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Tertiary (?).—White clays interbedded with thick bands of lignite cover considerable areas in the. Pomahaka basin. They are tentatively placed in the Upper Tertiary. Pleistocene and Recent. —Among the Pleistocene and Recent beds are the terraces of the Pomahaka, Molyneux, Waipori, and Post Office Streams, the Taieri, Tokomairiro, and Clutha Plains, the dunes along the coast, the heavy gravels above Jubilee Mine, and Shiel's sand-pit and at Kaikorai mouth. These include beds of lignite, white clay, and auriferous gravels. Igneous Rocks. —Tuapeka Scries contains red and green schists that probably are metamorphosed igneous rock. The Clinton conglomerate contains igneous boulders of unknown origin. A coarse pink feldspar porphyry crops out in the greywacke a mile and a half north of west from Otanomomo, a township four miles south of Balclutha, exposing about 10 ft. by 15 ft. of rock. Decomposed darkgreenish coarse-grained igneous rock forms a cliff to the left bank of Puerua Stream, a mile and threequarters south of west from Otanomomo. It apparently stands vertical, bedded in the greywacke In the Clinton greywacke, too, half a mile south-east from Waitepeka vesicular basalt crops oul along the small stream, and also a quarter-mile farther east just east of the road, and again another quarter-mile farther on. In several places as mapped fresh basalt breaks through schist, and is not in contact with younger rock. Similar basalt breaks through the Kaitangata conglomerate and the Taratu conglomerate. A quarter of a mile west of Lake Waihola two peaks of basalt agglomerate lie on the schist. Waihola Hill, Trig. L, Cemetery Hill, Trig. D, and the other peaks a mile and a quarter north-east, east, and south-west of Milburn Railway-station, and also the low hills alongside the railway near Allanton and Owhiro rest on schist. These are probably not older than the nearby volcanic rocks that rest on the Dowling Bay limestone considered by Finlay and McDowell as equivalent to Target Gully beds. Economic Geology. The district contains many large deposits of clay, some of which are being used. The mapping shows the extent of the formations in which each deposit occurs. Beds of conglomerate and sand abound, many consisting of clean quartz used for different purposes in industry. The schist, greywacke, igneous rocks, sandstone, and limestone have all been used as building stone. Rocks suitable for road-metal are abundant. The Milburn limestone and the Burnside calcareous mudstone are used for cementmaking. The limestone has been of great agricultural value on the Taieri Plains. It is still in demand as also is the phosphatic part of it. The Dominion Co. grinds together the limestone, phosphate, and greensand and produces a satisfactory fertilizer. Coal has been known in the subdivision since 1844. The extent of the coal-measures is shown on the maps. [( _ The " quartz grits" and " cements" of the miners, represented on the maps as Taratu conglomerate" and " Kaitangata conglomerate," are not known to contain payable gold in the subdivision. TONGARIRO DISTRICT. (By L. I. Grange and J. H. Williamson.) The district here described lies between Lake Taupo on the north and Waiouru on the south, and extends eastward from the Wellington-Auckland Main Trunk Railway to the Kaimanawa Mountains It includes the Tongariro National Park, and forms the southern portion of the active volcanic belt of the North Island of New Zealand, progress reports on the survey of which were published in the Geological Survey Annual Reports Nos. 21 to 24, for the years 1927-1931. Structure and Physiography. Structurally the district consists of an eastern highland of Pre-tertiary greywacke, which is part of the Kaimanawa Range, and a western plateau of younger Tertiary rocks which is part of the central plateau of the North Island. This highland area, the Kaimanawa Range, is a raised block here bounded by strong faults, the chief evidence for which is physiographic. From a distant aspect the range is even-crested, the peaks rising from 4,500 ft. to 5,000 ft. above sea-level, and there are remnants of a mature upland surface not yet destroyed by erosion. The highlands, which increase in height northward beyond the district, are drained by streams that issue from them by way of deep narrow gorges. The Kaimanawa Range is the watershed between the Hawke's Bay drainage system on the east and the Waikato and Rangitikei Rivers, the former of which draws water from the northern half of their western front and the latter from the southern half. The western plateau, which occupies more than three-fourths of the district, is here formed of Tertiary beds lying horizontal or dipping gently westward and overlain with volcanic debris. From it rise the volcanic piles of Ruapehu, Ngauruhoe, and Tongariro and dominate the landscape. From their tops the essential flatness <>f the plateau both within and beyond the district is clearly seen, but at close quarters its surface is extremely broken.

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