THE NEW ZEALAND OFFICIAL YEAR-BOOK, 1928

It has been acknowledged by the leading hydrologists in Europe that New Zealand possesses the most valuable mineral waters in existence. Not only are these mineral waters interesting from a tourist's point of view, but they are, because of their medicinal value, of great therapeutic importance, and, as a Dominion asset, worthy of the deepest scientific consideration.

From the spectacular aspect only a brief mention need be made in this article, as a full description of springs, geysers, and mud-pools has been given in Dr. Herbert's book, “The Hot Springs of New Zealand”—a book that presents a comprehensive and vivid picture of the main manifestations of thermal activity in New Zealand.

Dealing with the medical-scientific aspect of the mineral waters, the space of this article will permit only the shortest account of the treatments; and, as the Rotorua Spa is of premier importance, the article will be confined almost entirely to its operations.

Since and as the result of experience gained during the war the subject of hydrotherapy has been recreated on modern scientific lines, and the actions of thermal mineral waters have been investigated, both chemically and physiologically, in determining their therapeutic value in the treatment of disease.

The mineral waters which have been harnessed for therapeutic use at the Rotorua Spa are of two main varieties—viz., the “Rachel,” winch is an alkaline. sulphuretted water, emollient to the skin, and sedative in reaction; and the “Priest,” or free-acid water, which, due to the presence of free sulphuric acid, is mainly stimulating and tonic in reaction. There is, in addition to the foregoing, a valuable silicious mud similar to that found in Pistany, in Czecho-Slovakia, which, in its own sphere in hydrotherapy, exerts its influence as a curative agent.

However, it is in the “Priest” waters that one finds one's most valuable ally in the treatment of arthritis, fibrositis (the so-called rheumatic affections), and cases of nervous debility. The “Rachel” and mud baths are used mostly in those cases of fibrositis where the condition requires a softening effect; and in the types where pain is a manifest symptom these baths are invaluable as soothing and sedative agents.

In these natural acid baths the reactions are mainly stimulating, with increased hyperæmia in the parts submerged, and marked lessening of pain and swelling in the affected joints and tissues. Those waters containing free carbonic-acid gas are used for the oases of fibrositis in which the circulation requires the stimulating action of gaseous baths.

The “New Priest” waters, containing approximately 16.80 grains per gallon of free sulphuric acid, are utilized in the form of open pools, deep step-down baths, and slipper baths. They are prescribed at a suitable temperature for the individual case.

The “Old Priest” waters, containing a much lower degree of free acid (3.77 grains to the gallon), and of varying temperatures (from 84° F. to 102° F.), are used for treatment at their source. The waters, percolating through their pumice - bed, are confined in pools, and contain free carbonic-acid gas bubbling through the water.

The very strong “Postmaster” waters are also confined within pools on the natural pumice - bed, and, by a primitive arrangement of wooden sluice-valves, maintained at three ranges of temperature—viz., 104°, 106°, and 108° F. They contain 22.29 grains of free sulphuric acid to the gallon, and are strongly counter-irritant in their reactions.

In such a brief account as this one can only deal in generalizations, and the forms of treatment mentioned must necessarily be subject to wide variations. In any form of hydro-therapeutic treatment the regime must be adapted to the individual manifestations of the disease, and no routine rules or regulations can be laid down in spa operations.

The “New Priest” waters are, for the most part, prescribed for patients suffering from subacute or chronic fibrositis, subacute or chronic gout, and the various forms of arthritis. Except in cases of marked debility, those patients are given graduated baths, at temperatures ranging from 102° to 104° F., from ten to fifteen minutes daily. Most of the baths are fitted with a subaqueous douche having a pressure of 25 lb., which is directed under water on the affected tissues. The bath is usually followed by a light or hot pack, according to the needs of the case.

The subthermal “Old Priest” waters (temperature 84° F.), containing a high degree of free carbonic-acid gas, are particularly valuable in the treatment of functional nervous disease, and the methods of administration are similar to those obtaining at Nauheim. The reactions are markedly stimulating through the sympathetic nervous system, and bring about, by reflex action, a tonic effect on the heart.

The “Postmaster” baths are used in the treatment of the more chronic forms of fibrositis, arthritis deformans, and gout, requiring a more or less heroic type of procedure. They are usually prescribed in combination—i.e., a certain time in each pool, commencing with the lowest temperature. The hyperæmic reaction is most marked, and in many of the oases where pain is a predominant symptom there is a temporary paralysis of the surface nerves, as well as a strong reflex excitation of the heart. For this reason these baths are not given to patients suffering from cardiac weakness.

The mud baths being highly impregnated with silica, which has a bland, sedative effect on the tissues, are particularly indicated in cases of acute or subacute neuritis, gout, and certain skin conditions. The action of these baths is to induce an active hyperæmia in the patient with an actual absorption of free sulphur, which is present in considerable quantity. Also, the radio-activity of this medium (0.185 per c.c.) is possibly an active factor in the therapeutic action of these baths. In some of the cases undergoing mud-bath treatment the effect has been almost miraculous—instant relief from pain; reduction of swelling caused by inflammatory exudates—and such patients have been able to discard crutches or other adventitious aids and walk with more or less normal comfort.

Perhaps, of more recent date, the most efficacious effects of mud treatments have been manifested in cases of skin conditions—notably psoriasis: cases which have resisted all forms of drug treatment have cleared up in an almost magical manner; and so frequently have such cures been effected that one believes that the silicious mud of Rotorua has some markedly specific action as a therapeutic agent.

The treatment of gout depends entirely on the individual manifestations. In certain subacute and chronic types fairly high temperatures (104° to 106° F., with hot packs) of “Priest” water are employed, in order to hasten the absorption of exudates and the elimination of uric acid. In acute cases of acute gout more sedative measures are pursued, such as “Rachel” baths at neutral temperatures, local mud packs, and rest. As soon as the conditions permit, these patients are changed over to acid water baths. Cases of chronic gout exhibiting metabolic stagnation sometimes receive considerable benefit from the counter-irritant effects of the strongly acid “Postmaster” waters.

Separate establishments, containing the most modern apparatus of sprays, douches, hot steam, &c., are available for wet massage and treatments of the Aix-Vichy type.

The massage-rooms are fitted with the latest installations of electrical equipment—Bristowe tables, diathermy, high frequency, Bergonie chair, X-ray, Schnée baths, Greville hot air, and other apparatus for carrying out the most up-to-date methods of electrical-therapeutic treatments.

The baths are administered by a trained staff of attendants, and the massage, electrical-therapy, and douches carried out by a qualified staff of operators.

In every respect the hydrotherapy treatments aim at a restoration of function, and the measures employed are, for the most part, re-educative.

In connection with the Rotorua Spa is a sanatorium of seventy beds, where patients whose finances are restricted can receive treatment at an exceedingly moderate cost. The institution consists of cubicles and open wards. Thermal baths and massage-rooms in the building provide for the more helpless type of invalid.

From sixty thousand to eighty thousand baths are given annually, and an average of thirty thousand special treatments—massage, electrical therapy, &c.—is administered at the Rotorua Spa.

The usual course of treatment lasts from four to six weeks, and the high percentage of cures and improvements testifies to the value of the thermal mineral waters and the hydro-therapeutic treatments obtaining in this Dominion.

The largest sheet of fresh water in New Zealand is Lake Taupo, which is situated in the very heart of the North Island, at an elevation of 1,211 ft. above the sea. Its greatest length in a S.W.-N.E. direction is twenty-five miles, and its greatest breadth is about seventeen miles, but its shape is somewhat irregular owing to a large indentation on its western side. Its area is 238 square miles, its greatest depth is 534 ft., and it has a catchment area of about 1,250 square miles. About 60 per cent. of its water-supply comes from the Upper Waikato River, which drains the northern and eastern flanks of the central volcanoes as well as the western slopes of the Kaimanawa Range and its northern extensions. The lake discharges at its northeastern corner and forms the main Waikato River, which falls within a short distance over the Huka Falls, where the volume of water which passes over is estimated to reach an average of 5,000 cubic feet per second. The surroundings of the lake are picturesque, on the western side especially. Here it is bounded by cliffs of volcanic rock, generally between 100 ft. and 800 ft. in height, but at the Karangahape Bluffs they rise to over 1,000 ft. sheer. The northern shore is bold with promontories terminated with bluffs and intervening bays with gentler slope. The south side is generally fringed with alluvial flats, while the east is bordered in places with pumice cliffs, and is somewhat uninteresting, but relieved from absolute monotony by the graceful extinct cone of Tauhara. About twenty miles to the south rise the great volcanic peaks of Tongariro, Ngauruhoe, and Ruapehu, with their bush-clad foothills, forming a splendid panorama when seen from the northern shore of the lake.

To the south-east of the middle of the lake lies the Island of Motutaiko, in all probability the summit of a volcanic cone on the line of igneous activity which stretches north-east from the central volcanoes towards Tarawera, White Island, Tonga, and Samoa. The formation of the lake itself is attributable either to a great subsidence after volcanic activity waned, or to a great explosion which tore a vast cavity in the earth's crust and scattered the fragments far and wide over the middle of the Island; and evidence of declining igneous action is furnished by hot springs in the lake itself and near its shore, especially at the north-east corner near Wairakei and on the southern shore near Tokaanu. Earth-movements have in all probability continued down to recent times, for an old shore platform or wave-cut terrace surrounds the lake, indicating that its waters were formerly at a higher level, and changes in level of the ground on the northern shore of the lake, attended by local earthquakes, occurred during the year 1922.

The lake forms an enormous reservoir of power conveniently placed for exploitation; it is estimated that the Huka Falls would develop up to 38,000 horse-power, and its central position renders it peculiarly suitable for supplying a wide district. Although the immediate vicinity does not hold out much hope for its utilization, the rich agricultural districts which lie at some distance will no doubt rely on it in the near future as a convenient source of mechanical energy.

To the south of Taupo, nestling in the hills between the great lake and the northern slopes of Tongariro, lies Roto-Aira, a beautiful sheet of water, three miles in length and with an area of five square miles. It discharges by the Poutu River into the Upper Waikato. The other lakes of this region are small in size and usually occupy small explosion craters on the line of igneous activity mentioned above.

A most interesting group of lakes lies in the midst of the thermal region to the north-east of Taupo. These comprise the following: Rotorua, Roto-iti, Roto-ehu, and Rotoma, which belong to a system lying to the north-west of the area, and Tarawera, Rotokakahi, Tikitapu, Okareka, Rotomahana, Okataina, Rotomakariri, and Herewhakaitu, which lie to the south-east. The former group is connected either directly or indirectly with the Kaituna River basin, and the latter with the Tarawera River basin, both of which discharge their waters into the Bay of Plenty. All these lakes occupy either explosion craters or depressions due to subsidences of the crust or hollows formed by irregular volcanic accumulations. They lie at an elevation of about 1,000 ft. above the sea. The largest is Rotorua, which is nearly circular in shape, except for a marked indentation on the southern shore. It is 22 square miles in area, and 84 ft. deep, with flat shores; but in the middle, rather towards the eastern side, the picturesque and historical Island of Mokoia rises to a height of 400 ft. The lake discharges at its north-eastern corner by the Ohau Creek into Lake Roto-iti, a shallow and irregular depression, which runs in turn into the Okere River. To the north-east lies the small lake of Roto-ehu, separated from it by low ground, and farther on lies the picturesque Rotoma, of still smaller size.

The largest lake of the south-eastern group is Tarawera, lying to the north and west of the mountain of the same name; discharging directly into it are Rotokakahi, Okareka, and Okataina, the last two by subterranean channels, while Tikitapu and Rotomahana are separated from it by comparatively narrow ridges.

All these lakes owe their interest to the thermal manifestations which occur in their vicinity, and to the remnants of beautiful bush which have survived the eruption of Tarawera in 1886. They are also noted for their fishing, being well stocked with trout. Their water is available for power purposes to a limited extent, and a small installation is placed near the low fall where the Okere River discharges from Lake Roto-iti.

Two small lakes of volcanic origin are situated on the peninsula north of Auckland: these are Takapuna and Omapere. The former lies close to the City of Auckland, and occupies a small explosion crater near the sea; while Omapere is between the Bay of Islands and Hokianga, in a shallow depression, which owes its origin to the obstruction of the Waitangi River by a lava-flow. It is three miles long by two wide, and is placed at a height of 790 ft. above the sea.

About forty miles from the east coast, in the Hawke's Bay District, lies the most important lake of Waikaremoana, twelve miles in length by about six miles and a quarter in breadth at its widest part, but with an extremely irregular outline; it has an area of twenty-one square miles. Its surface is 2,015 ft. above the sea, and it has a maximum depth of 846 ft. It discharges by the Wairoa River to the northern shore of Hawke Bay. This lake is most favourably situated for the development of water-power, and it is estimated that it would generate, owing to its admirable position, as much as 136,000 horse-power. A few miles to the northeast lies the small lake called Waikare-iti, which discharges into the large lake.

The only other inland lakes of any importance in this Island are those situated in the lower course of the Waikato River, the most noteworthy being Waikare and Whangape. The former has an area of nearly eleven square miles and has a depth of 12 ft.; the latter is smaller, with an area of only four square miles and a depth of 9 ft. These owe their origin to flooding of low-lying land alongside the river—in all probability attributable to a slight lowering of the land in this part of the country, with the consequent inability of the river to discharge its surplus water without a proper channel being maintained.

Along the coast-line, especially behind the fringe of dunes, numerous small lakes are found, such as Rotokawa, near Kaipara, and Horowhenua, near Levin; and a large sheet of water occurs near the mouth of the Wairarapa Valley, called the Wairarapa Lake. The lake is very shallow, and is liable to remarkable variations in size owing to heavy floods from the neighbouring ranges. Between it and the sea is a considerable area of swampy ground in which are several small lakes, the largest of which, Lake Onoke, is separated from Palliser Bay by a narrow shingle-spit.

By far the great majority of the lakes of the South Island are dependent for their formation either directly or indirectly on the action of glaciers. They may be either small tarns high on the mountains or large lakes occupying considerable lengths of old stream-valleys which have been overdeepened by the excavating power of ice during the Pleistocene glaciation, or lakes formed by the filling of hollows in the irregular heaps of debris laid down on a plain at the base of the mountains or in a wide open valley. Accumulations of debris may also assist the first two causes in the formation of lakes, and some may owe the initial formation of their basins to tectonic causes, but these have been modified profoundly by other influences.

Included in the first class are numerous sheets of water from the size of small ponds upwards, found in all parts of the mountain region, but especially in the high plateau regions of western Otago, and to a limited extent in north-west Nelson. To the second group belong the large lakes of the eastern watershed of the Alps and a small number which drain west, such as Rotoroa and Rotoiti in the Buller Basin, while to the last must be assigned the majority of the lakes of Westland; but Brunner and Kanieri should perhaps be assigned to the second class.

Seeing that glaciation was not so intense in the northern portion of the Island, it is not surprising that the lakes of that region are small and few in number. Attention has, however, been drawn to Boulder Lake, in the valley of the Aorere River, since it might be used for power purposes in connection with the great deposit of iron-ore at Parapara. It is only 151 acres in extent, but it lies at an elevation of 3,224ft., and is conveniently placed for the establishment of an electric-power plant. Farther south, near the head of the Buller, are two larger lakes—Rotoroa and Rotoiti—occupying ice-eroded valleys dammed at their lower ends by moraine. The former has an area of eight square miles, and the latter two and three-quarter square miles; their heights above the sea being respectively 1,470 ft. and 1,997 ft., and the latter being 228 ft. deep.

In the valley of the Grey River are two lakes of considerable size—viz., Brunner and Poerua. These are shrunken and separated parts of a former extensive sheet of water which was ponded back behind a great glacier moraine. Lake Brunner is five miles long by four broad, has an area of 15.9 square miles, is 280 ft. above sea-level, and 357 ft. deep. It is surrounded on two sides by high wooded granite peaks, and on the other two by low ground. It discharges by the Arnold River to the Grey, but a very slight change of level would turn it into the Taramakau.

Lake Kanieri, which lies in the basin of the Hokitika River at the base of Mount Tuhua, is a beautiful sheet of water. It is five miles long by one and three-quarters wide, has an area of eight square miles, is 422 ft. above sea-level, and 646 ft. deep. It owes its origin partly to the hollow formed behind an immense morainic dam, and partly to the erosive action of the valley glacier. Farther south on the coastal plain of Westland are numerous small and picturesque lakes, wooded to the water's edge, lying behind heaps of glacial debris or in ice-eroded basins. The most notable of these are Ianthe and Mapourika, both of small size, the former with an area of only two square miles, at a height of 80 ft. above sea-level, and with a depth of 105 ft., and the latter remarkable for the fine panorama of mountain scenery, with Mount Cook in the background, which can be obtained from the shore of the lake. Along this strip of coast-line there are numerous lagoon-like expanses of water, cut off from the sea by areas of dune or of moraine, the chief of which is Mahinapua, which lies close to the Town of Hokitika. This is but 6 ft. above tide water, and has an area of one and a half square miles. The creek discharging from it is noted for the perfect reflections to be seen in the dark, peat-stained water.

On the eastern side of the main divide lie the great valley lakes which belong to the following river-basins: Hurunui—Lake Sumner; Rakaia—Lakes Coleridge and Heron; Waitaki—Lakes Tekapo, Pukaki, and Ohau; Clutha—Lakes Wanaka, Hawea, and Wakatipu; Waiau—Lakes Te Anau, Manapouri, and Monowai; Wairaurahiri—Lake Hauroko; Waitutu—Lake Poteriteri. These are all formed on the same plan; great glaciers have excavated the floor of a river-valley and have piled the debris across its lower portion, leaving a great hollow which was filled with water when the ice retreated. Even in those river-basins where no lakes now exist the traces of their former presence are evident; especially is this the case with the Waimakariri, Rakaia, and Rangitata Valleys. Besides these large lakes each valley has its quota of small ones, usually hidden away among the piles of moraine or ponded back behind shingle-fans. Among these small lakes should be noted the following: Tennyson, in the valley of the Clarence; Taylor, Sheppard, Katrine, and Mason, in the Hurunui; Pearson, Grassmere, and Letitia, in the valley of the Waimakariri; Evelyn, Selfe, Catherine, Ida, and Lyndon, in that of the Rakaia; Clearwater (or Tripp), Howard, and Acland, in the Ashburton; Alexandrina, in the Waitaki; Lochnagar, Hayes, and Moke, in the Clutha. In the valley of the Waiau there are numerous lakes of small size hidden away in bush-clad valleys, the chief of which is Mavora, which discharges into the main Waiau by way of its large tributary, the Mararoa. On the west coast of this region are also many insignificant lakes as far as size is concerned, such as Lake Ada, a well-known beauty-spot on the Milford Sound track, while farther north McKerrow, a lake of larger size, discharges into Martin's Bay.

The only other lakes in this Island that are worthy of mention are Waihola, Forsyth, and Ellesmere. The first mentioned occupies the lower portion of the Taieri Plain, and drains to the sea by a deep winding gorge cut through a ridge of rock-covered hills, the gorge being tidal for the greater part of its length. Lakes Forsyth and Ellesmere lie on the coast immediately south of Banks Peninsula, both ponded back behind a great shingle-spit formed by the drift of material brought down by the rivers and carried north under the influence of a strong shore current. Both are very shallow and liable at times to be invaded by the sea. Ellesmere is sixteen miles long by about ton broad, and Forsyth is about six miles long by one in breadth.

Among all these lakes three stand pre-eminent for their scenic interest—Wakatipu, Te Anau, and Manapouri. The first-named is walled in on both sides by steep mountains which rise at the head of the lake to over 8,000 ft. in the Humboldt Range, and to over 9,000 ft. in Mount Earnslaw. Te Anau has an uninteresting eastern shore, but its western shore is broken into three great arms, whose impressive scenery is strongly reminiscent of that of Milford Sound and George Sound; while Manapouri, with its many bush-clad islets and its indented shore-line with innumerable sheltered coves and pebbly beaches, belongs to the same type as Dusky Sound, the most beautiful of all in the fiord region.

The lakes of Canterbury lie in a treeless area and owe their scenic interest principally to the background of snowy peaks, while Wanaka and Hawea are intermediate in character between them and the more southern lakes of Otago.

The following is a summary of the statistics of the chief lakes of New Zealand:—

A reference to the section of this book dealing with water-power will give an idea of the enormous amount of energy awaiting development in the lakes of the South Island. The only one yet utilized to any great extent for hydro-electric purposes is Coleridge, in Canterbury. Some use is also being made of Monowai, in Southland, and Waikaremoana, in the North Island. The latter will be developed to a much greater extent in the near future, and will form one of three great schemes for supplying the hydro-electric requirements of the whole of the North Island.

Professor James Park writes: “Though so isolated, New Zealand contains within its narrow borders representatives of most of the Palæozoic, Mesozoic, and Cainozoic formations. Moreover, its structure is that usually associated with areas of continental dimensions; and for that reason it is often spoken of as an island of the continental type. It is a miniature continent; and the occurrence in its framework of thinogenic [shore or shallow-water] rocks, ranging from the earliest geological epochs to the present day, is undeniable evidence that it stands on a subcrustal foundation of great stability.” (N.Z. Geological Survey Bulletin No. 23, p. 24, 1921.)

The oldest rocks in New Zealand appear to be those of western Otago, where over a large area is exposed a complex of gneisses and schists, intruded by granite and other igneous rocks. The gneisses in the main are altered granites and diorites, but some of the schists, at any rate, are of sedimentary origin. A pre-Cambrian age was assigned to these rocks by Professor F. W. Hutton, but Professor James Park considers them to be probably of Cambrian age, and includes them in his Dusky Sound Series, the lower part of the Manapouri System.

Perhaps next in age to the western Otago gneisses and schists are the mica, chlorite, and quartz schists of Central Otago. In the absence of fossils, however, the age of these rocks is uncertain. Professor Hutton regarded them as pre-Cambrian, Professor Park assigns a Cambrian age, whilst Dr. P. Marshall considers them to be little, if at all, older than the Triassic. Recent field-work by the Geological Survey, however, strongly suggests that an unconformity separates the Triassic rocks of the Nugget Point district from the greywackes of the Balclutha district, which overlie the Otago schists. In December, 1924, fossils of Permian (if not older) age were discovered near Clinton in greywacke and associated rocks. The horizon of these fossils is far above the schists, and therefore a pre-Permian age for the schists is undeniable. Some schistose rocks in north, central, and western Nelson may be as old as, or even older than, the Otago mica-schists The gneisses and schists on the western side of the Southern Alps may for the present be classed with the Nelson schists.

The oldest known fossiliferous rocks in New Zealand are the Ordovician argillites (“slates”), greywackes, and quartzites occurring near Collingwood (Nelson), in the Mount Arthur district, and near Preservation Inlet in south-west Otago. Ordovician rocks probably have a considerable development in other parts of Nelson and in Westland, but no recognizable fossils have been found in those areas.

Rocks containing Silurian fossils occur in the Mount Arthur, Baton River, and Reefton districts, Nelson. They are principally altered limestone, calcareous shale or argillite, sandstone, and quartzite.

Considerable areas have been assigned to the Devonian period by Mr. Alexander McKay, but owing to the non-discovery of recognizable fossils definite proof of age is wanting. For a similar reason the age of most of the rocks placed in the Carboniferous period (“Maitai Series”) by McKay is uncertain. At Reefton the supposed Carboniferous rocks, which here contain many auriferous quartz-veins, are almost certainty of Ordovician age. In the typical locality near Nelson the fossils found in the Maitai rocks, according to Dr. C. T. Trechmann, indicate a Permo-Carboniferous age.

So far Permian rocks have not been satisfactorily identified in New Zealand, but, as previously stated, fossiliferous strata of this age, or slightly older, have been found near Clinton, Otago. The Maitai rocks near Nelson ought probably to be classified as Permian rather than as Permo-Carboniferous. Park considers his Aorangi Series to be of Permian age.

During some of the Palæozoic periods it is conjectured that New Zealand formed part of or was the foreland of a large land-mass that extended far to the west. This land-mass possibly persisted to late Palæozoic times, and may have been the now dismembered and all-but-lost continent known to geologists as Gondwanaland.

Since Hochstetter's visit (1859), Triassic and Jurassic rocks have been known to exist in New Zealand but the fossils were not extensively and accurately identified until the last decade, when Newell Arber and Trechmann published their valuable papers.

Newell Arber (1917) described an Upper Triassic flora from Mount Potts and Clent Hills (North Canterbury), and Hokonui Hills (Southland); Jurassic floras from North Canterbury and Southland; and a Lower Cretaceous flora from the neighbourhood of Oruarangi Point, south of Waikato South Head. Trechmann (1918 and 1923) examining marine molluscs and brachiopods from several localities, found that they ranged in age from Upper Triassic to Upper Jurassic, and correlated the different beds with European stages. The most fossiliferous localities are Hokonui Hills (Southland), near Nugget Point (Otago), Wairoa Valley (Nelson), Mokau watershed, Kawhia Harbour, and Waikato South Head, the three last-mentioned on or near the west coast of Auckland.

A broad belt of largely unfossiliferous but probable Trias-Jura rocks extends through western Canterbury and Marlborough, and is continued as a somewhat narrower belt on the north side of Cook Strait from Wellington to northern Hawke's Bay. Bocks of much the same appearance occur in the Lower Waikato Valley, in the Coromandel Peninsula, and in North Auckland. Some of these rocks may be of pre-Mesozoic age, but fossils to settle the point have not yet been found.

No angular unconformity has been found between the Triassic and Jurassic, and the rocks have marked lithological similarity. Consequently the mapping of the boundary between these two systems is difficult, and, with our present knowledge, its extension into the great areas of unfossiliferous greywackes is impossible.

Cretaceous rocks occur at several points on the east coast of Otago and in central Canterbury. They extend in a not-quite-continuous belt from Cape Campbell in Marlborough to the neighbourhood of Waipara in North Canterbury. At Amuri Bluff they are richly fossiliferous. To the Cretaceous belongs a somewhat extensive belt of rocks near the east coast of Wellington and southern Hawke's Bay. A continuation of this belt extends from a point north-west of Gisborne to the East Cape district. In North Auckland Cretaceous rocks cover considerable areas.

The oldest known workable coal-seams in New Zealand occur in Cretaceous rocks. Much controversy, however, concerning the age of our coalfields has arisen. The late Sir James Hector, and with him Mr. Alexander McKay, considered that the coal-measures belonged to a Cretaceo-Tertiary system that extended from the Upper Cretaceous to the Middle Tertiary. For many years Mr. McKay was practically the sole exponent of this theory, but since 1911 Dr. Marshall has advocated a very similar view. The truth, however, seems to be that the coal-measures concerning which there is a dispute are of two different ages. The Kaitangata, Green Island, Shag Point, Malvern Hills, and Broken River (Canterbury) coalfields are probably of Upper Cretaceous age. The other coalfields, as mentioned below, are Tertiary.

To the Eocene may be assigned the coal-measures of the Taratu-Milton, Grey, Buller, and Collingwood districts, and some of the coal-bearing patches of central Nelson. In various other localities possible Eocene coal-measures occur. The Wangaloa beds, near Kaitangata, contain an Early Eocene fauna, which has also been identified at Boulder Hill, North Taieri, near Dunedin, and are underlain by the Taratu-Milton coal-measures.

During the Early Eocene, as some geologists and biologists believe, New Zealand was again part of a continental area that extended far to the north, and was joined, or all but joined, to New Guinea and northern Australia. This continent may have included much of the area in the Pacific now studded with coral islands. Its former existence is inferred mainly from various features in our plant and animal life. According to the late Mr. T. F. Cheeseman, no fewer than 366 New Zealand plants are found also in Australia, but recent botanical work tends to reduce the number. More significant, perhaps, is the occurrence of many closely related species and genera in the two regions, for comparatively few of the 366 species are likely to have persisted since the Eocene. Many of our birds show marked affinities to Australian and Malayan species. In this connection an interesting line of support for a Tertiary extension of New Zealand to the north is afforded by the annual migrations of the New Zealand cuckoos and of the godwit.

During the Oligocene and Miocene periods New Zealand subsided until little of the present land-surface was above water. Consequently, notwithstanding extensive denudation in later periods, Middle-Tertiary strata are well represented in almost all parts of the country. They are typically developed in the Oamaru district (northeast Otago), and hence Hutton's name of “Oamaru Series” is generally applied to the Oligocene-Miocene strata of New Zealand. There is reason to think, however, that the lowest part of the Oamaru Series is of pre-Oligocene age, but until palæonto-logical work now in progress is completed a definite opinion cannot be expressed. Oamaru rocks are well represented in South Canterbury, in North Westland, in North Auckland, and in many other localities. Brown coal usually occurs at the base of the Oamaru Series, and about its middle a fairly thick fossiliferous limestone is usually developed. This marks the time when the Middle Tertiary sea was deepest. Some of the finest agricultural districts in New Zealand are in areas where Middle-Tertiary rocks predominate.

The present tendency of the Geological Survey is to separate, under various local names, the uppermost Miocene strata from the Oamaru Series, even though this be held to include the Awamoa or Pareora beds. Strata high in the Miocene cover large areas in the North Taranaki, upper Wanganui, and Gisborne-East Cape districts, and are found also in Marlborough, North Canterbury, &c. In North Taranaki they contain valuable seams of brown coal.

In many localities the Miocene rocks pass without detectable angular unconformity into strata considered to be of Pliocene age. In the Hawke's Bay and Wanganui districts these are marine and highly fossiliferous. They give rise to much good agricultural and more especially pastoral land adapted to sheep-farming or dairying. In Nelson and north Westland the Pliocene strata are largely composed of river-transported material, and are known as the Moutere Gravels. These in places are poorly auriferous. In Nelson they form a poor pastoral soil, but one well adapted for apple-culture.

Towards the close of the Miocene and during the Pliocene period many parts New Zealand, more particularly in the South Island, underwent elevation. As a result the North and South Islands (then quite different in outline from their present configuration), together with most of the outlying islands now in existence, such as the Chathams, Auckland Islands, &c., probably formed one large land-mass, which was united to, or almost reached, an Antarctic continent. Since many New Zealand plants^* are identical with, or closely allied to, South American forms, and there are also some striking resemblances in bird and other forms of animal life, some geologists and biologists believe that this Antarctic continent formed a bridge, though probably at no time quite complete, between New Zealand and South America. At the time of this continental extension the Southern Alps rose far above their present heights, and were covered with one vast snowfield that fed immense glaciers spreading far and wide over the lowlands to the east and the west. According to Park, during the Pleistocene a great sheet of ice spread over the whole of the present South Island and over part of the North Island. Moreover, this ice-sheet was joined to the Antarctic ice. The extreme views of Professor Parle are not shared by other New Zealand geologists, who, however, unanimously agree that a large area in the South Island was glaciated. The great ice-streams of Pleistocene times gave rise to rivers that carried enormous quantities of gravel and finer material derived from the mountains beyond the ice-front, and in great measure built up the lowlands of Canterbury and Westland. In the latter district the gravels sorted by these streams are in many places richly auriferous, but a greater and more permanent source of wealth is furnished by the fertile soil of the Canterbury Plains.

In many parts of Otago, Canterbury, Westland, and Nelson evidences of past glacial action are afforded by huge moraines, perched blocks, ice-worn surfaces (roches moutonnées), rock-benches, rock-basins, and other tokens of glaciation. To ice-action we owe some of the most magnificent features of the western Otago sounds. Some evidence of interglacial periods has been found, and doubtless more will be obtained by future investigations. At or before the end of the Pleistocene period the mountains lessened in height, through both denudation and a well-marked subsidence of the land. The climate grew milder, and the lowland ice melted away. The mighty glaciers rapidly retreated, geologically speaking, and are to-day represented only by the comparatively modest valley and mountain glaciers of north-west Otago, Canterbury, and Westland, with which may be included the small but permanent snowfield and glacier on Mount Ruapehu. While the glaciers were retreating, the rivers of Canterbury and Westland, swollen by the melting ice, were unusually active in transporting debris to the lowlands and the sea-coast. At this time, too, as well as at somewhat earlier periods, the volcanoes of the North Island furnished an abundant supply of fragmentary material, much of which was transported by the streams and used in building plains and river-flats. Many of these are fertile, but in those districts where pumice abounded a poor soil, difficult of utilization, has resulted. Thus the land gradually became much as we see it now. In recent times geological changes, such as the lowering of heights by denudation, the filling of lakes by sediment, the outward growth of coastal plains in some places, and the wearing-away of the shores in other places, have slowly proceeded, and are to-day, of course, still going on. Slow movements of the land are probably in progress, but these have not been certainly detected. In 1855, however, as the result of a violent earthquake, the northern shore of Cook Strait, near Wellington Harbour, was raised on the average at least 5 ft., whilst the southern shore near Tory Channel and towards the mouth of the Wairau River was almost correspondingly depressed. The Taupo earthquakes of 1922 also caused a measurable movement of the land surface near Taupo.

In the preceding paragraphs little notice has been given to igneous rocks or to volcanic action. The oldest igneous rocks of New Zealand are probably represented by the gneisses of western Otago, which, as previously stated, are mainly metamorphosed granites and diorites. Plutonic rocks intrude many of the Palæozoic and Mesozoic strata, and some of the formations also show evidence of contemporaneous volcanic action. Of the more ancient plutonic rocks granite is the most prominent. It occurs in many localities in Stewart Island, western Otago, Westland, and Nelson. It has, however, not been found in situ in the North Island, though in many localities boulders of granite and allied rocks, probably derived in all cases from ancient conglomerates, have been discovered. Ultra-basic igneous rocks, now largely altered to serpentine, occur in north-west Otago, Westland, Nelson, and to a minor extent in North Auckland.

* According to T. F. Cheeseman's “Manual of the New Zealand Flora” (Preface, page xiv), 112 New Zealand plants extend to South America.

Throughout the greater part of the Tertiary periods volcanic action in New Zealand was probably more intense than in any former age. During the Late Eocene or Early Miocene period eruptions, at first principally of andesitic rocks and later of rhyolite, began in the Coromandel Peninsula, and with brief intermissions continued throughout Miocene and Pliocene times. These volcanic rocks contain the gold-silver veins which have been extensively worked at Coromandel, Thames, Waitekauri, Karangahake, and Waihi.

There are many areas of Miocene and later volcanic rocks in North Auckland, and near the City of Auckland numerous small volcanoes were in action during the Pleistocene, or even later. Some of these—for example, Mount Rangitoto—have possibly been active within the last few thousand years. In Taranaki the beautiful cone of Mount Egmont was built up during Pliocene and Pleistocene times. It is in the central part of the North Island, however, that the most intense volcanic activity has been displayed. Volcanic rocks, more especially the rhyolitic pumice ejected during the Pliocene and Pleistocene, cover large areas. Vulcanism has not yet ceased, for minor eruptions of fragmentary material still take place from Ngauruhoe, a typical volcanic cone near Mount Ruapehu. The most striking evidence of volcanic-action, however, is afforded by the numerous steam-vents, hot springs, and geysers found in a belt extending from Ruapehu to White Island (in the Bay of Plenty), itself a volcano in the solfataric stage. It is more than a coincidence that this belt is in line with the Southern Alps. Solfataric action is generally regarded as a sign of dying vulcanism, but that the subterranean forces are still capable of mischief was shown by the eruption of Tarawera, an apparently extinct volcano, on the 10th June, 1886. On that occasion over a hundred lives were lost.

In the South Island vulcanism is apparently quite dead, for the hot springs of Hanmer Plains and the western side of the Alps are due to other causes. During the Miocene, however, volcanic outbursts took place in many localities, in some on a grand scale. Banks Peninsula is formed mainly of basaltic and andesitic rocks. Lyttelton and Akaroa Harbours are believed to represent ancient craters or centres of eruption. In the neighbourhood of Dunedin occurs a very interesting series of alkaline volcanic rocks. These were first described by the late Professor G. H. F. Ulrich, and in later years Dr. Marshall, Professor Benson, and others have given them much study. Recently alkaline volcanic rocks have been discovered in the outlying Chatham Islands.

In the course of a short article it is impossible to give any adequate idea of what has been accomplished by geological workers in New Zealand, or what remains yet to be done before even the foundation for future work shall be securely laid. The important applications of geology to agriculture and mining have hardly been mentioned, but elsewhere in this volume will be found descriptions of the agricultural and mineral resources of the Dominion. For detailed information the reader is referred to the bulletins of the New Zealand Geological Survey; to Professor Park's “The Geology of New Zealand,” which contains an excellent bibliography; and to the treatises on “Geology of New Zealand,” by Dr. P. Marshall, as well as to many other publications too numerous to be here named. Yet the “Transactions of the New Zealand Institute,” of which fifty-seven volumes have been issued, must be mentioned, more especially since they contain many articles dealing with the palæontology and geology of New Zealand, as well as numerous papers on other branches of natural science. Finally it may be stated that in each of the University Colleges at Auckland, Wellington, Christchurch, and Dunedin excellent instruction in geology is being given by capable and enthusiastic teachers, so that progress in solving the many knotty problems of New Zealand geology is now being made, and may be expected to continue.

Since 1888 there has been established in New Zealand a system of observing local earthquakes at selected telegraph-stations—about eighty in number—distributed throughout the extent of the Dominion.

Whenever a shook occurs and is felt by an officer in charge of one of these stations he fills up a form giving the New Zealand mean time of the beginning of the shock, its apparent duration and direction, and the principal effects observed by him. Some of the officers exhibit considerable care and skill in making up these returns, and the data have been used to determine principal origins of earthquakes within the New Zealand region.

All observers of earthquakes are cordially invited to forward their reports to the Government Seismologist, Dominion Observatory, Wellington, giving all or any of the following particulars:—

The Rossi-Forel scale of earthquake intensities is as follows:—

* A convenient means of verifying the time is provided by the wireless time-signals sent out every day, at 10.30 a.m. N.Z. time, by the Dominion Observatory on a wave-length of 600 metres.

Four seismographs, all with photographic registration, are installed in New Zealand: two are Milne horizontal pendulums, and two the now Milne-Shaw horizontal pendulums. One Milne and two Milne-Shaw seismographs are installed at the Dominion Observatory, Wellington, with their booms placed at right angles; and the other Milne seismograph is installed at the Magnetic Observatory, Christchurch.

A set of Wiechert seismographs with mechanical registration is installed at the Observatory at Apia, Samoa. By the courtesy of the Administrator copies of the records are forwarded to the Dominion Observatory.

One twin-boom Milne seismograph is installed at Suva, Fiji, and by the courtesy of the Government of Fiji the seismograms are forwarded to the Dominion Observatory. The Fiji records are useful in supplementing those of New Zealand.

The records of the New Zealand stations are sent to the General Secretary of the Seismological Committee of the British Association, to the Station Centrale Sismologique, Strasbourg, France, and to the principal observatories of the world, and thus form part of the general system of earthquake-observation being conducted throughout the world since 1890.

The accompanying diagram illustrates graphically the number and intensities of the earthquakes reported to the Seismologist in the years 1921 to 1926. These reports were supplied by officers of the Post and Telegraph Department, by private observers, and by the newspapers. Each vertical line represents the maximum effect of an earthquake, with the intensities according to the Rossi-Forel scale shown at the sides of the figure. It will be seen that two earthquakes in 1921, three in 1922, one in 1925, and one in 1926 reached intensity VIII on this scale. In 1926 eight other earthquakes reached intensity VI, and one reached intensity VII.

Deaths due to earthquakes in New Zealand are fortunately very few. In the last eighty years seven have been recorded. The shock of October, 1848, threw down a wall in Wellington, and three people were killed. On the 24th January, 1855, a death occurred at Wellington recorded as “accidental death from the falling of a chimney.” The large earthquake took place during the night of the 23rd January, 1855. On the 16th November, 1901, a child was killed by the Cheviot earthquake. On the 12th April, 1913, a Maori was killed at Masterton by material falling from the post-office, due to an earthquake. On the 7th October, 1914, a shepherd was killed by the Gisborne earthquake.

The climate of the Auckland Provincial District, speaking generally, combines degrees of warmth and humidity agreeable by day and comfortable by night. North of Auckland City conditions are almost subtropical, and in summer balmy easterly breezes prevail, and are responsible for delightful conditions. In winter the winds are more north and west, while changes to the south-west or south-east mostly account for the rainfall. Cumulus clouds are frequently formed in the afternoons, and, while tempering the heat of the day, also cut down sunshine records somewhat, but add considerably to the beauty of the land- and sea-scape. Southward of Auckland the climate is more varied, the west coast experiencing more rain, while the central parts are warmer in the day and considerably colder at night. In the winter months frosts, which are unknown farther north, now and then occur in the hours of darkness. Eastward from Rotorua (the great health resort and the centre of the thermal region) is to be found one of the most genial climates in the world, and Tauranga and Opotiki have charms all their own, especially for their weather and the fruits which ripen to perfection in those regions.

The monthly and annual means of the temperature, rainfall, and sunshine of Auckland and Rotorua are shown in the following tables:—

Hawke's Bay is one of the richest districts in New Zealand, and is favoured with a pleasant climate, being sheltered from westerly winds, though occasionally they are of the warm and dry (Foehn) type. It is rather dry, but ex-tropical disturbances are occasionally responsible for heavy downpours. Though the number of days with rain is less than, and sunshine above, that of other parts, the rainfall is still a good one, and fairly regular throughout the year, though some seasons have been notably dry. The meteorological records of Napier show reliable normals for the coastal districts. Inland the country is rather mountainous and less mild.

As disclosed by its meteorological records, Wellington, the capital city, has a mean climate for the whole Dominion. Wellington occupies a central position, and is situated near Cook Strait, which divides the two main Islands. It has a somewhat changeable but temperate climate, and, though occasionally subject to disturbances from warmer regions, is usually controlled by the terrestrial wind-currents which have a westerly direction round the world in the latitude of the “forties.” It is popularly regarded as a rather windy spot, for high winds are frequently experienced, although they hardly ever reach hurricane force. Its windiness is largely owing to local configuration, for places quite near Wellington experience very little wind; and to compensate for this rather disagreeable element is a bountiful sunshine, averaging 2,018 hours per annum. There is a plentiful rainfall, amounting to nearly 50 in.

The region between Wellington and Taranaki, following the Taranaki Bight, is probably as fertile and agreeable as any in Australia or New Zealand; but inland though very productive, conditions are not so favourable.

Taranaki has a rather heavy rainfall, and in most parts of this region the grass is always green. Its climate is mild, and cattle winter in the open. Wanganui and Manawatu districts (which lie between Wellington and Taranaki) have less rainfall than either Wellington or Taranaki.

It may be useful to make a comparison between the records of Wellington and those of Camden Square, London.

Nelson and Marlborough are highly favoured regions with regard to sunshine and shelter from marine winds. Long ago Bishop Selwyn said, “No one knows what the climate is till he has basked in the almost perpetual sunshine of Tasman's Gulf, with a frame braced and invigorated to the full enjoyment of heat by the wholesome frost or cool snowy breeze of the night before.”

Pastoral and agricultural industries are thriving, and Nelson is also famous for its fruit cultures—apples especially being celebrated for their variety, colour, and flavour. The rainfall about Nelson is very reliable, and averages from 35 in. to 45 in. per annum. Marlborough is also a sunny district, find its rainfall averages from 25 in. to 35 in.

Following are the rainfall and sunshine records for Blenheim:—

The climate of Westland is influenced by its position with regard to the prevailing westerly winds, its proximity to the sea from which these winds blow, and the mountainous character of its eastern half. The rainfall, as might be expected, is heavy, and ranges from about 70 in. per annum in the north on the coast to as much as 200 in. in the mountainous country. The weather-changes are chiefly due to atmospheric depressions, with lowest pressures passing south of the Dominion. Cyclones centred in the north, while bringing heavy rains to the North Island and the east-coast portions of the South, do not, as a rule, affect Westland, as easterly winds, which then prevail, are not conducive to cloud - formation in this district. Sunshine at Hokitika averages 1,929 hours a year, and, though not so abundant as in east-coast districts, this is a good average amount considering the rainfall. Westland is noted for a clear, beautiful atmosphere during fair-weather periods.

The chief health resort of the South Island, Hanmer Spa, is situated on a small plateau in the northern portion of the Canterbury Land District. On account of its altitude, 1,120 ft., it enjoys an invigorating climate, with a mean annual temperature only about one degree below that of Christchurch. Owing to its elevated position and nearness to the mountains Hanmer is in some winter seasons subject to rather severe snowstorms, such as are never experienced on the Canterbury Plains. The mean annual rainfall is 404$82 in., and the mean total sunshine 1,990 hours.

The district of Canterbury comprises a variety of topographical features. A plain stretches over a hundred miles from north-east to south-west, with a maximum width of about forty miles from the east coast to the foothills to the westward. The latter merge into the mountainous country culminating in the main range of the Southern Alps, which divides the provincial districts of Canterbury and Westland, and affords a protection from the heavily moisture-laden north-westerly winds. The rainfall of the Canterbury Plains is in consequence much restricted, the average being about 26 in. There is, however, a remarkable progressive increase from east to west, as is shown by the records. At Christchurch the mean is 25.30 in.; at Mount Torlesse Station (near Springfield), 40.24 in. The climate of Canterbury might almost be described as Continental in type, with large extremes of temperature between summer and winter and between day and night. Except in the three summer months frosts are numerous, and even in the early spring and late autumn they are at times severe enough to damage vegetation of a tender nature. In summer, day temperatures of over 90° in the shade are sometimes experienced. With regard to both climate and soil, the Plains have proved most suitable for agricultural farming, and much of the district is capable of growing splendid cereal and root crops. The prevailing winds in Canterbury are north-east and south-west, while north-westerlies are not, as often supposed, of frequent occurrence. They are most common in the springtime, and, being dry and warm, they have a somewhat enervating effect, though in winter-time they come as a welcome change from the keen temperatures then generally ruling. The bright sunshine, as recorded at Lincoln, shows a daily average for the year of 5.7 hours.

Otago, the southernmost part of New Zealand, is very diversified as regards both its physical features and its climate. Inland, in Central and North Otago, the climate is dry and clear—hot in summer and cold in winter. The rainfall for this district averages from 13 in. to 20 in. Near the coast, in the Dunedin district, the rainfall in more plentiful, averaging from 30 in. to 40 in. per annum, a good deal of which falls in light drizzling rains.

There are continuous rainfall records from various parts of Dunedin for seventy years, of which the median rainfall is 33.5 in., and the mean in the table following may be regarded as too high.

Queenstown, on Lake Wakatipu, amongst the mountains, at an elevation of over 1,000 ft., furnishes the following averages:—

At Invercargill, the chief town of Southland, the averages are as follow:—

The average rainfall of Southland is between 40 in. and 50 in., but towards Queenstown the rainfall is between 30 in. and 40 in. The rainfall is well distributed throughout the year, and there is less wind in winter than in summer.

Stewart Island has a wonderfully mild and moist climate, especially on its eastern side, with an average rainfall of 65.18 in.

The total rainfall for the year was above the average in most parts of the Dominion but below in the east-coast districts of the North Island southward of Gisborne, and at a few isolated places in North Canterbury and North Westland in the South Island.

Following is a brief summary for each month of the weather and the chief atmospheric systems which were in evidence:—

January.—January opened with strong southerly winds, and cold squally weather prevailed on the 1st and 2nd over most of the Dominion, the result of an intense disturbance located eastward of New Zealand, and apparently centred in the vicinity of the Chatham Islands.

Thereafter, however, though occasional spells of unsettled and wet conditions were experienced, warm and fair weather predominated. Between the 9th and 12th an ex-tropical disturbance, in moving down the western coast, brought some good rains to both Islands. This was particularly beneficial to Central Otago in terminating a considerable spell of dry weather.

The most generally unsettled period during the month was between the 20th and 24th. The North Island was under the influence of a cyclone passing in the north on the 21st and 22nd, and an easterly gale with heavy rain inflicted considerable damage to orchards and gardens in the northern districts. At the same time a westerly storm area caused northerly gales and boisterous conditions over the South Island. At Pokororo, in the Nelson district, 8.21 in. of rain fell in ten hours on the 22nd, causing a record flood.

The total rainfall for the month was above the average in all but the east-coast districts, while the deficiency there was not so serious as in the previous month, and conditions generally were favourable to farming pursuits.

February.—During the first fortnight of February conditions were dominated by three intense areas of low-pressure located eastward of the South Island, and strong southerly winds brought cold, unsettled weather and heavy rain, especially in the south.

Fair weather predominated between the 14th and 21st, except about the 18th, when considerable rain fell in Westland, the effect of a westerly disturbance passing in the south.

The latter portion of the month, though very changeable, was on the whole warmer, but on the 27th and 28th a strong southerly and general rains were experienced. This benefited the Hawke's Bay district, where dry conditions had persisted during the past six months.

The total rainfall was in excess of the average over the South Island, except about Nelson and Collingwood. It was also above about Kawhia, Wanganui, and Foxton, but elsewhere in the North Island it was below the average The difference was greatest in Otago, where the aggregate rain ranged from 100 to 200 per cent. above the mean.

The month was remarkably cool, and on several occasions frosts occurred in places widely apart.

March.—Anticyclonic pressure predominated during March, which proved a dry month over most of the Dominion. An excess of the average rainfall was recorded only in parts of the Wellington District and about Kawhia in the North Island, and in the Nelson and Marlborough districts and also at a few places in Westland in the South Island.

Some heavy and beneficial rains occurred about the 23rd, 27th, and 31st. On the 23rd the centre of a small but rather intense cyclone passed through Cook Strait, and this was followed by another on the 26th.

Westerly gales were experienced about Cook and Foveaux Straits on the 7th, 8th, and 9th, but generally there was little wind during the month.

On the whole, conditions were mostly cool and fair. The rainfall during the latter part of the month relieved the situation for farmers in many parts of the country.

April.—During the first three weeks of April the weather was fair, calm, and mild generally under anticyclonic conditions, though there were evidences of three areas of low-pressure passing to the south of New Zealand on the 3rd, 11th, and 16th respectively, and rain fell about these days in the West Coast districts of the South Island.

On the 22nd barometric pressure decreased for the advent of an extensive westerly depression, which caused strong westerly winds and unsettled weather, with occasional rain, until the close of the month.

The total rainfall was below the average in all parts except Westland, the greatest deficiency again being experienced on the east coast of the North Island.

May.—In contrast to the preceding month May proved very wet. The total rainfall was much above the average in almost all parts of the Dominion, only a few places along the East Coast reporting a deficiency.

There were three brief anticyclonic periods, culminating on the 7th, 17th, and 31st; but between these areas of high pressure were several disturbances associated with stormy conditions. An extensive westerly depression ruled over the Dominion between the 2nd and 6th. The gradient was more severe in the north than in the south, and gales, with heavy rain, were reported, especially in and north of Cook Strait. A sudden and steep fall in the barometer on the 9th accounted for boisterous conditions and a deluge on the West Coast; pressure then continued low and the weather unsettled for a week.

An ex-tropical disturbance made its appearance to the north of New Zealand on the 17th, and, travelling slowly south, the centre apparently passed about Cook Strait on the 23rd. This, uniting with an Antarctic “low,” resulted in nearly a fortnight of bad weather.

Temperatures were comparatively mild and, although a few sharp frosts were experienced, a good autumn growth of grass was reported.

June.—With the exception of the North Auckland District and a few high-level stations in the South Island, precipitation in June was below normal over the Dominion, the greatest deficiencies occurring in Hawke's Bay and Canterbury.

Anticyclonic conditions prevailed between the 5th and 9th and between the 16th and 26th, when fine dry weather was mainly experienced, bright days and cold nights, with frequent ground frosts.

The unsettled periods were associated with the passages of two ex-tropical disturbances and an intense westerly depression. Of the former, the centre of the first passing to the northward of New Zealand on the 3rd, brought heavy rain to the northern districts, while the second, moving ever the Dominion between the 27th and 30th, had a more general effect, and much dull misty and wet weather prevailed.

The westerly disturbance which ruled between the 11th and 16th was responsible for strong north-west to south-west winds and squally conditions, particularly in and southward of Cook Strait, with heavy rain on the West Coast. Some snow fell at this time in the high country of the South Island and the southern part of the North Island. Otago and Southland, however, escaped storm effects, and the weather in these districts was, as frequently occurs there in winter, remarkable for its mildness.

The range of temperature over the Dominion was rather larger than usual, and vegetable growth was nearly everywhere sufficient for stock requirements.

July.—During July areas of high-pressure were generally weak, except one ruling in the last three days. The weather, however, on the whole was dry and milder than usual, although, on account of three rather intense storms, some heavy rains occurred on the east coast of the Auckland peninsula and in the Taranaki and Wanganui districts, where the aggregate rainfall was above normal. Elsewhere there was a deficiency, which was most pronounced in the South Island, the whole of which, with the exception of Queenstown, experienced considerably less than the average precipitation.

Of the disturbances, a cyclone, developing to the north-westward on the 10th, attained its greatest intensity on the two following days northward of Kawhia and East Cape, although, owing to its influence, rains were experienced and snow fell on higher levels farther south. This storm was closely followed by a westerly depression, which caused strong northerly and westerly winds and more general rain, heavy falls occurring along the West Coast.

Between the 23rd and 28th another westerly disturbance, having two centres, brought gales and heavy rain, particularly to the Manawatu, Wanganui, and Taranaki districts, and severe floods caused considerable damage in these parts.

Frosts were fairly frequent in the east-coast districts, but the month may generally be described as “a good winter month.”

August.—August, regarded as the last month of winter in New Zealand, was on the whole dull and showery. Reports vary as to temperature and its effects, but the days were generally mild, though frosts occurred frequently in many parts of the country.

Rainfall was above the average over the greater part of the North Island and in Otago, but below the mean of former years in the Hawke's Bay and Poverty Bay districts and in the central part of the South Island, both on the east and west coasts, which is rather an unusual occurrence.

An intense westerly disturbance passed in the south on the 5th and 6th, accounting for gales, particularly in the North Island; and the most general rainfall, with snow on the higher levels, was reported at this time.

Three cyclones passed northward of New Zealand on the 10th, 17th, and 24th respectively, accounting for some heavy downpours in the northern districts. A westerly disturbance at the close of the month brought welcome rains to the Wairarapa and Marlborough districts, and, in spite of frequent showers previously experienced, ended what was regarded as a dry spell.

Growth was continuous and mostly favourable to agriculture, particularly in the South.

There was a fair amount of wind, with a prevalence of south-easterlies in the North Island, but conditions were calmer farther south.

September.—Meteorological conditions during September were remarkably variable, and presented features appropriate to all the seasons.

The first week was showery, and the week 22nd to 29th, while an extensive anticyclone dominated, was fine and warm generally. The remainder of the month was subject to numerous westerly disturbances, the most intense prevailing on the 15th and 16th. On the 16th a severe snowstorm was experienced, and, although the fall was not particularly heavy, it was fairly general over the Dominion southward of Raglan and Tauranga. Strong west to south-west gales were recorded at this time with stormy and wintry conditions.

The changeable weather during the first three weeks greatly retarded agricultural operations, but the mildness of the latter part of the month hastened vegetable growth, and on the last day general beneficial rains occurred.

Frosts were rather frequent, particularly along the East Coast, but they were not generally severe.

The aggregate rainfall was below normal over most of the North Island and in the northern and east-coast districts of the South, while in South Westland and Otago it was considerably above.

October.—The weather of October was, for the most part, remarkably wet, and except in the Poverty Bay and Hawke's Bay districts and in Westland both the total rainfall and the number of wet days were everywhere above the average.

Between the 10th and 12th an ex-tropical disturbance passed over the North Island, and stormy conditions were experienced. Very heavy rain fell at this time in the basin of the Waikato River, and caused the highest flood recorded for many years. Snow and hail also fell on the higher levels.

A westerly depression between the 14th and 19th brought further unsettled weather. particularly to districts with a westerly aspect. From the 20th to the 24th anti-cyclonic pressure dominated, and this was the only period during the month when fair weather prevailed generally.

An extensive westerly disturbance during the last week was complicated by a well-defined cyclonic system which invaded the larger area of low pressure. The centre of the latter storm passed through Cook Strait during the night of the 28th. There were some heavy rainfalls accompanying thunderstorms in the south at the close of the month.

Frosts were not frequent, but a severe one on the morning of the 13th did considerable damage to tender spring growth at places in both Islands.

November.—On account of numerous intense westerly disturbances November proved a wet, windy, and cold month—rainfall being in excess of the average in all parts of the country except at a few places in Hawke's Bay and Otago.

The outstanding feature of the month was the severe floods in Westland in the beginning of the month. Through the exceptional rise in the Buller River, Westport experienced one of the worst floods in the history of that town. The heavy rains at the end of the previous month had soaked the land and swollen the streams, while much snow had also fallen in the mountains. On the 3rd November an extensive westerly disturbance brought further heavy rain, and this combined with the melting of the snow accounted for record floods. About the same time the Waimakariri River, in Canterbury, rose to an abnormal height, and inundated much of the surrounding country.

During the month thunderstorms were rather frequent, and one in Hawke's Bay on the 12th did considerable damage to orchards.

Several light frosts occurred, particularly in the South Island, and the cold southerly which brought snow to the uplands on the 27th and 28th caused loss among newly-shorn sheep. Shearing and haymaking were greatly retarded, and growth in vegetation was backward for the time of the year in most parts of the Dominion.

Anticyclonic conditions ruled between the 20th and 24th, and this was the longest period of generally fair weather experienced during the month.

December.—Precipitation during December was above normal over most of the Dominion, the only parts recording a deficiency being the central portion of the North Island and the West Coast districts of the South Island.

Southerly winds and cold, changeable conditions prevailed during the first week of the month, owing to the presence of an intense storm eastward of the Dominion.

A barometric pressure of 28.97 inches was reported from the Chatham Islands on the morning of the 3rd, while in New Zealand it averaged 0.75 inches higher. Westerly depressions passing in the south on the 11th and 20th respectively accounted for strong north-west winds generally and heavy rain in the western districts.

Two disturbances were in evidence about Christmastide, one in the north bringing very heavy rain, but they neutralized each other so far as wind was concerned, though together accounting for mild, dull, and wet weather generally.

The weather, on the whole, was very changeable for a summer month, and detrimentally affected haymaking and shearing operations.

The following tables show the difference, above or below the mean, for each month in the year:—

Continuous line showing the mean monthly rainfall.

Dotted line showing the total monthly rainfall from January, 1926, to January, 1927 (inclusive).

Continuous line showing the mean monthly temperature in shade for past years.

Dotted line showing the mean monthly temperature from January, 1926, to January, 1927 (inclusive).