CussEN. — On the Piako and Waikato Biver-basins. 403 



In the bed of the Waikato Eiver at Hamilton several maire- 

 trees appear standing as they grew, the present land-surface 

 being 70ft. above them. In many of the gullies eroded by the 

 streams trunks of trees are found lying horizontally, and 

 some standing, their roots penetrating the old land-surface. 

 The most interesting example of this character, because of the 

 most recent occurrence, is that shown on Mr. E. B. Walker's 

 property at Mona Vale, near Cambridge. A drain was cut 

 about a mile in length through a spur of dry land to drain 

 the Mona Vale Swamp into a gully which led to the Waikato 

 Eiver. During a heavy rainfall some years ago a scour started 

 in this drain, which soon eroded a gully 70ft. in depth and 

 several chains wide. At the bottom of this gully the ancient 

 surface, consisting of a brown marly- looking soil, is exposed 

 to view. The trunks of trees are seen lying on the old land- 

 surface, and some are standing, their roots penetrating the 

 old soil where they grew. 



The Waikato flows in almost a direct course from Cam- 

 bridge to Ngaruawahia in a north-westerly direction, crossing 

 the former estuary diagonally. In a flat alluvial valley like 

 this we should naturally expect to find a winding river and a 

 broad and terraced river-valley, instead of which there is 

 a comparatively narrow valley, a deep-cut channel, and the 

 river runs in a direct course, until it is stopped by the Haka- 

 rimata Eanges, near Ngaruawahia ; it then follows the base of 

 the mountains to the Taupiri Gorge. 



Five miles and a half east of the Waikato Eiver, below 

 Huntly, there is a wide valley extending from the Manga- 

 whara Stream, in the middle basin, to the Matahura, in the 

 lower. It is very evident from the topography of the country 

 that this was at one time the outlet for the middle basin, and 

 the Waikato flowed through it and down the Matahura 

 Valley, through Waikare Lake and the Whangamarino Flats. 

 That the Taupiri Gorge, through which the river now flows, 

 was formed subsequently I think there can be very little 

 doubt. Captain Hutton, in his paper " On the Alluvial 

 Deposits of the Lower Waikato, and the Formation of Islands 

 by the Eiver," says : " There appears, therefore, to be no 

 geological evidence of the sea having been in the Lower 

 Waikato Valley since the upheaval of the Waitemata series — 

 that is, since it has had any existence. I therefore think that 

 the fact of the presence of several littoral plants in the Lower 

 Waikato basin, brought forward last year by Mr. Kirk, may 

 be best explained by supposing that they have spread down 

 the river from the Middle Waikato basin, after the forma- 

 tion of the Taupiri Gorge."* The evidence of changes in 



* Trans. N.Z. Inst., vol. iv., p. 334. 



