estimated at nearly 1,100,000 cubic ft. a minute. On the west the only two rivers of importance are the Buller and the Grey, the former justly famous for the grandeur of its gorges. Large and deep lakes fill many of the mountain valleys. Te Anau and Wakatipu (54 m. long) are the chief, though Manapouri is the most romantic. Aorangi (Mt. Cook) is easily first among the mountain peaks. Its height, 12,349 ft., is especially impressive when viewed from the sea off the west coast. On the north-east a double range, the Kaikouras, scarcely fall short of the Southern Alps in height and beauty. Apart from the fjords and lakes the chief beauties of the Alps are glaciers and waterfalls. The Tasman glacier is 18 m. long and has an average width of 1 m. 15 chains; the Murchison glacier is 10 m. in length. To the west of Aorangi glaciers crawl into the forest as low as 400 ft. above sea-level. Among waterfalls the Sutherland is 1904 ft. high, but has less volume than the Bowen and others. The finest mountain gorge, the Otira, is also the chief route from the east to the west coast. It begins on the western side of Arthur’s Pass, a gap the floor of which is 3100 ft. above the sea. Generally the open and readily available region of South Island extends from the Kaikouras along the east and south-east coast to the river Waiau in Southland. It has a mean breadth of some 30 m. In compensation the coal and gold, which form the chief mineral wealth, are found in the broken and less practicable west and centre, and these portions also furnish the water-power which may in days to come make the island a manufacturing country. (W. P. R.)
Geology.—New Zealand is part of the Australasian festoon, on the Pacific edge of the Australasian area. Unlike Australia, its geological structure is unusually varied, and owing to its instability, it includes, for its size, an unusually complete series of marine sedimentary rocks. It has, moreover, been a volcanic area of long-continued activity. The physical geography of New Zealand is closely connected with its geological structure, and is dominated by two intersecting lines of mountains and earth movements. The Southern Alps, the backbone of the South Island, rest on a foundation of coarse gneisses and schists, that are quite unrepresented in the North Island. The continuation of this line of old rocks is occupied by the basins of the Wanganui river and Taupo. E. Suess therefore suggested that the northern continuation of the Alps had foundered, and its summits been buried beneath the Pliocene marine rocks of the Wanganui basin and the volcanic rocks of the Taupo area.
The oldest rocks are Archean, represented by the band of gneisses and schists exposed along the western foot of the Southern Alps. To the south of the district in southern Westland, where the Alps have passed out to sea, the Archeans become more extensive; for they spread eastward and underlie the whole of the dissected tableland of Otago. It has been suggested that the jasperoids and diabases of the Tarawera Mountains on the North Island may be of Upper Archean age, from their resemblance to the Heathcotian rocks of Australia. No Cambrian rocks have as yet been discovered, but the Ordovician system is represented by the Aorere beds in the north-western part of the South Island. Here they contain numerous graptolites, including Tetragraptus, Dichograptus and Didymograptus. The Silurian system is represented by the Baton river beds to the west of the Aorere beds, occurring in the basin of the Motueka river, which flows into Tasman Bay. The Devonian system is well exposed in the Reefton mining field. The Carboniferous system includes either the whole or a large part of the Maitai beds. The Maitai beds include a thick mass of slates and sandstones, which form the bulk of the Southern Alps, whence branches extend southeastward to the coast. The beds take their name from the Maitai river near Nelson; they are largely developed in the mountains of the Tararua-Ruahine-Raukumara chain, on the eastern side of the North Island; they occur in the Kaikoura Mountains, and an outlier forms Mount Torlesse, near the eastern edge of the Southern Alps, west of Christchurch. The Maitai beds have generally been considered to be Carboniferous from the presence of species of Productus found in the Permo-Carboniferous of New South Wales. But Professor Park has obtained Jurassic fossils in the Maitai series; so that it will probably be ultimately divided between the Carboniferous and Jurassic. The two systems should, however, be separable by an unconformity, unless the Maitai series also includes representatives of the Kaihiku series (the New Zealand Permian), and of the Wairoa series, which is Triassic.
New Zealand includes representatives of all the three Mesozoic systems. The Hokanui group comprises the Triassic Wairoa and Otapira beds, and the Jurassic Mataura beds. The Wairoa series includes marine limestones characterized by Monotis salinaria, and the Otapira series is characterized by Spiriferina spatulata. The Mataura beds are largely of estuarine formation; they contain oil shales and gas springs.
The Cretaceous system includes the Waipara series, a belt of chalky limestones with some phosphate beds at Clarendon in eastern Otago. Their fossils include belemnites, ammonites, scaphites and marine saurians, such as Cimoliosaurus. These Cretaceous limestones are interbedded with glauconitic greensands, as at Moeraki Point in eastern Otago. The second type, of Cretaceous is a terrestrial formation, and is important as it contains the rich coal seams of Greymouth, Westport and Seddonville, which yield a high quality of steam coal. Cretaceous coals have long been worked in the North Island, north of Auckland, on the shores of the Bay of Islands, where the age of the coal is shown by its occurrence under the Whangarei or Waimio limestone.
The Cainozoic system is represented by Oligocene, Miocene, Pliocene and Pleistocene beds. The best-known Oligocene rocks are the limestones of Oamaru and the brown-coal measures of Waikato. The Oamaru limestones have been largely used for building stones; they are a pure white limestone, largely made up of foraminifera, bryozoa and shell fragments, and contain the teeth of sharks (e.g. Carcharodon) and of toothed whales such as Squalodon serratus. In southern Otago the Oligocene beds are brown coals and lignites with oil shales, which, at Orepuki, contain 47% of oil and gas, with 8% of water. The Miocene Pareora beds occur to the height of 3000 or 4000 ft. above sea-level, in both the North and South Islands. Some of its fossils also occur in the Oamaru series, but the two series are unconformable. In Westland the Miocene includes the Moutere gravels, which rest on the summit of Mount Greenland, 4900 ft. above sea-level.
Marine beds of the Pliocene are best developed in the Wanganui basin. They consist of fine clays with nodular calcareous concretions rich in fossils. The Pleistocene system in the South Island includes glacial deposits, which prove a great extension of the New Zealand glaciers, especially along the western coast. The glaciers must have reached the sea at Cascade Point in southern Westland. On the eastern side of the Alps the glaciers appear to have been confined to the mountain valleys. The Pleistocene swamp deposits are rich in the bones of the moa and other gigantic extinct birds, which lived on until they were exterminated by the Maori. The Cainozoic volcanic history of New Zealand begins in the Oligocene, when the high volcanic domes of Dunedin and Banks Peninsula were built up. The Dunedin lavas including tephrites and kenytes correspond to the dacite eruptions in the volcanic history of Victoria. The building up of these domes of lavas of intermediate chemical type was followed by the eruption of sheets of andesites and rhyolites in the Thames
