cover an area of about three acres, a mere trifle compared with the square miles of similar formations on Gardiner's River and in the Yellowstone Basin. In the same neighborhood is a system of bubbling mud-pools, miniature copies of those on the Yellowstone above the falls. The principal group, lying in a ravine nearly a quarter of a mile long, is described by Dr. Hochstetter as follows: "The entrance to the ravine is overgrown with a thicket and rather difficult of access; it also requires considerable caution, as suspicious places have to be passed, where the visitor is in danger of being swallowed up in heated mud. Inside, the ravine has the appearance of a volcanic crater. The bare walls, utterly destitute of vegetation, are terribly fissured and torn, and odd-looking rocky serratures, threatening every moment to break loose, loom up like dismal spectres from red, white and blue fumarole-clay--evidently the last remains of decomposed rocks. The bottom of the ravine is of fine mud, scattered with blocks of silicious deposit, like cakes of floating ice after a thaw. Here, a big caldron of mud is simmering; there, lies a deep basin of boiling water; next to this is a terrible hole, emitting hissing jets of steam, and further on are mud-cones from two to five feet high, vomiting hot mud from their craters with dull rumblings, and imitating on a small scale the play of large fire volcanoes." The gay colors of the Yellowstone mud-springs are frequently exhibited in the volcanic lake district of New Zealand, and so indeed are most of the other phenomena we have been studying, though on a far less magnificent scale. For example, the grandest "Firehole basin" on the island occupies the Shallow valley of a little stream the Waikato, for the distance of a mile. It is but a cabinet exhibition comparatively, yet the learned geologist of the _Novara_ expedition grows eloquent in his description of it. "In the morning a dense fog lay upon the Waikato, but it soon vanished, the sun shone brightly into the valley, and now--what a sight! In its swift course, forming rapids after rapids, the Waikato was plunging through the deep valley between steep-rising mountains; its floods whirling and foaming round two small rocky islands in the middle of the river, were dashing with a loud uproar through the defile of the valley. Along its banks white clouds of steam were ascending from hot cascades falling into the river, and from basins full of boiling water shut in by a white mass of stone. Yonder a steaming fountain was rising and falling; now there sprung from another place a second fountain; this also ceased in its turn; then two commenced playing simultaneously, one quite low at the river bank, the other opposite on a terrace; and thus the play continued with endless changes, as though experiments were being made with grand waterworks, to see whether the fountains were all in perfect order, and whether the waterfalls had a sufficient supply.