EROSIONAL HISTORY OF DPJFTLESS AREA 35 



ders afford no more than a suggestion of more than one 

 cycle. Associated sets of straight and crooked streams, on 

 the other hand, are strong evidence of more than one cycle. 



TABLE SHOWING THE RELATm: VALUES OF THE VARIOUS EVIDENCES OF 

 MORE THAN ONE CYCLE OF EROSION IN REGIONS 



Those antecedent streams which can be proven to have gone 

 to the final stage of stream adjustment and are not now in 

 adjustment prove more than one cycle of erosion; any ante- 

 cedent stream, except one in which warping has followed 

 establishment of the stream course or one which is due to 

 superimposition, is strong evidence of more than one cycle. 

 Windgaps made by the abandonment of watergaps in the 

 changing of streams from antecedent to adjusted courses 

 form strong evidence and other windgaps merely suggest 

 more than one cycle. Especially even-crested summit areas 

 in regions of folded strata, are good evidences of more than 

 one cycle of erosion, but from these ideal conditions the 

 value deteriorates almost to zero in regions of horizontal 

 strata or where accordance of summit areas is more im- 

 aginary than real. It is believed that carefully investigated 

 intermediate plains may prove more than one cycle and 

 that any intermediate plain of wide extent is strong evi- 

 dence. Fluvial deposits either on intermediate plains or on 

 summit areas might prove more than one cycle under cer- 

 tain conditions and would be valuable evidence in any case. 

 It is to be noted that most of the abstract evidences have 

 more weight in regions of folded strata than where strata 

 are horizontal. 



