KARRJO PLAINS. 271 



^hich predominates in Southern Africa. The mountain- 

 ranges are in many places traversed by deep valleys, named 

 kloofs. These are the passes that lead across from one part 

 of the country to the other, and which appear to have been 

 originally vast rents, which have become wider by the action 

 of the atmosphere and running water. The inclined plain, 

 or space between the most southern range of mountains and 

 the seacoast, varies from 20 to 60 miles in breadth, and, 

 reckoning from the interior of the country, forms the third 

 terrace of Southern Africa. The flat tract enclosed between 

 the southern chain and the Zwarteberg forms the second 

 terrace. The vast tract, or the Great Karroo, contained 

 between the Zwarteberg and the Nieuweveld Gebirgte, is 

 the Jirst terrace. The second and first terraces, which con- 

 tain so much Karroo ground, may formerly have been inland 

 seas or lakes. The great bank of gravel, sand, and clay 

 which ranges along the coast and under the sea, from the 

 Cape of Good Hope to Natal, and to south lat. 37°, may be 

 considered as another terrace. 



Description of the Karroo Plains. — The Karroo ground^ 

 which forms so striking a feature in the external aspect of 

 the Cape district, is loam or sandy clay, mixed with parti- 

 cles of ochre of iron. Lichtenstein says it is not more thjin 

 a foot in thickness. This may apply to some, but by no 

 means to the greater number of localities. From the nature 

 of the soil, and other concomitant causes, the vegetation 

 must at all times be very meager ; and in summer, when 

 the sun has dried the soil to the hardness of brick, it ceases 

 almost entirely. The mesembryanthemurru, and some other 

 succulent plants ; some kinds of gorteria, of bergia, and of 

 alters, whose roots, like the bulbs of lilacious plants, nature 

 has fortified with a tenfold net of fibres under the upper 

 rind, to protect them against the hardened clay : such plants 

 alone resist the destructive nature of this inhospitable soil. 



As soon as, in the cooler season, the rains begin to fall 

 and penetrate into the hard layer of loam, these fibres im- 

 bibe the moisture, and, pushing aside the clay, the germ 

 of the plant, under their protection, begins to shoot, and in 

 a few days the arid waste is covered with a delicate green 

 covering. Soon after, myriads of flowers ornament the 

 whole surface. " The mild midday sun," says Lichten- 

 stein, " expands the radiated crowns of the mesembiyan- 



