The Pamphlet Collection of Sir Robert Stout: Volume 68
"Francis Joseph Glacier
" Francis Joseph Glacier.
"Before we reached the glacier itself we had to cross a moraine, mostly consisting of small detritus, denoting by its mineralogical character that it came from the very summit of the snowy giants before us. My whole party had never seen a glacier, and some of the Maoris had never seen ice; thus the nearer we came the greater was their curiosity, and whilst I stopped some few hundred yards from the terminal face to take some bearings, the whole range, owing to the clear sky, being well visible, they all ran on, and I saw them soon ascend the ice, which, with the exception of a few small pieces of debris in the centre, was perfectly spotless, and presented a most magnificent sight. Having finished my work, I followed them, and soon stood under the glacial cave at the southern extremity, forming an azure roof of indescribable beauty, and which one of my European companions could only compare to the magnificent scenery of some London Christmas pantomime. The glacier not only fills the valley, the sides of which are formed of perpendicular walls of mica schist, but even from the ice large hillocks rise, consisting of the same rock, on which, better than anywhere I had ever observed, the planing and furrowing action of the ice can easily be studied. And no one having done so will afterwards feel surprised at the facility with which that wonderful and powerful plough of nature will furrow deep valleys, and model roches moutonnèes.—Haast, page 103.
"I have repeatedly alluded to the Great New Zealand Ice Period, or Glacier Epoch, and as this remarkable era plays such an important part in the physical geology of New Zealand, I may be allowed here to make a few remarks upon it for the general reader, the more so as there are scarcely anywhere alpine countries so easily accessible for the Scientific observer, bearing such clear and distinct traces of the post tertiary Glacier Period as the Alps of New Zealand. The action of the giant ice-ploughs, as we may well call these glaciers, has essentially assisted in preparing the lower regions for the use of man, since by it the narrow valleys have been widened, the rugged mountains rounded off, and large plains have been formed. Thus we find everywhere, as soon as we penetrate into the New Zealand Alps, where even the out running ridges near the plains often attain a height of 6000 feet, that the valleys are distinguished by rugged forms where the rivers which break through them have not only cut their bed deeply into the rocks, but have also formed such steep precipices that it is often impossible, even for the pedestrian, to pass along their banks, in order to reach the alpine lakes or plains situated in the valleys above. Inside of the eastern divergent chains, as soon as we enter the district of the earlier post tertiary glaciers, the valleys widen out to broal basins, the mountains on both sides—or even standing in the middle of the valley—have the recognised roche moutonnèe, or ice-worn rounded-hill form, and the fall of the rivers is less rapid. At the upper end of these fiats, which are filled up with drift, alluvium and glacial deposits, and through which the rivers have cut their new bed, lakes, surrounded by distinct moraines, are generally situated. The regular occurrence of these earlier terminal and lateral moraines supply us with the incontestable evidence that these lakes have been formed by the retreat of the glaciers. These lakes are found in every possible stage; some have already disappeared, the delta of the principal tributary entering from the Alps having completely filled the up; others are very much contracted by the deltas of the main affluent, and of the secondary water-courses descending from both sides; other again are great swamps, having become so shallow, through the enormous quantity of glacier silt deposited in them, that they also may soon disappear under the continually advancing masses of debris. The extent of these flats, and of the lakes in them, stand in almost all cases in exact proportion to the extent of the present glaciers at the end of the valley and, therefore, of course to the height, extension, and other orographical conditions of the alpine chains. The form and width of the valleys above the alpine lakes show in the most striking way that they must once have been the bed of great glaciers, to the action of which they principally owe their present form. They are frequently, even up to the present glaciers, of the same width as the lakes. On both sides of them, several thousand feet above the level of the valley, enormous moraines are found stretching along the mountains, so that one can often follow the terminal moraine at the lower end of the lake for twenty miles upwards. Roches moutonnèes occur everywhere. * However where the colossal glaciers of the Ice Period have pierced through to the Canterbury plains, the secondary ridges are also rounded off and the valleys widened."
— Haast, page 189.
"The natural consequence of such enormous accumulations of snow was the formation of glaciers of gigantic proportions descending in course of time by the pre-existing or newly-formed channels towards the see grinding down the rugosities of bottom and sides. The action of the glaciers beginning to lay open the rocks of the higher ranges soon offered sufficient material for morainic accumulations, first on the glaciers themselves and afterwards on the terminal faces. The scooping action of the iec-plough having once begun to eat into the plateau-like ranges, not only in the main course of the glaciers, but also into the lateral valleys, became more extended every day, and furnished more and more material for the formation of huge moraines. In their turn these moraines were destroyed by the great torrents issuing from the glaciers, and ample material was furnished for building up fan-like courses for the former. Boulders, sand, and ooze raised considerably the sea bottom along both coasts of the island, and the low land at the foot of the alpine ranges was more or less enlarged according to the physical features obtaining. It will thus be seen that without invoking the aid of cosmical causes Much might or might not have existed, I attribute the great glaciation of New Zealand to physical causes still now in operation, although on a much smaller scale, and without even assuming that the country had risen to a higher level than it occupies at present."
— Haast, page 374.
On this point Hochstetter says:—"In enquiring into the causes the pleistocene glaciation of the South Island, we need not resort to the hypothesis of a general Ice Period caused by Cosmical influences, and which was supposed to have covered the surface of the globe from the Poles to the Torrid Zone with snow and ice, but find the most reasonable explanation in the physical causes now in existence, if we only suppose that the Southern Alps during the Pleistocene Period differed somewhat from their present features, forming higher and more plateau-like ranges, while the climatic influences, as well as the action of water and ice at that period, were the same as at present. My views is this respect are perfectly in accord with those advocated by my friend, Dr. Haast."
Here we have a picture giving Haast's idea of the probable former extension of the glaciers down to the Canterbury Plains, shewing what an immense mass of ice must then have extended to within 30 miles of the present coast line; and another of the fan-shaped deposits in the neighbourhood of Waimakiriri, shewing a well-defined semi-circular series of ridges from 450 feet down to 63 feet above sea level, the contour lines running nearly exactly parallel as the plain descends. Now applying this to our own Province, I will read you a brief extract from Hutton, only premising that there is some difference of opinion as to the earlier and later extensions of the glaciers; but they are chiefly referred to the Pliocene or Post-pliocene Age, that is to say, to the upper tertiary, or post tertiary. On this point there is room for a good deal more investigation—it is sufficient for our present purpose that there have been earlier and later periods of extension and retrocession. Hutton says:—
* Note.—Mr. F. R. Chapman, who is familiar with the Swiss Alps, tells me he has only seen one true rochc moutonnee in New Zealand, in one of the Sounds.