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Dimension Stone. —There was a considerable expansion in the production of stone for building and monumental work during 1948, 22,319 tons being produced, as against 14,528 tons during 1947. This increase is due entirely to the marked expansion in the production of Oamaru building-stone, of which 20,179 tons were produced, as compared with 2,932 tons in 1947. Small amounts of granite from Coromandel and Bluff, sandstone from Charteris Bay, Lyttelton, and marble from Hanmer of approximately the same order as in 1947 were produced during the year, but there was a marked decrease in the production of Milestone, which was practically confined to Christchurch quarries. Salt. —Continued progress was made in the development of an area at Lake Grassmere, where salt is to be produced by the solar evaporation of sea-water. As yet there has been no production of salt in significant amount, but the Government, after consideration of a report by an overseas engineer experienced in the production of salt, has decided to take a substantial interest in the project. General. —Small amounts of quartzite, fuller's earth, and diatomite were produced during 1948, while sand, gravel, rock, &c, for various uses, such as building aggregate, road-construction, &c, were produced in quantity and accounted for the major portion by volume of the production of quarries. GEOLOGICAL SURVEY The Geological Survey issued a revised geological map of New Zealand on the scale of 16 miles to an inch and an accompanying explanatory forty-eight-page booklet summarizing the main features in New Zealand geology. The central volcanoes of the North Island were again the scene of activity, and on Bth February Ngauruhoe erupted and continued to sth March ; no damage was done. Geologists are now working in four of our coalfields —Invercargill, Mataura, Balclutha, and Greymouth—and will soon be at work in three more —Huntly, Ohura, and Mokau. Recent geological field-work shows that no workable coal crops out in the coal-measures of West Southland along the south-east of Fiordland. To find how much lignite can be worked opencast in Southland, holes are being drilled at Mataura. In Kaitangata recent work indicates that workable coal does not extend beyond Tuakitoto in the west and Taratu in the north, but that the prospects in the east side of Kaitangata and near Benhar are bright. Heaphy, Karamea, Collingwood, Murchison, and Garvey Creek Coalfields have been, and Reefton is being, examined. Limestones for dusting the coal-mines were examined in the West Coast. Parts of North Auckland, Rotorua, East Coast, Canterbury, and Southland are being geologically examined and mapped. At Wairakei and Tokaanu, wells were drilled for hot water. Dam-sites were investigated along the Waikato and at Taupo and foundations at Murupara. To investigate how to find and utilize underground steam, the director visited Larderello, and work is going ahead in Rotorua. A magnetometer survey has covered Tikitere and is being extended. Pakotai copper was studied electrically, but the neighbouring areas showed no other similar deposits. By testing the Canterbury Plains by electric restivity the ground water and seepage irrigation water were detected more efficiently than previously.

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