The Crystal Mountains of Angola may represent its western boundary; while the absence of mesozoic strata beneath the Cretaceous rocks of the mid-Sahara indicates that the system of Karroo lakeland had here reached its most northerly extension.
The Karroo is admirably adapted to sufferers from pulmonary complaints.
Within this nearly complete circle of crystalline rocks several geological formations have been determined, of which the age cannot be more definitely fixed than that they are vastly older than the Karroo formation and newer than the Swaziland schists.
Northwards the Karroo (q.v.) is bounded by the ramparts of the great inner tableland, of which only a comparatively small portion is in Cape Colony.
This plateau is called the Southern or Little Karroo, Karroo being a (4) second range of hills, (5) second plateau (the Great Karroo), (6) main chain of mountains guarding, (7) the vast interior tableland - is characteristic of the greater part of the colony but is not clearly marked in the south-east and north-west borders.
Indica, and therefore of Lower Karroo age, appear in the south but are overlapped on the north by Jurassic strata.
The Karroo beds lie almost horizontally, in marked contrast to the highly inclined older rocks.
Rocks of pre-Cape age rise from beneath them on the north and west; on the south and east the Lower Karroo and Cape systems are bent up into sharp folds, beneath which, but in quite limited areas, the pre-Cape rocks emerge.
After the periodical rains, the Karroo and the great plains of Bushmanland are converted into vast fields of grass and flowering shrubs, but the summer sun reduces them again to a barren and burnt-up aspect.
West of the Zwaarteberg the Little Karroo merges into the Great Karroo.