JAGGAR: EROSION AND SEDIMENTATION. 297 
cases so often described of parallel tributaries in nature, supposedly 
caused by joint systems, are generally an original or superposed rhyth- 
mic tributary system controlled by the law of drainage rhythm. ‘The 
Cony AN CAES AE AA YEN TARO A 
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Fig. 3. Stream-robbery model, ultimate rill pattern. ‘Tracing of Plate 6. 
object of such experiments as those here described should be to reduce 
each element in the problem to its simplest form, and to vary one 
