THE SOIL CONSERVATION SERVICE 



257 



Thin soil mixed with rock fragments 



Sparse vegetation 

 -Wide sandy washes 



CONCAVE UPWARD 

 Stream incapable of 



transporting all 

 weathered material 



Uniform depth of 

 soil under slope 



STRAIGHT SLOPE 

 Weathering movement 

 down slope and removal 



balanced 



An intermediate condition 

 partaking of many 

 special conditions 



I Distinct Soil Profile 



H Mass movement or soil creep, supplies stream with soil- 

 IE Little or no surface wash under a 

 complete mantle of vegetation 

 and its litter 



Vegetation 

 near water's edge 



CONVEX UPWARD 



Soil creep and bank stream 



erosion operate as geologic 



norms of erosion 



Erosional potentials created by 

 - stream cutting into country rock 



Zone of accelerated erosion 



4 



EFFECT OF 



ACCELERATED EROSION 

 ON NORMAL SLOPE PROFILES 

 Reversal of processes as result of cultivation on 

 slopes in convex profile topography showing 

 typical convex profiles under vegetation 

 and concave under cultivation 



FIG. 127. Characteristic slope profiles responsive to geological norms of erosion. 

 (After W. C. Lowdermilk.) 



