46 BULLETIN 677, U. S. DEPAETMENT OP AGEICULTTJRE. 



levels along the Raccoon Creek drainage in the extreme southeastern 

 corner of the detailed survey. 



Rising above any of these elevations, a high ridge of land extends 

 almost from the margin of the Raccoon Creek swamps, northeasterly 

 across the area to its extreme northeastern corner. The summit of 

 this ridge is clearly indicated upon the soil map by the areas oc- 

 cupied by the Colts Neck gravelly sandy loam. From tliis summit 

 the land surface slopes rather steeply down to the upper levels of 

 the higher terrace. 



It is probable that the extreme summit of this higher ridge repre- 

 sents remnants of an older formation which has elsewhere been re- 

 moved by long-continued erosion. The slopes are undoubtedly 

 formed from soil wash from this higher and partly destroyed forma- 

 tion, mingled with a considerable amount of material which has been 

 brought to its present condition through the Aveathering of underly- 

 ing marl formations. Such areas are particularly in evidence in the 

 southeastern third of the area, where considerable tracts of both the 

 CoUington fine sandy loam and the Colts Neck loamy sand are found. 

 These two types owe their origin and characteristics to the influence 

 of the underlying marl formations, representing chiefly different 

 degrees of weathering to which the original materials have been 

 subjected. Where the marls are still comparatively fresh they retain 

 much of their original greenish color. Where they have been more 

 thoroughly weathered they have assumed a decidedly reddish tinge, 

 which serves to differentiate the resulting soils as members of the 

 Colts Neck series. 



The greater part of the drainage of the area is accomplished 

 through the medium of several small streams. Those found in the 

 eastern and southern parts of the area are tributary to Raccoon 

 Creek. Their courses are relatively short and their gradients are 

 steep. At their lower ends they have cut deep gorgelike channels 

 through the lower terrace. At their upper ends they usually head 

 in slight gullies or in springy areas within the upland. The streams 

 of the remainder of the area flow almost directly to the Delaware 

 River. They also head in springy areas in the upland. The land 

 along their courses through the area mapped in detail is somewhat 

 swampy. Their banks are low but steep. 



Drainage is effective over all of the upland, and the run-off is so 

 rapid upon the steeper slopes that heavy rains are likely to do some 

 damage through erosion of soil from the fields. 



This is particularly the case along the flanks of the ridge crossing 

 the southeastern corner of the area. 



