jo Quaternary Formations of Southern New Jersey. 



As the main valley was aggraded, its tributaries were obstructed, 

 and deposition in them must have accompanied deposition in the 

 main valley. None of the streams tributary to the main valley 

 from the south and east between Raritan Bay and Salem bore 

 glacial waters, and hence the deposits they made in their valleys 

 were of local debris, derived from their own drainage basins.' 

 The same was true of some of the small streams coming to the 

 main valley from the north. At the same time, deposits were 

 probably making in the valleys of streams flowing from the main 

 divide of the Coastal Plain southeast to the Atlantic. The lower 

 ends of these valleys were not being aggraded by deposits in 

 just the same way that the lower ends of tributaries to the 

 Raritan Bay-Trenton-Salem valley were, if the hypothesis out- 

 lined above be the true one. Furthermore, the streams flowing 

 southeastward from the Coastal Plain divide were not laden with 

 glacial debris, as were the main streams north of the main 

 valley. The presumption is, therefore, that if the attitude of the 

 land remained much as it was during the time of erosion just 

 preceding, deposition in the. valleys of the southeastward flowing 

 streams was much less than that in valleys of streams carrying 

 glacial debris. 



If, on the other hand, the Pensauken formation is marine, its 

 sediments being laid down during a time of submergence, the 

 deposits in the valleys which led to the sea directly may have 

 been more considerable. Even in this case, however, deposition 

 of sediments brought in by streams not fed by glacial waters was 

 probably less than that contributed by streams which came out 

 from the melting ice. 



The third view of the origin of the formation is hardly more 

 than a combination of the other two. In this case, the propor- 

 tion of the formation which is fluvial might be conceived to be 

 very large or very small, or to be anywhere between these ex- 

 tremes. 



After the deposits of Pensauken sands and gravels in the 

 Raritan Bay-Trenton-Salem valley had reached a thickness which 

 exceeded two score feet in but few places, deposition ceased. 

 This may have been because the area became somewhat higher, 



