CLIMATE GEOLOGICAL STRUCTURE. 313 



plains, traversed by hill and rock, and thickly strewn with 

 quartz, which reflects a dazzling and perplexing light. Two 

 to three days' journey south of Rehoboth, the dense thorny 

 bush, so peculiar to Damara-land, ceases, and with the ex- 

 ception of a few mimosas along the water-courses, and occa- 

 sional ebony-trees, the arboreous vegetation is scanty and 

 stunted. For more than six months of the year it is scorched 

 by an almost vertical sun. The rains, which are always 

 accompanied by heavy thunder, are periodical and very par- 

 tial. In its northern portion, the wet season sets in at the 

 same time as in Damara-land ; but in a southerly direction, 

 the rains are later and more uncertain ; and, as has been said 

 in the last chapter, little or none falls about the lower course 

 of the Orange River and the neighborhood. The springs 

 (which are often either hot or salt) are indiiferent and scantily 

 distributed. The periodical water-courses, therefore, afford 

 the chief supply. 



The Namaquas, as well as the Damaras, are loud in their 

 complaints that less rain falls now than half a century back. 

 Indeed, the numerous ancient beds of rivers in the vast sandy 

 plains, and the deeply-scored slopes and sides of the now 

 ''sunburnt" and crumbling hills, clearly indicate that almost 

 the whole country north of the Orange River, as far as Euro- 

 peans have penetrated from the Cape side, has at some 

 former period been much more abundantly watered. In 

 some parts, the destruction of forests, which are well known 

 to retain and condense vapory particles, may partly account 

 for such atmospheric changes ; but in this region we must 

 look for other causes. 



In a geological point of view, Great Namaqua-land pre- 

 sents many interesting features. Between the Orange River 

 and Walfisch Bay, beginning at the sea-side, three distinct 

 terrace-like risings of the country are recognized. Besides 

 the granite, which is the prevailing rock, great masses of 

 (juartz are met with either, as aforesaid, scattered over its 



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