Geology of the Provinces of Canterbury and Westland, New Zealand : a report comprising the results of official explorations
Explorations of the Rivers Rangitata and Ashburton, 1861
Explorations of the Rivers Rangitata and Ashburton, 1861.
In order to obtain a general insight into the geology of the country I selected the River Rangitata to its sources as my base of operations. And after the necessary preparations were made, I started on the 20th February, 1861, for that river, accompanied by my friend the late Dr. A. Sinclair, who went with the intention of assisting me in the botanical researches to be made in the mountain ranges. Until June of the same year I examined this river as well as the Southern Ashburton and their different main branches to their very sources, fixing on the unsurveyed ground all the principal topographical features. This journey brought us into Alpine regions of imposing beauty and grandeur, only surpassed by the still more sublime scenery which further explorations of the central Alps round Mount Cook revealed during the course of the next year.
Following the valley of the Northern Ashburton, we reached on the 26th February the remarkable broad opening in the ranges by which the valleys of the Rangitata, Ashburton, and Rakaia are united, and of which a considerable portion is filled by morainic accumulations, between which a number of small picturesque lakes are situated. page 4We followed this opening to the Rangitata, having the snow-covered peaks of the central range before us; and after descending several hundred feet into the bed of the River Potts where it joins the Rangitata, we crossed that river and reached Mesopotamia, then the sheep station of Mr. Samuel Butler, where I established my headquarters. Here the valley of the Rangitata is several miles broad, and a number of terraces rise to a considerable altitude one above the other to nearly 3500 feet above the level of the sea, or 1900 feet above the river-bed. Here and there rounded hills, often in the form of sugar loaves, true roches moutonnées, appear amongst them, showing at a glance that this country had once been subjected to the action of ice for a considerable time. During the nest week, in order to become acquainted with the geological structure of the country, we explored Butler's and Forest Creeks to their sources, both wild mountain torrents flowing in their upper portion through deep rocky gorges. We also ascended several peaks, of which Mount Sinclair, 7022 feet high, at the head of Forest Creek and the southern termination of Two-thumb Range offered an extensive and magnificent view. The valleys of the Rangitata and Ashburton, with a portion of the Canterbury plains, and all the ranges to the east, were not only lying as a map before us, but the Southern Alps appeared also in all their sublime grandeur on the opposite side, the noble form of Mount Cook standing prominently above them all. From west to north the whole range was visible, reaching from Mount Cook to Mount Tyndall at the head waters of the Godley River; peak above peak, in bold majestic outlines, all glistening in snow and ice, a sight never to be forgotten. The course of the Godley was also visible, but a long spur concealed Lake Tekapo and the Mackenzie Country from our view. On the 12th of March, after having finished our preparations, we left Mesopotamia to ascend the Rangitata to its sources. Although the river-bed in these middle Rangitata plains is in most places nearly a mile wide, and the water flows in numerous branches, it is only at very low water that the river can be crossed on foot, and even when the water is not very high, horses find it difficult to bear up against the current. After ten miles travelling over level ground amongst dense scrub, mostly consisting of Discaria toumatoo, the Wild Irishman of the settlers, the junction of the two main branches was reached. I first ascended the southern branch, naming it the Havelock. From this point the river-bed continues for several miles to be more than a mile broad, and only gradually becomes narrower. The scenery page 5rapidly increases in grandeur, peak above peak, pinnacle above pinnacle appear covered with snow, wherever it finds a resting place. The mountains on the southern banks of the river, although very broken, being only the outrunning spurs of the Forbes Range, are not so picturesque, being intersected by deep valleys, whilst on the northern banks rise the precipitous flanks of Cloudy Peak, their base washed by the main stream. Towering to the blue heaven two gigantic pyramids here stand, the one in front of the other, the wild majesty of which defies description. Between them glaciers of the second order descend, their white masses shining like molten silver, but only visible where deep rents seem to have cloven the mountain asunder. Several small but beautiful waterfalls are seen, often many hundred feet high, but generally not in a continuous fall, the breaks between them as they jump from ledge to ledge adding however not a little to the splendour of the scenery. In some spots the waters wind amongst the rocks like streaks of silver, little promontories or forest vegetation alternately concealing them for a time, until they appear again clinging to the mountain sides. In another place, high above the river-bed, a streamlet falls over an overhanging rock, but instead of reaching the bottom, the wind takes possession of it, blowing it into an almost imperceptible mist, over which the sun threw, when we passed, a magnificent rainbow. Five miles from the junction of the Havelock with the Clyde the beech forest (Fagus Solandri) which still now and then grew upon the steep mountain sides, disappeared, and a new and strange vegetation took its place. Crossing and re-crossing the river where it seemed best fordable, we halted ten miles above the junction, where another important stream joined the Havelock from the west-south-west. A magnificent peak rose to a great altitude at the end of the valley, covered with perpetual snow, from which the ice streams descended towards the valley, the terminal faces of which we could discern at its head. Another reason why I selected this spot as a camping place was, that here behind an outjutting spur a little flat occurred, covered with coarse grass, so that we had some feed for the horses. The river-bed, still a mile broad, consisted of boulders in its whole extent, amongst which numerous watercourses meandered, shifting however with every fresh.
On the early morning of March the 14th we started towards the first source branch, and after crossing the different streams into which the Havelock is here divided, and of which the last one gave us considerable trouble, owing to the very large boulders in its channel, page 6we arrived at last on the left bank of the tributary, which I named the Forbes. The ground here became so rough that we were obliged to leave the horses behind, and climbing over the huge boulders and masses of debris, brought down no doubt by avalanches, through and over which the foaming water was roaring, we soon reached the first tributary of this stream, descending at an inclination of 20 degrees from a glacier of the second order, hanging some 2500 feet above, on the side of the huge mountain, down which its icy outlet rushed with such fury that we had difficulty in crossing it. Signs of avalanches became now very numerous, couloir succeeding couloir and the mountain sides were everywhere covered with debris and blocks of rock, and although these signs of destruction were great, the power of nature was still greater. Everywhere amongst these blocks, where the least stability could be obtained, plants, often in great luxuriance, had driven their roots. The clear atmosphere of New Zealand, which is deceptive when judging of distances, was still more so here. The snowy giants seemed quite close before us, and it was only by walking continually towards them that their distance became apparent.
After three miles walking the valley became narrower, the river rushed over enormous blocks of rock, which impeded its progress so that it wandered from one side to the other, compelling us constantly to climb over the huge blocks or along the rocky walls of the jutting spurs. A large green parrot, quite unknown to me, flew screaming over the valley, wondering at the intruders on his domain, whilst a few Paradise and blue ducks on the edges of the river uttered their well-known notes. After two hours' climbing, having passed in the mean time over several other outlets from glaciers of the second order, we reached a large stream, pouring down the steep mountain side with a thundering roar. The feeder of this torrent hung like a huge frozen tear from the slope of the mountain. We had great difficulty in crossing it, the water rushing against our legs like a mill-stream against the paddles of a water-wheel. Climbing another small ridge before us, squeezed between two precipitous promontories, the first true glacier came in sight. It was about 600 feet broad, 100 feet high, consisting of well stratified ice, the layers of a thickness of from three to five feet, concave and apparently adopting the form of the valley. The ice itself was very dirty at the terminal face, and the whole surface was deeply covered with fragments of rocks, some of enormous size, so as to conceal it page 7entirely. From a vault at least 30 feet high and broad, the stream rushed turbid with suspended matter, leaping over and sometimes confined between enormous blocks, often the size of small houses, which the glacier continually throws in its way. I climbed down to the cave the ice of which at the extremity of the glacier was so much decomposed that by a single blow of the hammer huge blocks were shivered to a thousand pieces. But I was not allowed to stand there very long. Seeing that a part of the vault was giving way, I retreated, and being warned by the call of my companions, I had to stoop behind a huge block, whilst a large fragment of rock several tons in weight fell down, leaping over my place of shelter, and falling into the river with a tremendous crash.
By joint observations with two aneroid barometers and the boiling water apparatus, I found the altitude of the terminal face of the glacier to be 3837 feet above the sea level. As it was impossible, owing to the falling blocks, to ascend the glacier itself, I followed the lateral moraine, but soon came to the straits through which it squeezes itself. The walls on both sides for about a thousand feet were nearly vertical, and were scratched and polished. As it was not possible to pass these straits, I ascended the hill a few hundred feet, but found that the upper surface of the glacier continued charged with morainic accumulations as far as I could see. Behind the straits the valley enlarged to a basin, bounded in a straight direction by nearly perpendicular walls, at which the almost vertical stratification was visible. This magnificent wall, many thousand feet high, was perfectly bare of vegetation, and only in a few deep holes patches of snow appeared which otherwise would not have found any resting place. It was really a scene of wild grandeur. Main tributaries descended from both sides of the chain skirting this huge wall, and forming in the basin the trunk glacier. This glacier having an east-south-east direction is the most important feeder of the Forbes stream. Another stream, but of smaller dimensions, joins it in a straight line, with its general course, east-north-east, a few yards beyond where the principal stream leaves its icy vault. Not being able to find a ford I could only make observations from the point of junction. This second glacier, inferior in size, consisted of white ice, perfectly clear, no moraines of any kind reposing upon it. Only a few solitary blocks appeared scattered upon its pure surface. Vast snow slopes clothed the side of the range, stretching to the bases of the pyramidical peaks, rising above them in savage beauty with only page 8occasional deep snow holes in their steep sides. The gentle lines of this nevé, by which this second glacier was fed were, notwithstanding, clearly defined. It formed a concave saddle between the towering giants at both sides, only pierced throngh by a few sharp needles, and showing that the smaller joints of this comb were only concealed by the soft snow garment thrown over them.
All the same phenomena could be observed which invest the formation of glaciers with such a lively interest. The unbroken surface of the glacier was lower down rent and crevassed, a greater inclination had to be passed over, an ice cascade was formed, the towers and minarets of which stood in utter confusion during their descent, and contrasted greatly with the unbroken ice above. But soon the scattered masses were again brought near each other, they were welded together into a continuous sheet, and only now and then broad pinnacles of rock pushed their bold heads between the slowly descending ice streams, which uniting, formed at last the trunk glacier. Where the ice cascade occurred the colours of the ice were most lovely, azure blue being predominant; but also mixed tints between blue and green, and even changes into a deep green were met with. This second glacier had its terminus about 200 feet higher than the first one described, but it seemed that sometimes it descended a considerable distance lower. A sharply defined line on the side of the mountains running parallel with the glacier, and some 20 or 30 feet above, proved its greater dimensions and descent in some seasons. The mountain sides above that line were covered with graas and flowers, below it only shingle occurred; this line did not cease above the terminal face of the glacier, but continued for a few hundred feet lower, when it curved towards the river. It was evident to me that it owed its existence to the glacier, which in winter was not only higher in point of altitude, but also advanced further into the valley. The limit of descent of the glaciers was, as I observed by further examination, very much determined by the circumstance whether they were covered with moraines or not, the first ones being more sheltered from the sun's rays were always larger when reaching their termini, and invariably travelled farther down the valley than those of which the ice was unprotected.
It was not without a certain feeling of awe that I stood thus in the lonely wilderness, gazing in admiration at one of the most beautiful phenomena of nature, and this feeling was still heightened by remembering that never before had a human foot stood upon this spot. The page 9weather was most lovely, no clouds in the deep blue heaven; but in the afternoon, the wind, coming from the south-west, brought well-shaped cumulus, which appearing on the mountain summits, up which they seemed to have crept, instead of continuing their course, rapidly fell down the nearly vertical and ribboned walls, soon disappearing entirely from our sight, being condensed when they reached the nevé. We returned to our camp, and had a heavy thunderstorm during the night, the loud peals of thunder awakening a thousand echoes in the mountains, the wind was so high that we thought every moment our tent would break down. The river near our camp roared every moment louder and louder, and we could distinctly hear the boulders roll along its bed, borne on by the furious waters. Towards morning the storm subsided, blue sky was visible between the rapidly flying clouds, which followed each other in apparently endless succession. It being impossible to continue my researches up the swollen river I examined during the day the mountain side above oar camp and the descending streamlets. Their waters were already clear again, whilst the Havelock for many days continued to be not only very high, but also yellow and thick from suspended matter.
Having a long day's work before us, we started next morning before daybreak; the stars of smaller magnitude had already disappeared, and the first light very soon began to illumine the sky. The huge mountains round me stood in all their stern majesty, having a cold, steely and frozen appearance, but now the sun smote their highest summits with his golden beams, throwing a deep rosy hue over their vast snowfields. A wonderful change took place in their appearance, filling the soul with admiration and delight. Soon on our way, following up the main stream, we had a troublesome walk over boulders of very large size, nearly filling the valley, here a mile wide from side to side. The rise in the ground became now more visible, and the river, still high, dividing and uniting every moment, roared loudly. With every footstep new views were obtained. High upon the mountains considerable snowfields were visible, with glaciers of the second order descending to the steep sides, from which fine waterfalls hung like silver threads upon the mountain walls. The ranges grew gradually more gigantic, and the river which still had a general south-easterly by south course, here turned south-south-east, flowing along the main chain. At this turn it is joined by two other tributaries, coming also from large glaciers.
The valley from the turn became much narrower, and we had to climb every moment over rocks and ridges jutting into the foaming page 10water. For several miles the mountains on both sides were so very steep that no true glacier could be formed, and the same magnificent cascades continued therefore to descend into the valley. We had to wade some of these streams, which, notwithstanding they reached only to our hips, required all our strength to bear up against their enormous pressure. But now a new and more serious impediment presented itself in the shape of a large overhanging rock, along which the river rushed in great fury; we tried to round it, but the water was too deep, so that we were compelled to climb it. Looking down into the river below us we observed at another place a natural bridge over the river, formed by the remains of a huge avalanche, into which the water had excavated a cavern, and through which it was then flowing. Although the summer was already declining, it had hitherto resisted the sun's rays, which, it is true, could reach it only for a few hours during the day. It being impossible to descend, we had to climb up the face of the rocks higher and higher, till we were at last some 1000 feet above the river, when a magnificent scene was presented to us. Before us lay a broad valley running nearly north, on its western side the gigantic peaks of the central chain, on its eastern side, running parallel with it, another high range, both uniting six miles from our place of observation. Here a stern pyramid rose, towering with its pointed peak above all its neighbours. From both sides considerable glaciers descended, pouring their ice streams into the valley; those on the western side coming from a very large nevé lying at the base of this rocky giant. On both sides some fine waterfalls were formed by the outlets of several glaciers of the second order, of which one appearing to fall from a height of about one thousand feet, dissolved in mist before it reached the valley. Scarcely any sign of vegetation was here visible on the sides of the mountains, all seemed ruin, desolation, and destruction. Descending to the terminal face of the glacier I found it nearly 1500 feet broad, and 100 to 150 feet high, the glacier having for the first few miles only a slight inclination. The altitude of the outlet I ascertained from barometrical measurement to be 3909 feet above the level of the sea.
The high pyramidical peak from which the lateral chain between the Havelock and Clyde runs off in a south-east direction I named Mount Tyndall. It was nearly evening before my necessary bearings and observations were completed, and climbing back from the summit of the ridge, a last view was obtained; after which we descended to our camp. For several days I was occupied with surveying and geological re-page 11searches, and remained camped in the same spot; every change in the weather, sunshine and clouds, morning and evening, giving us new opportunities of admiring the astonishing scenery around us.
On March 18th we returned to Mesopotamia to give our horses rest and food, they disliking the snow grasses, having when camped near the head of the valley principally fed on the leaves of the Celmisia coriacea, the cotton plant of the settlers. After laying in a new supply of provisions we started again on March 22nd, selecting this time the eastern main tributary of the Clyde, which I had named the Lawrence. The bed of this river for several miles offered fair travelling ground over shingle reaches, after which, either large morainic accumulations or enormous shingle cones obstructed the course of the river to such an extent, that the water was confined to a narrow channel, through which we found it impossible to advance with the horses. We therefore camped about seven miles from the head of the valley, and started on the 25th of March in the early morning towards the glacier, the terminal face of which, after considerable difficulties, was reached about noon. Owing to the fact that the river had now assumed the character of a wild mountain torrent, often running between perpendicular rocky banks, or foaming over and between enormous blocks of rocks, we were often obliged to seek our road through the sub-alpine vegetation on the mountain sides. The growth of the scrub was in many places so dense, that it was necessary to walk literally on the top of it, the natural consequence being that we broke occasionally through, and then could only release ourselves with the greatest trouble and exertion. This denseness of vegetation occurs principally in those localities where the north-west winds have bent the branches in one direction, giving them the appearance of clipped hedge-rows.
Returning on the next day to the Clyde, I remained camped near the junction of the Lawrence with that river, in order to make a collection of fossils in the Mount Potts Range which I had discovered in my way up; whilst Dr. Sinclair with my servant returned with our horses to Mr Butler's station for provisions. It was when crossing one of the main streams of the Rangitata, which was rising rapidly, that my deeply lamented friend lost his life, trusting too much to his own strength. My servant returning to me with the sad intelligence that he had seen Dr. Sinclair enter one of the branches, but not observed that he reached the other bank we started immediately to see if it were not too late to give any assistance, page 12but finding that the river was now quite impassable near the spot where the accident had happened, we kept down on the left bank of the river towards Mr. Butler's station. Not being able to extricate ourselves in the dark amongst the swampy terrain above the junction of the Potts, we only reached it next morning. Before arriving at the station we met Messrs. John King and Frederick Shrimpton, of Timaru, who were on a visit at Mesopotamia, and who had started before daylight up the river to look for the rider of one of my horses, which had arrived late in the evening at the station with Dr. Sinclair's blankets fastened to the saddle. After a hasty meal we started again together up the river, when we found the body some 300 yards below the spot where Dr. Sinclair had entered the river.
We brought the body of my lamented friend to Mesopotamia, and buried him on March 29th. Near the banks of the river, just where it emerges from the Alps, with their perpetual snowfields glistening in the sun, amidst Veronicas and Senecios, and covered with Celmisias and Gentians, there lies his lonely grave. With almost juvenile alacrity he had climbed and searched the mountain sides, showing that, notwithstanding his advanced age, his love for his cherished science had supplied him with strength for its pursuits, until at last-, overrating his powers, and not sufficiently aware of the treacherous nature of alpine torrents, he fell a victim to his zeal. Great and deep was my sorrow, and with a saddened heart I had to continue alone the work upon which we had set out together.
Having to wait for the return of my servant whom I had sent to Christchurch with the necessary documents concerning this sad accident, I was only able to start again on April 9th to examine the head waters of the Clyde, the remaining third main branch of the Rangitata. For the first eight miles this branch has a broad shingle bed, over which we could proceed without any trouble, after which the valley narrowed considerably, the river sometimes flowing close to perpendicular rocks compelled us frequently to cross its channel; and although the water was very low, it gave us the greatest trouble, not alone owing to the rapid flow of the water, but also to the enormous boulders in the bed of the river affording only very treacherous footing to the horses. We camped at the junction of the McCoy, another important source branch from the north, finding here a little grassy spot. The view up this stream was most magnificent, it seemed as if the mountains on both sides, consisting of the same sandstones and slates as before page 13described, had been rent asunder, so that the river flowed through an immense fissure. The McCoy is five miles long, and besides several streams coming from glaciers of the second order, it is formed by the junction of three glacier streams, of which the central and largest issues from a glacier of considerable size, covered entirely with moraines, and passes between two huge promontories. The two others, descending from north-east and north-west, are without any moraines, they both descend from a large nevé lying at the eastern and western base of the central pyramidical peaks, from the southern recesses of which the main glacier descends. Their extremities lie again 400 to 500 feet higher than the former, owing to the circumstance that they are not sheltered by a thick deposit of debris like the central one. Also here, where the nevé ends, the ice is very much broken and crevassed, having most splendid bluish tints. It would be easy to ascend the north-western nevé, which seems to have an easy gradient, and would lead over a col into the Lyell glacier at the head of the western branch of the Rakaia. At one spot the snow exhibited the deep red colour, owing to the presence of Protococcus nivalis.
Another day was devoted to following the main stream to its sources It would be possible to ride to this glacier on horseback, of course only in autumn, and after a period of dry weather, although the boulders are often of enormous size, but by crossing and re-crossing it could be accomplished by an able horseman. I preferred leaving the poor horses behind, as they could find so little suitable food, to save them another day's heavy journey. Climbing along the precipitous sides of the mountains, and wading through smaller branches, we arrived after three miles of laborious walking, at the main glacier, filling up the whole valley, and presenting a very fine sight. The extremity of this glacier, the largest which I visited in this journey, presents a straight wall of an altitude of 150 feet, showing the usual bedding; the ice is very dirty, and many large boulders are imbedded in the body of the glacier itself. In the centre is a wide ice vault from which the stream rushes over huge boulders. The glacier is covered deeply with a moraine, consisting of blocks, often of a gigantic size, which fall when they reach its termination with a tremendous crash from the edge. During my stay, a block of at least 10 tons, just above the ice cavern, fell down into the water, dashing it high in all directions. In the perpendicular face of the glacier was a round hole 30 feet below its moraine roof, through which a little streamlet fell like water from the gutter of a house. page 14On both sides of the cave, lying closely to the ice, moraines were formed along which the explorer could climb.
The direction of the glacier is for the first mile from its extremity, north; its terminal face stretches obliquely across the valley, which is no doubt occasioned by the junction of another large glacier stream coming from the west, and here washing its base. The glacier from which this stream is derived lies in a deep gorge with nearly vertical walls, terminating about 150 feet above the Clyde glacier. Its extensive nevé lies at the eastern slopes of Mount Tyndall, opposite another nevé from which one of the branches of the Havelock glacier descends. A col with an unbroken snowfield would bring the Alpine traveller to the nevé of the latter. The breadth of the Clyde glacier is 1300 feet, but a line at a right angle with the valley would reduce it to 1000. I climbed the mountain side near the junction of the two glacial streams to have a better view of it, and could not cease to admire the exquisite wild beauty of the splendid scenery around me. It would be very difficult to give any idea of the varied shape of the mountains around. Needles are seldom seen, but huge pyramidical peaks frequently rise above the general line of the chain. Some of them are so precipitous that for several thousand feet no snow can cling to their walls, which stand above the dazzling garment at their feet in stern grandeur. Cumulus clouds at a great altitude came from the north-west, and the change from sunshine to shade gave an additional charm to their forms. I made the terminal face of the Clyde glacier 3762 feet above the sea, the mean of barometrical observations and of the boiling water apparatus, both agreeing within 23 feet. The water coming from the cave was of a deep semi-opaque blue colour, and had not the milky hue which such waters generally exhibit, the long continuation of fine weather having brought about this change. It was near sunset when I had finished my observations, and we therefore hurried back to our camp, but found that the river since the morning had risen a little; the difference in temperature between the cold night and the warm sunny day causing a greater waste of ice.
Having thus accomplished my work at the head waters of the Rangitata, I returned to Mesopotamia, where I was occupied for some days in packing my collections, which had been stored there, and sending them with a dray to Christchurch. On April the 26th I said good-bye to my kind host, and left this interesting locality, which offers to the physical geographer an endless page 15supply of valuable facts, and proceeding along the right bank of the Rangitata I arrived on the 28th at the Peel Forest station. On the way I examined the porphyritic zone in the McLeod range, and the tertiary outlier with seams of brown coal in Coal Creek, passing over the low saddle by which, in the great glacier period, one of the branches of the Rangitata glacier reached the Canterbury plains. For some days I was occupied with a geological exploration of Mount Peel, and a survey of the morainic accumulations in the banks of the Rangitata, after which I descended the river to the upper ferry, as owing to a heavy freshet it was impossible to cross it on horseback. I proceeded next across the plains to the Southern Hinds, which I ascended to its source, and after paying a visit to the Gawler downs, the geological structure of which proved of considerable geological importance, I crossed the Northern Hinds and Southern Ashburton, and reached the Mount Somers station on the evening of May 9th. On the outlying spur of the small terraced hill between the two last-mentioned rivers, I found that some large rocky projections, the so-called Two Brothers, consisted of palagonite tufa, a very interesting volcanic deposit, which was hitherto known only to exist in a few other localities in the Northern Hemisphere. Having devoted some days to an examination of the extensive porphyritic zone of Mount Somers, and the tertiary beds at its base with the picturesque limestone caves washed out in them, I again ascended the Southern Ashburton on May 11th, to the junction of the River Stour. Following this tributary to the saddle by which the Upper Ashburton plains are reached, we had from this spot a most beautiful view. Immediately in front of us a small nearly circular lake lying between the moraines, which here cross the valley from side to side, enlivened by numerous waterfowl, formed a charming foreground, the middle portion consisted of the Ashburton plains with its lakes and water-courses, above which the wild serrated Arrowsmith range, covered with perpetual snow, rose majestically into the glorious evening sky, illuminated brilliantly by the last rays of the sun. On the 13th of May I crossed with my pack-horses the Ribbon-wood range, which is here over 5000 feet high, in order to reach the valley of the Ashburton near its sources. Owing to the great steepness of that range on its western side, where the horses had to be led down amongst rocky precipices and moving shingle reaches, we had the greatest difficulty in reaching the bottom of the valley, and it was quite dark before a suitable spot was found where the tent could be pitched. Next evening we camped at the highest spot in the page 16valley, where there was some grass for the horses, and proceeded the following day to the glacier at the head of the valley, the outlet of which forms the principal source of the Ashburton. We had to climb for some distance amongst large blocks of rock before the glacier was reached, the terminal face of which I found to be 4832 feet above the level of the sea. This glacier, although smaller than those at the head of the principal branches of the Rangitata, is exceedingly beautiful. The ice is quite pure, and is broken half a mile above its termination into numberless fine seracs, forming one of the most splendid ice cascades I ever saw. On both sides the mountain slopes are very precipitous, consisting often of nearly perpendicular walls of rocks several thousand feet high, which offered an instructive insight into the geological structure of that stupendous mountain chain. The weather was exceedingly favourable, fine cloudless days, rendering travelling quite an enjoyment; but the nights were here so very cold that the water was frozen Every morning in the pools near our tent.
To reach again the Upper Ashburton, I followed the river to the point at which it enters these plains. We had some very deep and rocky gorges to cross, but found the scenery very picturesque. Another week was devoted to an examination of the Clent hills, where I made a rich harvest of impressions of fossil ferns; I also descended Trinity valley to its junction with the Rangitata, where small coal seams in the palæozoic rocks, like those of the Clent hills, raised my hopes that large and workable seams might be discovered if I persevered in my search; and finally I visited Lake Heron, with its remarkable sugarloaf hill, a fine roche moutonnée, and its neighbourhood. The winter, with mist, rain, and snow, had now fairly set in, and I was therefore obliged to retreat to lower regions, leaving with great regret the magnificent alpine scenery which for several months past had afforded me so much instructive enjoyment. On June 1st I started on my return journey, and reached Christchurch on June 5th.