is substantially greater. For a long time that was a puzzle, but 

 I think we have now worked out the answer. It is a problem that 

 perhaps is peculiar to New Zealand but maybe happens in other 

 parts of the world. I think it might conceivably be of interest to 

 workers along this coast because I think it is now generally ac- 

 cepted that here the salt marsh is developing on a subsiding 

 coast line. Now the Auckland coast is a highly mobile coast if 

 1 can call it that. In other words, that coast has come up and 

 down quite frequently and quite substantially in the last 150, 000 

 years. I have come to the conclusion that what we have there 

 is two salt marshes. The oldest portion, which shows erosion 

 very much like the type of erosion indicated by Professor 

 Steers, represents an old salt marsh, a great part of which I 

 think was possibly removed as a result of erosion when the land 

 sank. The existing salt marsh is the second salt marsh that has 

 developed on that area. There is such a shallow depth over the 

 peat deposits because this is a relatively young salt marsh but 

 there are relics of the older one which goes back something like 

 say 1200 years. This present one I think started somewhere 

 around 500 years ago. This ties in with the data supplied to me 

 by my colleagues, the geologists, who have studied coastal move- 

 ment up and down in the Auckland harbor, and in addition have 

 also carried out some accretion measurements in the same man- 

 ner that Professor Steers used in Norfolk. 



The other thing that I would say is that when we work out the 

 rate of formation of the salt marshes in New Zealand we find 

 that the time scale, based upon rates of accretion, is then com- 

 parable to the time scale that I have worked out in collaboration 

 with Professor Steers for the salt marshes in Great Britain. It 

 also ties in with the time scale that has been worked out on the 

 island of Skalling in Denmark where some work has also been 

 done. There is another phenomenon that Professor Steers didn't 

 mention which I think is worth drawing your attention to. You 

 can very often see three successive terraces on the salt marsh. 

 The salt marshes of Solway Firth I think are developing on a 

 rising coast line rather than on a subsiding coast line, and I 

 believe that the terraces there are associated with the continued 

 elevation of the coast line, which in turn is associated with 

 changes that have taken place in the main channel running out of 

 Solway Firth. The channel has caused erosion, and a bank re- 

 sults where the channel has migrated away again and a new 

 marsh is formed. With repetition a further terrace can be form- 

 ed. Of course most of you are familiar with salt marshes devel- 

 oping on subsiding coast lines all along this coast so that you 

 haven't got that phenomenon, but it is something that I think is 

 worth looking for where you have got salt marshes fornaing on a 

 rising coast line. Now I would like to add one further comment 

 on the point raised by Dr. Redfield because I am familiar with 



