Grand Erg Oriental small but ancient settlement of Ghadames at the Libyan frontier. Another and better road from Hassi Messaoud goes south, also crossing the grand erg where it passes a well called "Hassi Tartrat", before reaching the erg's far side. Further south lies the Ahaggar mountains. The cities of Wargla and Touggourt lie outside the western limits of the erg. Nearby, within the accepted boundaries of the "Grand Erg Oriental", the landscape is described as being "practically free from [sand] dunes" evidently due to strong, persistent winds. Petroleum and other hydrocarbons have been extracted in Algeria, from areas in and surrounding the
Grand Erg Oriental the language of the nomads, who habitually reside in such places." For these and similar reasons concerning the desert ecology of water, the geographer and historian of the Sahara E.-F. Gautier once wrote referring to the Grand Erg Oriental as "the great Igharghar Erg". Accordingly, surface moisture, seasonal pastures, and wells may reflect unseen conditions beneath the sands. What appears as an entirely inhospitable erg can elsewhere, in stark contrast, offer the fruits of "some buried wadi". To the north of the erg, the Aurès mountains provide abundant runoff. These waters feed the artesian aquifer of the Jerid, despite its