Pensauken Formation — Local Details. 113 



A cross section drawn from Timbuctoo (a mile west of Mount 

 Holly) to Chesterfield, crosses six of these patches of uncertain 

 Pensauken, with their bases ranging from 55 to 85 feet. All of 

 them lie on or close to the outcrop of the same bed of the Mata- 

 wan group. Along a parallel section farther west, through beds 

 of the Delaware phase of the formation, the bases of the Pen- 

 sauken remnants have elevations of 65 to 85 feet. The first 

 series of beds therefore corresponds fairly well with the Pen- 

 sauken remnants in elevation. 



If a section from Rancocas village to Crosswicks village (far- 

 ther from the Delaware) be so drawn as to include the bases of 

 various Pensauken remnants, these bases have slightly greater 

 altitudes, 80 to 108 feet. That is, the bases of the eastern beds 

 of arkose Pensauken are higher than the bases of the non-arkose 

 remnants still farther east. But the belt from Rancocas to 

 Crosswicks, where the bases are highest, is the belt where the 

 most resistant member of the Matawan formation comes to the 

 surface. It is believed that this outcrop had not been brought 

 down to the pre-Pensauken peneplain, when the Pensauken depo- 

 sition began. 



It is certain that the region to the west was built up to the 

 level of the Rancocas-Crosswicks section, and it is probable that 

 the region to the east was equally aggraded. On the other hand, 

 it is conceivable that this low-level belt (Timbuctoo to Chester- 

 field) was not built up to the level of the Delaware plain in 

 the Pensauken epoch. If so, a marsh or even a lake might have 

 developed east of the main belt of Delaware deposition. Per- 

 haps the green loams are a product of this condition. On the 

 whole, however, the flat low lands northeast of Mount Holly are 

 probably to be explained the same as those about Mount Laurel. 



West and northwest of Juliustown, Pensauken gravels, etc., 

 cap divides between the branches of Barkers Brook, at levels of 

 100 feet and less. This area has 4 to 8 feet of gravel and sand, 

 lying on Cretaceous. The stony material is quartz, chert, and 

 ironstone, not very distinctive. The correlation of these areas 

 is doubtful, and they are regarded as Pensauken on the basis of 

 position only. 



8 QUAT 



