34 Quaternary Formations of Southern New Jersey. 



north of the north branch of Timber Creek. Its general relations 

 are shown in Fig. 22, which is slightly diagrammatic and slightly 

 composite, since it brings in hills which lie a little to- one side or 

 the other of a straight line. 



North of Davidstown, there are two areas within a mile of 

 each other, covered with remnants of the Bridgeton formation. 

 In both cases, it is thin and more or less cemented, and in both 

 it probably represents no more than the base of the formation 

 which has escaped erosion. 



Exposures. — Exposures are plentiful. A mile southeast of 

 Green Tree, at the school house, 4 to 6 feet of gravel are ex- 

 posed, similar to that of the Beacon Hill formation; but since it 

 contains bits of red shale, it is regarded as Bridgeton. There is 

 another exposure a mile northeast of Green Tree in the 166- foot 

 hill, and several about Creesville. In the 125-foot hill three- 

 fourths of a mile east of Hurffville, 7 feet of gravel character- 

 istic of the formation are exposed between the levels of no and 

 120 feet. The gravel is very compact and more or less cemented, 

 with a characteristic bed of coarse material, containing shale, at 

 the base. Another characteristic exposure was seen in the 153- 

 foot hill 1%. miles northeast of Hurffville, where the partially 

 cemented gravel contains pieces of red shale up to 4 inches in 

 diameter; and another in the 134-foot hill, east of Mechanics- 

 ville. Other exposures occur in lower hills, where the correla- 

 tion of the material is open to question. 



Between Davidstown and Spring Mills, there are two hills 

 which rise to the Bridgeton level (about 140 feet). In the more 

 southwesterly of these hills, about a mile from Davidstown, 

 there is a good exposure of the Bridgeton formation which con- 

 tains more than the normal amount of coarse material, the 

 bowlders ranging up to 2 feet in diameter. They include a 

 variety of sandstones, quartzose schists, conglomerate, and quartz. 

 The base of the formation here has an elevation of about 130 feet. 

 The character of the material is illustrated by Figs. 10 and 21 

 (pp. 16 and 42). 



Base. — The base of the formation has an elevation of about 

 150 feet at Cross Keys, but declines to 135 feet at Green Tree. 

 Still farther northwest, between Creesville and Hurffville, outliers 



