The next feature to be noticed is the jointed structure of the rocks. Although the joints cross each other in all directions, apparently without order, there are two prevailing systems of joints which have an important influence on the configuration of the surface. These are: First, a system of vertical cross-joints at right angles to the stratification, and running in unbroken lines for great distances, with such regularity that they might easily be mistaken for planes of stratification were it not for the frequent occurrence of beds of trap-rock, the outcrop of which marks unmistakably the true bedding; secondly, a system of joints, more or less inclined to the horizon, not running in parallel planes, but arranged in a series of curves radiating from a common centre.
The effect of this system of jointing, combined with the strike of the beds, or the direction of the axis of folding, is to produce two distinct systems of valleys in the central chain, the direction of which is very remarkable. The one radiates from a common centre, situated about fifty miles north of Mount Darien, in the sea near Cliffy Head. This system includes all the principal valleys from the Teremakau on the north to the Makarora on the south, their direction varying from N. 82° E. to S. 30° W., giving the idea that the country has been starred, just as a mirror is starred by a violent blow. To the other system belong the valleys of rivers and watercourses, running either on the strike of the beds, or in the direction of the cross-joints, or in a zigzag course, following alternately these two directions and giving to the cliffs which bound these valleys a peculiar rectangular appearance, resembling ruined masonry on a gigantic scale.
The western slope and part of the central chain consist of crystalline rocks and metamorphic schists resting on a basis of granite, that presents itself here and there to the view in the rugged bluffs and declivities on the west coast. To the eastward of the crystalline zone stratified sedimentary rocks appear, such as slates, sandstones, conglomerates and indurated shales. These compose the greater part of the eastern side of the central chain, exhibiting everywhere huge foldings. The extensive development of limestones such as are peculiar to the European Alps is totally lacking, and it is easily seen that only the eastern half of a complete mountain system has been preserved, while the western half is buried in the depth of the main.
Flora and Fauna.
At Mount Cook the botanist has a splendid field before him. The alpine and sub-alpine flora is of the most beautiful and diversified character, and to the traveller making his first visit from Australia or the Northern Hemisphere it will also have the charm of novelty. Among the shrubs there is considerable variety, and many of the bushes are during the autumn laden with prettily coloured berries. Among the larger trees a variety of beech is most prominent. The pretty green foliage of the broadleaf is also conspicuous, and a number of the Coniferæ. But it is probably among the herbaceous plants that the botanist will delight most to linger.
On Mount Torlesse, in the lower and more eastern range, Dr. von Haast, during his early explorations, collected over two hundred flowering plants, over thirty of which were new to science, and even in these later years new discoveries are still being made.
Splendid herds of red deer inhabit the heights and vales of the lesser Alps, so that after the mountaineer has bagged his peaks he can change his ice-axe for his rifle and bag a few fine heads as well. Recently chamois have been successfully acclimatized in the Mount Cook region, while elk and moose have been liberated in other localities. In the rivers of both the North and the South Island there are fish that will make the rods bend and the reels give to some purpose.
The birds of the alpine and sub-alpine regions are especially interesting. The kiwi and the kakapo, those strange flightless birds of the South and West, will prove a novelty to the explorer from northern climes; while the inquisitive friendly weka, with his rudimentary wings, and the curious kea, who digs into the loins of the living sheep with his powerful hooked beak to make a meal of the kidney fat, will be a never-failing source of interest to the traveller, who will find the former a thief and the latter rather a noisy companion whilst he is endeavouring to seek repose in one or other of the iron-roofed mountain huts. Wood-pigeons and a bush parrot known as the kaka are also to be found, and, in unexplored country, may make a welcome addition to the larder. A native thrush, two species of cuckoo that come down from the equatorial islands, wrens and fly-catchers are also met with; while the tui and the bell bird sometimes fill the woods with glorious song. In a chapter on mountains there is not space to do them all justice; but anyone who is specially interested in that strange bird, the kea, will find his habits and his character more fully described in my recently published book, A Climber in New Zealand.
Glaciers.
The following table, showing comparative sizes of the Canterbury or east coast glaciers compiled by Mr. T. N. Brodrick of the New Zealand Government Survey Department, will give some idea of the extent of the glaciation and prove interesting to anyone contemplating a mountaineering expedition to the Southern Alps: