68 Quaternary Formations of Southern New Jersey. 

 General Description. 



SEQUENCE OE EVENTS. 



Pre-Pensauken erosion. — After the deposition of the Bridgeton 

 formation, conditions in the southern part of the State changed 

 so that erosion succeeded deposition. The southwestern part of 

 the State at least seems to have been somewhat higher than 

 during the Bridgeton epoch, possibly a little higher than now 

 during at least a part of the interval of erosion. 



Some of the drainage lines, during this epoch of erosion, did 

 not differ greatly in position from those of the present time, 

 while others were notably different. One main line of drainage 

 seems to have been from Raritan Bay to Trenton, and thence 

 down the Delaware. This indeed seems to have been the course 

 of the master stream of this part of the Coastal Plain. Streams 

 from the north joined this master stream at various points be- 

 tween Raritan Bay and the present Delaware, and other streams 

 doubtless joined it from the southeast and east. 



The postBridgeton-prePensauken interval of erosion was a 

 long one, — long enough for the development of a broad plain 

 of erosion between Raritan Bay on the northeast and Salem on 

 the southwest. This plain was about 20 miles wide at New 

 Brunswick, and wider still to the northeast; 12 miles wide at 

 Monmouth Junction, 15 to 20 miles wide from Trenton to Phila- 

 delphia, 10 miles at Chester, and 20 at Salem. Cretaceous forma- 

 tions underlie the larger part of this plain of erosion. The 

 main divide of southern New Jersey lay but a few miles to the 

 southeast of this broad valley,, along the line connecting the 

 Atlantic Highlands, Mount Pleasant, Clarksburg, and Berlin. 



During the period of erosion which developed the great valley 

 noted above, streams flowing southeast from the main divide of 

 the southern part of the State developed broad valleys which are 

 to be correlated with the Raritan Bay-Trenton-Salem plain ; but 

 the plains of these minor valleys were much less extensive and 

 less well defined, and have been less carefully studied, and the 



