the geology of the region bears no resemblance to that of the great karoo (see the diagram on the left, of a ns geological cross-section through the little and great karoos). the valley is an integral part of the cape fold mountain belt, with the two ranges on either side composed of extremely hard, erosion-resistant, quartzitic sandstone belonging to the 450- to 510-million-year-old table mountain group (i.e. the oldest layer of the cape supergroup). the valley floor is covered, in the main, by the next (younger) layer of the supergroup, namely the much softer bokkeveld shales. the dolerite of the great karoo did not penetrate these rocks, so karoo koppies are not seen in the little karoo.