Frequently its bed had to be cleared of palm trees to make it passable for the pack train, and big boulders and heavy undergrowth made travel rough.

Then, ascending a cordon which led directly up to the main range, we followed for a while a dim trail on which the Apaches used to drive the herds of cattle they had stolen, and which is said to lead to a place so inaccessible that two Indians could keep a whole company at bay.

The surface soil we had lately been travelling over was covered with boulders and fragments of conglomerate.
The Sierra Madre was now so close that the tilted masses of its rocks seemed to overhang our tents threateningly where we had pitched them at its foot.

From this camp we had about the same splendid view as from the ridge of Huehuerachi we had just left behind; and between us and the foot-hills of the Sierra de Bacadehuachi stretched out a vast mass of barren-looking rocks and hills.

The Mexicans call them _agua blanca_, a designation also applied to the small water course that runs through them in a northerly and southerly direction, but which from our point of view could not be made out in the chaotic confusion.