The next point of interest was the delta of the Upper Waikato, where that river flows into the lake. Here the strand was covered with a light fluvial drift and pumice sand, through which our horses struggled fetlock deep. At this point the river flows into a semicircular bay, formed by a bend in the lake shore, which was here covered with flocks of a small graceful species of seagull, called by the natives _tarapunga_. The head and breast and under part of the body of this bird were snow white, the wings of a light grey, tipped with black, and the tail white with black bars. It frequents all parts of the lake, but is found more generally at its southern end. We forded the river some little distance above the extreme point of the delta, where the bed of the stream was about forty yards in width, and where the overhanging banks, worn away by its perpetual energy, were evidently in a constant state of transition. The river, owing to the melting of the snows at Ruapehu, was coming down at a rapid rate, and the water sweeping over our horses' backs nearly carried them from under us. The bed of the river was moreover covered with large boulders, and the animals plunged desperately in their endeavours to keep their footing against the strong stream. The banks hereabout were covered with _toetoe_ grass and strewn with drift timber in those parts where the river during the heavy floods had burst its boundary and swept over the surrounding country. This is one of the most dangerous crossing-places around the lake at the time of a strong fresh, as the waters in their rapid descent from the highlands to the south carry everything in their course into the broad lake beyond. FOOTNOTES: [Footnote 41: The river, after leaving the falls, flows through a deep valley, which would seem to indicate, by its peculiar trough-like character, that the bed of the stream must, at some age or another, have been considerably higher than it is at the present time, and that the river gradually cut its deep channel through the yielding pumice formation, until the great barrier of rock forming the falls was met with, since which period it has cut its lower bed some fifty feet beneath. In this lower valley the shores rise abruptly from the margin of the water to a height of from forty to sixty feet, and then merge into a series of level plateaux or terraces, which, stretching inland for some distance, are again succeeded by others of a similar kind, which, in many places, rise in regular gradations above each other, like giant steps. For miles down the valley of the river the wonderful terraced elevations, formed entirely of disintegrated pumice rock, which is everywhere rounded by the action of water, form the principal features of the country, and some of the hills which compose them are so symmetrical in form, and level and angular in outline, that they appear to have been built up by artificial means.]