Having satisfied myself as to the geological formation of the Kaimanawa Mountains, I next determined to trace up the Whangaehu and Waikato Rivers to their source in Ruapehu. Striking our camp at Mamanui, we took a south-westerly course for some distance, until we struck the Whangaehu River, which we found winding across the desert in the form of a wide, rushing stream. Once on the opposite side, we were again fairly on the Onetapu Desert, and we shaped our course in the direction of the eastern side of Ruapehu, where a tremendous ravine seemed to lead right into the very heart of the mountain. When passing over some portions of the great scoria plain, we found all of the plants and shrubs peculiar to the region growing together with dwarf trees, but all so artistically dispersed by the hand of Nature as to appear like miniature gardens, with winding walks that formed a perfect labyrinth. In fact, so beautifully and carefully designed were some of these parterres, that it was almost impossible to believe that they had not been artificially formed. Every species of plant that we had hitherto found in the district grew in them, with a vast variety of shrubs we had not before observed, while the scoria winding about the clumps of vegetation was so even as to appear as if it had been artificially rolled down. The Whangaehu River, which takes its rise in the eastern side of Ruapehu, is one of the largest streams in the colony. Bursting forth high up in the snows of the mountain, it crosses the desert in an easterly direction, and then, with the fall of the country, takes a swift bend towards the south in its course to the coast, where it joins the sea, in a distance of about sixty miles from its source. From the point where it issues from the mountain, and for many miles as it winds through the plains, its waters are rendered perfectly white from the enormous amount of alum with which they are charged. We had been informed by the natives at Tokanu that the source of this river rose in an enormous black rock, or dark bluff, which forms a conspicuous feature near the eastern base of the mountain, and it was therefore towards this point we directed our course.