The Rocks of the North Wall. The rock bands on the opposite walls, a large part of the way down, are like those found on the same north wall seen from El Tovar. First there is the band of cherty limestone, from which a sloped talus leads to the creamy sugary sandstone. Immediately below this begins the "red," which descends in strata of varying width and color down to a rather narrow-appearing slope of red talus, which leads the eye to the widest member of all the Grand Canyon strata. This is the so-called red-wall limestone. All these strata, from the rim down, are said to be in the Upper and Lower Carboniferous Systems.

Below this majestic wall appear the variegated strata of the Cambrian, in grays, buffs, olives, greens and yellows.

The Tilts. Now we see a large exposure of the nonconformable strata, which, on account of their very markedly tilted condition, have been named "The Tilts." Below this is found the Archaean rock.

It is hard for any but the well-trained observer to realize that practically the same conditions that exist on the north wall, exist on the south wall, directly under his feet, except that the Algonkian is absent. The talus shuts off the view, and it seems impossible that there can be such great precipice walls as the opposite mural face reveals. It is not as high, however, on this side as it is on the other, by fully one thousand six hundred and fifty feet. The difference is caused by the great upthrust in the earth's crust, which detached Powell's Plateau from the Kaibab Plateau.