To begin with, vast lakes, which once swept westward from the bases of the Rocky Mountains, were emptied into the Pacific.  Next the draining currents transformed into rivers, cut their way through the soil which formerly covered the table-lands and commenced their attrition upon the underlying continent of sandstone.  It was a grinding which never ceased; every pebble and every bowlder which lay in the way was pressed into the endless labor; mountains were used up in channelling mountains.

The central magician was insatiable and pitiless; he demanded not only the waters, but whatever they could bring; he hungered after the earth and all that covered it.  His obedient Afreets toiled on, denuding the plateaux of their soil, washing it away from every slope and peak, pouring it year by year into the canons, and whirling it on to the ocean.  The rivers, the brooklets, the springs, and the rains all joined in this eternal robbery.  Little by little an eighth of a continent was stripped of its loam, its forests, its grasses, its flowers, its vegetation of every species.  What had been a land of fertility became an arid and rocky desert.

Then the minor Afreets perished of the results of their own obedience.  There being no soil, the fountains disappeared; there being no evaporation, the rains diminished.  Deprived of sustenance, nearly all the shorter streams dried up, and the channels which they had hewn became arid gullies.  Only those rivers continued to exist which drew their waters from the snowy slopes of the Rocky Mountains or from the spurs and ranges which intersect the plateaux.  The ages may come when these also will cease to flow, and throughout all this portion of the continent the central magician will call for his Afreets in vain.

For some time we must attend much to the scenery of the desert thus created.  It has become one of the individuals of our story, and interferes with the fate of the merely human personages.  Thurstane could not long ignore its magnificent, oppressive, and potent presence.  Forgetting somewhat his anxieties about the loved one whom he had left behind, he looked about him with some such amazement as if he had been translated from earth into regions of supernature.

The canon through which he was flying was a groove cut in solid sandstone, less than two hundred feet wide, with precipitous walls of fifteen hundred feet, from the summit of which the rock sloped away into buttes and peaks a thousand feet higher.  On every side the horizon was half a mile above his head.  He was in a chasm, twenty-five hundred feet below the average surface of the earth, the floor of which was a swift river.