The existence of a body of water of the area of Lake Taupo, and of its form and depth in the centre of this elevated region, may be accounted for in several ways. It may have originated in the terrific throes of an earthquake, or by a fracture or break in the plateau. I am, however, of opinion that the present basin of the lake was at one time an active crater, which had its existence long prior to the period when the volcanic cones surrounding it sprang into existence, and that at the time of its activity it was considerably higher than it is at the present day, its subsidence or depression having been caused by one of those sudden changes peculiar to regions subject to volcanic disturbance. Moreover, many of the leading geological phenomena, as exemplified throughout the surrounding country, would seem to point to this conclusion. Perhaps one of the most remarkable features of the Taupo volcanic zone at the present day is its vast pumice plains, which radiate, as it were, from a common centre over an extensive area of country. The largest of these plains stretches in a north-easterly direction from the lake shore, with a gradual fall or incline in the same direction. It is through the western margin of this plain that the Waikato winds through its terraced valley, and it is around this valley that may be more distinctly seen the enormous deposits of pumice, which have been distributed far and wide, as it were, by the action of rapidly rolling waters. From every outward indication it would appear that this vast deposit of pumice rock had its origin in the once active crater forming the basin of the great lake, and that both Ruapehu and Tongariro rose above their still higher planes long after the period when the great Taupo crater now forming the cup of the lake was the principal outlet of volcanic fires in this wide field of Plutonic action. As a matter of fact the distribution of pumice drift around the enormous base of Ruapehu and Tongariro is as nothing when compared with the great pumice formation of North-Eastern Taupo, and this statement will apply equally to the plains westward and south-westward of the lake. The greatest overflow or distribution of pumice appears to have been, as before pointed out, at the north-eastern division of the lake basin, where the area of depression is greater than at any other part, and at a point over thirty miles distant from either Tongariro or Ruapehu. It was, I believe, when the fires of the great lake volcano died out that the waters rose from the subterranean springs below, and overflowing the then more elevated crater, distributed the light pumice rock over the area of country which had a gradual fall then as now in the direction in which the extensive deposits of pumice are still to be found. This enormous crater was, no doubt, at one time the highest point of the island, until its period of volcanic extinction and subsidence set in,