An excursion which Cotter and I made to the top of the Three Brothers proved of interest. A half-hour’s walk from camp, over rolling granite country, brought us to a ridge which jutted boldly out from the plateau to the edge of the Yosemite wall. Upon the southern side of this eminence heads a broad, débris-filled ravine, which descends to the valley bottom; upon the other side the ridge sends down its waters along a steep declivity into a lovely mountain basin, where, surrounded by forest, spreads out a level expanse of emerald meadow, with a bit of blue lakelet in the midst. The outlet of this little valley is through a narrow rift in the rocks leading down into the Yosemite fall.
Along the crest of our jutting ridge we found smooth pathway, and soon reached the summit. Here again we were upon the verge of a precipice, this time four thousand two hundred feet high. Beneath us the whole upper half of the valley was as clearly seen as the southern half had been from Capitan. The sinuosities of the Merced, those narrow, silvery gleams which indicated the channel of the Yosemite creek, the broad expanse of meadow, and débris trains which had bounded down the Sentinel slope, were all laid out under us, though diminished by immense depth.
The loftiest and most magnificent parts of the walls crowded in a semi-circle in front of us; above them the domes, lifted even higher than ourselves, swept down to the precipice-edges. Directly to our left we overlooked the goblet-like recess into which the Yosemite tumbles, and could see the white torrent leap through its granite lip, disappearing a thousand feet below, hidden from our view by projecting crags; its roar floating up to us, now resounding loudly, and again dying off in faint reverberations like the sounding of the sea.
Looking up upon the falls from the valley below, one utterly fails to realize the great depth of the semi-circular alcove into which they descend.
Looking back at El Capitan, its sharp, vertical front was projected against far blue foot-hills, the creamy whiteness of sunlit granite cut upon aërial distance, clouds and cold blue sky shutting down over white crest and jetty pine-plumes, which gather helmet-like upon its upper dome. Perspective effects are marvellously brought out by the stern, powerful reality of such rock bodies as Capitan. Across their terrible, blade-like precipice-edges you look on and down over vistas of cañon and green hillswells, the dark color of pine and fir broken by bare spots of harmonious red or brown, and changing with distance into purple, then blue, which reaches on farther into the brown monotonous plains. Beyond, where the earth’s curve defines its horizon, dim serrations of Coast Range loom indistinctly on the hazy air. From here those remarkable fracture results, the Royal Arches, a series of recesses carved into the granite front, beneath the North Dome, are seen in their true proportions.
The concentric structure, which covers the dome with a series of plates, penetrates to a greater depth than usual. The Arches themselves are only fractured edges of these plates, resulting from the intersection of a cliff-plane with the conoidal shells.
We had seen the Merced group of snow-peaks heretofore from the west, but now gained a more oblique view, which began to bring out the thin obelisk-form of Mount Clark, a shape of great interest from its marvellous thinness. Mount Starr King, too, swelled up to its commanding height, the most elevated of the domes.
Looking in the direction of the Half-Dome, I was constantly impressed with the inclination of the walls, with the fact that they are never vertical for any great depth. This is observed, too, remarkably in the case of El Capitan, whose apparently vertical profile is very slant, the actual base standing twelve hundred feet in advance of the brow.
For a week the boundary survey was continued northeast and parallel to the cliff-wall, about a mile back from its brink, following through forests and crossing granite spurs until we reached the summit of that high, bare chain which divides the Virgin’s Tears from Yosemite Creek, and which, projecting southward, ends in the Three Brothers. East of this the declivity falls so rapidly to the valley of the upper Yosemite Creek that chaining was impossible, and we were obliged to throw our line across the cañon, a little over a mile, by triangulation. This completed, we resumed it on the North Dome spur, transferring our camp to a bit of alpine meadow south of the Mono trail, and but a short distance from the North Dome itself.
After the line was finished here, and a system of triangles determined by which we connected our northern points with those across the chasm of the Yosemite, we made several geological excursions along the cliffs, studying the granite structure, working out its lithological changes, and devoting ourselves especially to the system of moraines and glacier marks which indicate direction and volume of the old ice-flow.