Robertson Karoo low hills and flats covered in small succulent vegetation, usually growing on rocky shale-based soils. The climate is semi-arid due to the region lying in the rainshadow of the large mountain ranges to the south-west, but the rainfall does tend to occur mainly in winter. This vegetation type has a large number of endemic species and several endemic genera. Robertson Karoo Robertson Karoo is a semi-arid vegetation type, restricted to sections of the Breede River Valley, Western Cape Province, South Africa. It is a subtype of Succulent Karoo (geographically an extension of the "Little Karoo") and is characterised by the
Karoo sediments. This exposed the dolerite sills, which were more resistant to erosion than the Karoo sediments, forming one of the most characteristic features of the Karoo landscape, namely the flat topped hills, called "Karoo Koppies". 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