Search foe Coal in the Ashburton and Rangitata Districts and Continuation of Geological Survey, 1864.

Having during my surveys of 1861, near the head waters of the Rivers Rangitata and Ashburton, met with large fossiliferous beds of probably young palæozoic age, situated about sixteen miles apart from each other, amongst some of which a few small seams of fine coal were exposed, I was not then able to spare so much time for their investigation as I should have wished, the winter with heavy snowfalls having set in. A set of the fossil shells and plants collected during that journey in the localities in question, were sent by me to the well-known palæontologist, Professor F. McCoy, in Melbourne, for examination, who informed me that they were nearly all identical with those that accompany the Coal measures of New South Wales. I therefore proposed to devote some time towards a more detailed examination of the country referred to, and started in the middle of February (1864), for that district, beginning my surveys at the upper course of the River Hinds. Having ascended, first the southern, and afterwards the northern branch, to their sources, I examined afterwards the Gawler downs, a separated series of hills, consisting mostly of a large number of streams of melaphyre. Another day was employed in visiting the gorge of the Rangitata, where, in the vertical walls, beautiful sections are laid open, and where some of the most interesting phenomena in connection with the Great Glacier period of New Zealand can be studied. On February 24th I left the Hinds, and proceeded towards the sources of the Cameron, a river which joins the outlet of Lake Heron, shortly after it issues from this lake, both forming the South Rakaia branch. Having crossed the extensive morainic accumulations round this pretty lake, we reached the large shingle fan of the Cameron, which, together with another of nearly the same size, coming into this valley from the opposite side, has given its present form to the lake. Here travelling was easy, until we reached the gorge-like valley of the river page 61itself amongst the high ranges. We now entered into a truly alpine region, and were surrounded by a rich vegetation, which grew also most luxuriantly along the mountain slopes for a considerable altitude. In front of us rose the majestic Arrowsmith range, the crenellated bold outlines of which were brought out still more prominently by a cloudless deep azure sky above us. Numerous snow-fields nestled on its flanks, from which a glacier of considerable proportion descended into the valley. About four miles from the glacier we had to camp, as it was impossible to take the horses any further, owing to the valley being often filled with enormous blocks of rock on both sides of the river channel, which itself became occasionally very rocky.

On February 27th we ascended to the glacier, which in honour of my companion during this journey, the Hon. J. Hawker, Speaker of the House of Representatives of South Australia, I named the Hawker glacier. This glacier, which is formed of two main branches, uniting about 1200 feet above its terminal face, descends to an altitude of 4478 feet above the sea. Its terminal face is 1500 feet broad, and the river issues from an ice cave about twenty feet high; it is only separated by a narrow but high rocky ridge from the Ashburton glacier, and surrounded by walls several thousand feet high, exhibiting well the stratification of the alternating sandstones and slates. Returning to Lake Heron, I remained there for several days to study the geological features of the surrounding country. The shores of this little lake are very characteristic, and give a clear insight into the great glaciation of the district, roches moutonnées abounding in its neighbourhood, of which the so-called Sugarloaf, a nearly perfect cone, 3822 feet above the sea, or rising 1557 feet above the lake on its eastern side, is the most conspicuous. I also made here, as afterwards in the Upper Rangitata district, a number of observations with the spirit-level, which proved that the numerous terraces, of which some occur as high as 5200 feet along the mountain sides, were not of marine origin, but simply either old morainic accumulations, remains of ancient river-beds, or the deposits of small glacier lakes—the waters of which were stowed up at considerable altitudes by the enormous ice streams, during their greatest extension. Nearly a week was devoted to a search for coal in the Clent Hills, but I was not able to find any larger seams than those previously observed, which only owed their existence to the presence of large flattened endogenous trees, the bark of which had been altered to coal. On March 12th I proceeded to the Rangitata, where, during a fortnight, I continued my search for page 62coal in the Mount Potts range, in Mount Harper and other ranges; where rocks similar to those of the Clent Hills were observed by me, but without obtaining any more favourable results. Large collections of fossils were however made, and the observations on the glacial phenomena, here on a truly gigantic scale, continued. Finally, I visited the River Stour, a tributary of the Ashburton, where two years ago I had found a large rolled piece of green carbonate of copper, when I was returning to Christchurch during snowy weather. For several days I searched over the whole part of the range from which it might have come, but without success, and I arrived at the conclusion that it had been washed out from the morainic accumulations close by, and brought from the sources of the Rakaia. At the beginning of April, I returned to Christchurch.