CONDITION OF TONGARIRO.

Auckland Star, Volume XXIII, Issue 33, 9 February 1892, Page 5

CONDITION OF TONGARIRO.

DESCRIPTION OF THE MOUNTAIN,

Fortunately, a topographical survey of the Tongariro mountains was completed last year by Mr Laurence Cussen, so thab any "changes that are made in the configuration of Ngauruhoeby the present disturbance will be easily ascertained. We make the following interesting extracts, descriptive of the condition of the Tongariro mountains from Mr Cussen'a report : —

" The craters of Ngauruhoe, the Red Crater, and To Mari are the three vents from which (in the order mentioned) the latest discharges of lava have taken place. Reference to the map will show that they are (together with tho Blue Lake Crater, Nga-Punaa-Tama Crater, and the warm crater lake on the summit; of Ruapehu) all in one straight line, and if the line be produced to the northwards it will pass through the boiling springs at Tokaanu. This lino bears 36° 30' east of north, and if it be still drawn northward, through the Lake country, it will bo found to pas 9 through the Whakarewarewa Springs and along the eastern side of Rotorua, in the direction of White Island. Steam is still issuing from Te Mari, the Red Crater, and, of course, from Ngauruhoe, whilst the crater lake on Ruapehu occasionally gives forth a column of steam. The lava streams from Ngauruhoe, the Red Crater, and Te Mari have all the same outward appearance, and apparently are much of the same age—the lava is'dark, 3coriaceous and heavy, having all the appearance of basalt. " Tongariro, as seen from the westward, looks like a single great cone with a flat top nearly three miles wide, with the tall symmetrical sugar-loaf peak of Ngauruhoe towering 7,500 ft high, just beyond its southern rim. As will be seen,_ however, it is composed of several distinct though dilapidated cones, the lava streams from which have bo overlapped in their descent; as to form one compact mountain mass at the base. The lower slopes of the mountain are composed of these lava streams ; to the westward they spread out over tho plateau in broad fanshaped spurs, between which the streams forming the head tributaries of the Whanganui River take their rise. On the north side they run down to Rato Aim, a distance of 3 milea in sinuous and rather Bteop Epurs, the bill sides being covered, in part, by forest. Round the lower elopes of the mountain on all sides tussock-grass, blue-grasp, flair, and fern, and small herb - bearing plants, with bright blossoms and juicy edible berries, grow, the latter in greater abundance than I have seen them anywhere else except on the Kaimanawa Ranges, Large numbers ot half-wild horses are at large on the lower slopes ot the mountain, and, notwithstanding the great cold in the winter time, they seem to thrive well. Sheep fatten quickly, and excellent mutton is produced on the Tongariro slopee. The wild dogs, however, which inhabit) tho mountain!?, and seem to find refuge amongst the steep lava ridges, are a serious trouble to the sheep farmers, and, notwithing continuous efforts for years, they have failed to exterminate them. As yet tbero is little or no vegetation on the summit of the mountain, though surface soil is fast forming, which seems to be of a fertile nature, of a dark, soft, and somewhat spongy loam. " Seen from the eastward, Tongariro has a very different appearance to that which it presents on the west. The mountain looks as if it had been cleft by three great rents, which, starting at the summib of tho cone, score its sides in a south-easb direction for about three miles. In these chasms the Mangahouhounui, Oturere, and Waihohonu Streams rise; they are separated

by great walls or ridges of rock, which may or may not have been distinct lava streams. ■In" places these walls aro 800 feet in height. At the head of the Mangahouhtfunui, close to the summit of the cone, the chasm spreads out into a crater-lika basin, with vertical inward faces of rock which are deeply cleft in many places ; the width of the basin is miles, its depth is from 600 feet to 700 feet. It appears like a crater, breached to the south-east where the Mangahouhounui flows, but whether it be so, or a space bounded by tho walls of a number of smaller craters, I could not determine. Ac the head of the Oturere is another basin as that which I have just described, only the iatter is much larger, its width being over two miles ; to the north its walls are 800 feet in height. They were unmistakably the interior of a crater, but whether it was of tho great) dimensions it would appear to be from the present configuration it is impossible to say. In wet weather this basin is occupied by a shallow lake. One of the most recent lava streams of Tongariro, that of the Red Crater, flowed over the floor of this crateral hollow and spread out round the base of its northern walls.

"The summit of Tongariro is formed of a number of oxtinct cones, whose crater walls are in a more or les3 perfect state of preservation. They record a long: series of changes, the volcanic action seeming to have made for itself a new channel at each succeeding change, and the craters appear to have diminished in size in their downward course, the new formation , breaking up the walls of their predecessors, and pouring lava streams down the mountain sides in fresh places. It ia easy to conceive, had the action continued through one vent, what a mighty volcanic cone might haya been built up, as, for instance, was the caEe at Ngauruhoe. On the top of Tongariro are now to be seen eight large and well-defined craters, which are for the most part encircled by walls composed of their own ejecta, but partly also by the dilapidated walls of former craters.

" Ngauruhoo, one of the prominent features of the volcanic chain, is a beautifully symmetrical cone, rising in almosb sugar-loaf shape from amidst the ruins of former conea, its height above the sea betntr 7,515 ft; the sidos aro formed partly of scoriss-ash and cindors alternating with lava streams, the average slops being from 37deg. to 40deg. We ascended the mountain twice during tho progress of my survey ; ibis easiest ascended on the south west side, where a lava stream flowed down from near tho summit to the baee, which, though rough and rugged to climb over, affords good footing, its slope varying between 30deg. and 40deg. On reaching tho summit on both occasions we found it impossible to eeo down into tho crater, so dense was the column ot steam rising from it. Jets of steam and vapour rush out from clefts at every point round tho bottom and aides with great force, and with a hissing ncise so loud that we could with difficulty hear each other talk ; the vapours, charged with pungent ga3oß and acids, wero all bub suffocating, making ib dangerous to approach too close to the crater lips. Occasionally tht wind, which came strong from tho southwards, blew the steam on ono side, and enabled us to get a glimpse of portions of the interior. The crater is almost circular, with stoep rugged sides to the east, the upper portions of which are overhanging. The diameter ia 25 to 30 chains, and the depth is, I believe, 120 ft. On the north-west side, just within tho margin of tho crater, a second cone has been built up. It is about 15()fb in height, and ite crater has a diameter from 5 to 8 chains of regular funnel shape; it is slightly breached on the north-west side where two lava streams have tiovved out in recent times, one said to be in the year 1869. Both these streams afford instructive ovidenco of how steep a elope lava will cool and consolidate at; they extend down the stoop cone, almosb from the summit to the base, at an angle of 39deg. Considerable changes muet have taken place in tho summit of the couo since Hochstetter visited the district in 1859, as shown by his sketches, and compared to those taken from photographs as tho mountain now appears.

"The summit has, however, not been much altered since I visited it in the year 1880 ; a few feet of the overhanging lips on the eastern sido, where our trig, station stood, have fallen in, and on the north-east gide about 100 ft of tho crater margin have aUo broken down, due to tho action of acid vapour?. Thecolumnofsteamfrom thecrater lias been much greater and more persistent during my recent visit than I noticed it on former occasions; its density varied considerably at times. I observed an increase of activity when the barometer was falling and a decrease with a rising barometor. The base of the cone covers an area, of nearly 4,000 acres ; its walls must be well braced together to resist the eiiects of explosions and the enormous proasura of the ascending lava column, which found release only ab the summit, at an elevation of 7,480 feet above the soalevel, or 5,500 ft above the plateau : no lissures appear on the steop sides of the cone from which lava could have flowed. Two miles to the south of Ngauruhoe summit is the interesting crater lake called Nga-puna-a-Tama ; it is of an elongated shape, half a mile long from east to west, und a quarter of a mile in width. It is surrounded by high crater walla from 400 ft to 500 ft in height and sloping regularly down to the edge of the lake. " Situated in a direct line between this crater lake and N2auruhoe is a somewhat extensive rift, three-quarters of a mile in length and nearly half a mile wide ; it 3 sides are steep and in some places precipitous, being from 300 ft to 400 ft in height. At its northern end some very typical forma of the columnar structure are seen in rhyolite lava (for sketches of which I am indebted to Mr T. Evan).

" A group of thermal springß at a height of 4,800 feet, situated on the north of the Tongariro cone, and called by the natives Ketetahi, are said to possess powerful medicinal qualities. There are also some mineral springs near the source of the Mangatepopo. One is a soda-water spring of considerable density. The general character of the rocks on Tongariro as stated by Professor Thomas is rhyolito, augite, with audesite, forming the most recent discharges. The last lava streams from To Mari, the Rod Crater, and Ngauruhoe, are of the lattor class, and in appearance, texture and weight are so like basalt that an ordinary observer could not tell the difference.

" I should not, perhaps, close my report without a word about the scenery in this district. I scarcely think there is in nature a scene moro lovely than that to be viewed from Ihe summit of Tongariro, looking north-east across Roto-Aira, and the extinct cones ot Pihanga and Kakaramea, and over tho grand inland sea of Taupo Lake, whilst from tho same point looking south are seen the dilapidated cones and cratei'3 of Tongariro'e summib, with Ngauruhoe's steep cone, and the snowclad masses of Ruapehu; nor i 3 there, in my opinion, in the colony a more charming journey, so far as landscape 13 concerned, than that round the margin of RotoAira, and along the western slopes of Tongariro and Ruapoliu to Waimarino. It is very beautiful to watch the effects of tho eetting or rising sun amongst these mountains. In the early morning the high peaks are first illuminated, whilst a soft yellow light tips the lower elevations, and soon golden showers spread over mountain and valley, leaving the ravines marked as dark streaks at the bottom. The sunset effects are, perhaps, even still moro lovely ; the higher peaks are suffused with a crimson glow, whilst the lower slopee are enveloped in dark twilight, the rosy tints remaining with the snowy peaks after the sun has left) all the rest of the landscape,"