Pensauken Formation — Local Details. 139 



Between South River and Cheesequake Creek. — The Pensau- 

 ken is well developed about South Amboy and Ernston. Its 

 surface reaches an altitude of 170 feet near Ernston, though it 

 rises above 150 feet in but few places. Its base has an altitude 

 of about 90 to 100 feet in most places, thus giving it a probable 

 maximum thickness of about 70 feet. 



The section shown along the Pennsylvania Railroad a mile or 

 so southwest of the depot is representative : 



5) 2 feet moulding sand or loam, locally almost a clay loam. 



•4) 6 feet coarse gravelly sand. 



3) 15 feet yellow arkose sand free from gravel. 



2) 6 feet arkose sand, brownish in color, with some pebbles. 



1) 4 feet of coarse gravel, including occasional bowlders; granitic 



and shale pebbles common. 

 Cretaceous. 



Sections showing material like parts of the above are common. 

 At the crossing of Bordentown Avenue and the Raritan River 

 Railroad, several large bowlders (3 feet and less in diameter) 

 have been seen at the base of the formation. 



South and west of South Amboy there are numerous exposures 

 at high levels. In general the gravelly material is almost wholly 

 quartz. A three-fold division of the formation prevails, namely 



3) Quartz-chert gravel, 2 to 15 feet. 



2) Arkose sand, 10 to 40 feet. 



1) Coarse gravel, with cobbles and even bowlders, bits of shale 

 and granite, y 2 foot to 4 feet. 



About Ernston and toward Sayreville the material and its 

 relations are the same as at South Amboy. 



One and three-fourths miles southwest of Ernston, along the 

 railway near the old Poor Farm, the base of the Pensauken runs 

 down to 20—30 feet, and possibly lower. A quarter of a mile 

 or so farther northeast, the base of the formation is above 90 

 feet. Again, a little more than half a mile west of Morgan 

 Station, Pensauken is seen at 20 feet. These low-lying remnants 

 do not appear to be displaced, though possibly they are. If not, 

 they mark 'the position of rather deep pre-Pensauken valleys, 

 like those east of Camden. 



