A few words must here be written regarding the country now about to be traversed—that is to say, from Ghresat, the spot where we emerged from the valley of the southern slopes of the Atlas Mountains, as far as Dads. Not only does my sojourn in the latter place make it a fit opportunity for my description of the road, but the physical features of the country before us also render it expedient, for it is immediately to the east of Dads that the watershed lies that separates the rivers flowing south and west to the Draa, more especially the Wad Dads itself, and those the course of which is east, and which form the basin of the western tributaries of the Wad Gheris. This river, after uniting with the Wad Ziz at Tafilet, is eventually absorbed by the desert at the marsh of Dayet ed Daura, to the south of that oasis. This long strip of country lying between the great range of the Atlas Mountains and Jibel Saghru, or the Anti-Atlas, consists of a plain some sixty miles in length and averaging about thirty wide, rather more at Ghresat and somewhat less at Dads. This plain, with an elevation of roughly 4800 feet at Ghresat and 4700 at the southern extremity of the tribe of Dads, near Aït Yahia, slopes slightly from north to south and from east to west, the rivers which leave the Atlas flowing mostly almost due south until they meet either the Idermi or the Dads, where these two streams have an easterly and westerly course respectively, before uniting near Mesgita to form the more important Wad Draa. The soil of this plain consists for the most part of sand strewn with small stones of almost black colour, with here and there large boulders, sometimes of limestone, at others of black igneous formation. The peculiarity, however, of this strip of desert—for, with the exception of the immediate river banks and oases, it consists of little else—is the manner in which the river beds are sunk below the level of the surrounding country. Usually on approaching a river one first perceives a flat-topped range of low hills crossing the plain from north to south. These hills passed, one comes, generally from half a mile to a mile farther on, to a steep descent, leading to the bed of the river in question, the same formations being found on the opposite side. At Dads and in other spots the cliffs that have to be descended before the bed of the river is reached are of considerable altitude, and the number of the population of all the districts hereabouts varies according to the breadth of the valleys between the cliffs, for on this depends the amount of land that can be put under irrigation and cultivated, and accordingly the quantity of life the soil can support by its products.