Pensauken Formation — Locae Details. icg 



with the latter generally. The ironstone masses were perhaps 

 residual on the surface when the northern materials were de- 

 posited on and among, them. The upper part of the Pensauken 

 here is not arkose. It would appear that the lands to the south- 

 east must have been higher than now, or at least must have 

 yielded more sediment than now, to have furnished the Pen- 

 sauken material above the basal layer. 



At Deacons Station, extensive excavations reveal the presence 

 of large bowlders (up to 4 feet in diameter) of crystalline rock, 

 and slabs of red and black shale 1 and 2 feet in diameter. At 

 this place, the arkose phase of the formation is interstratified 

 with the non-arkose phase. The sources of the materials there- 

 fore alternated from time to time, while the lower 10 feet was 

 accumulating. The upper part here is largely arkose. The 

 eastern edge of this area marks the approximate southeastern 

 border of the Delaware (arkose) phase of the formation. Of 

 the coarse material (cobble size and larger) in the formation 

 here, sandstone predominates greatly over all others, in most 

 places. Granite bowlders up to a foot in diameter are decayed 

 and soft to the core. Of the finer gravel, quartz is the leading 

 constituent. 



A good exposure half a mile southeast of Deacons showed an 

 abundance of granitic and other northern material. Red shale 

 and Stockton sandstone are readily recognized, also slabs of 

 black shale, similar to that at Milford. Ironstone slabs up to 

 6 feet in diameter occur here, — not masses formed in situ, but 

 transported masses showing some evidence of wear. At other 

 pits in the vicinity, notably i l / 2 miles southeast of Deacons 

 Station, there are seams of clay in the formation, and pellets of 

 clay, arranged in seams. The section here shows 2 feet of com- 

 pact arkose sand and gravel, under 8 feet of glauconitic sand. 

 The material is coarser at the west and finer to the east, and 

 glauconite, essentially absent at the west, is abundant at the east. 



Northwest of Jacksonville, as at many other places, the base 

 of the formation is uneven enough to show that the underlying 

 surface had considerable relief when the formation was deposited. 



If the Delaware Valley to the west was built up to a level 



