THE GEOLOGY OF NEW ZEALAND. 
239 
climate must be proportionably refrigerated. Nor will this 
be the only change effected: large tracts of level land will be 
also upheaved. That this has already been the case to a 
considerable extent is evident from the extensive plains on the 
eastern side; that it is still going on is also evident from the 
observation of every one who is acquainted with the island. 
Large mud flats are now being formed at the mouth of almost 
every river, and there are low plains covered with timber, which 
are scarcely above the highest tides. That this will continue to 
be the case is most probable. The rapid streams and rivers 
flowing from the adjacent lofty mountains must bring down im¬ 
mense quantities of stone and soil, which Nature in her secret 
laboratory is preparing to form future plains for man’s use. The 
courses of these streams, or rather torrents, being so short, and 
the mountain sides so sharp and precipitous, as to be acted upon 
by every storm, vast masses are thus being continually detached, 
having been previously loosened by earthquakes ; entire sides 
of mountains frequently slip down ; the heavy rains increasing 
the body of water in the rivers, aid in transporting their debris 
to the ocean bed, where they are dispersed and spread out, 
layer above layer, until repeated upheavements lift the whole 
to the surface, first as mud flats, then above the level of 
ordinary tides, when it speedily becomes covered with a 
luxuriant vegetation. 
A SKETCH NEAR WANG APE, ON THE NORTH-WEST COAST. 
