46 Quaternary Formations of Southern New Jersey. 



considerable areas of the Bridgeton formation, as about Wil- 

 liamstown, at elevations above 140 feet, about Blue Bell at eleva- 

 tions above 120 feet, about Newtonville at elevations above 100 

 feet, about Richland at elevations of about 90 feet, and at lower 

 elevations to the southeast.- 



At Williamstown a gravel pit at an elevation of 160 feet, on 

 the north slope of the 164-foot hill in the northwest part Of the 

 village, shows 10 feet of gravel. The structure of the upper part 

 is very irregular, but the lower part is well stratified in nearly 

 horizontal beds. The lower part is arkose, coarser than the upper 

 part, and contains less loam. Pebbles and bits of rock more than 

 i~y 2 inches in diameter are rare, though occasional cobbles are 

 present. Shale was not seen, but there are pieces of crystalline 

 rock of the Philadelphia gneiss type (mainly of quartz and 

 mica). 



South of Williamstown, there are numerous shallow pits and 

 cuts which show gravel and sand similar to that at Williams- 

 town, but shale and crystalline rock are not seen, and from the 

 habit of the formation would not be expected in such shallow 

 exposures as most of those of this region. The base of the 

 gravel, the horizon in which these constituents are most abund- 

 ant, is rarely seen. Coarse material of the size of cobbles is 

 rather common in spots, as east of Janvier. 



The base of the gravel was seen at several pits between Wil- 

 liamstown and Richland, with the Cohansey sand below. The 

 coarse gravel and cobbles at the base are present in many places, 

 but, as a rule, without shale and crystalline material. 



About Richland, there are numerous exposures in cuts and 

 pits. The Southern Railway of New Jersey makes a cut 10 feet 

 deep, showing orange-colored coarse sand, with seams of gravel 

 and occasional cobbles or larger pieces of rock. 



From the main divide along which the section shown in Fig. 

 29 is taken, the Bridgeton cap extends out over some of the 

 minor divides between tributary streams. It also caps certain 

 isolated hills or small areas set off from the main divides by 

 erosion. One of these minor divides extends east of Richland, 

 between Deep Run and South River, both tributary to Great Egg 



