The Tamesna Plain is to the east . The Telemsi Fosse is to the west The low , western part of the Azaouak Valley is to the south . The massif 's valleys open to the Tamesna plain on the east , to the Telemsi fosse on the west , to the western basin of the Azaouak valley on the south , and to the Tanezrouft on the north .