marked off from one another in just this sharp way, as if each one was, indeed, the work of a separate day of creation. Nature appears at long intervals to turn over a new leaf and start a new chapter in her great book. The transition from one geologic age to another appears to be abrupt: new colors, new constituents, new qualities appear in the rocks with a suddenness hard to reconcile with Lyell's doctrine of uniformitarianism, just as new species appear in the life of the globe with an abruptness hard to reconcile with Darwin's slow process of natural selection. Is sudden mutation, after all, the key to all these phenomena? We ate our lunch on the old Cambrian table, placed there for us so long ago, and gazed down upon the turbulent river hiding and reappearing in its labyrinthian channel so far below us. It is worth while to make the descent in order to look upon the river which has been the chief quarryman in excavating the canon, and to find how inadequate it looks for the work ascribed to it. Viewed from where we sat, I judged it to be forty or fifty feet broad, but I was assured that it was between two and three hundred feet. Water and sand are ever symbols of instability and inconstancy, but let them work together, and they saw through mountains, and undermine the foundations of the hills. It is always worth while to sit or kneel at the feet of grandeur, to look up into the placid faces of the earth gods and feel their power, and the tourist who goes down into the canon certainly has this privilege. We did not bring back in our hands, or in our hats, the glory that had lured us from the top, but we seemed to have been nearer its sources, and to have brought back a deepened sense of the magnitude of the forms, and of the depth of the chasm which we had heretofore gazed upon from a distance. Also we had plucked the flower of safety from the nettle danger, always an exhilarating enterprise. In climbing back, my eye, now sharpened by my geologic reading, dwelt frequently and long upon the horizon where that cross-bedded Carboniferous sandstone joins the Carboniferous limestone above it. How much older the sandstone looked! I could not avoid the impression that its surface must have formed a plane of erosion ages and ages before the limestone had been laid down upon it. We had left plenty of ice and snow at the top, but in the bottom we found the early spring flowers blooming, and a settler at what is called the Indian Gardens was planting his garden. Here I heard the song of the canon wren, a new and very pleasing bird-song to me. I think our dreams were somewhat disturbed that night by the impressions of the day, but our day-dreams since that time have at least been sweeter and more comforting, and I am sure that the remainder of our lives will be the richer for our having seen the Grand Canon. III THE SPELL OF THE YOSEMITE I