Page:The journal of the Royal Geographic Society of London. Volume 34, 1864. (IA s572id13663720).pdf/310

102 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 being 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, and 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 slopes 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 moraine, 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 groove, which has been cut by this snow-bank between the rock and the moraine, is not less than 400 feet.

By a slightly-dangerous climb we got up the glacialised surface of the rock, and on to the top of the great moraine which is heaped up against it. The frequent landslips which take place from the face of the moraine-cliff do great havoc among the trees that grow on top, leaving their roots 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 Podocarpus), broad leaf. New Zealand holly (Eurybria dentata), moka, 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 valley, which runs north and south, crossing the main valley, which is continuous with that of the Sound. As these valleys 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 the eastern side, being opposite to that upon which the greatest accumulation of ice must always have taken place.

Although the mountains rise so precipitously from the valleys,