Karoo an immense volume of rocks which was formed, geologically speaking, in a short period of time. Although almost the whole of the Great Karoo is situated on Karoo Supergroup rocks, the geological Karoo rocks extend over a very much larger area, both within South Africa and Lesotho, but also beyond its borders and onto other continents that formed part of Gondwana. The Karoo Supergroup was formed in vast inland basin starting 320 million years ago, at a time when the part of Gondwana which would eventually become Africa lay over the South Pole. Icebergs that had calved off the glaciers
Karoo 10–20 km from the foot of the Swartberg mountains is least karoo-like, in that it is a well-watered area both from the rain and the many streams that cascade down the mountain, or through narrow defiles in the Swartberg from the Great Karoo. The main towns of the region are situated along this northern strip of the Little Karoo: Montagu, Barrydale, Ladismith, Calitzdorp, Oudtshoorn, and De Rust, as well as such well-known mission stations such as Zoar, Amalienstein, and Dysselsdorp. The southern 30– to 50-km-wide strip, north of the Langeberg range, is as arid as the western Lower Karoo, except