The pisolites show a positive correlation between Al2O3 and SiO2, and a strong negative correlation between these oxides and Fe2O3 (Table 4). The pisolite cortices show higher concentration of Al2O3 and SiO2representing kaolinite; alternating with Fe2O3 cortices of goethite and hematite. There is no systematic correlation between Sr and CaO except positive correlation in the matrix of pisolitic ironstone, which indicates that the large parts of CaO in matrix of pisolitic ironstone is of secondary origin (Basta et al.,2000).