326 Transactions. — Geology. 



was probably dammed up, and they gradually thin out towards 

 the head of the valley, where their depth is only 3 feet. The 

 bed rock at the head of this valley is " blue papa." 



The deep-channelled bed of the Whauganui Eiver between 

 Taumarunui and the sea, with its perpendicular banks, often 

 over 200 feet high, carved out of the blue marl beds, the 

 absence of river terraces or anything approaching a wide, 

 extensive river valley, all bear evidence of the rapid upheaval 

 of the land in the interior. The distance from Taumarunui 

 to Whanganui by the river is about 130 miles. No road nor 

 native track, so far as I know, traverses the country, which 

 is accessible only by the river. The journey from Taumarunui 

 to the coast hi a canoe takes four days. The whole course of 

 the river is a succession of magnificent gorge scenery, a 

 luxuriant, tropical-like growth of fern-trees and variously-tinted 

 undergrowth, fringing the banks and mixed among stately forest 

 trees, which overhang the river high above. There are several 

 extensive rapids, which require skill and care to pilot the canoe 

 over. Picturesque buttress-like headlands have been rounded 

 out on the marl beds by the current of the river. They look 

 like the prow of some great vessel ; their sides are marked by 

 rows of holes, one tier above another, formed by the poles 

 used to propel canoes up the stream. 



Pumice Deposits. 



I have frequently referred to the superficial pumice deposit 

 in the district. It is found most persistently in all the valleys, 

 terraces, and flats within a radius of 40 miles round, from 

 the south-west to the north-east, from the centre of Taupo 

 Lake, sometimes covering tbe surface with a deep deposit of 

 large and small particles, and rendering land which otberwise 

 would be fertile quite arid and useless. It is particularly 

 detrimental in the valleys of tbe Tuhua District and Upper 

 Whanganui, where large areas of level land along tbe river 

 sides and on the terraces are rendered unfit for cultivation. 

 Tins pumice deposit appears everywhere more or less within 

 the limits mentioned above ; but on the mountain tops and 

 down tbeir slopes it is seen for the most part merely as a 

 thin sprinkling, and accumulates more in tbe little valleys and 

 flats on tbe hillsides, frequently to a depth of 25 to 50 feet, 

 carried there, no doubt, by the surface waters and the wind. 

 In the Tuhua District, a few miles to the south-east of Tauma- 

 runui, a fine tract of about 10,000 acres of good soil, derived 

 from tbe blue papa rock, is partly spoiled by the pumice filling 

 the valleys and covering tbe rolling country on the slopes of 

 the hills. I have carefully studied this pumice deposit with 

 a view to ascertaining the mode of distribution. Between 

 Taupo Lake and the valley of the Ougarue, a distance of 



