Glacial and periglacial features, formed during the Quaternary, are present throughout the Atlas Mountains in Morocco and Algeria. Moraines, U-shaped troughs, roche moutonée, riegels and cirques all provide evidence of former glacier occupation in these mountains. At least three discrete glaciations have been identified, the most recent of which occurred during the Soltanian. During the most extensive recorded phase of Pleistocene glaciation, snowlines were lowered to c. 3300 m a.s.l. in the High Atlas. Snowlines were progressively lower from the southwest of the range to the northeast with snowlines of c. 2400-2500 m a.s.l in the Middle Atlas and c. 1900-2100 m a.s.l in the Algerian Tell. This difference can probably be attributed to a precipitation gradient from north to south, with greatest levels over the Mediterranean coastal mountains of the Algerian Tell. © 2004 Elsevier B.V. All rights reserved.