Le Bas and Mohr (1968) and Mohr (1962a) report the presence of trachytes, nephelinite, melilite basalt, tinguaite and aenigmatite-bearing phonolites in the upper Webi Valley. Field relationships are not known and neither is the relationship to the large Encuolo volcano lying just to the north.
LE BAS, M.J. and MOHR, P.A. 1968. Feldspathoidal rocks from the Cainozoic volcanic province of Ethiopia. Geologischer Rundschau, 58: 273-80.MOHR, P.A. 1962a (reprinted 1971). The geology of Ethiopia. University College of Addis Ababa Press, Addis Ababa. 268 pp.