Geological Survey of Canterbury. 25 



terminal face, and reached just before dark, the outlet of the Classen 

 glacier. Searching once more for a ford, we at last found one, and 

 although the water was so very rapid that we could only with the 

 greatest exertion bear against it, we all waded safely across, and 

 in another hour reached our camp, after a long day's journey. 



The next few days were devoted to ascending several of the 

 tributaries of the main river, all having glacier sources, and to study 

 their geological structure and physical features, and on March 6th we 

 broke camp and descended the river, in which, on the banks, or upon 

 some of the islets, groves of large specimens of Discaria toumatoo, the 

 Wild Irishman of the settlers, were growing. Some of them which I 

 measured were 16 to 18 feet high and over two feet in diameter at the 

 base. They formed with the gigantic Aciphylla Colensoi, the Spaniard 

 or Bayonet grass, an often impenetrable thicket which, when they had 

 to be passed, most severely punished man and horse. Arriving at the 

 junction of the eastern branch of the Grodley, I ascended that river, 

 which I named the Macaulay, to its glacier sources. The valley of 

 this picturesque stream is crossed several times by huge morainic 

 accumulations, through which the river has cut itself narrow gorges, 

 and which we had sometimes considerable trouble to pass. The 

 sources of the Macaulay come from several small but interesting 

 glaciers, lying at the southern flanks of Mount Forbes, and some 

 beautiful and high waterfalls offer a peculiar attraction to this valley. 

 Also here several high mountains were ascended, of which Observation 

 Peak between both rivers offered a glorious panoramic view. 



On March 12th I returned to Lake Tekapo, where I devoted a few 

 days to an examination of its shores, which generally consist of thick 

 beds of glacier silt. I also visited the islands in the centre, true 

 roches moutonnees, and consisting of very hard blue semi-crystalline 

 sandstones. It is evident from the appearance of the deltas, which 

 advance often very far into the lake, that it is filling up rapidly, even 

 without taking into consideration that the bottom must be raised not 

 inconsiderably in course of time by the enormous amount of glacier 

 silt brought in continually by the large torrents which feed it. Close 

 to the principal lake several smaller lakes and numerous lagoons are 

 lying amongst the ice-worn rocks and the morainic accumulations. 

 Amongst the former, Lake Alexandrina, the physical features of which 

 I found full of interest, is the most considerable. After having shod 

 the horses and replenished our stores, we started again on March 19th 

 for an exploration of the river which joins Lake Tekapo on its 



