Pensauken Formation — Local Details. 99 



Rulons are hardly consistent with these levels. They probably 

 are older, perhaps accumulations of postBridgeton-prePensauken 

 age. In constitution these deposits consist of various combina- 

 tions of sand and clay with a variable amount of gravel, all from 

 formations up stream, or at elevations above the valleys. 



The question concerning the Auburn, Asbury, and Mickleton 

 patches is the following: Is the low-lying Pensauken surface 

 (Auburn, 60 to 70 feet; Robbins Hill, 50 to 60 feet; Asbury 

 Station, 70 to 80 feet; Mickleton, 60 feet) a surface of depo- 

 sition (on the Swedesboro Plain), or a surface of degradation 

 developed in the Pensauken below its original top? If the latter, 

 the Pensauken here may have been a part, genetically, of the 

 high-level Pensauken to the east. The evidence of this region, 

 taken by itself, would look to the distinctness of the two phases of 

 the formation. 



If the Swedesboro Plain were built up to the level of the 

 Woodstown Plain, it would at first seem that arkose should 

 have extended onto the upper plain; but farther northeast the 

 facts seem to deny the necessity of this conclusion. At James- 

 burg, for example, the Pensauken was very thick, and was built 

 up to the top of the corresponding upland ; but only the lower 

 part of the Pensauken at Jamesburg is arkose, and the higher, 

 overspreading part is not. If a plain of erosion developed at 

 no feet at Jamesburg, we should have the general relations of 

 the Swedesboro region duplicated. 



South of Wenonah, in the south bank of Mantua Creek, there 

 is the following section, interpreted as Pensauken : 



5) 3 feet reddish-brown clay. 



4) 8 feet of gravel, sand and loam, interstratified. 

 3) 4 feet grayish sand, loam, and clay interbedded. 

 2) 3 feet gravelly and glauconitic sand and green clay. 

 1) 1 foot of iron-cemented conglomerate. 

 Cretaceous. 



This section stands in a general way for the sections of the 

 formations east of the arkose part. 



Betzveen Mantua and Coopers creeks. — The arkose Pensauken 

 in this region appears to have been limited at the east by an old 



