So sure are the inhabitants of these oases that it is not going to rain that their houses are built merely as a shelter against the sun and wind.  They are made of the canes that grow in the jungles of the larger river bottoms, or along the banks of irrigating ditches.  On the roof the spaces between the canes are filled with adobe, sun-dried mud.  It is not necessary to plaster the sides of the houses, for it is pleasant to let the air have free play, and it is amusing to look out through the cracks and see everything that is passing.

That evening we saddled in the moonlight.  Slowly we climbed out of the valley, to spend the night jogging steadily, hour after hour, across the desert.  As the moon was setting we entered a hilly region, and at sunrise found ourselves in the midst of a tumbled mass of enormous sand dunes—­the result of hundreds of medanos blown across the pampa of Majes and deposited along the border of the valley.  It took us three hours to wind slowly down from the level of the desert to a point where we could see the great canyon, a mile deep and two miles across.  Its steep sides are of various colored rocks and sand.  The bottom is a bright green oasis through which flows the rapid Majes River, too deep to be forded even in the dry season.  A very large part of the flood plain of the unruly river is not cultivated, and consists of a wild jungle, difficult of access in the dry season and impossible when the river rises during the rainy months.  The contrast between the gigantic hills of sand and the luxurious vegetation was very striking; but to us the most beautiful thing in the landscape was the long, glistening, white mass of Coropuna, now much larger and just visible above the opposite rim of the valley.

At eight o’clock in the morning, as we were wondering how long it would be before we could get down to the bottom of the valley and have some breakfast, we discovered, at a place called Pitas (or Cerro Colorado), a huge volcanic boulder covered with rude pictographs.  Further search in the vicinity revealed about one hundred of these boulders, each with its quota of crude drawings.  I did not notice any ruins of houses near the rocks.  Neither of the Tejada brothers, who had been past here many times, nor any of the natives of this region appeared to have any idea of the origin or meaning of this singular collection of pictographic rocks.  The drawings represented jaguars, birds, men, and dachshund-like dogs.  They deserved careful study.  Yet not even the interest and excitement of investigating the “rocas jeroglificos,” as they are called here, could make us forget that we had had no food or sleep for a good many hours.  So after taking a few pictures we hastened on and crossed the Majes River on a very shaky temporary bridge.  It was built to last only during the dry season.  To construct a bridge which would withstand floods is not feasible at present.  We spent the day at Coriri, a pleasant little village where it was almost impossible to sleep, on account of the myriads of gnats.