The doctor and George Houston here left us, and went on to a salt-lick famous for game, but this proved a failure, some one having carelessly set fire to the tract. Indeed, in summer it is hard not to start these almost endless fires, since a spark or a bit of pipe-cinder will at once set the grasses ablaze, to the destruction of hunting and the annoyance of all travellers, to whom a fire is something which suggests man, and the presence of man needs, sad to say, an explanation. At 6 A. M., August 6th, Captain G. and the lad Lee also went off on a side-trail after game, and with lessened numbers we broke camp rather late, and rode into dense woods down a steady descent on a fair trail. The changes of vegetation were curious and sudden--from pines and firs to elders, stunted willows and sparse cottonwood bending over half-dry beds of torrents, with vast boulders telling of the fierce fury of water which must have undermined, then loosened and at last tumbled them from the hillsides. These streams are, in the early spring, impassable until a cold day and night check the thaw in the hills, and thus allow the impatient traveller to ford. Gradually, as we rode on, the hills to our left receded, and on our right the summits of Index and Pilot stood up and took the morning--long, straggling volcanic masses of deep chocolate-brown, black as against the crystalline purity of cloudless blue skies, rising in the middle to vast rugged, irregular cones fourteen thousand feet above tide. From the bewildering desolateness of these savage peaks the eye wanders to the foot-hills, tree-clad with millions of pines, and lower yet to the wide valley of the West Branch of Clarke's Fork of the Yellowstone, through which a great stream rushes; and then, beyond the river, park over park with gracious boundaries of fir and pine, and over all black peak and snow-clad dome and slope, nameless, untrodden, an infinite army of hills beyond hills. The startling combination of black volcanic peaks with gray and tinted limestone still makes every mile of the way strange and grand. In one place the dark rock-slopes end abruptly in a wall of white limestone one hundred to two hundred feet high and regular as ancient masonry. A little below was a second of these singular dikes, which run for twenty miles or more.