1?RAVERS. — On the great Ploods of Pebi'uary, 1868. tO 



The Hurunui aud Waiau-ua Plains form together a long oval tract of 

 practically level country, lying nearly east and west in its longest diameter, 

 surrounded by mountains, and occupying the centre of the Amtiri District, in 

 the Province of Nelson. The eastern and larger portion of this oval is called 

 the Hurunui Plain, and is traversed diagonally from north-west to south-east 

 by the river of that name. The western and smaller part of the oval is 

 called the Waiau-ua Plain, and is also traversed from north-west to south- 

 east by the river of that name. This latter portion lies at a lower level 

 than the Hurunui Plain, for reasons to which I will shortly refer. The 

 whole area presents the appearance of an ancient lake basin, the bed of 

 which had been filled with gravels brought down by its various feeders 

 before the waters had been drawn off through the channels cut from its 

 southern side to the sea, by the rivers which now traverse its bed. These 

 rivers are the Hurunui aud the Waiau-ua, the first of which, after 

 debouching from the mountains at the north-western end of the oval, flows 

 diagonally across its upper part to about the middle of its southern side, where 

 it enters a gorge and passes on to the sea ; and the second of which, debouch- 

 ing from its own gorge above referred to, at a point a little below the middle 

 of the northern side of the oval, also flows across it diagonally (on a line 

 nearly parallel to the course of the Hurunui) to the south-eastern end of the 

 oval, where it also enters a gorge through which it flows to the sea. Each of 

 these rivers has removed in its course from its debouchure onto the plain 

 to the gorge which it enters on the southern side, an immense quantity of 

 the materials of which the lake bed was originally composed, leaving that 

 part of the latter which lies between their courses as an undisturbed level 

 tract, some twelve miles long, standing considerably above the general level 

 of those portions of the oval which have been acted upon by the two rivers. 

 Moreover, each of these rivers occupies a more or less defined channel in 

 the lower ground through which it now flows, that of the Hurunui gradually 

 widening to about three-fourths of a mile until it reaches the point at which 

 it enters the gorge, where it again contracts, while that of the Waiau-ua 

 rapidly spreads until it attains a width of from one to two miles, and as 

 rapidly contracts again towards the point at which it enters its own lower 

 gorge at the south-eastern end of the oval. 



A stream called the Pahau, which in its ordinary state is most insigni- 

 ficant, flows from the mountains on the northern side of the oval about 

 midway between the debouchures of the Hurunui and Waiau-ua, running 

 in a shallow depression across the higher ground between these two rivers, 

 until it joins the Hurunui close to its entrance into the gorge on the south 

 side of the plain. 



