286 SOUTH AFRICAN SPRINGS. 



This paucity of springs may be explained, as Mr. Barrow 

 remarks, by attending to the nature of the rocks, and their 

 mode of arrangement. Where two of the formations of 

 the district occur together, as sandstone and granite for 

 example, and the sandstone lies upon the granite, whose 

 upper surface vs above the level of the neigWaouring coun- 

 try, springs will occur abundantly around the line of junc- 

 tion of the two formations. In this case the water perco- 

 lates through the sandstone, which is a porous rock ; but 

 its farther progress downwards is arrested by the granite, 

 which is a dense and compact rock, and therefore, when it 

 reaches the surface of the granite, it accumulates there, and 

 either remains stationary, or flows along its surface, until 

 it finds an opening at the surface, where it issues forth in 

 the form of springs. On the contrary, if the sandstone de- 

 posite rests upon granite, whose upper surface is below the 

 level of the surrounding country, the percolating water, on 

 reaching the granite, will accumulate there, and flow off by 

 rents into the lower and distant parts of the country, but 

 few springs will be observed issuing from the sandstone. 



Hot Springs. — The only hot springs particularly de- 

 scribed by travellers are those of Brand Valley and Zwarte- 

 berg. 



Brand Valley. — The hot spring here is larger than that 

 at Zwarteberg. It forms a shallow pond of about fifty feet 

 across, of the most transparent water, in the middle of which 

 several strong springs bubble up through a bottom of loose 

 white sand, and afterward flowing in a very copious stream, 

 become a rivulet, which, for at least a mile and a half, con- 

 tinues so hot, that its course along the valley may, at any 

 time of the day, but more particularly early in the morning, 

 be traced by the steam which perpetually arises from it. 

 The pond is sheltered by a small clump of white poplars, 

 ■which thrive perfectly well, although growing at the very 

 edge of the water, and bedewed with the hot steam, which 

 ascends to their highest branches. No plant, it seems, can 

 grow in the water itself; but the margins of the bank are 

 thickly covered with sedge, particularly cyperus fascicularis. 

 Royena glabra, a species of rhus, and a variety of plants, 

 stand within the influence of its heat. The thermometer, 

 when plunged into the pond, rose only to 144° Fahrenheit, 

 but to the hand it felt nearly scalding hot ; so that th« 



