126 nn, J. w. HF.sr.nr fTAURisoN on 



form the double pan H. However, we are not without signs 

 that the whole system is, under the influence of the wind on 

 the water, once again linking up. 



It is well to note here that, long ago, the pan E very 

 probably bore the same relation to G as F, in some future 

 time, will bear to I. 



Leaving this set, by the examination of those just above 

 it we shall gain further hints as to how the cessation of current 

 ending in relict channel pans may arise. Originally, when 

 the broader channel was carved in the marsh, the western end 

 of the larger island now visible had been strong enough to 

 cause a bifurcation in the channel with the consequent boring 

 of a side runner toward C. But although this promise of 

 resistive power was not kept, the "isthmus" of the protruding 

 finger held out long enough for local expansion indicative of 

 future pans to be scoured out ; then the break at B resulted, 

 so that the flowing tide, instead of passing onward to C, 

 simply resumed its original direction. With the lack of water, 

 the channel was colonised by Glyceria, and the chain of pans 

 at C isolated. 



A further source of pans has been seen in the suncracks 

 which cover the marsh like a network in dry hot seasons. 

 Rarely such ?nay be the explanation, but in my view it is very 

 unlikely. In such a summer I have seen even the broader 

 and deeper pans dried up, and the mud on the bottom con- 

 tracted into a curiously regular reticulation of suncracks. 

 These were submerged once again in August of the same 

 year, and since then they have been examined at regular 

 intervals ; despite the gales and vicissitudes of several winters, 

 the original cracks show few signs of change. If such be the 

 case there, is it probable that suncracks on the firmer soil of 

 the main marsh will serve as nuclei for huge pans? 



The Vegetation. 



We are now equipped for an examination of the various 

 plant communities of the salt marsli. Considerable work on 

 such formations has been done at odd stations on our coasts 



