Pensauken Formation — Local Details. 97 



of various ages, some of which antedate, and some of which 

 follow the main Pensauken deposits, and their definite separa- 

 tion is impracticable. 



At Auburn the Pensauken gravel is cemented locally by iron 

 oxide to conglomerate, the cemented beds being 4 or 5 feet thick. 

 This may be seen in a gravel pit just east of the village, and again 

 about a mile east of Auburn, on the south bank of Old Mans 

 Creek, capping an isolated hill. Other examples of the cemented 

 Pensauken are seen on the north side of the valley, 1 to 1^2 

 miles northeast and east of Auburn. Farther up the valley 

 cementation is less common. There is apparently some relation 

 between the cementation and the nature of the base, cementation 

 being more common where the Pensauken lies on the Cretaceous 

 (Auburn to Harrisonville Station), than where it covers the 

 Miocene (Harrisonville to Harrisonville Station). 



Other patches of arkose Pensauken exist west of Swedesboro, 

 at levels of 70 feet and less, declining to 40 at the west. Here the 

 younger Cape May formation overlaps the low western edge of 

 the arkose Pensauken. and the Pensauken descends beneath the 

 Cape May, at Center Square. Its base therefore declines west- 

 ward toward the Delaware. 



Just south of Robbins Hill, the non-arkose phase of the Pen- 

 sauken gravel occurs at 100 feet, and is very like the correspond- 

 ing phase at Auburn at the same level. The arkose Pensauken 

 here is distinctly lower. This relation, taken by itself, suggests 

 a twofold division of the Pensauken, a younger, lower, arkose 

 division, and an older, higher, non-arkose division ; but evidence 

 suggesting the unity of the two phases is at least equally good, 

 even in this region, and is convincing (Knapp) in some others. 



A characteristic section of the non-arkose Pensauken, a mile 

 west of Harrisonville, is as follows : 



5) 3 feet yellow loam and sand. 



4) 8 feet gravelly yellow sand, gravelly gray sand, and clay loam, 



gray sand and clay in alternating thin beds. 

 3) 2 feet pale bluish white gritty clay. 

 2) 6 feet of compact gravel. 

 1) 8 feet of gray sand with about 5% of glauconite. 



Cretaceous. 



7 QUAT 



