438 



Transactions. — Geology. 



western end of the limestone, on its north bank, had further 

 proof of the inferior position of the greensands. 



Here a small stream, coming from the northern slopes of 

 Mount Harris, joins the Waihao. Part of its course is through 

 a limestone gorge ; nearer its junction with the river the lime- 

 stone walls diverge, but again approach towards the infall of the 

 creek. The basement beds of the limestone are 20 to 30 feet 

 above the creek at its junction with the river on the east side, 

 and higher on the west side. On the west side the limestone 

 forms a high bluff overlooking the river, which sets as a deep 

 pool at its foot. The lowest beds seen are dark, almost black, 

 with greensand grains. The creeklet ripples over these inlo the 

 pool. On the right hand (down the river) they form a flat 

 ledge above ordinary flood-mark. Fossils were collected here, 

 the same species as at Waikakahi Bridge farther down the river. 

 The fossiliferous beds are overlaid by the "marl beds" under 

 the limestone, and the dip of the conformable junction line can 

 be traced from the side of the cliff facing the river round the 

 corner, and up the little creek till it crosses and returns on the 

 opposite bank. This carries us to the road-line, the creek beiug 

 crossed by a bridge, above which greensands overlie the marly 

 beds. The limestone frowns above, on the right bank of the 

 stream ; the greensands and other beds just described pass under 

 the limestone. And again we are satisfied that the Waihao 

 greensands cannot and do not overlie the limestone. The same 

 beds are seen at Waikakahi Bridge ; and if the passage of the 

 greensands under the marl is less evident, on account of the 

 junction being in low ground and obscured by the alluvial banks 

 of the river, there is, at least, from what is seen, every 

 probability that they do. 



A section on the north or left bank has been given by 

 Professor Hutton (see ante, p. 433). That part of the same sec- 

 tion from where the greensands (4) are made to rest on the 

 east end of the limestone ridge (3), and thence across the valley 

 marked " W.B." on Hutton's section, I sketch below, but sub- 

 dividing the strata as I read the section in 1880. There is 

 certainly some difference in the rendering, which the reader 

 must try to reconcile if he can. 



Section on Left Bank of Waihao River, from east end of limestone to 

 south-west slopes of Waimate Hills. 

 SW ME 



7 



1. Mutai slates and pandstoues. 2. Shales, fire-clays, Qud coaly-beds. 8. Quartzose 

 grits, etc. 4. Grey sands (sulphurous), with hard bands and concretions. 



6. Waihao greensands (lower part). 6. Waihao greensanda (upper part). 



7. Clay DiarlB. 8. Greenaauds. 9. Waihiio limestone. 



