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be much more complete. The longitudinal drainage corresponding to the 

 strike appears to have been established during the Kaukau cycle and a 

 hypothetical earlier erosion period, for the adjustment of stream-courses 

 to structure which has been preserved in later cycles points to prolonged 

 denudation, and in rocks presenting but slight variation in hardness it 

 is unlikely that anything like complete adjustment could be attained in a 

 period as brief as that occupied by later cycles. 



While some adjustments may have been completed in the Tongue 

 Point cycle, there is no doubt that most streams in the initial stage of 

 that cycle followed subsequent courses. 



Owing to a peculiar set of circumstances, referred to elsewhere, the 

 captures that have taken place during the present cycle have to some 

 extent destroyed rather than completed the earlier adjustment. It is 

 possible that some of these retrograde changes took place as far back as 

 the Tongue Point cycle. 



The Tongue Point Cycle. 



The stage reached in the Tongue Point cycle was adolescence or early 

 maturity. In the streams of the Makara-Ohariu system (fig. 2), for 

 example, the stream-courses were graded, and the valley-floors occupied by 



Fig. 4. — Graded Reach in the Makara Stream. 



On the foreground and on right and left are benches of the flood-plain of the Tongue 



Point cycle. 



broad flood-plains, of which abundant traces remain as benches along 

 the sides of the valleys now trenched by the deep, young valleys of 

 the revived streams, and scored across by the young ravines of insequent 

 tributaries. 



Fig. 4 represents the valley of the Makara. The sketch was made 

 from a broad bench of the flood-plain of the Tongue Point cycle. Portions 

 of this are seen also on the other side of the valley. In Plate XVIII, 

 fig. "1, a view is given, looking southward, up the valley from about the 

 same point. It shows the elevated flood-plain of the Tongue Point cycle 

 on the left, and in the centre the later, steeper-grade flood-plain de- 

 veloped by the stream, in a graded reach, in the present cycle. By 

 lateral swinging and migration of meanders on this flood-plain the stream 

 has cut back the valley-slope on the right to a steep scarp. 



