32 Quaternary Formations of Southern New Jersey. 



logically very like the Pensauken, but topographically very dis- 

 tinct from it. Adams Hill corresponds topographically and in 

 its capping of Bridgeton, to Big Mannington and Scull hills, 

 already referred to. To the southeast, at Richwood, the surface 

 rises to 176 feet. The thickness of the Bridgeton here appears 

 to be nearly or quite 60 feet. 



At Jefferson the surface of the Bridgeton has a maximum 

 elevation of 166 feet, and its base an altitude of 120 to 130 feet; 

 but this probably does not represent the full thickness of the 

 formation as originally deposited. A mile and a half north of 

 Pitman Grove, remnants of the Bridgeton appear at various 

 levels between 120 and 150 feet, while the base ranges from 1 lu 

 to 130 feet, and possibly even below the lower of these eleva- 

 tions at some points. 



An uncertain patch. — A half mile west of Hurffville, west of 

 Mantua Creek, is a hill having a summit altitude of 93 feet. 

 There are gravel pits on the east side of this hill, showing a maxi- 

 mum depth of more than 20 feet of gravel, more or less cemented 

 into conglomerate. The gravel contains shaly material. 



This patch of gravel is one of the most puzzling in the entire 

 area. It is much lower than the proper horizon of the Bridgeton, 

 and is at the proper level for the Pensauken. On the other hand, 

 the constitution of the material seems to put it with the Bridge- 

 ton, for the Pensauken of this region is not arkose, and does 

 not contain red shale, unless this remnant is Pensauken. If it 

 is Bridgeton, its base is considerably lower than that of any 

 other remnant of this formation in this vicinity. If it is Pen- 

 sauken, it is unlike any other Pensauken material in this imme- 

 diate vicinity in constitution. It may be a deposit derived from 

 the original Bridgeton, still retaining some of the soft materials 

 characteristic of that formation, though not now in its original 

 position, or it may be a mass of Bridgeton material displaced 

 from its original position, at a time when the topography was 

 very different from what it now is. 



The base. — The base of the formation in the vicinity of Rich- 

 wood is somewhat irregular, the observed range in altitude 

 being from about 105 to 140 feet. The formation, which is 



