H.—34.

Along the eastern margin of Lake Wakatipu remnants of the gravel terraces can be traced, though in places they are no more than a veneer over the schist. They are best developed at the old fans the streams formed when the lake was at a higher level, as, for example, at Shepherd's Hut Creek, where three distinct, even steps can be observed rising to a height of some 150 ft. above the lake. The creek, like the others in the district, has entrenched itself in the fan and is actively engaged in building a fresh delta at its present mouth. Where the streams, including Rough Creek, flow into the lake round the southern end of Trig. G ridge they also have entrenched themselves in the terraces, which have risen to 170 ft. above the Lake, showing no less than seven distinct levels. The greatest development of the gravel terrace is to be found from Stone Creek to point southeast of Glenorchy. The development of three distinct levels is again noteworthy and is especially clear on the north flank of " The Bible " —a triangular remnant of the old delta of the Buckler Burn, some 50' acres in extent, which rises in steps of 60 ft., 130 ft., and 170 ft. above the lake-level, A small creek has cut deeply into the gravels, exposing some fore-set bedding together with bands and lens of fine-grained lake-beds. Along the southern bank of the Buckler Burn, where a 120 ft. terrace is exposed for nearly a mile, finely-developed fore-set beds are shown dipping to the west at about 25° to 30°. At the point where the terrace commences to rise toward the higher level gravel, an example of back-set bedding similar to the fore-set, but dipping to the north-east, was observed. The main terrace rising to 170 ft. level can be again seen at Temple Creek ford, where small remnants have escaped erosion, near Scott's homestead about a mile and a half north of Temple Creek, and at Twelve-mile Creek. These terraces correspond in all their characteristics to those developed at " The Bible." The remaining occurrences of the 170 ft. level terrace is in the vicinity of the Bees Bridge and Camp Hill, where a large area has been preserved between Lovers' Leap and Camp Hill. This can be traced from the mouth of the Earnslaw Burn valley along to the Jordan Creek, and on the opposite side, at the base of Mount Alfred at Paradise, a corresponding terrace remnant was observed. As a considerable area of this large terrace has been removed by erosion it would suggest that a fairly large river was responsible, and as all the present streams flowing on the gravel flats of the Lower Bees valley are small and would be incapable of removing such a vast amount of gravel, the suggestion that the Dart at one time flowed through at Paradise to the present Rees valley must be seriously considered. This view is strengthened by the structure of the gravels on the Paradise Saddle and by the 170 ft. terrace occurring on both sides of the valley. The actual reason why the Dart chose this course in not clear, but the possibility of the Routeburn having blocked the Dart valley with an enormous fan should not be overlooked. At higher levels than the 170 ft. level considerable gravel deposits occur, the best example being at Chinaman Flat, where the valley lying between the Trig. D ridge and the main mountain ridge is completely filled with gravel similar to that of the other terraces. From Chinaman 40 ft. terraces can be traced round the southern end of the Trig. D ridge and can be observed to spread out and extend down to the 170 ft. terraces. Extensive patches of high level gravel are to be found between the Mount Judah Road and the Buckler Burn. These correspond to those on the opposite slope and seem to be an old delta of the Buckler Burn, built when the lake was at a higher level than it is to-day. Patches of similar high level gravels occur on the hillslope between Temple and Twelve-mile Creek at about 1,000 ft. above the lake-level. In the Upper Rees valley 40 ft. to 50 ft. terraces have been cut in the gravels which were deposited by the Rees at an earlier stage of alluviation. These terraces are particularly well developed north of Muddy Creek. Similar terraces were also observed in the upper valley of Earnslaw Burn. From the evidence afforded by the gravel terraces just described it seems safe to conclude that Lake Wakatipu was about 170 ft. higher than its present level and must have remained at that level for some considerable period, thus enabling the main streams to build out their large deltas. This level corresponds with terraces occurring at other points around the lake and with the Kingtson Moraine at the southern end of the lake. The relation of the higher gravels to the lake-level must remain for the present an unsolved problem. Economic Geology. Scheelite. —The production of calcium tungstate or scheelite, an ore of tungsten, has for many years been the chief mining activity, its value and quantity making it an economic mineral of first importance to the district. During the late " eighties" the Wakatipu Scheelite Co. pioneered the mining for this mineral at Mount Judah, producing 18 tons of ore, for which was received the net price of £12 per ton. In 1892 the price fell and production ceased. It was not until the early years of this century that the production again took an upward trend, a certain amount of alluvial scheelite being produced from the Buckler Burn, Precipice, or Temple and the Twelve-mile creeks in response to the increasing overseas demand. During the year 1906 the newly formed Glenorchy Scheelite Co. reopened the original mine on the Glenorchy lode, Mount Judah, producing 13J tons of concentrates. As the overseas demand and price steadily increased, the scheelite production of the district rose in accordance, resulting in a considerable number of new claims being worked, some by the Glenorchy Scheelite Co., or Syndicate as it was known after 1911, and others by independent parties of miners. This production reached its maximum in 1917, when 116|-tons of concentrates valued at £22,753 was shipped from Glenorchy. After

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