Bridgeton Formation^ — Locae Details. 31 



In most places, the Bridgeton of this immediate region rests 

 on the Miocene, but on Scull Hill it appears to lie on the Cre- 

 taceous. The base of the Bridgeton shows itself topographically 

 on the slopes of many of the hills, especially where underlain 

 by Miocene, in an increased angle of slope. This is because the 

 Miocene beneath is somewhat less resistant than the Bridgeton. 



A feature of the Bridgeton of this region is the presence in 

 it of an occasional bowlder of Miocene quartzite (locally known 

 as "bull's head" bowlders). These peculiar bowlders are rather 

 common south and southwest of Swedesboro, within a radius of 

 3 or 4 miles. At few other points are they so abundant. 

 They are, however, wide-spread, and seem to point to extensive 

 weathering and erosion of the Miocene after some parts of it 

 had become indurated. Bowlders of this sort exist as far east 

 and south as Hammonton, Folsom, and Tuckahoe. 



Exposures. — A mile northwest of Harrisonville, in the 134- 

 foot hill, a gravel pit shows 12 feet O'f compact sand and gravel, 

 more or less cemented. There are other exposures between this 

 point and Mullica Hill to the northeast, and Swedesboro on the 

 northwest. 



BETWEEN RACCOON CREEK AND MANTUA CREEK. 



Distribution. — Between the upper courses of these creeks in 

 the vicinity of Richwood (Five Points), the Bridgeton forms 

 a nearly continuous mantle over older formations. About Glass- 

 boro and to the northwest the continuity is interrupted, as in 

 corresponding situations farther south, being restricted at the 

 east to the divides, farther west to the higher parts of the divides, 

 as about Jefferson, and finally to the tops of isolated hills. The 

 most northwesterly remnant is at Adams Hill, a mile or so east 

 of Mickleton. The general relations of the formation between 

 these creeks is shown in Fig. 19. This section corresponds, in 

 all essential respects, with Figs. 16 and 18, farther south. 



The relation of the Bridgeton to the Pensauken is well shown 

 about Mickleton. The arkose phase of the Pensauken lies below 

 100 feet, and above this level Adams Hill rises to 133 feet, 

 capped by an isolated remnant of the Bridgeton, which is litho- 



