CussEN. — Thermal Activity in Ruapehii Crater. 375 



subject will be of interest, chiefly as disclosing the fact that the 

 volcanic forces considered to be long since spent on Ruapehu are 

 still active, in at least so far as the solfatara stage is concerned. 



It was not until the 9th April that the snow on the lower 

 slopes of the mountain, where it is usually too soft to walk over, 

 had sufficiently melted off to allow of an ascent. We made a 

 start on the 9th, following up the valley of the Whakapapa 

 River for some three miles to an open plain at the foot of the 

 mountain, covered with native blue-grass (Patiti) and tussock ; 

 here we left our horses, and travelled on on foot for about four 

 and a-half hours, crossing over lava ridges and deep ravines 

 in a southerly direction, to reach a long prominent ridge which 

 ran down in a tolerably regular line from the top of the cone to 

 its base. Finding a convenient camping-ground in a deep 

 ravine, where a small tongue of the stunted bush which covers 

 the lower western slopes of the mountain runs up into the gorge, 

 we camped for the night to await the first opportunity of clear 

 weather for our ascent. The next morning a thick heavy fog 

 hung over the mountain, and came down throughout the day in 

 a drizzling rain, which, however, cleared up towards evening, 

 and there was a hard frost during the night. The morning 

 was beautifully clear, with a cloudless sky. We left our camp 

 while the stars were yet bright, as we had 4,000 feet to ascend, 

 our camp being about 5,000 feet above the level of the sea, and 

 very nearly at the limits of vegetation. For about an hour and 

 a half we followed up the gorge, shut in on both sides by high 

 precipitous rocks and ridges of lava, over which it was difficult 

 to get a passage. At the head of the gorge, however, we found 

 a practicable passage, and reached the back of the spur we had 

 selected for our ascent just as day was dawning. 



The scene was indeed a magnificent one, as the first rays of 

 the sun lit up the snowy peaks towering high above us, and 

 gradually shone over the snow-fields and great dark ridges and 

 gorges of the mountain. All around us were examples, most 

 varied and instructive, of volcanic phenomena, and the forms 

 and shapes assumed by the cooling lava. The ridge on which 

 we stood was probably built up by the most recent eruptions 

 from the mountain, formed of alternate sheets of lava and layers 

 of ashes ; at its base were immense masses of jagged scoria 

 rocks, piled up in irregular heaps and presenting most grotesque 

 shapes and forms. To the south of the ridge, and running 

 down from under the snow, was a well-defined stream of lava, 

 embracing in its course large blocks of half-molten rocks, 

 around which the lava stream had cooled, giving them the 

 appearance of stones standing in a river current. At the base 

 of this flow was a most beautiful example of the columnar 

 form assumed by cooling lava, A large mass of the cooluig 

 metal would seem to have become detached, and rollecl 



