day Raritan Bay (MacClintock and Richards, 1936) and by Holocene 

 estuarine deposits as sea level rose. Williams and Duane (1974) reported 

 an elongate buried basin, with the sediment fill characterized by large- 

 scale and very complex cross-stratification, immediately east of Sandy 

 Hook spit. The basin is oriented north-south, measures about 2 miles 

 (3.2 kilometers) wide and 5 miles (8 kilometers) long, and is cut about 

 120 feet (36.6 meters) into Cretaceous strata. The crossbed strata fill- 

 ing the basin are composed primarily of fine to very coarse sand and pea 

 gravel. Williams and Duane (1974) suggested this buried basin is a com- 

 plex of two or more major channel networks, possibly the confluence of 

 the ancestral Hudson and Raritan Rivers. If this interpretation is 

 correct, then the Raritan Channel underlies the length of Raritan Bay 

 and is covered by Sandy Hook spit, which has accreted due to littoral 

 processes northward during Holocene time. 



41 



