Cockayne. — Observations on Coastal Vegetation. 315 



deed, twice that amount, while certain parts of the east coast 

 hardly get 50 cm.* The number of rainy days, too, is much 

 greater in the west than in the east. The climate of the west 

 is also comparatively uniform, whereas in that part of the east 

 where dry conditions prevail the summers are hotter and the 

 winters colder than elsewhere on the coast — in fact, — 8° C. is 

 not uncommon close to the shore of the Canterbury Plain. Much 

 of the east, too, is subject to violent hot and dry north-west 

 winds, known nowhere else in New Zealand, and which have 

 been sufficiently described by me elsewhera (11 ; p. 110). 



The form of the coast-line is varied. In some places high 

 mountains descend steeply — at times, indeed, almo^st perpen- 

 dicularly — to the water; in others there are steep cUfEs against 

 which the sea dashes ; while in many places the land is com- 

 paratively flat, being frequently raised but a few feet above the 

 sea-level, or in some parts so low as to be subject to inunda- 

 tion. 



The exposure of the coast wdth regard to the ocean is very- 

 various. Large stretches of land abutting directly upon it are 

 subject to the full fury of wind and wave ; and this, of course, is 

 much augmented if they face the prevailing wnd, or lessened if 

 there is some sheltering headland. In other parts of the coast, 

 on the contrary, are deep fiords, extending for many miles in- 

 land, and there, of course, very much calmer conditions prevail, 

 to which the vegetation bears ample testimony. Shallow estu- 

 aries shut ofE from the sea by banks of gravel and sand are not 

 xmcommon, and here another condition of affairs exists for plant- 

 life. Similar conditions are also afforded by tidal rivers, along 

 whose banks coastal formations extend inland. 



The geological structure of the coast is of considerable phyto- 

 geographical importance. Here it need only be pointed out 

 that rocks of diverse kinds occur — volcanic, granitic, calcareous, 

 sandstone, shale. &c. How far plant-distribution is correlated 

 Anth the composition or age of the geological formations has 

 not been worked out at any detail as yet for any part of New 

 Zealand; at most a few very general facts are available. 



As for the actual sea-shore, it may be sandy, rocky, shingly, 

 gravelly, or muddy. Shells in many places also are abund- 

 ant. Sandy shores merge into dunes, generally of no great 

 height. Gravelly and rocky shores are succeeded by clifEs, 

 stony terraces, gravelly dunes, steep banks, &c., while muddy 

 shores are frequently the forerunners of salt meadows. Boggy 

 and swampy places also occur near the sea, fed by fresh-water 



* See the highly instructive rainfall map of the South Island (3fi ; 

 p. 238). 



