CussEN. — Oil the Piaho and Waikato Eiver-hasins. 401 



waters of the river were ponded back into the valleys above, 

 which they o'ccupied in the form of a sinuous lake, extending 

 upwards for over eight miles, and covering the Waipa Plains, 

 which were evidently the bed of a lake. The topography of 

 the country bears strong evidence of this. We find the re- 

 mains of a deep alluvial deposit which filled the valleys run- 

 ning in between the spurs in level plains. Through these 

 deposits the streams, in eroding this channel, exposed strata, 

 horizontally laid, consisting of rhyolite sands, pumice, and 

 detritus, including the trunks of trees. At Paeroa, where the 

 Auckland Agricultural Company's homestead at Cranston is 

 situated, this deposit has a depth of 130ft , as exposed by the 

 washed-out gully of the Piarere Stream. It extends down the 

 Hinuwera Valley, and almost disappears at Parakau, four 

 miles from the present bed of the Waikato. 



Eeference to the map will show the elevation of the lake- 

 bed on the Waipa Plains to be 340ft. above sea-level. A 

 terrace of about the same height fringes the valley of the 

 Waititi Stream on the opposite side of the Waikato, and 

 extends down the river-side to Piarere. It is a remarkable 

 fact that the height of the old river-bed in the Hinuwera 

 Valley is only 280ft. at Piarere, and the valley slopes 

 gradually down towards Matamata. Were the contour and 

 levels of the valley as we now find them there would be 

 nothing to impound the water in the lake, the old Waipa 

 lake-bed being 60ft. above the outlet in the Hinuwera Valley. 

 I shall have occasion to refer to this question again in con- 

 sidering the causes which brought about the changes in the 

 river's course. 



The highest terrace in the Maungatautari Gorge has an 

 elevation of 300ft. above the sea. Water-worn rocks appear 

 on both sides of the river at that height, and between them 

 on either side of the river are seven rows of terraces extending 

 down to the present river-channel, which is cut deep and pre- 

 cipitous through the rhyolite rocks. 



The broad plain in central Waikato, in which the towns 

 of Cambridge, Hamilton, Ngaruawhia, &c., are situated, has 

 an area of 500 square miles. All over the lower areas of this 

 plain we find an alluvial deposit, varying in depth from 150ft. 

 downwards. The character of this deposit is unmistakable — 

 it is no doubt the alluvium of the Waikato Eiver, and differs 

 in no way from that at Waiotapu, Whakarnaru, and Hinu- 

 wera. Pumice-drifts are not found to any extent in the beds 

 of any of the other rivers which flow into the Waikato middle 

 basin. How these deposits came to be laid down as we now 

 find them is an interesting physiographical question. The 

 surface-height of the land at Cambridge is 220ft. above the 

 sea, at Hamilton it is 120ft., at Ngarato 125ft., and at Morrins- 

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