Hill. — Artesian-water Basins of Heretaunga Plain. 437 



the Waipukurau and Waipawa Gorges, led subsequently to the 

 formation of large and important lake-areas — in fact, a chain of 

 lakes — between Waipukurau and the gorge north of Patangata, 

 and the surplus waters from these lakes reached the sea, some 

 in the direction of Te Aute, some through what is known as the 

 Middle Road leading from Havelock to Patangata, and some 

 through the hills in the direction of the Kidnappers. 



But the fracturing of the Havelock limestones, and alterations 

 in the level of the Te Aute Valley rift, caused the diversion of 

 the waters into what is now the bed of the Tukituki, thus causing 

 the disappearance of the chain of lakes that are easily traceable 

 to-day. 



The Ngaruroro and the Tutaekuri formed a single tributary 

 of the Great Wairarapa, but following the period of subsidence 

 they became separate rivers and entered the then Heretaunga 

 Bay, the Ngaruroro to the westward of Maraekakaho, and the 

 Tutaekuri at the Moteo. where it eventually filled up the fanlike 

 area between Fernhill and. the mill near Crissoge. 



We have now to consider the growth of the plain that has 

 been built up, not, it may be, phcenix-like on the remnants of a 

 subsiding area, but yet at a rapid rate considering that only the 

 rivers named have played any part in the work of rebuilding and 

 reconstruction. To make the matter clearer, it should be stated 

 here that what is ordinarily known as the Heretaunga Plain is, 

 from a geological point of view, only a portion of it. The area 

 of deposition, and not merely the area that we know has been 

 raised above sea-level, is the subject of our inquiries. As one 

 portion of an area is being raised above the level of the sea, 

 another portion, and in fact other portions, are receiving deposits 

 that are tending to raise them up to water-level, and it is neces- 

 sary, therefore, in considering the growth of the Heretaunga 

 Plain, to see how far that growth has affected the bay that at 

 present extends beyond the limits of the Heretaunga Plain. In 

 times of flood the waters that reach the plain not merely 

 overflow and spread fanlike deposits made up of the materials 

 brought down, but the waters passing slowly into the sea carry 

 much of the fine sediment to be deposited at varying distances 

 and depths from the mouth or mouths of a river. 



Those who have ever watched the formation-work as carried 

 on by navvies when a railway is in course of construction must 

 have noticed the carriage of material in trucks to be thrown 

 down an embankment when being formed as a part of the 

 permanent-way. Many loads of material are slowly thrown 

 down before the horizontal movement takes place, but the filling- 

 up is certain, and, as the necessary level is reached, the material 

 continues to be thrown down to widen and form a base that 



