28 
TITE GEOLOGY OF AUCKLAND. 
distinguish five craters on Tongariro, three of which are to a 
certain extent active. Steam is always issuing from them, and 
the natives state that from the principal crater, called Ngauruhoe, 
on the top of the highest cone of eruption (7,500), occasional 
eruptions of black ashes and dust take place, accompanied with 
loud subterranean noises. I may remark, that the shape of the 
cone is changing, the western side, for instance, having, during 
the great earthquake at Wellington, in 1854, fallen in, so that 
the interior of the crater is now visible from the higher points 
in the Tuhua district on the Upper Whanganui. The 
remarkable fact, that snow does not rest upon some of the upper 
points of the Tongariro system, while the lower ones are covered 
all the winter through, shows that those parts are of a high 
temperature. 
I had no opportunity myself of ascending Tongariro, but I 
have met with the following interesting account of an ascent of 
the highest cone of eruption by Mr IT. Dyson, which was com¬ 
municated to the New Zealander by A. S. Thomson, M.D. :— 
Mr. Dyson's Account of his Ascent of Tongariro. 
“In the month of March, 1851, a little before sunrise, I 
commenced my ascent alone, from the north-western side of the 
Rotoaire lake. I crossed the plain and ascended the space to 
the northward of the Whanganui river. Here I got into a valley 
covered with large blocks of scoria, which made my progress 
very difficult. At the bottom of the valley runs the Whanganui 
river. After crossing the river, which at this place was then 
not more than a yard broad, I had to ascend the other side of 
the valley, which, from the unequal nature of the ground, was 
very tedious, and I kept onwards as straight as I could for the 
top of the mountain. At last 1 came to the base of the cone, 
around which there were large blocks of scoria which had evi¬ 
dently been vomited out of the crater, and had rolled down the 
cone. The most formidable part of my journey lay yet before 
me, namely, the ascent of the cone, and it appeared to me from 
the position where I stood that it composed nearly one-fourth 
of the total height of the mountain. I cannot say at what 
angle the cone lies, but I had to crawl up a considerable por¬ 
tion of it on my hands and feet, and as it is covered with loose 
