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by soundings near the mouths should therefore indicate only a little less 

 than the total amount of subsidence. 



For the following reason Pelorus Sound (PS, fig. 1) is selected for the 

 application of the test. The soundings in Queen Charlotte Sound* present 

 irregularities, the chief of which is a bar of shallow water (11 fathoms) just 

 within the main entrance (Q, fig. 1). This is accounted for by the fact that 

 the flood tide enters, not by the broad, main entrance, but by a smaller 

 opening, Tory Channel (TC, fig. 1), on the south-east s'de and then flows 

 down the Sound, causing permanent slack water at the mouth, which has 

 thus become a locus of d position for fine sediment. This anomaly is a 

 result of the northward flow of the flood tide through Cook Strait. 



Pelorus Sound, on the other hand, exhibits no similar irregularity. There 

 is general agreement of the depth of water in the arms of Pelorus Sound 

 with that within Queen Charlotte Sound, and in the former there is a gradual 

 increase in depth from the head to the mouth. The tide runs with sufficient 

 strength to carry the bulk of the sediment out to sea. 



In the mouth of Pelorus Sound soundings indicate a depth of 40 

 fathoms, suggesting that the subsidence is about 300 ft. This estimate 

 agrees fairly well with that based on normal river grade, but the whole 

 argument is ineffective if at some stage of the subsidence a very long pause 

 occurred, allowing of the accumulation in the Sounds of a great thickness 

 of sediment. 



The Tuamarina Valley, unlike those opening on Queen Charlotte Sound, 

 is not now occupied by an arm of the sea. Clearly, however, it has been 

 affected by the same subsidence, and invaded by the sea. In fact, the rail- 

 way traveller cannot fail to note its resemblance to the Sound left behind 

 at Picton. It is occupied now by flat land and swamp. 



The Old Shore of Cloudy Bay. 



Again, after Tuamarina Railway-station is passed and the valley left 

 behind, an old abandoned coast opens out, bold and straight, while at the 

 foot of the cliffs, instead of the sea, the Wairau Plain is spread out. 



^ %ft£5i- 



Fig. 4. — A View along the Old Shore NoRTH-EASTWAitD from Tuamarina. 



The straightness of this fossil coast, coupled with the fact that it trun- 

 cates rock structures indifferently, suggests that its course was determined 



* See Admiralty Chart, New Zealand, sheet 5. 



