MLLFORD SOUND AND THEREABOUTS.

Southland Times, Volume III, Issue 4, 17 November 1863, Page 3

MLLFORD SOUND AND THEREABOUTS.

(FromDr Hector's Report.) _The geological structure of the mountains around \ Milford Sound is more complicated than in any other part of the West Coast that I have examined. The prevailing rock is syenitic gneiss, associated, with mica schist greenstone porphTy,andfelspathic schist, succeeded towards the lower part of the Sound by finegrained gneiss of newer age, felstohes, quartzites, and clay slates. No metallic ores were observed, but several might be expected to* occur among the last-mentioned group of strata, if a locality were found to have been traversed by fissures in which vein-stone could form. When sailing about the Soundj we frequently saw large shoals of the cow fish, which is an immense porpoise ten to twelve feet in length. They swim with great speed, raising their large blank fin out of the water every few minutes, and sometimes leaping several feet clear of the surface. I shot one, but having no harpoon could not secure him before he sunk. Several seals were also seen about the Sound, and the mouth of the Sound, but, though easily shot, it was impossible to secure them, the water being so deep close to the shore, as they also sink when dead. Fish are not so abundant in Milford Sound as they are to the south, but we got a few trumpeter and sea perch of excellent quality, and also several small species of fish which I have not seen elsewhere on the coast. On the 17th August, there having been several days of fine weather with south-east wind, I made another attempt to examine the Cleddau River, taking with me three men, a tent, ancl provisions for some days. The woods were very dry and pleasant, and the stream so much lower than during the previous week, that we were able to skirt it in many places where I had previously to wade across it.

Following up the middle of the three branches which join to form this river, by evening we had made about 8 miles — the latter part of the journey being very rough work, on account of the great size of the boulders which block the channel, and over which we had to scramble at the risk of slipping into the torrent ; this did happen to two of the party, but fortunately with no worse result than a thorough drenching in the icy water. The fall of the river is very great; and the bed of the stream is everywhere composed of glacier detritus, sometimes rudely stratified, and filling the valley to the height of 1500 feet above the sea level, the "immediate river valley bein"- excavated between this accumulation and the steep smooth wall of rock

against which it rests. * Next day we followed up one of the branches to its source. The upper part of its valley is cut to the depth of 540 feet, through a true moraine, consisting of earthy clay, containing regular blocks of rock of all sizes up to 30 and even 40 feet in diameter.

The stream ends quite abruptly against a glacialised surface of rock, which sl< p s to a height of 3000 feet at an angle of from 30 ° to 40 ° . The snow, which falls from the mountains, is unable to lie on this polished surface, and sliding down, wedges in at the back of the morain, forming a miniature glacier, though without the true ice structure, at an elevation of only 1000 feet above the sea level. The depth of the grove, which has been cut by this snow bauk between the rock and the morian, is not less than 400 feet.

By a slightly dangerous climb, w e got up the glacialised surface of the rock, and on to the top of the great moriane, which is heaped up against it. The frequent landslips which take place from the face of the moraine cliff does great havoc among the trees that grow on top, leaving thej-oots -bare, so that they die, and are easily thrown over. The forest is very open, and some of the trees are of good size. The principal trees which I observed at an altitude of 1800 feet, were the black birch, the iron wood, or batta, the remu, totara, cedar (a second species of Potocarpus), broad leaf, New Zealand holly (Rurybria deritata), moko, and several others.

At this altitude, on westerly exposures, there are few lichens, or mosses, as the woods are well aired and the soil dry. We were now in the third great longitudinal vally, which runs north and south, crossing the main valley, which is continuous with that of the Sound. As these galleys conform to the trend of the strata," they probably indicate lines of softer rock, along which the erosion was more easily effected by the descending glaciers. In these valleys, the moraine matter is heaped principally on thfi eastern side, being opposite to that upon which the greatest accumulation of ice must always have-taken place. The study of the deposits which fill these valleys possesses yreat practical interest from their intimate relation to the gold drifts on the eastern side of the mountains.

Although the mountains rise so precipitously from the valleys, they are no so steep towards their summits, where there is genarally a large area, presenting slopes on which snow could rest under circumstances favorable for its accumulation, and ff-rm the source of glaciers which would descend into the lower valleys. Pembroke Peak (6,623 feet), is covered with perpetual snow, which on its south-east face extends as low as 4000 feet, with aslope of 20 ° to 30 ° , and there terminate in a cliff of glacial ice, judging by its intense blue tint compared with Chat of the surrounding snow ; and did it not overhang *a precipice, this ice would doubtless descend as a glacier to a very low altitude. Now the average height of the mountain ri6ge9 is nearly 6000 feetand with the present conditions of- climate, an elevation of the land equal .to 2000 feet would according to the best esti-

mate I can-form praise about six-ten ths of the area of this mountain district to that altitude, which is certainly considerably a"bove the snow line in the 'strict sense, of from where the snow never disappears during the summer, unless by gravitation after assuming the glacier form by regelation.

It is a mistake to imagine the size of glaciers generated from a mountain range merely by its altitude, as -it is truly the area which, in the district is elevated above the snow line, that determines their extent. If this be the ease, the area must always be diminishing rapidly, from the eroding action of the descending ice, and therefore the extent of the glaciers must also diminish. Judging from the structure of the Sounds in the west side of the mountains, and that of the Lake district on the east side, I am inclined to think that the opposite sides of this mountain range have undergone repeated and alternate oscillations to the extent of at least 1000 feet in either direction from a nominal point ; and that the Western district being at present near to the period of greatest depression, the reelevation of the land to the other extreme woujd be almost sufficient to extend the glaciers to their ancient limits, for the residual excess of cold to effect this could easily be accounted for by the necessary alterations in the physical geogiaphy of the country which would accom[any such re-elevation.

The immense lapse of time and number of secular returns of these conditions is well shown by the remains of the high level valleys, which Were the wide channels for glaciers of earlier date, but are now represented as fringing shelves along the sides of more profound valleys, just like the terraces skirting the valley of a river, which is changing its course from side to side, of a gradually deepening channel. From the altitude we had attained, 1 could see that there was no hope of finding a saddle at the head of this valley, which appears to be surrounded by precipitous mountains 5000 feet in height, with detached snowy peaks several thousand feet higher.

As the weather was very threatening, we made our way back to the camp of the previous night, and regained the schooner next day during a violent storm, with rain from the south-west.

On the 24th August, giving up all hopes of the arrival of the Maories — of whom we heard nothing since we were in Chalky Inlet — I left the head of Milford Sound and dropped down to Anita Bay, where we anchored at dark ; and next morning, at 4 a.m., taking advantage of the land breeze, sailed to the northward, to the Awarua River, which is laid down on the chart 18 miles further up the coast. After making G miles, the wind died away, when we were off Yates' Point, which is the first promontory to the north of L'ilford Sound. As the yacht lay becalmed, with too heavy a swell running to allow of our towing, and, as it was necessary that the Awarua should be carefully examined before we attempted to enter it with the craft, I went on in advance with three hands in the whaleboat.

Keeping close in shore, I had a good view of the coast,' and satisfied myself that it would be quite possible to get along it from Milford Sound northwards. The appearance of the country is considerably altered from that to the south of Milford Sound, as the high snowy mountains trend to the E.N.E. from Pembroke Peak, and retire b hind lower wooded hills, which, howevtr, are too steep to be of any value, unless the bush conld be replaced by pasturage.

The coast line forms a succes>ion of bold headlands, which generally have a group of sharp rocks or a long reef extending f r om them to the seaward. Between these headlands are shallow bays, with deep sindy or shingle beaches, on which the surf breaks with tremendous violence. Three of these bays are of large size — each having a large valley extending from it into the interior in a southerly direction: and it is as flowing into the mort northerly of these that the Awarau of the Admiralty Surveyor is laid down on the chart The proper Awarau of the Maoris, according to all the information that I am able to collect, is, however, a large river that falls into Jackson's Bay to the north of that river, which I named the Jackson last summer, but which I have since learnt is known to the Maoris as the Terrewhatta.