11

C—ll

I.—Recent. In the Lower Aorere Valley the Recent alluvial deposits constitute farming lands on both sides of the river. The bed of the river is known to be auriferous, and for a time a dredge was at work on it; but this was of insufficient power; and, besides, objections to its working were raised by the settlers on the banks of the river, and compensation not being granted by the Government, this also may be a cause why dredging has been discontinued. Above the junction of Appo's and Stanton's Creeks the banks of the river have in places been worked for gold, and in the recent gravels of the beds and banks of the Slate River, and most of its tributaries, gold-workings have been carried on since the early days of the Collingwood Goldfield. There is in the vicinity of Rockville a considerable breadth and area of gravel-terraces which, though now considerably higher than the bed of the river, are by Park—and I believe rightlyreferred to the Recent period. Above the Suspension Bridge, on the road to the Quartz Ranges, there are recent deposits on both banks of the river; but of these the more important lie on the left bank, while behind these rise higher terraces of gravels that are properly referred to the next older series. In the Parapara watershed the low flats at the head of the Inlet belong to this series. The Parapara Hydraulic Sluicing and Mining Company during the past year erected ah elevating plant to work an area of these deposits held by them. The drifts thus intended to be worked have resulted mainly from the destruction of the gravel and cement hills that lie to the westward between Washbourne's Flat and the Lower Parapara River. This flat forms a portion of the area reported on by Sir James Hector in 1890, and the elevating-plant has been erected at the further or northern end of No. 3 lead, of which Sir James says : " The gravel of No. 3 lead seems, therefore, to have been dispersed in a thin layer over an area of about forty acres, and a rough estimate of the contents gave 2,000,000 loads, which, at 2dwt. per ton, would give a value of £800,000." When I visited the locality during the present year the elevating-plant had just been erected, and was scarcely more than in working order. A shaft had been sunk from which it was said a good prospect had been obtained—a prospect greater than would be required to warrant Sir James Hector's estimate of the auriferous contents of this area. However, on account of the shaft caving in, this prospect, taken by one of the workmen, could not be confirmed personally by the manager. The elevating-plant, after being completed, was at work for some time, but the result has not yet been made public. The general opinion is that the ground did not turn out as rich as anticipated. Appo's Flat has a deposit of recent gravels swept down from the upper part of the watershed and deposited partly on the felspathic sandstones and slates, towards the upper end of the flat, and partly on beds of auriferous quartz-drift underlying on the middle and lower parts of the flat. These recent gravels along the creek, and at the upper, end of the flat, yielded in the early days a considerable amount of gold, and Mr. F. West, who, for a considerable number of years has been the only miner on the flat, followed the gold-bearing superficial wash by driving to the dip as far as the water would admit or the ground could, with the means of draining it, be profitably worked. Mr. West informs me that, from first to last, a value of about £5,000 has been taken from Appo's Flat. This is irrespective of the gold obtained from the gorge of the creek above Appo's Flat, and from the upper valley of the creek as far as the Red Hill battery site, which was a considerable amount. The gold in Appo's Creek, and the superficial auriferous deposits over Appo's Flat, has clearly not been derived from the felspathic sandstones and slates, and quartzites of the neighbourhood, but from the quartz-drifts and coarser conglomerates occurring as deeply-involved strata along the upper valley, of Appo's Creek, and also present on the hills surrounding Appo's Flat, as well as underlying the recent drifts of the flat itself. A portion of the gold won from Lightband's Gully was obtained from the recent gravels of the bed of che creek ; but this was directly and immediately derived from the older quartz-gravels that corresponds to those of the lower Parapara, and Golden Gully at the other, or south-west, extremity of the line of involved strata. Several localities to the north-east of the Slate River, notably Golden Gully, Macgregor's Creek, and Lightband's Gully, have derived their auriferous gravels from the underlying or neighbouring older quartz-drifts by a process of denudation and concentration that thus produced, as a special example, the rich superficial drifts of the northern part of the Golden Gully area. As the older deposits, from which the more recent have been derived, will have to be described under another heading, further reference to the more modern derived deposits is unnecessary. In the Slate River, and its many tributaries, gold has been traced to beyond the line of Golden Gully, the Castles, and the Quartz Ranges ; and, what is remarkable, as the streams are followed to the south-east of the line of involved strata, the gold is of a finer grain than north-west of or below the line. ll.—Pleistocene. These rocks have their principal development in the lower Aorere Valley, where they form broad, swampy terrace flats, or pakihis, that constitute very uninviting country from an agricultural, or even a pastoral, point of view r . These beds are, however, to some extent gold-bearing, and one or two gullies immediately south-west of Collingwood have been prospected, and decided indications of a paying prospect obtained. Lashes claim, near the junction of Appo's and Stanton's Creeks, may show the presence of recent gravels, but, preferably, I have considered them as Pleistocene. The same indefiniteness also applies to the classification of the gravel terraces between Doctor's Creek, the Slate and Aorere Rivers, but it is really a matter of little consequence whether particular gravel deposits, of which there may be doubt, are referred to recent or Pleistocene. I have shown an area of Pleistocene gravels between the Lower Kaituna and the Aorere, because they are evidently and manifestly distinct from the gravels of the lower flats and alluvial deposits along the river. Mr. Park has mapped the same beds as Recent (see map and report of 1889, " Geological Reports "), while under Pleistocene he has included a variety of deposits that are of