Zubair is the most important formation in Lower Cretaceous deposition cycle in Iraq. It consists mainly of inter bedded Sand stone, Shale, Siltstone and sometimes thin beds of Carbonate. This Formation has five members in Iraq; the Upper Shale is one of these members. Geochemical analysis of Upper Shale member consists mainly of SiO2 with little have of Alo3, CaO, Feo3, MgO, K2O, TiO2 and SO3. Also the trace element funded in Upper Shale rocks consists of (Cs, Ba, Pb, Y, Co, Zn, Cu, Zr, Nb, Ni, Ga, V, U, Sr, Cr, Mn and P). Clay minerals composition is more in north of Rumaila than the south.