The range is largely made up of sandstone sedimentary rocks leaning on a Precambrian crystalline basement. The northern ridge is marked by the Lusatian Fault, a geological disturbance zone separating the Bohemian sandstones from the Lusatian granodiorite. During the Tertiary volcanic magma streams broke through the sandstone layer and solidified into basalt and phonolite. Several sandstone contact areas were also hardened to columns and distinct rock formations.