The detailed sedimentological study of the Senonian in the Wanina basin of Aït Ourir basins attached to the northern slope of the High Atlas Marrakech, gave the deposit silty carbonato-evaporite, which are carried out in an environment of type sebkha where alternate phases of detrital inputs, under a hot and arid climate and in conditions of bridging favoring the installation of evaporite deposition, and the phases of carbonate deposits more marine installed under the action of a slight increase in sea level degenerating quickly, in an upper intertidal temporarily emerged. In general these carbonate benches mark to their surfaces a rupture of the sedimentation that is materialized by ferruginous hardened surfaces.