Pensauken Formation — Local Details. 105 



3) 8 feet coarse gravel and brown sand and loam|, compact. 

 2) 16 feet coarse brownish sand of arkose type. 

 1) Yz foot coarse gravel and cobbles. 



Pebbles and cobbles of crystalline rock are abundant in the 

 gravel, and most of them are so> decomposed as to be easily 

 crumbled in the hand. Most of them are well rounded. Bits 

 of red shale of Triassic origin are as abundant as those of all 

 sorts of igneous rock, and are mostly in well-worn disc-shaped 

 pieces; but there are occasional angular pieces of larger size. 

 In the area about Cinnaminson, the base oi the Pensauken has 

 an average altitude of about 60 feet; but at the west it is as 

 low as 30 feet, and elsewhere locally as high as 70 feet, thus 

 showing considerable irregularity. From Cinnaminson the base 

 declines 40 feet in a mile to the northwest, toward Pompeston 

 Creek. 



East of Palmyra an exposure in the hill on which the Riverton 

 waterworks stand, a gravel pit at 70 feet, shows 75 per cent, of 

 the stony material of the gravel to have a diameter of less than 

 1 inch, though cobbles 3 inches in diameter are common. Quartz 

 is the chief constituent (90 per cent.), while red shale and gran- 

 itic material make about 2 per cent.,. and chert and quartzite the 

 remainder. The gravel is very compact, and has little sand. In 

 the vicinity, however, other exposures show arkose sand with 

 but little gravel. Near North Pennsville one section showed 

 some clay associated with the sand and gravel. This recalls the 

 phenomena at Fish House. 



Near New Albany, the hilltop remnants of the Pensauken 

 occur at elevations which range from 80 feet for the base at 

 New Albany, down to 50 feet at Hunters Hill, 1% miles to the 

 northwest. At Fairview, the range is from 70 to 90 feet. 



The arkose material came down Delaware River, and built 

 up the lowland. This phase of the formation is limited south- 

 eastward by an old scarp at some points, while at others the 

 scarp was broken down, and the northward gravel went up the 

 side valleys a little to the southeast of the general line of the 

 scarp, as in the vicinity of Moorestown. 



Southeast of the scarp, the old Woodstown Plain was 30 to 

 40 feet higher than the Swedesboro Plain. It was cut by valleys 



