Cape May Formation — Local Details. 179 



Half a mile to a mile south and southeast of Stevens Station 

 the surface of the Cape May formation is affected by an un- 

 dulatory topography — sag and swell type — comparable to that 

 affecting the Pensauken formation about Fresh Ponds. The sur- 

 face elevation here is 30 to 40 feet, and the surface material pre- 

 cludes the eolian origin of the topography. It may be the result 

 of the unequal settling- of the underlying Cretaceous beds. 

 Similar topography occurs at higher levels, as a mile and a 

 quarter southeast of Bustleton, just north of the Burlington- 

 Columbus road, at an elevation of about 80 feet. 



Blacks Creek. — In the valley of this creek the Cape May for- 

 mation appears on the right bank of the stream, constituting a 

 fairly distinct terrace, the upland margin of which is ill defined 

 in many places. In Bordentown the terrace reaches an elevation 

 of 60 feet, and broader and more conspicuous terraces occur at 

 60 to 70 feet 2 or 3 miles up the creek. The well-defined terrace 

 terminates about 3 miles above the city, where the creek changes 

 its course. Farther up the stream, the volume of material refer- 

 able to this formation is small, but it is found in meager develop- 

 ment up Bacon Run nearly to Georgetown. South of Chester- 

 field and Blacks Creek, on the left banks of the several tribu- 

 taries above, there is a considerable accumulation of glauconitic 

 sand above the Cape May level, — at 8o< feet south of Chesterfield 

 and at no to 120 feet 2 miles farther southeast. The sand is 

 disposed as a broad low ridge, and is probably eolian. 



A mile from the Delaware, the Cretaceous surface in the slope 

 of the valley is about 40 feet above the creek; 3 miles from the 

 Delaware it is 25 to 30 feet above the creek; 5 miles above, 20 

 feet; and 7 miles above, about 5 feet. In other words, the 

 lower end of the valley is lower now by some 40 feet than it 

 was before the deposition of the Cape May formation, while 7 

 miles from the Delaware the depth of the valley is nearly the 

 same as in the Cape May epoch. The left slope of the valley is 

 higher and steeper than the right most of the way, and is covered 

 with a thick mantle of loam, probably wind blown. 



Loam covers the upland above the Cape May formation, and 

 this upland loam appears to be continuous with that over the 



