In describing the watershed of this wide region, I may point out that the area of the lake basin may be defined by those divisions of the country which give rise to the rivers, creeks, and other waters flowing into it, and which have their origin for the most part in the extensive mountain ranges scattered over various parts of the table-lands. Although on the most recent maps of the colony only about eight rivers, namely, the Waitahanui, Hinemaiai, Tauranga, Waimarino, Upper Waikato, Waihaha, and Waihora, are represented as flowing into the lake, I found on the western shore, in addition to other smaller streams, the Kuramanga, Kuratao, Whareroa, Mangakara, Whanganui,[40] Waikino, and Waikomiko, besides three other streams on the northern shore, the names of which I was unable to obtain. It will therefore be seen that there are not less than seventeen rivers running into this lake, with innumerable smaller streams, while it should be remarked that the only river or stream of any kind flowing out of this immense area of water is the Waikato, at the north-east end. Most of the rivers on the eastern side of the lake receive their waters from the north-western slope of the Kaimanawa mountains, and those from the west, from the Tuhua, Hauhungaroa and Hurakia ranges. Comparatively little water flows into the lake at the northern end, since the country thereabouts dips mostly in the direction of the valley of the Waikato. It is in fact at its southern end that the lake receives its greatest volume of water from the Upper Waikato river, and its numerous tributaries. This river, rising at an altitude of 7000 feet on the eastern side of Ruapehu, is fed by the snows of that mountain, and of Tongariro, as well as by the enormous watershed of a large portion of the Kaimanawa mountains, along the western base of which it runs in its winding course to the lake, receiving likewise on its way the eastern streams of the Kakaramea ranges, and the overflowing waters of Lake Rotoaira, as they descend by the Poutu river. With but one outlet to relieve it of this tremendous watershed, it is not surprising that the waters of the lake rise rapidly during the rainy season, while with the continuance of heavy winds its waves are lashed into fury, and break upon its shores with the force and roar of a raging sea.