We left Ngatokorua with a pressing invitation to return again, and took an easterly course across the Waimarino Plains, in the direction of Tongariro, with the view of tracing up the source of the Whanganui River, which, we had learned from the natives, rose somewhere in the northern side of the volcano, and after that I had determined to examine the tapued springs and the crater of Ketetahi, which were situated a short distance further to the east on the same mountain. The whole country we passed through to reach Tongariro consisted of a series of magnificent plains, richly grassed, surrounded for the most part by forest, and dotted here and there with patches of bush that grew in the centre of the plains and bordered many of the streams. We crossed the Mangahuia and Whakapapa rivers, both swift streams, flowing in a north-westerly direction to join the Upper Whanganui. Beyond the Waimarino Plains was an equally attractive stretch of country of the same description, known as Okahakura, and through the centre of which wound the Mangatepopo River, likewise a tributary of the Whanganui. When we ascended the hills and rugged spurs which surrounded the great volcano of Tongariro on the north, we found them to be composed mostly of scoria and trachytic rock, but covered for a long distance up their sides with a thick vegetation of native grasses and dwarf shrubs. The tops of the larger spurs were, however, very rugged and barren, while the depression round the lip of the crater, which we had observed when at the summit of the great cone, was distinctly visible, and naturally made the mountain appear less elevated on this than on its southern side. The splendid cone was, however, now covered with a white canopy of snow almost to its base, while the summit here and there was tinged of a bright yellow with deposits of sulphur crystals, and as its white coil of steam floated over its gracefully pointed top the effect was beautiful in the extreme. On one of the principal spurs to the north-west of the great cone we found the source of the Whanganui bursting out through a narrow rocky gorge at an altitude of 3700 feet above the level of the sea, the water evidently arising from mountain springs, and at certain times from the melting of the snows. The river from this point runs rapidly down the winding gorges of the mountains, and, after receiving in its course the waters of numerous other streams, winds across the Okahakura Plains, and afterwards enters the dense forests of the Tuhua, and then taking a bold sweep to the north-west receives the waters of the Ongaruhe and numerous other streams, as it flows in its long course to join the sea in the south. The Whanganui, which, after the Waikato, forms the most important river of the North Island, receives the whole of the western watershed of the great central table-land, besides that of other divisions of the country.