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11. TAUMARUNUI AS A POTENTIAL OIL-FIELD. (By L. I. Grange.) Between the 10th and 17th December the writer stayed at Taumarunui and examined the country for several miles in all directions to ascertain whether there is a likelihood of oil-pools being present. Mr. E. R. Martin, of Taumarunui, who knows the district well, accompanied the writer on all his trips and pointed out his discoveries. General Geology. • The following beds, in defending order, occur in the district: — Mokau beds —argillaceous sandstone. Mahoenui beds—alternating mudstone and sandstone, with pebbly limestone and conglomerate at the base. Mesozoic beds —greywacke and argillites. The oldest rocks are greywackes, argillites, and grits of Mesozoic age, which outcrop in the Mangakahu, Taringamutu, and Pungapunga valleys. The exposure in a branch of the Taringamutu five miles up from the Ongarue Stream appears to be faulted up. The writer did not see the outcrop, but was informed of its presence there by the Taumarunui County Clerk. The beds are shattered, and consequently strikes and dips could not be obtained. Lying with great unconformity on the Mesozoic strata are the Tertiary beds. At the bottom are shallow-water deposits, consisting of greywacke conglomerate, pebbly limestone, and calcareous sandstone. Patches of these beds, totalling about 100 ft. in thickness, lie on the upfaulted block of greywacke in the Taringamutu valley. In the Pungapunga conglomerates (about 25 ft. thick) were found. These beds are the basal members of the Mahoenui Series, or possibly belong to the underlying Te Kuiti Series of the Mokau Bulletin. Resting on the beach beds is a thick series of alternating mudstones and sandstones belonging to the Mahoenui Series. Generally the mudstone bands are 18 in. thick and the sandstone 4 in. Al2 ft. band of sandstone outcrops near the mouth of the Taringamutu, but thicknesses greater than 1 ft. are rare. In places, as at Piriaka and near the end of the Taringamutu Road, the sandstone bands are absent. The beds, which outcrop over a wide area, have,, according to the observations made, a westerly dip averaging about 6°. Their total thickness is probably between 6,000 ft. and 7,000 ft. West of the Ongarue River the Mahoenui beds are overlain by the Mokau beds, composed of argillaceous sandstone, and these in turn by strata referred to the Mohakatino Series. Supposed Indications op Oil. Mr. Martin showed the writer a weak gas-vent on Mr. Ingram's farm, on the Wanganui River Road, two miles south of Taumarunui. A rod was pushed down about 18 ft. in a swampy abandoned course of the Wanganui River, and when it was withdrawn gas bubbled up for three or four minutes. The gas burnt with an ordinary flame. After it ceased to bubble up, the rod was pushed down again, but no gas came up. A sample of the gas sent to the Dominion Analyst was found to have the following composition : — Per Cent. Carbon dioxide C0 2 .. .. .. .. 4-23 Methane CH t .. .. .. .. 33-11 Oxygen 0 2 .. .. .. .. 0-39 Nitrogen N 2 .. .. .. .. 61-97 100-00 Several strong salt springs issue from the limestone and conglomerates resting on the greywacke in the Taringamutu valley, but occurring thus they cannot be taken as evidence of the existence of oil. The irredescent films on the surface of the stagnant water at many points are iron oxide, and are not indications of oil. Prospects of Oil. In considering oil in the Taumarunui district, only the Mahoenui beds have to be taken into account. The Mahoenui beds do not contain any thick reservoir rocks ; the limestones and conglomerates are tight. The observations of the structure of the series do not indicate a favourable structure for the accumulation of oil, and the prospects of obtaining oil in the Taumarunui district are decidedly poor. DOMINION OBSERVATORY. REPORT OF THE DOMINION ASTRONOMER AND SEISMOLOGIST FOR THE YEAR 1929. Buildings and Equipment. The buildings and equipment have been kept in good order and condition. The Observatory grounds have been kept in good order by the Wellington City Corporation. Astronomy. Astronomical Observations. Observations of the meridian transits of stars and the sun have been made for the purpose of controlling the time service. The meridian transits of the sun are observed on every fine day, except on Saturdays, Sundays, and Government holidays, and the stars are observed whenever necessary.

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