Ckawford. — On Changes in the Hataitai Valley. 343 



the sand is niuch mixed with recent marine shells. A rise of the land must 

 now have taken place, for it next appears to have been covered by dense 

 forest of the usual trees of the district, viz., totara, rata, kahikatea, 

 manuka, etc. 



The forest has then been destroyed, possibly by the advent of man, and 

 has been replaced by swamps and by a shallow lake (Burnham Water) in 

 the centre. The swamps supported a vegetation of raupo, flax, etc., and 

 before being drained a stick could be easily thrust down for about seven 

 feet, until it struck the hard sand bottom. Burnham Water was evidently 

 formed after the destruction of the forest, because roots of large trees are 

 found in its bed clearly in situ. 



How long ago was it that the land was depressed to the extent of 15 feet ? 

 To fill the Hataitai Valley with sand, gravel and shells must have taken a 

 considerable time ; but this time it must be impossible to arrive at, for the 

 sea might have gone on for ages at the work, grinding away, and shifting, 

 and replacing. For the age of the forest we should probably have to allow 

 some centuries. The swamp era must also have occupied a very long time. 

 The seven feet of soft vegetable matter consolidated into about 5 or 6 inches 

 of peat. How many centuries must we allow for this accumulation of 

 vegetable matter ? 



I have in a previous paper on wind-formed lakes shown how Burnham 

 Water was formed. Probably the advent of the Maoris occurred during the 

 forest period. Hataitai having been a great settlement from which eventu- 

 ally the South Island was colonized, the ground would naturally be cleared 

 by the natives, and thus the forest would be destroyed. Then the wind 

 would have got its opportunity of scooping out the bed of Burnham 

 Water. 



At what period did the moa live on Hataitai ? Many remains have been 

 found near the Maori ovens, and I myself found a head in the bed of 

 Burnham Water. 



Altogether, I think we might be safe in making a rough guess of ten 

 centuries as the date of depression of the land. It may have been less, 

 it may have been indefinitely more. 



As the imbedded timber from the old forest is excellent firewood, and as 

 in clearing the ground for ploughing it must be removed, all traces of its 

 previous existence will disappear during the next few years. 



