ERAT aey sahil at ht i Sey ahs (x25 i/o 
Travers.—On the great Floods of February, 1868. 79 
The Hurunui and 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 Amuri 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 and 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, 
