GLACIAL AND POST-GLACIAL HISTORY 657 



RELATION OF HUDSON WATER BODY TO WATER BODY WEST OF 



PALISADE RIDGE. 



As already indicated, if the Hudson water body was an arm of the 

 sea, so also were the waters in the lowland west of the Palisade Ridge 

 by the time the ice had retired beyond the Sparkill Valley or earlier. 

 If the Hudson water body was a lake, the waters west of the Pahsade 

 Ridge, ^ which may be called Newark Bay Lake, were probably inde- 

 pendent while the ice was present and either drained through Arthur 

 Kill, or first through that outlet and later into the Hudson by Kill 

 van Kull. This Newark Bay Lake, no doubt, disappeared long 

 before the Hudson Lake. It is interesting to note that when the ice 

 had retreated beyond the Sparkill Valley, which crosses the Palisade 

 Ridge just north of the New Jersey boundary (Fig. 9, No. 14, p. 429), 

 the waters of this Newark Bay water body coalesced with those of the 

 Hudson water body through this narrow valley, the bottom of which 

 is now 20-30 feet above tide at the west side of the Palisade Ridge. 

 Since the land was at this time down at the north by 75-90 feet more 

 than at the south, it follows that this Sparkill Valley was the lower 

 outlet, and that when the Hudson water body had been lowered to the 

 level of this valley, the Newark Bay water body disappeared. What- 

 ever cutting, therefore, was done at a southern outlet was accom- 

 phshed before the ice had retired beyond this valley. It is likewise 

 interesting to note that with this amount of northern depression the 

 slope of the Hackensack Valley floor, for instance, would have been 

 just the reverse of the present. If, when the water body disappeared 

 this was true, the lower Hackensack, for instance, and other streams 

 would have flowed in the reverse of their present direction and joined 

 the Hudson water body through the Sparkifl Vafley. Since there is 

 no evidence, so far as the writer is aware, that such a reversal has 

 taken place, it would follow that by the time the Hudson water body 

 disappeared there had been an uphft sufficient to produce a slope 

 southward. That uplift must have been as much as 45-60 feet, and 

 may have been more. Since the water-level must have been lowered 

 this same amount in order to disclose the floor, it would seem that 

 the disappearance of the water in this area was due to uphft. This 



I For discussion of hypotheses to account for this water body see R. D. Salisbury, 

 Glacial Geology of New Jersey, pp. 195-200. 



