I70 QUATERNARY FORMATIONS OF SOUTHERN NEW JERSEY. 



have flowed through Bear Swamp; but the valleys of Stony 

 Brook and Bear Swamp are so nearly at the same level that the 

 waters flowing about the P'enns Neck upland could have been 

 diverted easily from the one route to the other. 



Bear Brook. — The Cape May formation appears all along the 

 northeast side of this short valley, well toward its source. Locally 

 it assumes the form of definite terraces, but more commonly 

 it is not so disposed. Its surface differs from that of the upland 

 chiefly in being more sandy. The material consists of gravel, 

 sand, and loam. 



The upper Millstone {above Princeton Junction). — This river 

 heads east of the Clarksburg! hills, and traverses a greater range 

 of formations than other streams of the region, except Assanpink 

 Creek. In general it may be said that the Cape May formation 

 of this valley consists of a thin body of material mostly on the 

 right bank of the stream, from Red Tavern to Princeton Junc- 

 tion. In many places it is disposed as a distinct terrace 10 to 20 

 feet above the stream, composed of the loose sand and gravel 

 characteristic of the formation. At other places the terrace 

 form is wanting, and there is at the surface no sharp distinction 

 between the distinctive Cape May material below, and older for- 

 mations above. The indefiniteness is partly the result of the 

 loam mantle. The material in most of the valley seems to have 

 come largely from formations at higher levels in the vicinity, 

 while little seems to have come down from the head of the 

 valley. The conspicuous thing about the formation here is its 

 definite relation to the stream. Above it, the slopes are mantled 

 with loam which appears to stand in no definite relation to the 

 underlying formation. Where the loam is well developed, there 

 are undrained depressions, usually small and shallow. 



In the upper reaches of the valley, in the vicinity of Bergen 

 Mills and below, there is much sand which resembles that along 

 Crosswicks and Doctor creeks, probably eolian in its present 

 position. In this vicinity the valleys of Cranbury Brook and 

 Millstone River head in the same flat, and a shallow ditch would 

 divert one stream into the valley of the other. 



