Structural and magnetic properties of the two-layered Ruddlesden-Popper phase SrO(La1-xSrxMnO3)(2) with x=0.3-0.5 are highlighted. Intrinsic properties of these naturally layered manganites include a "colossal" magnetoresistance, a composition-dependent magnetic anisotropy, and almost no remanence. Above the Curie temperature there is a nonvanishing extrinsic magnetization attributed to intergrowths (stacking faults in the layered structure). These lattice imperfections consist of additional or missing manganite lagers, as observed in transmission electron microscopy. Their role in influencing the properties of the host material is highlighted.