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S. S. BUCKMAN 



[APRIL 



consequents, there would be established a principle of permanence of 

 river valleys, making drainage restoration a certainty. The valley 

 would remain a valley even though denudation had removed its sides 

 far below the original floor of the consequent stream. There is Dr. 

 Ellis's suggestion with regard to the left or antidip tributaries of the 

 Severn ; as it would be put now, they are obsequents which occupy 

 and have deepened valleys of consequents, or Thames streams. 

 Diagrammatically the history has been this : — First, consequents 

 flowing N.W. to S.E. (Fig. 1, A), secondly, consequents cut into by a 

 subsequent, and obsequents started up the consequent valleys (Fig. 1, B). 

 Then the obsequents proceed farther up the consequent valleys, their 



Dcvide 



Divide 



Fig. 1. — Theoretical diagrams illustrating (A) consequent streams threatened by a subsequent, 

 (B) consequent streams captured by subsequent, and initiation of obsequents. 



relative lengths according with the successive dates of capture of the 

 consequents. Naturally, then, the obsequents should have a direction 

 S.E. to N.W., and they have. See the sketch map (Fig. 2), which 

 illustrates the actual result, closely in accordance, it will be seen, with 

 the theoretical diagram (Fig. 1, B). This matter is very important ; and 

 it follows from considerations of these cases that the beheaded conse- 

 quent and the growing obsequent should be found occupying opposite 

 sides of the divide with in many cases a continuous valley (Fig. 3). 



Therefore in such valleys, which would form passes, the obsequent 

 and consequent streams should be opposite to one another. 



From many actual cases I select a rather striking example : — 

 Two cases are shown in Fig. 4, the Isborne and the Coin, in a deep 

 pass : a branch of the Windrush and a branch of the Isborne — the 



