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Salt.—Further progress was made in the development of the project whereby salt is to be produced by solar evaporation of sea-water at Lake Grassmere, but there was no production of any significance during the year 1949, though this is confidently expected to be reached during the present year. General.—Small amounts of quartzite and diatomite were produced during 1949, while sand, gravel, rock, &c., for various uses such as building aggregate, roadconstruction, &c., were produced in increased amounts and accounted for the major portion of the production of quarries. GEOLOGICAL SURVEY Regional surveys of the Motatau Subdivision, in North Auckland, and Hauroko Subdivision, Southland, have been completed, and the bulletins are in course of preparation. Bulletins descriptive of the geology of the Dannevirke and Wanganui Subdivisions and of the Heaphy, Karamea, and Geraldine provisional one-mile sheets, as well as one of the coastal area between Bruce Bay and Haast River, await publication. Other sheets descriptive of West Coast geology are in course of preparation. A palseontological bulletin on the Tertiary and Recent Ostracoda of New Zealand also awaits publication. Regional surveys in Southland, Hawke's Bay, and North Auckland are proceeding. A district office at Ngaruawahia was established in September as headquarters for the detailed survey of the Waikato Coalfield. The survey of the Kaitangata Coalfield has advanced considerably and the supplementary survey of Ohai field is practically complete. Activity on the West Coast has been confined to Reefton, Garvey Creek, Fletcher Creek, and Punakaiki Coalfields. Several cyclostyled reports on the survey of the coalfields were issued during the year. Systematic observation of wells and springs in the Rotorua-Taupo area was continued throughout the year, and a concentrated effort is under way, in co-operation with the Ministry of Works, to test the Wairakei areas as a possible source of steam for generation of electricity. Water-supply problems for local and public bodies as well as for Government Departments and industrial and private supplies have been reported on throughout New Zealand. A paper on the " Conservation and Protection of Underground Water in New Zealand " was prepared for the International Water-supply Association. The preliminary gravimetric survey of the North Island is completed, and indicates that the newly acquired gravimeter will prove an invaluable instrument for interpreting geologic structure. Seismic and magnetic methods were employed to investigate dam-sites for the State Hydro-electric Department in both Islands and electric logging of drill-holes undertaken. Additional investigations carried out during the year included limestones at many localities throughout the country for agricultural lime and cement manufacture ; greywacke and basalt for aggregate in the Waikato ; sands for glassmaking and moulding in Canterbury and Otago ; serpentine for the fertilizer industry at Wairere ; clay for Ceramics at North Auckland and Orepuke ; bentonite for general purposes at Waimarama and Masterton district; greywacke for coastal and river protection at Kaikoura ; clay and decomposed greywacke for bricks at Tawa Flat; tuffs for pozzolanas at Oamaru and Te Kuiti; antimony at Alexandra and Bannockburn ; copper sulphide at Waitahuna ; diatomite at Middlemarch ; ironsands at Cape Foulwind ; suitability of rocks as aggregate with high and low alkali cement and with bituminous mixes.

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