In describing the physical and geological features of Ruapehu, I will only treat these subjects briefly at this stage, and only with a view of affording a general idea of the great mountain, the description of which will be more fully dealt with when describing the ascent of its northern peak and the exploration of the sources of the Wangaehu and Waikato Rivers on its eastern side. As during these two ascents we accomplished considerably over 10,000 feet of actual climbing over its surface, we had a good opportunity of examining this colossal monument of plutonic fires, and judging from the magnitude of the results of igneous action we then beheld, both in wonder and admiration, there can be no doubt that there is no better or more interesting field for geological research than that afforded by this marvellous centre of extinct volcanic forces. Ruapehu is situated immediately in the centre of the great table-land which forms the most elevated portion of the North Island, and in the very heart, as it were, of the extensive system of extinct volcanic cones, which constitutes one of the most remarkable and interesting features of this division of the country. The mountain, which takes rank among the largest extinct volcanoes in the world, assumes the form of an enormous truncated cone, with a far-reaching base of oblong form, and which gradually narrows towards the summit, at which point the mountain is nearly a mile in length from its northern to its southern peak. Its base, if calculated from where it springs from the level plains, may be estimated at about sixty miles in circumference. At each end of the mountain are two colossal cone-shaped peaks, and between them the minor peaks rise up in fantastic shapes, which change in outline and assume varying proportions with almost magical effect, as the mountain is beheld from different points of view. In fact, it is the succession of magnificent scenery thus produced which forms one of the grandest features of this marvellous monument of volcanic forces. For the greater part, the country surrounding Ruapehu is entirely open, and consequently the grand mountain is seen to wonderful advantage as it towers majestically to the skies. Immediately to the north are the Tongariro and Waimarino Plains, to the east is the Rangipo Table-land, in the centre of which, and stretching down the sides of the huge mountain, is the Onetapu Desert--a vast expanse of scoria, covering some fifty square miles--while to the south are the Murimotu Plains. On its lower northern and eastern slopes the mountain gives life to a vegetation in all respects similar to that found on Tongariro, but on its southern and western sides a primeval forest, in which the trees are of colossal growth, creeps almost up to the edge of the snow-line. To really realize the magnitude of this mountain king of the North Island, one must stand on its summit and look down upon its scoria-strewn base, covering millions of acres, explore its deep,