112 A NEW ZEALAND NATURALIST'S CALENDAR. 



on the sand above or between tide marks, and that which 

 swims in the open ocean and which is thrown ashore by 

 the surf. After days of very heavy weather, especially 

 when the wind has blown from the south or south-east, 

 the beaches are strewn with wreckage not wreckage in 

 the ordinary sense of the term, but that of the animal and 

 vegetable life which dwells at or below low-water mark, 

 and which by the great rise and fall of the waves gets torn 

 from its rocky bed. When there is a great range of tide 

 and at the same time a heavy surf on the ocean, the flotsam 

 and jetsam of the beaches is found to be quite different 

 from the other forms of beach life. 



The sandhills along our shores are usually an index of 

 a rising coast-line; I do not think they are ever found 

 where the coast is sinking. If we walk along one of our 

 ocean beaches we will find that while there is only a thin 

 belt of sand at the southern or south-western end there 

 is a very wide stretch of it at the other end this is well 

 seen by contrasting the beach at St Clair with that at 

 Lawyer's Head. The same phenomenon will be found 

 to repeat itself up or down the coast, wherever the coast- 

 line has a more or less north and south direction. Simi- 

 larly, at the Green Island beach the sandhills commence 

 on the north side of Brighton, and are at first very narrow, 

 but they spread over a great area at Black Head, near 

 Green Island, and are still spreading up from the sea. At 

 low water the tendency is for the wind to keep moving 

 the sand in a northerly or north-easterly direction. The 

 opposite wind, the north-east, though often felt so strongly 

 in Dunedin, is not, as a rule, a strong wind on the coast. 

 It is here mostly localised by the form of the hills and 

 harbour, and it does not carry much sand. 



The struggle between land plants and the sea, which I 

 referred to in a previous note, is well shown on the sand- 

 hills. There are a few plants which are only to be found 

 in such localities, and these are characterised by their 

 fibrous roots and long creeping stems, which can send 

 up buds here and there even when buried under several 

 inches of sand. These are the natural sand binders which 



