96 Quaternary Formations of Southern New Jersey. 



There are numerous patches of Pensauken on the north side 

 of Old Mans Creek, which appear to represent former stream 

 accumulations of gravel and sand. It is probable that the streams 

 have since, by monoclinal shifting and otherwise, abandoned 

 their old channels filled with gravel and sand, and that these 

 channels, by subsequent erosion, have become low ridges. The 

 Pensauken remnants from Harrisonville west, therefore, may 

 perhaps mark roughly the former course of Old Mans Creek, 

 or its antecedent. The constitution of the Pensauken changes 

 down stream. Each formation crossed by the stream contributed 

 material to the deposit below its outcrop, and these materials are 

 easily distinguished. This variation in constitution is, of course, 

 good evidence of the fluviatile origin of the material. 



The remnants of the formation differ in their topographic 

 positions and relations. At Harrisonville the remnants are well 

 down the slopes of the valley, at levels of 80 to 100 feet, and 

 not distinctly separated from the Cape May formation. Near 

 Auburn, they are on slopes mostly between 70 and 50 feet, and 

 on a divide up to 100 feet, and are topographically distinct from 

 the Cape May. Some of the patches on the north side of Old 

 Mans Creek are continuous from elevations of 100 feet, down to 

 50 feet. If the lower part is not displaced, it shows a pre- 

 Pensauken slope 'toward the axis of the present valley of 40 to 

 50 feet. At Auburn, on the south side of the creek, the relations 

 are similar. If these beds were on slopes originally, the surface 

 must have been built up in Pensauken time, to a level which is 

 now 100 feet or so above sea level. As in many other places, it 

 is not demonstrable that the Pensauken in the valley of Old 

 Mans Creek above Auburn, is the exact equivalent of the arkose 

 Pensauken west of Auburn ; but their topographic relations seem 

 to place their deposition at about the same time. 



On the other hand, it cannot be too often reiterated that the 

 deposition of sediment in valleys is a more or less continuous 

 process. Even in a region like this, where epochs when de- 

 position predominated, alternated with epochs when erosion pre- 

 dominated, there was some deposition in times of dominant 

 erosion, and doubtless some erosion in times of dominant depo- 

 sition. In the region, therefore, there are doubtless gravels 



