192 Quaternary Formations oe Southern New Jersey. 



In this basin, as in those farther north, there is a strong con- 

 trast between the steep left slopes of the valleys, and the gentler 

 slopes on the right where the Cape May formation is chiefly 

 developed. 



Three or four miles back from the Delaware, the low divides 

 between the tributary streams are covered with 2 to 4 feet of 

 loam which was not derived from the formations beneath. Far- 

 ther from the Delaware, the surface material on the uplands 

 seems, in general, derivable from beds beneath. The loam over 

 the Delaware lowlands seems much like that over the uplands. 

 The latter may have been derived from the former, having been 

 shifted and re-deposited. 



The Delaware lowland between Mantua Creek and Raccoon 

 Creek. — The Delaware lowland here has a width of 3 to 4 miles. 

 Most of it is below 20 feet, but some parts rise to 30. Tidal 

 marshes occupy half the area, and the remainder is covered with 

 loam or sand, wind-blown sand being common. Along the 

 streams there are in places 2 to 6 feet of sand and gravel ; but it 

 does not extend back far from the water courses. 



In the region about Gibbstown, Repaupo, and Bridgeport, 

 there is little material that can be definitely correlated with the 

 Cape May formation. There is a thin veneer of loam in many 

 places, a foot or two thick, which is perhaps to be so classed; 

 but there are also areas of nearly bare Cretaceous at various 

 levels, from 10 feet up. 



Beneath the thin covering of sand and loam lies the Cre- 

 taceous. If all its superficial cover were removed, the Cretaceous 

 surface would not be very unlike the present surface. The sand 

 beds of the Cretaceous were doubtless the source of much of 

 the sand which has been blown about, making district dunes in 

 places, as half a mile southwest of Paulsboro, and about Bridge- 

 port. It does not appear that deposition was ever heavy over 

 this lowland, vet it is certain that the tributary valleys were 

 filled up to what is now the level of 30 feet or so, where they 

 join the Delaware lowland. If the Cape May deposits once filled 

 the Delaware to the same level, they have been removed, and 

 this seems hardly probable. The amount of post-Cape May 



