It will help comprehension of the picture quality of this remarkable canyon to recall that it is carved out of the products of volcanism; its promontories and pinnacles are the knobbed and gnarled decomposition products of lava rocks left following erosion; its sides are gashed and fluted lava cliffs flanked by long straight slopes of coarse volcanic sand-like grains; its colors have the distinctness and occasional luridness which seem natural to fused and oxidized disintegrations. Geologically speaking, it is a young canyon. It is digging deeper all the time. Yellow, of course, is the prevailing color. Moran was right. His was the general point of view, his message the dramatic ensemble. But, even from Artists' Point, closer looking reveals great masses of reds and grays, while Inspiration Point discloses a gorgeous palette daubed with most of the colors and intermediate tints that imagination can suggest. I doubt whether there is another such kaleidoscope in nature. There is apparently every gray from purest white to dull black, every yellow from lemon to deep orange, every red, pink, and brown. These tints dye the rocks and sands in splashes and long transverse streaks which merge into a single joyous exclamation in vivid color whose red and yellow accents have something of the Oriental. Greens and blues are missing from the dyes, but are otherwise supplied. The canyon is edged with lodge-pole forests, and growths of lighter greens invade the sandy slants, at times nearly to the frothing river; and the river is a chain of emeralds and pearls. Blue completes the color gamut from the inverted bowl of sky. No sketch of the canyon is complete without the story of the great robbery. I am not referring to the several hold-ups of the old stage-coach days, but to a robbery which occurred long before the coming of man--the theft of the waters of Yellowstone Lake; for this splendid river, these noble falls, this incomparable canyon, are the ill-gotten products of the first of Yellowstone's hold-ups. Originally Yellowstone Lake was a hundred and sixty feet higher and very much larger than it is to-day. It extended from the headwaters of the present Yellowstone River, far in the south, northward past the present Great Fall and Inspiration Point. It included a large part of what is now known as the Hayden Valley. At that time the Continental Divide, which now cuts the southwest corner of the park, encircled the lake on its north, and just across the low divide was a small flat-lying stream which drained and still drains the volcanic slopes leading down from Dunraven Peak and Mount Washburn.