90 Transactions. — Miscellaneous. 



turbed, and the sand is so placed as to be capable of retaining moisture, it 

 is generally covered with vegetation (more or less luxuriant according to 

 the degree of moisture present), of the special character which affects this 

 description of habitat. I give at the foot of this paper a list of the most 

 conspicuous dune plants indigenous to New Zealand, many of which would 

 be found valuable in other countries. 



Now this vegetation confines the sand, and would, if undisturbed 

 by man, or by grazing or burrowing animals, entirely prevent its motion 

 under the influence of the wind, whilst, wherever the surface is not 

 confined by plant growth or by a crust of vegetable matter, the sand 

 is constantly rolled forward in the direction of the prevailing winds. 

 Instances, indeed, are abundant in other countries, of populous and 

 fertile districts having by this means been converted into barren wastes. 

 A recent example of this was observed in connection with the dunes which 

 lie between the Adour and the estuary of the Gironde, on the west coast of 

 France, the sands of which were found, where not fixed by vegetable 

 growth, to advance eastward at a mean rate of about sixteen and a half feet 

 a year, the result being that a large extent of fertile land was destroyed before 

 effectual measures could be taken to arrest the evil. Other instances of the 

 mischief which results from disturbing the vegetation upon the surfaces of 

 sand dunes will be given in the sequel, whilst, to bring the matter home, I 

 may mention that Mr. Hadfield (who occupies a tract of land between the 

 rivers Otaki and Ohau, on the west coast of this Provincial District) informs 

 me that the sands of the dunes between those rivers are advancing inland 

 at a rapid rate and threaten great injury, unless effectual steps be taken to 

 prevent it. I have observed the same thing occurring on the shores of 

 Pegasus Bay, but in less degree owing to the fact that the strong westerly 

 winds which are frequent there, blow off shore, and prevent any rapid 

 inland extension of the sand under the influence of the easterly winds which 

 prevail on that coast. 



It has been a question of interest in Europe, whether, and to what 

 extent, the generally bare condition of coast dunes is to be attributed to the 

 improvidence and indiscretion of man, and recent investigations seem to 

 have shown that, in almost every case, the inland advance of dune sands 

 may be traced to man's interference with natural operations. A patent 

 instance of this is given in connection with the dunes of the Prische 

 Nebrung, on the coast of Prussia. It is related by Willibald Alexis (as 

 quoted by Mr. Marsh, in his interesting and valuable work on Physical 

 Geography), " that the dunes of the Nebrung were formerly covered with a 

 great pine forest, which extended to the water's edge, and bound, with its 

 roots, the dune sand and the heath uninterruptedly from Dantzig to Pillau. 



