GLACIAL AND POST-GLACIAL HISTORY 



655 



that it is of such a nature as to resist erosion. It would be expected, 

 indeed, that after a certain amount of erosion of the moraine the 

 concentration of the larger bowlders which are common in moraines 

 would form a pavement in the bottom of the channel and would check 

 the down-cuttingj. 



Fig. 27. — New York and vicinity as it would appear if depressed enough to permit 

 the entrance of the sea over the probable original height of the barrier at the Narrows 

 and at Perth Amboy, and if the depression south of the Raritan River were forty to 

 fifty feet. 



Black color indicates land not covered by waters during the hypothetical depression. The outline 

 represents the present coast. 



In conclusion, it may be stated that, while no single argument 

 seems to be fatal to the salt-water hypothesis accounting for the 



