Page:Popular Science Monthly Volume 65.djvu/374

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370
POPULAR SCIENCE MONTHLY.

THE LAKES OF NEW ZEALAND.[1]
By KEITH LUCAS.

IT is difficult to make general statements which will sum up any points in the morphology of the lakes of New Zealand. This difficulty arises in the main from the strange heterogeneity of the lake basins. It would be hard, for example, to find any points of resemblance between two lakes such as Taupo and Wakatipu. In the latter the lake-basin seems to be an integral part of the surrounding country; its slopes continue the slopes of the mountain-sides. It is a mountain valley filled with water, and if it were drained dry it would scarcely appear in any way remarkable. Contrast with this the basin of Taupo. It is a trough abruptly sunk in a country which seems wholly unprepared to receive it. The perpendicular cliffs which form its western shore drop suddenly down from among hills whose slopes are comparatively gentle; in one place the cliff even forms a clean section through a large hill, cutting it from base to summit with a perpendicular face over 1,000 feet in height.

In their relations to the surrounding country, Manapouri may be classed with Wakatipu, and Rotoiti with Taupo. In the former group there is a correspondence between the position of the deepest water and the gradient of the land in the immediate nighborhood; in the latter group no such relations can be traced. In Wakatipu the greatest heights combined with the steepest gradients are those of the Remarkables and Cecil peak, and between these the deepest water lies. In Manapouri the same conditions are fulfilled by the Cathedral peaks and Cone peak. The existence of this relation indicates a rough correspondence in type between these two southern lakes and such familiar types as the lakes of the English Lake District.

A further point of similarity between Wakatipu and Manapouri is the presence in each of a large flat area where the water is deepest. This peculiarity of form is not to be confused with the tank-like form of Taupo. In the former, sloping sides lead down to a level floor, which marks the limit of depth; in the latter, perpendicular sides lead to a level floor, beyond which there is a further slope to the deepest point. In Lake Taupo, the steepest gradient leading to the highest point is found at Karangahape, on the western shore, but the deepest water lies in the northeast part of the lake. In Rotoiti there is a similar


  1. Conclusion of an article in the Geographical Magazine for June.