Karoo are exposed. These are locally known as the Cango Group, but are probably continuous with the Malmesbury Group that forms the base of Table Mountain on the Cape Peninsula, and similar outcrops in the Western Cape. In the Little Karoo, the outcrop is composed of limestone, into which an underground stream has carved the impressively extensive Cango Caves. The Great Karoo and Little Karoo lie almost entirely within two of South Africa’s eight botanical biomes, namely the Succulent Karoo biome and the Nama Karoo biome, both of which, like the Karoo Geological System, are more extensive than the geographical or
Karoo sills (see below), creating multiple flat-topped hills, or Karoo Koppies, which are iconic of the Great Karoo. The vegetation of the Upper is similar to the Lower Karoo, so few people make a distinction between the two. The main highway (the N1) and railway line from Cape Town to the north enter the Lower Karoo from the Hex River Valley just before Touws River and follow a course about 50 km south of the Great Escarpment up to Beaufort West. Thereafter, they gradually ascend the Great Escarpment along a broad valley to Three Sisters on the Central Plateau and the