The oases themselves are small, and few in number; their combined area would give an extremely insignificant figure in comparison to the total expanse of the arid surfaces of the desert. In the Occidental Sahara they are rather a hindrance than an obstacle, for the main caravan routes cross them in many places. The Tuareg Tanezrouft is extended eastward toward Tripolitania by the Tiniri, which is its equivalent in sterility although it does not resemble it in formation. To travel across such a terrain is torture, almost impossibility. But aside from details of this nature which differentiate the various sections, the Libyan plateau, whether of calcareous or sandstone formation, retains its same unbroken horizons and its uniform character of tanezrouft throughout. In critical moments, the Saharan natives know the danger of emotion; and in one of their legends this danger is personified.