398 Transactions. — Geology. 



x\bt. XLVI. — Notes on the Piako and Waikato Eiver- 

 hasins. 



By Lawrence Cussen. 



\_Bead before the Aiic'kland Institute, 23rcl October, 1893.] 



I HAD the honour to read a paper before the Auckland 

 Institute in December, 1888, on the Waikato Eiver-basins.''' 

 There was little time to discuss the subject on that occasion, 

 and, as the changes in the course of the river are of an in- 

 teresting and somewhat recondite character, I believe some 

 of the members will be glad of an opportunity of discussing 

 them. I have been enabled to add considerably to my 

 previous notes and to include portions of the Waipa and Piako 

 basins during recent journeys through the districts, and 

 fresh evidence of changes in the level of the land and altera- 

 tions in the courses of the rivers during comparatively recent 

 times will be submitted to you. 



It has been my fortune during many years past frequently 

 to visit every part of the Waikato basins, and, in conducting 

 the topographical survey of the country, I was afforded an 

 excellent opportunity of studying its surface configuration. 

 Unlike many of the great questions with which geologists have 

 to deal, the study of the earth's surface-features requires no 

 special scientific training — it is within the limits of our most 

 familiar experiences. One needs but the time and opportunity, 

 with some experience. Nature's features are bare before us — 

 we can read on the faces of the cliffs and the terraces, in the 

 steep or gentle grade of the valley to the river, and in the 

 character and distribution of the surface-soils and water-laid 

 materials, the half-hidden history of the past. These notes 

 refer to a comparatively recent time from a geological view 

 — a period during which the surface configuration of the 

 country was very much as we see it at the present dav. 



The Waikato Eiver rises amongst the peaks of Euapehu, and, 

 flowing along the eastern base of the Tongariro and Euapehu 

 volcanic chain, receives the drainage of the great mountains 

 and several considerable streams from the Kaimanawas, and 

 enters Taupo Lake at Tokaanu. Taupo Lake is 24f miles in 

 length, and 16^ miles in width ; its average depth is about 

 400ft. It is bounded in most places by steep lava-cliffs and 

 associated tuffs. Two well-marked terraces surround the 

 lake and the valleys leading into it. One stands 100ft. above 



* Trans. N.Z. Inst., vol. xxi., p. 406. 



